Sensation and Perception Final
Distinguish between the two main types of pain, including their dynamics, qualities, localization, and potential causes.
"Fast": typically has a rapid onset, and it is localized to a specific area of the body. Fast pain is usually associated with tissue damage or injury, and it serves as a protective mechanism to prevent further damage to the affected area. "Slow": has a slower onset and a longer duration compared to fast pain. Slow pain can be caused by a wide range of factors, including inflammation, nerve damage, or disease. It is often described as aching or throbbing, and it can be difficult to manage.
Explain the roles played by three different sensory systems, the motor system, and the cognitive system in haptic exploration.
(1) the sensory system, which was involved in detecting cutaneous sensations such as touch, temperature, and texture and the movements and positions of your fingers and hands; (2) the motor system, which was involved in moving your fingers and hands; and (3) the cognitive system, which was involved in thinking about the info provided by the sensory and motor systems
List the qualities that a molecule must have to be smelled
- Volatile - Small - Hydrophobic
Explain shape-pattern theory: Which of the two major steps of olfaction is it related to, and how is it proposed to work?
According to shape-pattern theory, odor molecules are recognized by specific olfactory receptors in the olfactory epithelium based on their shape and chemical structure. Each odor molecule has a specific shape that fits into a specific olfactory receptor site, similar to how a key fits into a lock. When an odor molecule binds to a specific olfactory receptor, it triggers a series of chemical reactions that generate an electrical signal that is transmitted to the olfactory bulb.
Outline the pathway taken by taste signals after the taste cells, noting where in the pathway neurons synapse. Name the appropriate anatomical structures in this pathway.
After the taste cells, taste signals are transmitted via sensory neurons through three cranial nerves: the facial nerve (VII), glossopharyngeal nerve (IX), and vagus nerve (X), depending on the location of the taste receptors.
Explain the relations between amplitude, frequency, and loudness for the detection threshold and the feeling/pain threshold.
At the detection threshold, frequency has a greater impact on perceived loudness than amplitude, while at the feeling/pain threshold, both amplitude and frequency contribute to the perceived loudness, with higher frequencies requiring higher amplitudes to achieve the same perceived loudness as lower frequency sounds, and higher amplitudes eventually becoming uncomfortable or painful.
Define the type of stimuli that olfaction transduces
Chemical stimuli
Define consonant production with relation to manner of articulation, place of articulation, and voicing.
Consonants are produced by obstructing or restricting the airflow through the vocal tract using the tongue, lips, teeth, and other structures. The manner of articulation refers to how the airflow is obstructed or restricted. The place of articulation refers to where in the mouth the airflow is obstructed or restricted. Voicing refers to whether the vocal cords are vibrating during the production of the consonant.
Explain the experiment used to illustrate perception of angular rotation, with reference to the stimulus, relevant physical events within the inner ear, the neural response, and perception throughout the experiment.
Constant rotation →Adaptation of neural response due to physical change in semicircular canals
Define distinctive features ̧ minimal pairs, and allophones, and explain how they relate to each other and to phonemes
Distinctive features are the characteristics or attributes that distinguish one phoneme from another. Minimal pairs are pairs of words that differ by only one phoneme and have different meanings. Allophones are different variations of a phoneme that are produced in different contexts but do not change the meaning of a word.
Name at least two other common top-down influences that affect pain perception.
Emotion and attention
Briefly (~1-2 sentences) outline how food molecules are delivered to taste receptors.
Food molecules dissolve in saliva and interact with taste receptors located on the microvilli of taste receptor cells located within taste buds on the tongue, soft palate, and back of the throat.
Name and define the three causes of pain, and list the four types of pain receptors
Inflammatory pain is caused by damage to tissue or inflammation of joints or by tumor cells. Neuropathic pain is caused by lesions or other damage to the nervous system. Nociceptive pain is pain caused by activation of receptors in the skin called nociceptors, which are specialized to respond to tissue damage or potential damage. Four types of pain receptors in nociceptive pain are Heat, Chemical, Pressure, Cold
Define lack of invariance in speech sounds within and among speakers and coarticulation, and explain how each poses a problem to categorical perception of phonemes
Lack of invariance in speech sounds refers to the fact that the acoustic properties of speech sounds vary depending on a number of factors, such as the speaker, the speaking rate, and the surrounding sounds. This lack of invariance presents a challenge for categorical perception of phonemes because listeners must be able to extract the invariant properties of a speech sound that are specific to the phoneme category and ignore the variability introduced by the speaker and the speaking context. Coarticulation is a phenomenon in speech production where the articulators anticipate or overlap the movements required for adjacent sounds. For example, the tongue may start moving towards the position for the next sound before the current sound is completed. This results in the acoustic properties of a speech sound being influenced by the surrounding sounds. This poses a problem for categorical perception of phonemes because listeners must be able to extract the invariant properties of a speech sound that are specific to the phoneme category even when the sound is influenced by the sounds that come before and after it. Both lack of invariance and coarticulation pose a challenge to categorical perception of phonemes because they introduce variability into the acoustic properties of speech sounds. However, listeners are able to overcome these challenges by using their knowledge of phoneme categories and the language they are listening to.
Explain the idea of local representation versus global representation in neural coding of stimulus qualities, and relate this to olfactory processes in the olfactory bulb and piriform cortex.
Local representation means that different aspects of a sensory stimulus, such as its features or components, are represented by different neurons in the brain that are spatially localized to specific regions. In contrast, global representation means that different aspects of a sensory stimulus are represented by distributed networks of neurons that are not localized to specific regions. In the olfactory system, local representation is observed in the olfactory bulb, where different odorants are detected by distinct populations of olfactory receptor neurons that project to specific glomeruli. However, in the piriform cortex, which is the higher brain region responsible for the perception and interpretation of odors, global representation is thought to play a more important role.
Explain the three top-down perceptual effects on speech
McGurk effect: The McGurk effect is a perceptual phenomenon in which the perception of speech sounds is influenced by visual information from the speaker's lips and face. The effect occurs when a person hears a sound that is incongruent with the visual information they see, resulting in a perception of a third, hybrid sound. Visual cues: Visual cues refer to the information that is seen from the speaker's lips and face, including lip movements, facial expressions, and body language. Visual cues can provide important information about speech sounds, including information about place of articulation and voicing. Phonemic restoration: Phonemic restoration is a perceptual phenomenon in which a missing or obscured sound in a spoken word is perceived as if it is present. This occurs because listeners use their knowledge of the language and the context to "fill in" the missing information.
Explain what it means to be a non-taster, taster, or super-taster
Non-tasters are individuals who have a reduced ability to taste certain flavors or compounds in food. This may be due to genetic variations that affect the number or sensitivity of taste buds on the tongue. Non-tasters may have difficulty detecting certain flavors, such as bitterness or sweetness, and may require more intense flavors or seasonings to enjoy their food. Tasters are individuals who have an average ability to taste flavors and compounds in food. They have a normal number of taste buds and are able to detect a wide range of flavors and textures in food. Super-tasters are individuals who have an increased ability to taste certain flavors and compounds in food. They may have a higher density of taste buds on the tongue or be more sensitive to certain compounds. Super-tasters may find some flavors, such as bitterness or spiciness, to be particularly intense or unpleasant. They may also have a heightened perception of sweetness.
Contrast retro-nasal and ortho-nasal olfaction. Explain which one contributes to the experience of flavor, and how
Ortho-nasal olfaction refers to the detection of odors through inhalation of air through the nostrils, whereas retro-nasal olfaction refers to the detection of odors through the nasal cavity during exhalation, which occurs when we swallow or chew food. Ortho-nasal olfaction plays a crucial role in the perception of flavor, as it allows us to detect the volatile compounds that contribute to the aroma of food as we inhale through the nostrils. Retro-nasal olfaction also contributes to the perception of flavor by allowing us to detect the same volatile compounds that are released from food during chewing or swallowing, but in a different temporal sequence. As we chew or swallow food, volatile compounds are released and detected by the olfactory receptors in the nasal cavity during exhalation, which helps to enhance the taste and texture of the food and create a more complex flavor experience.
List the relevant anatomical structures of the vestibular system
Otolith organs: These are two sac-like structures, called the utricle and saccule, located in the inner ear that detect linear acceleration and changes in head position. Semicircular canals: These are three fluid-filled tubes located in the inner ear that detect rotational movements of the head.
Explain the general factors involved in vestibular perception, including the percepts, their stimuli, and the qualities encoded by neural responses.
Otolith organs: main percept is linear motion (linear acceleration) and tilt (w/ respect to gravity) Semicircular canals: main percept is angular motion (angular acceleration) All these percepts encode for qualities of amplitude and direction
Define phonemes
Phonemes are the smallest units of sound in a language that can change the meaning of a word
Outline the process of olfactory transduction within the olfactory sensory neurons
Receptor binding → increase in cAMP in neuron → increase opening of Ca2+ channels → depolarization toward action potential threshold → increase in spike rate of olfactory sensory neuron
Explain briefly (~1 sentence) which type of touch receptor is most involved in tactile acuity and perception of pattern + embossed details, and why. Relate tactile discrimination ability/tactile acuity to the distribution of this type of touch receptor across the body, and to the cortical map in S1.
Research shows that the fiber associated with a Merkel receptor fires in response to a grooved stimulus pushed into the skin, therefore demonstrating that the SA1 fibers are most involved in perceiving details. Reegions of high acuity, like the fingers and lips, are represented by larger areas on the cortex.
Explain how resonance arises within the outer ear, and its relation to the function of human sound sensitivity by frequency
Resonance in the outer ear occurs when the shape and structure of the ear canal and the surrounding structures amplify certain frequencies of sound. The ear canal acts as a resonant chamber, enhancing the energy of sound waves that match the natural frequency of the ear canal. The resonance of the outer ear is important for the function of human sound sensitivity by frequency. The human ear is most sensitive to frequencies in the range of 2-4 kHz, which happens to be the range where the ear canal resonates most strongly. This means that sounds in this frequency range are naturally amplified by the outer ear and can be perceived more easily.
Describe two main types of hearing loss
Sensorineural hearing loss occurs due to damage to the inner ear, auditory nerve, or the neural pathways that process sound. The most common cause of sensorineural hearing loss is damage to the hair cells in the cochlea, which can occur due to aging, exposure to loud noise, head trauma, or certain medications. People with sensorineural hearing loss often have difficulty hearing faint sounds and distinguishing speech in noisy environments. Conductive hearing loss, on the other hand, occurs when there is a problem with the transmission of sound from the outer or middle ear to the inner ear. Common causes of conductive hearing loss include ear infections, fluid buildup in the middle ear, wax buildup, or abnormalities in the structures of the ear. People with conductive hearing loss often have difficulty hearing faint sounds and may experience muffled or distorted speech.
What are sound waves and how do they arise?
Sound waves are vibrations in the air or other medium that travel as a series of compressions and rarefactions. These vibrations are caused by the movement of an object, such as a speaker cone, that pushes and pulls air molecules around it. As the object moves forward, it compresses the air in front of it, creating a region of high pressure called a condensation. As the object moves back, it creates a region of low pressure called a rarefaction.
Explain what specificity coding and population coding are in taste, and relate the principle behind these coding schemes to neural coding in other sensory modalities.
Specificity coding: Responses of specific nerve fibers code for type of taste sensation Population coding: Pattern of responses across nerve fibers code for type of taste sensation
List the five basic taste qualities and the types of molecules generally associated with each
Sweetness - This taste is generally associated with molecules such as sugars and artificial sweeteners, which stimulate the sweet taste receptors on the tongue. Saltiness - This taste is associated with molecules such as sodium chloride (table salt) and other salts that contain sodium ions. Sourness - This taste is associated with molecules that are acidic, such as citric acid (found in citrus fruits) and acetic acid (found in vinegar). Bitterness - This taste is associated with a wide variety of molecules, including caffeine (found in coffee and tea) Umami - This taste is associated with molecules such as glutamate and nucleotides
Describe taste buds, taste cells, and taste receptors.
Taste buds are specialized structures located on the tongue and other parts of the oral cavity, such as the soft palate and the back of the throat. Taste buds consist of several types of cells, including taste receptor cells, which are responsible for detecting the different taste qualities.
Explain how temporal coding of textures is thought to work, including what types of receptors + afferents are thought to play a role in it and how they are thought to do so
Temporal cues occur when the skin moves across a textured surface like fine sandpaper. This type of cue provides information in the form of vibrations that occur as a result of the movement over the surface. Temporal cues are responsible for our perception of fine texture that cannot be detected unless the fingers are moving across the surface. Associated with activation of Meissner (RA1) and Pacinian (RA2).
Explain the genetic basis of olfactory abilities, including variability across mammalian species and among individual humans
The ability to perceive and distinguish different odors is largely determined by genetic factors, including the number and diversity of olfactory receptor genes. In mammals, olfactory receptor genes make up the largest gene family, comprising up to 5% of the genome in some species. The number and types of olfactory receptor genes can vary greatly between different mammalian species. For example, dogs have up to 1,000 different types of olfactory receptor genes, which allows them to detect and distinguish a wide range of scents. Humans, on the other hand, have a much smaller number of olfactory receptor genes (around 400) and are less sensitive to certain odors compared to many other mammals. Even among individual humans, there can be significant variability in olfactory abilities due to genetic differences. Some people may have genetic variations that affect their sense of smell, making them more or less sensitive to certain odors. For example, some people may be "super smellers" and able to detect very low concentrations of certain odors, while others may have a diminished sense of smell due to genetic factors or other factors such as aging, smoking, or certain medications.
Explain the odor map, including what it represents and where.
The odor map is a representation of the spatial organization of olfactory receptor neurons (ORNs) and their projections in the olfactory bulb. The odor map is thought to play a critical role in the processing and perception of odors, and is essential for the discrimination and recognition of different odors in the environment. The odor map is organized such that different types of odorants activate different populations of ORNs, which in turn project to specific clusters of neurons called glomeruli in the olfactory bulb. Each glomerulus receives input from a specific subset of ORNs that express the same type of odorant receptor, and the activation of a particular glomerulus is thought to represent the presence of a particular odorant or class of odorants.
Explain the primary function of taste
The primary function of taste is to allow us to evaluate the safety and nutritional value of the food and drink we consume.
Explain how taste signals are processed in primary gustatory cortex, and how they are processed in brain locations beyond.
The primary gustatory cortex, located in the insular cortex, is the first cortical area to receive taste information. Taste signals are processed in the primary gustatory cortex by specialized neurons called gustatory neurons. These neurons respond selectively to specific taste qualities, such as sweet, sour, salty, bitter, and umami, and their firing patterns encode the taste quality and intensity.
Name the two brain regions where vestibular neurons synapse prior to cortex, and describe very briefly (<5 words!) where vestibular signals project to in the cortex
The two brain regions where vestibular neurons synapse prior to the cortex are the vestibular nuclei and the cerebellum. Vestibular signals project to multiple regions in the cortex, including the parietal cortex, the insula, and the visual and motor areas.
Define the placebo effect, and explain how it is thought to work
This decrease in pain from a substance that has no pharmacological effect is called the placebo effect. The key to the placebo effect is that the patient believes that the substance is an effective therapy. This belief leads the patient to expect a reduction in pain, and this reduction does, in fact, occur.
Explain the relevant axes and types of motion for vestibular perception.
Translation: Head can travel forward and backward across x-axis, can translate left and right across y-axis, or up and down across z-axis Rotation: Pitch: Rotation around y-axis, Roll: Rotation around x-axis, Yaw: Rotation around z-axis
Define vestibular sense broadly, list their general functions, and contrast them with proprioceptive and kinesthetic senses.
Vestibular senses sense head motion and head orientation with respect to the force of gravity They integrate with other senses to help: - Stabilize visual percepts - Maintain balance - Control autonomic functions - Orient in space
How touch receptors' and proprioceptors' signals are integrated to give information about the 3D arrangement of surfaces
When an object comes into contact with the skin, the touch receptors are activated, and the information about the object's texture, shape, and temperature is transmitted to the brain. At the same time, the proprioceptors provide information about the position and movement of the body part that is in contact with the object. The brain integrates this information to create a perception of the object's 3D arrangement.
Explain rarefaction
When an object moves back in, air molecules spread out to fill in the increased space
Explain what haptic exploration is, and the types of motions associated with it
perception in which three-dimensional objects are explored with the fingers and hand
Outline the path that neural signals take from the auditory nerve to primary auditory cortex (A1), including relevant details about locations of structures and the pathways taken between them, especially where axons cross the midline of the brain.
1. Auditory nerve: The auditory nerve carries auditory information from the ear to the brainstem. The nerve fibers from the cochlea join together to form the auditory nerve. 2. Cochlear nucleus: The auditory nerve fibers synapse on neurons in the cochlear nucleus, which is located in the brainstem. The cochlear nucleus receives information from both ears and is the first site of integration of auditory information. 3. Superior olivary complex: Some fibers from the cochlear nucleus project to the superior olivary complex (SOC), which is located in the brainstem. The SOC is important for processing binaural (two-eared) auditory information, such as sound localization. 4. Inferior colliculus: Neurons in the SOC project to the inferior colliculus (IC), which is located in the midbrain. The IC is important for processing complex sounds and for coordinating auditory information with other sensory modalities. 5. Medial geniculate nucleus: Neurons in the IC project to the medial geniculate nucleus (MGN) of the thalamus, which is located in the forebrain. The MGN serves as a relay station for auditory information on its way to the cortex. 6. Primary auditory cortex (A1): Neurons in the MGN project to the primary auditory cortex (A1), which is located in the temporal lobe of the brain. A1 is responsible for processing basic auditory features, such as frequency, intensity, and timing of sounds. A1 also contributes to higher-level processing, such as sound perception and recognition.
Describe the path for olfaction from the nostrils to the olfactory bulb (inclusive), including the names and functions of all relevant anatomical structures.
1. Nostrils: Air containing odor molecules enters the nose through the nostrils. 2. Nasal Cavity: The nasal cavity is lined with specialized cells called olfactory receptor neurons (ORNs), which are responsible for detecting odor molecules. The ORNs are located in a small patch of tissue called the olfactory epithelium, which is situated on the roof of the nasal cavity. 3. Olfactory Nerve: When an odor molecule binds to an ORN, it triggers a nerve impulse that is carried by the olfactory nerve, a bundle of nerve fibers that extends from the olfactory epithelium to the olfactory bulb. 4. Olfactory Bulb: The olfactory nerve fibers enter the olfactory bulb, which is located at the base of the brain. Here, the nerve impulses are processed and interpreted as specific odor perceptions. 5. Olfactory Tract: From the olfactory bulb, the olfactory tract carries the processed information to various regions of the brain, including the amygdala (which is involved in emotional responses) and the hippocampus (which is involved in memory formation).
Outline the process of auditory transduction, starting with a sound wave and ending with the effect on neurotransmitter release by receptor cells—and how this affects the firing of auditory nerve fibers.
1. Sound waves enter the ear and travel through the outer and middle ear, eventually reaching the inner ear. 2. In the inner ear, sound waves cause the basilar membrane, a flexible membrane that runs the length of the cochlea, to vibrate. 3. As the basilar membrane vibrates, it causes the hair cells, which are located on top of the membrane, to move back and forth. 4. The movement of the hair cells opens ion channels, allowing potassium ions to flow into the cell and triggering a depolarization. 5. The depolarization of the hair cells causes the release of neurotransmitters, which activate auditory nerve fibers that are connected to the hair cells. The activation of the auditory nerve fibers generates action potentials that are transmitted to the brainstem and eventually to higher centers in the brain for processing. The specific pattern of depolarization and neurotransmitter release by the hair cells is thought to be responsible for encoding different aspects of sound, such as frequency and intensity. The firing of auditory nerve fibers is also influenced by the degree of depolarization of the hair cells, as well as the number and frequency of action potentials generated by the hair cells.
Explain how a 10-decibel change in stimulus intensity relates to change in perceived loudness
A 10-decibel (dB) change in stimulus intensity corresponds to a perceived doubling or halving of loudness, depending on the direction of the change
Explain what is shown on a frequency spectrum
A frequency spectrum is a graphical representation of the different frequency components that make up a complex sound wave. It shows the strength, or amplitude, of each frequency component in the sound wave as a function of its frequency. A frequency spectrum can be obtained by using a mathematical technique called Fourier analysis, which breaks down the complex sound wave into its individual frequency components.
Define what a sound spectrogram is
A sound spectrogram is a visual representation of the spectrum of frequencies in a sound signal over time. It is created by using a spectrograph, which is a device that measures the intensity of different frequencies present in a sound wave and displays them as a graph. The x-axis of a sound spectrogram represents time, while the y-axis represents frequency. The intensity of each frequency at each point in time is represented by the color or brightness of the corresponding point on the graph.
What is the relationship between sound waves and pressure?
A sound wave creates a variation in the normally constant air pressure
Explain the distinction between an odor and an odorant
An odorant is a chemical compound that is capable of stimulating the olfactory receptors in the nose and thereby inducing a specific odor perception An odor is the subjective perception of a smell by a human or an animal.
Describe the three sets of polar-coordinate axes used to describe the location of a sound source. Across which axis are humans best at localizing sound?
Azimuth (left-right) Elevation (up-down) Distance (from listener) Humans are best at localizing sound along the azimuth axis, which is the horizontal angle between the sound source and the listener. This is because the human auditory system is particularly sensitive to differences in the timing and intensity of sounds arriving at the two ears, which allows the brain to compute the location of the sound source in space
Explain the four types of mechanoreceptors, including their names, their locations in the skin, their spatial and temporal receptive field properties, and what types of touch experiences they contribute to.
Merkel receptor: located close to the surface of the skin, fires continuously therefore it is slow adapting, small receptive field, associated with details, shape, and texture Meissner corpuscle: located close to the surface of the skin, small receptive field, fires only when stimulated therefore it is rapidly adapting, associated with controlling hand grip and perceiving motion across the skin Ruffini cylinder: located deeper in the skin, responds continuously to stimulation, larger receptive field, associated with perceiving stretching of the skin Pacinian corpuscle: located deeper in the skin, larger receptive fields, associated with sensing rapid vibrations and fine texture
Define categorical perception in relation to phonemes, and explain why it is necessary
Categorical perception refers to the phenomenon where speech sounds (phonemes) are perceived as belonging to discrete categories, rather than a continuous spectrum. This means that small differences in the acoustic properties of speech sounds within a category are not perceived or distinguished as different, while larger differences that cross category boundaries are perceived as distinct and separate sounds.
Explain two types of tasks used to investigate categorical perception in adults
Categorization task: In a categorization task, participants are presented with a series of speech sounds that vary along a continuum between two different phonemes, such as /b/ and /p/ in English. Participants are then asked to categorize each sound as belonging to one of the two phoneme categories. For example, they may be asked to indicate whether each sound they hear is a "b" or a "p". The goal of this task is to identify the boundary point at which participants shift from categorizing the sounds as one phoneme to the other. This boundary point is typically identified as the point at which there is a sharp shift in categorization responses, indicating a categorical perception of the sounds. Discrimination task: In a discrimination task, participants are presented with pairs of speech sounds that are either within the same phoneme category or across different categories. They are then asked to judge whether the two sounds they hear are the same or different. The goal of this task is to identify the discrimination boundary, or the point at which participants can reliably discriminate between two sounds as being different. This boundary is usually aligned with the categorical boundary found in the categorization task, indicating that discrimination performance is better across category boundaries than within categories.
Explain how cochlear amplification works
Cochlear amplification refers to the process by which sound signals are amplified within the cochlea of the inner ear, specifically in the region known as the outer hair cells. This amplification is important for enhancing the sensitivity and selectivity of the auditory system, allowing us to detect and distinguish sounds of different frequencies and intensities. The process of cochlear amplification can be summarized as follows: 1. Sound waves enter the ear and travel through the outer and middle ear, eventually reaching the inner ear. 2. In the inner ear, sound waves cause the basilar membrane, a flexible membrane that runs the length of the cochlea, to vibrate. 3. As the basilar membrane vibrates, it causes the hair cells, which are located on top of the membrane, to move back and forth. 4. The outer hair cells within the cochlea have the ability to change shape in response to the movements of the basilar membrane. 5. When the outer hair cells change shape, they amplify the movement of the basilar membrane, effectively amplifying the sound signal that is being received. 6. This amplification enhances the sensitivity and selectivity of the auditory system, allowing us to detect and distinguish sounds of different frequencies and intensities.
Define complexity and how it relates to hearing
Complex tones are made up of a number of pure tone (sine-wave) components added together.
List at least four factors that influence food preferences.
Cultural background: Culture plays a significant role in shaping our food preferences. People tend to prefer foods that are commonly eaten in their cultural group and may even have specific dishes that are associated with important cultural celebrations or events. Personal experiences: Personal experiences, such as positive or negative memories associated with certain foods, can influence food preferences. For example, if someone had a particularly enjoyable experience with a certain type of cuisine or dish, they may develop a preference for it. Genetics: Genetic factors can play a role in determining our food preferences. Some people may be more genetically predisposed to prefer sweet or salty foods, for example. Availability and accessibility: Availability and accessibility of certain foods can also influence our preferences. If certain foods are more readily available in a certain region or country, people in that area may develop a preference for those foods over others. Additionally, if certain foods are more affordable or easier to obtain, people may be more likely to prefer those options.
Explain the general functions of the skin for humans, state which layer of skin touch receptors are located in, and define glabrous skin.
General functions: warning function, prevents body fluids from escaping, protects against outside invaders Mechanoreceptors are found in both the epidermis and the dermis Glabrous skin refers to nonhairy skin
Explain the relations between amplitude, frequency, and loudness in plots of "equal-loudness curves," and use such a plot to predict points of equal loudness across different frequencies.
Equal-loudness curves are plots that show the sound pressure levels required at different frequencies to create the perception of equal loudness to the human ear. These curves indicate the sound pressure levels required at each frequency to achieve the same perceived loudness. The relationship between amplitude, frequency, and loudness in equal-loudness curves can be described as follows: At low frequencies, a higher amplitude is required to achieve the same perceived loudness as higher frequencies. At intermediate frequencies, a lower amplitude is required to achieve the same perceived loudness as lower and higher frequencies. At high frequencies, a higher amplitude is required to achieve the same perceived loudness as lower frequencies.
Explain three common causes of hearing loss
Eustachian tube in infants is more horizontal, cannot drain fluids as easily as adults which can cause temporary conductive hearing loss or permanent sensorineural hearing loss Otosclerosis is a condition that affects the bones in the middle ear and can cause conductive hearing loss. It occurs when abnormal bone growth develops around the stapes bone, which is one of the three small bones in the middle ear that vibrate in response to sound waves. Cholesteatoma is an abnormal growth of skin cells in the middle ear, usually behind the eardrum. It is often caused by repeated ear infections or by a tear or retraction in the eardrum. Cholesteatomas can grow larger over time and may lead to hearing loss, infection, and other complications. The growth of a cholesteatoma can cause conductive hearing loss, which occurs when sound waves cannot pass from the outer ear to the inner ear effectively.
Describe the types of papillae, including their distributions on the tongue, anatomical qualities, and where taste buds are located in/on each
Filiform papillae - These are the most numerous and are distributed over the entire surface of the tongue. They are conical in shape, have no taste buds, and are responsible for the rough texture of the tongue. Fungiform papillae - These are mushroom-shaped papillae that are scattered over the tongue, with a greater concentration at the tip and sides. Each papilla contains several taste buds, and they are responsible for detecting sweet, sour, salty, and bitter tastes. Circumvallate papillae - These are the largest papillae and are located at the back of the tongue in a V-shaped row. They contain up to 100 taste buds each and are responsible for detecting bitter tastes. Foliate papillae - These are located on the sides of the tongue towards the back and contain several taste buds, primarily for detecting bitter and sour tastes. They are most prominent in infants and young children and tend to diminish in size and number with age.
How is the modern "dual-stream" model of speech in the brain different from this classic model?
First, the dual-stream model proposes that there are not just two major pathways involved in speech processing, but rather four distinct pathways. The dorsal pathway and the ventral pathway are still included, but the model also includes two additional pathways: a ventral "what" pathway that processes lexical and semantic information, and a dorsal "how" pathway that is involved in mapping speech sounds to motor representations for speech production. Second, the dual-stream model proposes that the ventral pathway is not solely responsible for phoneme recognition, as was suggested in the classic model. Instead, the model suggests that the dorsal pathway also plays a role in phoneme recognition, by mapping speech sounds to motor representations for speech production. Third, the dual-stream model does not posit distinct speech production and comprehension centers in the brain, as Broca's and Wernicke's areas were proposed in the classic model. Instead, the model suggests that multiple brain regions are involved in both speech production and comprehension, and that these regions are connected by a network of white matter tracts. Finally, the dual-stream model emphasizes the importance of feedback loops between the two major pathways, as well as between different brain regions involved in speech processing. These feedback loops allow for the integration of sensory and motor information, and enable the brain to adapt to changes in the speech environment.
Explain (at a basic level) what Fourier analysis of sound stimuli does
Fourier analysis of sound stimuli is a mathematical technique that is used to break down a complex sound wave into its individual frequency components. The complex sound wave is first captured and then analyzed using a mathematical algorithm known as the Fourier transform.
Define frequency and how it relates to hearing
Frequency is the number of cycles per second that the change in pressure repeats. Generally, the higher frequency = the higher pitch.
Explain briefly (1-2 sentences) how a selective adaptation experiment used to support temporal coding of textures
Hollins and coworkers (2001) used this procedure by presenting two adaptation conditions. The first condition was 10-Hz (10 vibrations per second) adaptation, in which the skin was vibrated with a 10-Hz stimulus for 6 minutes. This frequency of adaptation was picked to adapt the Meissner corpuscle, which responds to low frequencies. The second condition was 250-Hz adaptation. This frequency was picked to adapt the Pacinian corpuscle, which responds to high frequencies. Following each type of adaptation, subjects ran their fingers over two fine textures—a "standard" texture and a "test" texture. The subject's task was to indicate which texture was finer. When subjects had only been exposed to the 10-Hz stimulus, they could tell the difference between the two surfaces, but when they had been exposed to the 250 Hz stimulus, they could not. Thus, adapting the Pacinian corpuscle receptor, which is responsible for perceiving vibration, eliminates the ability to sense fine textures by moving the fingers over a surface.
Explain the physical basis of the interaural time difference, and the proposed mechanism for neural coding of the ITD in the brainstem
ITD (interaural time difference) refers to the difference in time between when a sound arrives at one ear versus the other. ITD provides important information to the brain about the location of the sound source along the horizontal axis, or azimuth. The physical basis of ITD is due to the difference in distance between the two ears and the sound source. When a sound is emitted from a source off to one side of the head, it will arrive at the closest ear before it arrives at the other ear. This difference in arrival times is the ITD, and it is largest for low-frequency sounds, which have longer wavelengths and are thus diffracted less by the head. In the brainstem, the ITD is first computed in the medial superior olive (MSO), which is a collection of neurons that receive inputs from both ears. These neurons compare the timing of the inputs from each ear, and send signals to downstream neurons that represent the ITD. The MSO neurons use a mechanism known as coincidence detection, in which they respond most strongly when inputs from both ears arrive simultaneously, indicating that the sound source is located directly in front of the listener. The ITD is represented in the activity of the MSO neurons, with the magnitude of the ITD being encoded by the firing rate of the neurons. The information about ITD is then sent to the inferior colliculus and higher auditory areas, where it is integrated with other cues such as interaural level differences (ILD) to create a more accurate representation of the sound source location.
Explain what impedance mismatch is, what structure of the middle ear serves to overcome it, and how.
Impedance mismatch refers to the difference in impedance, or resistance to the flow of sound waves, between the air-filled outer ear and the fluid-filled inner ear. This impedance mismatch can cause a significant loss of energy as sound waves pass from the outer ear to the inner ear, which can result in a reduction in the perceived loudness of sounds. The middle ear serves to overcome this impedance mismatch by transmitting sound waves from the air-filled outer ear to the fluid-filled inner ear. The middle ear contains three small bones, known as the ossicles, which amplify and transmit sound waves. The ossicles help solve this problem in two ways: (1) by concentrating the vibration of the large tympanic membrane onto the much smaller stapes, which increases the pressure by a factor of about 20 and (2) by being hinged to create a lever action—an effect similar to what happens when a fulcrum is placed under a board, so that pushing down on the long end of the board makes it possible to lift a heavy weight on the short end
Explain how population coding across afferent nerve fibers can give information about the curvature of surfaces, and name the type of nerve fibers and their associated touch receptors.
Merkel cells are specialized touch receptors located in the skin, which are sensitive to pressure and fine details in textures. They are associated with slowly adapting type I (SAI) nerve fibers, which fire continuously as long as a stimulus is present. SAI fibers have small receptive fields and are highly sensitive to edges and curves. As a finger moves along a curved surface, the SAI fibers associated with Merkel cells at the edge of the fingertip are activated, and their firing rate increases as the curvature becomes more pronounced. This increase in firing rate across the population of SAI fibers provides information about the shape and curvature of the surface being touched.
Explain the physical basis of the Interaural Level Difference, and the proposed mechanism for neural coding of the ILD in the brainstem.
Interaural level difference (ILD) is the difference in sound pressure level (SPL) between the ears, which arises because the head casts an acoustic shadow that reduces the intensity of sounds arriving at one ear relative to the other. ILD provides important information to the brain about the location of a sound source along the horizontal plane, or azimuth, particularly for high-frequency sounds. The physical basis of ILD is due to the head acting as a barrier to sound waves, causing a reduction in sound intensity as the waves pass through it. The extent of the reduction depends on the frequency of the sound wave, with higher frequency sounds being more affected. The reduction is most pronounced when the sound source is on one side of the head and the sound waves have to travel around the head to reach the opposite ear. In the brainstem, ILD is first computed in the lateral superior olive (LSO), which is a collection of neurons that receive inputs from both ears. These neurons compare the level of the inputs from each ear and send signals to downstream neurons that represent the ILD. The LSO neurons use a mechanism known as lateral inhibition, in which they inhibit the activity of neurons receiving input from the ear with the lower level of stimulation, resulting in an enhancement of the activity of neurons receiving input from the ear with the higher level of stimulation. This enhances the neural representation of the ILD and contributes to the neural coding of sound source location. The information about ILD is then sent to the inferior colliculus and higher auditory areas, where it is integrated with other cues such as interaural time differences (ITD) to create a more accurate representation of sound source location.
List and label the structures that make up the middle ear.
Malleus, incus, eardrum, stapes,
List and label the structures that make up the outer ear.
Pinna, auditory canal
List two functions of the nose other than olfaction
Respiratory function: The nose is responsible for filtering, warming, and humidifying the air we breathe in before it reaches the lungs. Defense against infection: The nose produces mucus that helps to trap and remove bacteria and viruses from the air.
Explain the two models of how sound frequency is coded, including both where and how frequency is supposed to be represented. Explain strengths and weaknesses of each model, and which is best for explaining pitch coding for different frequencies.
Place theory: According to the place theory, different frequencies of sound are encoded at different locations along the basilar membrane of the cochlea. Specifically, high-frequency sounds are encoded at the base of the cochlea, while low-frequency sounds are encoded at the apex. Strengths: This model is supported by experimental evidence showing that different regions of the basilar membrane are more sensitive to different frequencies of sound. Weaknesses: The place theory cannot fully explain how the auditory system is able to distinguish between sounds that have similar frequencies but different spectral content, such as harmonic and inharmonic tones. Temporal theory: According to the temporal theory, the frequency of sound is encoded by the timing of action potentials generated by auditory nerve fibers in response to sound. Specifically, the frequency of sound is encoded by the rate at which nerve fibers fire in response to sound. Strengths: This model can explain how the auditory system is able to distinguish between sounds that have similar frequencies but different spectral content, as the timing of action potentials can reflect the spectral content of a sound. Weaknesses: The temporal theory cannot fully explain how the auditory system is able to distinguish between sounds that have frequencies above the upper limit of temporal coding (about 4 kHz in humans).
Explain how experience-dependent plasticity can affect mapping and cortical magnification in S1.
Plasticity can create more cortical area for parts of the body that are used more. What this plasticity means is that while we can specify the general area of the cortex that represents a particular part of the body, the exact size of the area representing each part of the body is not totally fixed.
Explain the transduction mechanisms for: - Salty - Sour - Sweet, bitter, and umami (no need to distinguish)
Salty: ↑Na+ influx → depolarization → ↑Glutamate → Action potentials Sour: H+ ions block K+channels → ↓K+ efflux→ depolarization → Action potentials Sweet, bitter, and umami: Lock-and-key mechanism → Taste cell depolarization → neurotransmitter release (varies) → change in action potential firing of afferent nerve (varies)
Explain what tactile discrimination is, and the two methods for testing tactile discrimination abilities.
The classic method of measuring tactile acuity is the two-point threshold, the minimum separation between two points on the skin that when stimulated is perceived as two points. The two-point threshold is measured by gently touching the skin with two points, such as the points of a drawing compass, and having the person indicate whether he or she feels one point or two. Grating acuity is measured by pressing a grooved stimulus onto the skin and asking the person to indicate the orientation of the grating. Acuity is measured by determining the narrowest spacing for which orientation can be accurately judged.
Outline the neural pathways for touch and pain, starting from skin and ending in area S2. For each, include where cells synapse and where axons cross the midline
Signals from all over the body are conducted from the skin to the spinal cord. After the signals enter the spinal cord, nerve fibers transmit them to the brain along two major pathways: the medial lemniscal pathway and the spinothalamic pathway. The lemniscal pathway has large fibers that carry signals related to sensing the positions of the limbs (proprioception) and perceiving touch. These large fibers transmit signals at high speed, which is important for controlling movement and reacting to touch. The spinothalamic pathway consists of smaller fibers that transmit signals related to temperature and pain. Fibers from both pathways cross over to the other side of the body during their upward journey to the thalamus. Most of these fibers synapse in the ventrolateral nucleus in the thalamus, but some synapse in other thalamic nuclei. From the thalamus, signals travel to the somatosensory receiving area (S1) in the parietal lobe of the cortex and possibly also to the secondary somatosensory cortex (S2)
Explain the types of receptive-field organizational schemes that can be found in: - Thalamus - S1 - S2
Thalamus: Center-surround receptive fields: This type of receptive field is found in thalamic neurons that process visual and somatosensory information. In this scheme, the center of the receptive field responds maximally to a specific type of sensory input, while the surrounding region inhibits responses to other types of input. S1: In S1, receptive fields are organized in a somatotopic map, which means that neighboring regions of the skin are represented by neighboring regions of the cortex. This organization reflects the spatial arrangement of sensory receptors in the skin, with larger areas of the cortex devoted to more sensitive regions, such as the hands and face. S2: S2, or the secondary somatosensory cortex, receives input from S1 and other sensory regions, and is responsible for integrating tactile information with other sensory modalities, such as vision and hearing. In S2, receptive fields are organized in a similar somatotopic map as S1, but with more complex and larger receptive fields.
Explain the acoustic reflex
The acoustic reflex is a protective mechanism of the middle ear that occurs in response to loud sounds. When a loud sound is heard, the stapedius muscle in the middle ear contracts, which causes the stapes bone to move less freely and reduces the transmission of sound to the inner ear.
Define amplitude and how it relates to hearing
The amplitude of the sound wave, or the distance between the highest point of a compression and the lowest point of a rarefaction, determines the volume of the sound. A larger amplitude wave will have a louder volume, while a smaller amplitude wave will have a softer volume.
Briefly describe the classic neurological model of speech.
The classic neurological model of speech proposes that there are two major pathways in the brain that are involved in speech processing. The first pathway, called the dorsal pathway or the "where" pathway, is involved in processing the location and movement of speech sounds. It begins in the posterior superior temporal gyrus (pSTG) and connects to the inferior parietal lobule (IPL) and the prefrontal cortex. The dorsal pathway is thought to be involved in mapping speech sounds to their spatial locations and in coordinating the movements of the articulators. The second pathway, called the ventral pathway or the "what" pathway, is involved in processing the identity of speech sounds. It begins in the superior temporal gyrus (STG) and connects to the inferior frontal gyrus (IFG). The ventral pathway is thought to be involved in mapping speech sounds to their phonetic identities and in accessing lexical and semantic information. The classic neurological model of speech also proposes that there are two major speech areas in the brain: Broca's area and Wernicke's area. Broca's area is located in the posterior part of the left frontal lobe and is involved in the production of speech. Wernicke's area is located in the posterior part of the left temporal lobe and is involved in the comprehension of speech. These two areas are connected by a bundle of nerve fibers called the arcuate fasciculus, which allows for communication between the two areas.
Explain the concept of a "cone of confusion," and two ways we can localize sounds located within a "cone of confusion.
The concept of a "cone of confusion" refers to a region in space where sounds arriving at the ears produce the same interaural time differences (ITD) and interaural level differences (ILD), making it difficult to determine the exact location of the sound source. One way to localize sounds located within a cone of confusion is by using spectral cues. Spectral cues are differences in the spectral content of a sound wave that arise due to interactions between the sound wave and the listener's head, torso, and pinnae. These interactions result in sound waves with unique spectral patterns at the ears for different locations of a sound source. By comparing the spectral content of the sound arriving at each ear, the listener can determine the location of the sound source even if it is within a cone of confusion. Another way to localize sounds located within a cone of confusion is by using head movements. The listener can move their head to change the position of their ears relative to the sound source, and this can produce changes in the ITD and ILD that allow for more precise localization. For example, if the sound source is directly in front of the listener, moving the head slightly to one side can produce a change in the ITD and ILD that makes it easier to determine the location of the sound source.
Explain what the decibel (dB) scale is, how dBSPL (dB sound pressure level) is determined, and why we use the decibel scale in relation to loudness.
The decibel (dB) scale is a logarithmic scale used to measure the intensity of a sound wave. dB = 20 x logarithm (p/p0) The decibel scale is used in relation to loudness because human perception of loudness is not linearly related to the physical intensity of a sound wave. Instead, the human ear is more sensitive to changes in sound pressure at low levels, and less sensitive at high levels. This means that a sound that is twice as loud as another sound is not necessarily twice as intense in terms of sound pressure
Explain how the duplex theory of surface perception synthesizes spatial coding and temporal coding
The duplex theory suggests that spatial and temporal coding work together to provide a comprehensive representation of surface texture. Spatial coding allows the brain to detect the spatial arrangement of tactile features, while temporal coding provides information about the dynamic properties of the texture, such as its roughness, slipperiness, and fine details. By combining both types of information, the brain is able to form a rich and detailed representation of surface texture that is essential for perception and interaction with the environment.
Define the two major steps in the process of olfaction, and state what neural structures are thought to be associated with each.
The first step in olfaction involves the detection and transduction of odor molecules by the olfactory receptor neurons (ORNs) in the olfactory epithelium. When an odor molecule binds to an ORN, it triggers a series of chemical reactions that generate an electrical signal. This signal is then transmitted along the axons of the ORNs to the olfactory bulb. The second step in olfaction involves the processing and perception of the odor signal by neural circuits in the brain. When the olfactory bulb receives input from the ORNs, it processes and integrates this information, which is then transmitted to higher brain regions, including the piriform cortex, amygdala, and orbitofrontal cortex.
Explain the fundamental frequency and harmonics of a complex sound.
The fundamental frequency is the lowest frequency component that makes up a complex sound wave. It is the frequency at which the entire wave vibrates and is the basis for determining the pitch of a sound. For example, when we hear a musical note, the fundamental frequency is what determines whether we perceive it as a high or low note. Harmonics are multiples of the fundamental frequency and are present in most complex sounds. When an object vibrates, it not only produces its fundamental frequency but also generates higher frequency components that are multiples of the fundamental frequency. These higher frequency components are known as harmonics.
Explain the gate-control model of pain
The gate control model begins with the idea that pain signals enter the spinal cord from the body and are then transmitted from the spinal cord to the brain. In addition, the model proposes that there are additional pathways that influence the signals sent from the spinal cord to the brain. The central idea behind the theory is that signals from these additional pathways can act to open or close a gate, located in the spinal cord, which determines the strength of the signal leaving the spinal cord.
What are the receptor cells of hearing?
The hair cells
Explain the perceptual process for the head-rotation senses, including the transduction processes, amplitude coding, and direction coding for each.
The head-rotation senses are detected by three semicircular canals, the anterior, posterior, and lateral. The semicircular canals contain hair cells that are embedded in a gelatinous structure called the cupula. When the head rotates, the endolymph inside the canals lags behind due to inertia, causing the cupula to bend and move the stereocilia on the hair cells. This mechanical deformation of the stereocilia triggers the opening of ion channels in the hair cell membrane, allowing positively charged ions, such as potassium ions, to enter the cell. This generates an electrical signal that is transmitted down the afferent nerve fibers. The amplitude of the electrical signals generated by the hair cells encodes the velocity of head rotation. The faster the head rotates, the greater the deflection of the cupula, and the greater the amplitude of the electrical signals generated by the hair cells. The direction of head rotation is encoded by the pattern of electrical signals generated by the hair cells.
Explain the sensory homunculus in S1, including explanation of cortical magnification and tactile acuity in S1 representations.
The homunculus shows that adjacent areas of the skin project to adjacent areas in the brain, and that some areas on the skin are represented by a disproportionately large area of the brain.
Explain the idea of an isomorphic neural image, and how this relates to the idea of spatial coding of patterns and embossed details.
The idea of an isomorphic neural image refers to the neural representation of a sensory input, such as an image, in which the spatial arrangement of neurons in the brain mirrors the spatial arrangement of features in the input. In other words, nearby neurons in the brain respond to nearby features in the input, and the overall pattern of activation across neurons reflects the overall pattern of features in the input. This idea is closely related to the concept of spatial coding, which is a fundamental principle in sensory processing. Spatial coding refers to the way in which sensory information is organized in space, such that neighboring regions in the sensory input correspond to neighboring regions in the brain.
Explain the perceptual process for the linear-motion and tilt senses, including the transduction processes, amplitude coding, and direction coding for each.
The linear-motion and tilt senses are detected by the otolith organs. The movement of the otoliths causes the otolithic membrane to bend and move the stereocilia on the hair cells. This mechanical deformation of the stereocilia triggers the opening of ion channels in the hair cell membrane, allowing positively charged ions, such as potassium ions, to enter the cell. This generates an electrical signal that is transmitted down the afferent nerve fibers. The amplitude of the electrical signals generated by the hair cells encodes the magnitude of linear acceleration or the angle of tilt. The greater the acceleration or tilt, the greater the displacement of the otoliths, and the greater the amplitude of the electrical signals generated by the hair cells. The direction of linear acceleration or tilt is encoded by the pattern of electrical signals generated by the hair cells.
Briefly describe the motor theory of speech perception
The motor theory of speech perception suggests that our perception of speech sounds is based on the activation of the same neural representations that are involved in the production of those sounds. In other words, when we hear speech sounds, our brain processes them in a way that is similar to how it processes the movements involved in producing those sounds.
Explain the "place model" that explains how both loudness and pitch are coded
The place theory suggests that the frequency of a sound is determined by which part of the basilar membrane is most stimulated by the sound wave. Higher frequency sounds will cause more stimulation at the base of the cochlea, while lower frequency sounds will cause more stimulation towards the apex of the cochlea.The place theory also explains how loudness is coded in the auditory system. It suggests that the amplitude of a sound wave determines the number of hair cells that are stimulated and the degree to which they are stimulated. As the amplitude of a sound wave increases, more hair cells are stimulated, and they are stimulated more intensely, resulting in a stronger signal being sent to the brain. This results in a perception of increased loudness.
Argue whether preferences for taste in the strict sense are more innate/inherited or more learned.
The preference for taste is a complex phenomenon that can be influenced by both innate and learned factors. While some aspects of taste preference may be innate or inherited, such as a genetic predisposition to liking sweet or bitter flavors, other aspects of taste preference are learned through exposure and experience. Research suggests that infants are born with a preference for sweet flavors and a dislike of bitter flavors. This innate preference for sweet flavors is thought to have evolutionary roots, as sweet flavors in breast milk provide energy and signal safety to the infant. Similarly, the aversion to bitter flavors may have evolved as a protective mechanism against consuming potentially harmful substances. However, taste preferences can also be learned through experience and exposure. For example, cultural factors can play a significant role in shaping our taste preferences. People tend to prefer foods that are commonly eaten in their cultural group, and exposure to a wide variety of foods during childhood can shape taste preferences for life. Additionally, individual experiences with food, such as positive or negative associations with certain flavors or textures, can influence taste preferences.
Explain how speech sounds are produced by the various structures of the vocal tract, including the processes of voice and filtering.
The process of speech production begins with the lungs, which provide the air pressure necessary for speech. As air is expelled from the lungs, it passes through the larynx, where the vocal cords vibrate to create sound. This vibration produces a fundamental frequency, which determines the pitch of the sound. The sound produced by the vocal cords then travels up through the pharynx, where it is filtered and shaped by the various structures of the vocal tract. The tongue, lips, teeth, and palate work together to create different speech sounds by modifying the shape and size of the oral cavity.
Explain the general process of transduction for the vestibular senses at the receptor cells and afferent neurons
The receptor cells in the otolith organs and semicircular canals are specialized hair cells. These hair cells have tiny hair-like projections called stereocilia, which are embedded in a structure called the kinocilium. When the head moves, the fluid inside the canals and the otoliths move, causing the stereocilia to bend. This triggers the opening of ion channels in the hair cell membrane, allowing positively charged ions, such as potassium ions, to enter the cell. This generates an electrical signal that is transmitted down the afferent nerve fibers. The afferent neurons in the vestibular nerve then carry the electrical signals generated by the hair cells to the brainstem and cerebellum.
Explain vowel production, how vowels can be represented on frequency spectra, and what formants are.
Vowels are produced by vibration of the vocal cords, and the specific sounds of each vowel are created by changing the overall shape of the vocal tract. This change in shape changes the resonant frequency of the vocal tract and produces peaks of pressure at a number of different frequencies The formants of a vowel are the peaks in the frequency spectrum that are most amplified, and they are related to the resonant frequencies of the vocal tract. There are typically two or three formants associated with each vowel, and their relative frequencies determine the quality of the vowel sound
Explain condensation
When an object moves forward, it pushes the surrounding air molecules together, which causes a slight increase in the density of molecules near the diaphragm
Describe the relations between familiarity + intensity and liking in smell. Explain whether liking of smells is likely to be purely innate or to have a learned component, and justify your answer.
The relationship between familiarity, intensity, and liking in smell is complex and can vary depending on the individual and the specific odor. In general, familiarity with an odor tends to increase liking, while intensity can either increase or decrease liking depending on the specific odor and individual preferences. Research has shown that humans have an innate preference for certain smells that are associated with survival, such as the smell of food, flowers, and body odor. However, most of our olfactory preferences are learned through experience and exposure to various odors. For example, cultural and individual differences in olfactory preferences have been observed, such as the preference for certain types of food and spices in different cultures. Additionally, exposure to certain odors can influence liking through associative learning. For example, an individual who associates a certain smell with a positive experience, such as the smell of freshly baked cookies with happy memories from childhood, is likely to have a positive association with that smell and like it more than someone who does not have that association. In summary, while there may be some innate preferences for certain smells, most of our olfactory preferences are learned through experience and exposure. The relationship between familiarity, intensity, and liking in smell is complex and can vary depending on individual preferences and experiences.
Explain how olfaction is tied to the accuracy and emotional content of memories, and briefly summarize why it olfaction is so closely linked with memories
When we smell an odor, the olfactory sensory neurons send signals to the olfactory bulb and then to the piriform cortex, which is the primary olfactory cortex. From there, the signals are sent to other brain areas, including the amygdala and hippocampus, which are involved in emotion and memory, respectively. These areas integrate the odor information with emotional and contextual information, creating a strong and often emotional memory trace.
Briefly define the three vestibular reflexes discussed in class
Vestibulo-ocular reflexes: stabilizes visual images on the retina during head movements Vestibulo-autonomic reflexes: regulates autonomic functions in response to vestibular stimuli Vestibulo-spinal reflexes: controls postural and locomotor movements in response to vestibular stimuli
Define vocal pitch, state what vocal tract feature it is associated with, and explain how it varies by demographics.
Vocal pitch refers to the perceived highness or lowness of a sound produced by the vocal cords. It is associated with the length, tension, and thickness of the vocal cords. The length and tension of the vocal cords are primarily determined by anatomical factors, such as age, sex, and body size. Generally, men have longer and thicker vocal cords than women, which results in a lower pitch. Additionally, as people age, their vocal cords tend to thicken and lose elasticity, which can lower their pitch.
Define voice onset time, and relate it to the appropriate distinctive feature
Voice onset time (VOT) refers to the time delay between the release of a stop consonant (such as /p/, /t/, or /k/) and the onset of vocal cord vibration for the following vowel. In other words, it measures how long it takes for the vocal cords to start vibrating after the air has been released. VOT is related to the distinctive feature of voicing. The presence or absence of vocal cord vibration during the production of a stop consonant determines whether it is perceived as voiced or voiceless
List and label the parts of the inner ear that are necessary for auditory transduction.
cochlea, hair cells, basilar and tectorial membrane