psy exam 3

•In terms of brain activation, how does watching someone get injured compare with being injured yourself?

What lit up? In both cases, activity was seen in insula and cingulate (emotional) and sensory regions. Believed to represent a neurological expression of empathy, which may serve to bind people socially

•Understand the physiology of the taste receptors: how do salty, sweet, sour and bitter substances each lead to action potentials in the taste nerves?

(Stimulating a taste receptor cell: Salt and Sour - both tastants are small, charged molecules and use ionotropic receptors) Salt: -Na+ enters thru channel on microvilli à -Depolarization allows Na+ and Ca2+ in thru voltage-gated channels à -Neurotransmitter release à -AP in taste nerve Sour: (Acids in water have a free proton (hydrogen; H+) -H+ blocks K+ channel à -K+ can't leave cell à depolarization à -Or: H+ enters to depolarize cell -Na+ and Ca2+ into cell thru voltage-gated channels à -Neurotransmitter release à -AP in taste nerve Stimulating a taste receptor cell: Bitter, Sweet and Umami tastants stimulate metabotropic receptors (all different metabotropic receptors) Bitter, sweet and umami: -Tastant molecule binds to metabotropic receptor on microvilli à G-protein activated à -2nd messenger made à -Ca2+ let into cell from internal stores, Na+ into cell as well à -Neurotransmitter release à -AP in taste nerve (Likely differences in exact mechanisms between these 3 tastants)

•What is the accessory olfactory bulb (AOB)? What is the vomeronasal organ? Do humans have these? What is their role? How do the receptors in the AOB differ from those in the main olfactory bulb?

-Accessory olfactory bulb (AOB) •Humans don't have this •Added on in back of MOB •No connection (anatomical or physiological) with MOB Activated by vomeronasal organ (VNO Vomeronasal organ (VNO) -Amphibians, most reptiles, many mammals (some primates), not birds or humans* -Fewer types of receptors compared to regular olfactory receptors -Each receptor responds to only 1 pheromone -Very sensitive (1 in 1 hundred billion) -No adaptation (olfactory receptors show massive adaptation) -Responds to pheromones

If the skin is anesthetized, but proprioceptive/kinesthetic receptors are intact, can you still grasp/manipulate an object? Why or why not?

-Anesthetize skin (kinesthetic receptors work, touch receptors don't) à subject can't maintain stable grasp of objects he/she must manipulate NO

•What is perception for action?

-Using somatosensation to grasp and manipulate objects in a stable and coordinated manner, and to maintain proper balance and posture -Anesthetize skin (kinesthetic receptors work, touch receptors don't) à subject can't maintain stable grasp of objects he/she must manipulate

•Could you discuss how changes across the lifespan can affect the experience of pain?

Age differences in postoperative pain are scale dependent: a comparison of measures of pain intensity and quality in younger and older surgical patients. Age differences in pain perception are less consistent. Some studies indicate older adults are more sensitive to experimental pain than young adults, whereas others suggest a decrease in sensitivity with age. Pain is commonly under-recognized undertreated in older adults compared to younger adults. age?

•What happens to brain activation as pain intensity increases?

As pain intensity increases, more and more brain regions become active. Pain intensity-related activation occurred bilaterally in the cerebellum, putamen, thalamus, insula, anterior cingulate cortex, and secondary somatosensory cortex, contralaterally in the primary somatosensory cortex and supplementary motor area, and ipsilaterally in the ventral premotor area. These results confirm the existence of a highly distributed, bilateral supraspinal mechanism engaged in the processing of pain intensity.

•Sweet: What do you know about the receptors for sweet tastes and their relationship to artificial sweeteners? Can we differentiate between real sugars and artificial sweeteners, and if so, how?

Evoked by sugars (CH2O)n; simple carbs; glucose, sucrose, fructose, lactose -Glucose: main source of energy in humans and very sweet-tasting -Sucrose (table sugar): tastes even sweeter and is combination of glucose and fructose Artificial sweeteners, low-calorie foods and weight gain: maybe uncoupling of sensory properties of foods from their metabolic consequences disrupts regulation of food • -In one study, women who consumed saccharin gained weight - -In another study, aspartame increased appetite - -When the taste of sweet isn't consistently associated with calories, our brains get very confused Artificial sweeteners (sometimes called sugar alternatives) can replace sugar in foods and drinks to give you a sweet taste but with few or no calories. They are often several hundred times sweeter than sugar. So compared to sugar, only a little is needed for the same sweet taste.

•What is cognitive habituation? What 3 factors probably work together to cause it?

Example: You don't smell the odor of your house or your place of work Takes a while to develop and up to weeks to reverse Three mechanisms at play: 1. Receptors take longer to emerge after internalization 2. Continuous exposure to odorant molecules = absorbed into bloodstream à transported to olfactory receptors via nasal capillaries à receptors are constantly adapted 3. Cognitive-emotional factors

•What is action for perception?

Exploratory procedure: feel an object to learn about it -Different procedures tell you different things Exploratory procedure: A stereotypical hand movement pattern used to contact objects in order to perceive their properties; each exploratory procedure is best for determining one or more object properties. Lederman and Klatzky described hand postures and motions that were associated with the perception of specific object properties by touch

•How do some chemicals lead to the sensation of warmth (or hot) or coolness?

Feelings like warmth and cold are triggered by electrical signals carried by sensory nerves. At the endings of these nerves are specialized cells called receptors, which are activated either by extreme temperatures or by certain chemicals The most likely possibility is that there are certain chemicals inside our body that can trigger these central cold receptors. Maybe some of these chemicals are released when we have a fever, which would explain why we get chills even though our body temperature is higher than normal.

•What is haptic perception?

Haptic perception: Knowledge of the world that is derived from sensory receptors in skin, muscles, tendons, and joints, usually involving active exploration. -This is an active process: action for perception Touch relies on action to get info (as opposed to vision or audition, which are more passive). We then use this perception to act:perception for action

•What are the types of kinesthetic/proprioceptive receptors? Where are they and what kind of information do they convey?

Kinesthetic Mechanoreceptors Muscle spindle: -Convey rate at which muscle fibers are changing in length -Fires upon stretch of a muscle -Reflex leads to contraction of muscle Muscle spindles can help determine which muscles are flexed and which are relaxed. For instance, curling your arm so your hand moves towards your shoulder causes your biceps to contract and your triceps to relax. This information is sensed by muscle spindles. Muscle spindles are located within extrafusal (skeletal) muscle fibers and consist of connective tissue surrounding intrafusal fibers in a capsular structure. Muscle spindles are innervated by myelinated afferent nerve fibers, which enter the capsule of and spiral around the intrafusal fibers. Golgi tendon organs -Receptors in tendons (connect muscle to bone) -Info about tension in muscle (which pulls on tendon) -Also involved in reflexes •Contract muscle à muscle pulls on tendon à GTO stimulated à leads to relaxation of muscle Info to cerebellum from GTO in spinocerebellar tract Golgi tendon organs (GTOs) are proprioceptors that are located in the tendon adjacent to the myotendinous junction

•Are all axons the same? What is the result of increasing the diameter and/or myelination of axons?

Larger diameter axons have a higher conduction velocity, which means they are able to send signals faster. This is because there is less resistance facing the ion flow. ... The larger the diameter of the axon, the less likely the incoming ions will run into something that could bounce them back. -Dorsal column-medial lemniscal (DCML) pathway: Carries signals from skin, muscles, tendons, and joints (faster). -Spinothalamic pathway: Carries most of the information about skin temperature and pain (slower).

•What evidence points to the hedonic value of odorants (i.e., whether or not we find them pleasurable) being innate and what evidence points to it being learned?

Learned: •Infants don't display preferences or discriminate between pleasant and unpleasant (as judged by an adult) smells • •Infants exposed to volatile things in utero or during breastfeeding (garlic, cigarette smoke) showed preference for these smells compared to infants not previously exposed to them • •Differences between cultures suggest learning and not hard-wired responses • •No smell is universally horrid • •But, Trigeminal aspect of perception is likely innate, as we have innate desire to avoid pain • •Maybe part of the impression is innate and part (most) is learned... Innate: •Critters living in specific habitats and with limited food sources and predators (Specialists) have hardwired responses to particular odorants that are adaptive. •Generalist species that exploit many environments and have many food choices and varying predators need to be able to learn about odors and respond appropriately based on that experience. •Learned taste aversion: more related to the smell of the food/drink in humans

•Can we perceive patterns with the skin? What are the limitations on this capability?

Not great at this, but we can do it if the pattern is small enough to fit on 1 fingertip. -can't "read" more than 1 finger at a time (suggests narrow haptic field of view; the area of skin we can "take in" all at once) When visual stimuli are blurred so that their resolution matches that of the touch system, people tended to confuse the same stimuli as they did when trying to recognize them with their sense of touch.

•What types of somatosensory info do we get from the mouth that is relevant to the entire taste experience? What cranial nerve carries that info?

Oral somatosensory awareness refers to the somatic sensations arising within the mouth, and to the information these sensations provide about the state and structure of the mouth itself, and objects in the mouth. There are two cranial nerves that innervate the tongue and are used for taste: the facial nerve (cranial nerve VII) and the glossopharyngeal nerve (cranial nerve IX).

•Genetically and behaviorally, what is the difference between a non-taster and a taster/supertaster? Anatomically, what is the difference between a taster and a super-taster? What has cross-modality matching told us about taster status? What are some health consequences of taster status?

PTC/PROP tasted by some people, not by others...depends on a single gene -Recessive: tt = nontaster -At least 1 dominant: TT or Tt = taster or supertaster •But different thresholds within this group...so supertasters and tasters. What makes this difference? •Combination of genetic PROP status and number of fungiform papillae on tongue (which are independent of each other) •Fungiform papillae also innervated by nerve for touch (general touch and pain and temp; trigeminal), so lots of fungiform papillae intensify all oral sensations The tongue of this average taster has 16 fungiform papillae. Some people may have as few as 5, in extreme cases. • (b) This supertaster's tongue has 60 fungiform papillae in the area. •Tasters and supertasters taste bitter things as even more bitter...might avoid veggies or alcohol/tobacco -Older men getting colonoscopies: taste PROP as most bitter = most colon polyps (precursor to colon cancer) -Non-tasters more likely to smoke and drink (can't taste the bitterness as much) •Fats can be unpleasant to supertasters à fewer high-fat foods à less cardiovascular disease?

•How do Pacinian corpuscles work?

Pacinian corpuscles are one of the four major types of mechanoreceptor. They are nerve endings in the skin, responsible for sensitivity to deep pressure touch and high frequency vibration. Structure Similar in physiology to the Meissner's corpuscle, Pacinian corpuscles are larger and fewer in number than both Merkel cells and Meissner's corpuscles[1] . The Pacinian corpuscle is oval shaped and approximately 1 mm in length. The entire corpuscle is wrapped by a layer of connective tissue. It has 20 to 60 concentric lamellae composed of fibrous connective tissue and fibroblasts, separated by gelatinous material. The lamellae are very thin, flat, modified Schwann cells. In the center of the corpuscle is the inner bulb, a fluid-filled cavity with a single afferent unmyelinated nerve ending. Function Pacinian corpuscles detect gross pressure changes and vibrations. Any deformation in the corpuscle causes action potentials to be generated, by opening pressure-sensitive sodium ion channels in the axon membrane. This allows sodium ions to influx in, creating a receptor potential. These corpuscles are especially susceptible to vibrations, which they can sense even centimeters away [1] . Pacinian corpuscles cause action potentials when the skin is rapidly indented but not when the pressure is steady, due to the layers of connective tissue that cover the nerve ending [1] . It is thought that they respond to high velocity changes in joint position. Pacinian corpuscles have a large receptive field on the skin's surface with an especially sensitive center [1] . They only sense stimuli that occur within this field.

•Is pain a "sensation" or a "perception"? Okay, it's a perception. What is the sensation?

Pain is considered to be a human primate instinct and can be defined as a distressing sensation, as well as an emotional experience that is linked to actual or potential tissue damage, with the sole purpose of notifying the body's defence mechanism to react towards a stimulus in order to avoid further tissue damages. Subjective experience arising from a noxious stimulus •Sensory, emotional, cognitive •To alert us of danger •Very bad to not be able to feel pain

•What is the newest type of touch receptor discovered and what stimulation does it convey?

Pleasant touch receptors -Classic categories of discriminative touch: tactile, thermal, pain, and itch -Newly uncovered fifth component of touch: pleasant touch •Mediated by unmyelinated peripheral C fibers known as "C tactile afferents" (CT afferents) •CT afferents not related to pain or itch •Respond best to slowly moving, lightly applied forces (e.g., petting) •Processed in orbitofrontal cortex rather than S1 or S2

•What makes something an odorant? Are there compounds that should be odorants but we cannot smell?

Requirements of an odorant (odor-inducing substance) •Volatile (can float thru air) •Small (<5.8x10-22 g) •Hydrophobic •Not all molecules that "should" smell to humans (according to above criteria) do smell to us -natural gas (methane) -CO (bi-product of methane) -why don't we smell them??

•What is shape-pattern theory?

Shape-pattern theory is dominant theory Shape-pattern theory account of odorant-receptor binding and activation (A) Odorants (chemicals) fit receptors with shapes that best accommodate them. (B) The specific pattern of activity elicited by a given set of receptors determines the specific scent perceived •Lock (receptor) and key (odorant) •Odorant molecules have different shapes •Olfactory receptors have different shapes •Different scents (as a function of odorant shape or OR-shape fit) activate different arrays of olfactory receptors in the epithelium à •Various arrays produce specific firing patterns of neurons in OB (a pattern is generated across the glomeruli), which determines what scent we perceive

•Dogs have more olfactory receptor neurons that humans, and rats have more types of olfactory receptors than humans. What are the functional consequences of these differences?

So mice can differentiate between odors that smell the same to humans. Humans: 10 mil OSNs per nostril Humans: ~350 types of receptor proteins (rodents have ~1000) ...consequence of this?? Doesn't affect how well someone smells; does affect sensitivity to certain odorants More receptors à more sensitive to odors More intense odor = less pleasant

•How is S1 organized? What are the Brodmann's areas for Somatosensation? What does the homunculus tell us? Besides cortex, what else is somatotopically organized? (Axons?,primary motor cortex) What is somatotopy?

Somatotopic organization: homunculus S1 gets info from medial lemniscus (via thalamus) Cells in Brodmann's areas 3, 1, 2 respond to different type of sensory information (SA cutaneous receptors; FA cutaneous receptors; receptors in joints, respectively) Stimulation of S1 à contralateral tingling, numbness (Penfield) •Various neocortical regions have specific cellular architectures (i.e., cytoarchitectures)These were used by Brodmann to catalogue the entire cortex •He numbered each area that he identified by microscopic analysis •Turns out some of them also have functional specificity •Examples: -4; primary motor cortex -3, 1, 2; somatosensory area -17-striate cortex; primary visual cortex Permanently Lost if Lesion to S1 •Position sense •Tactile localization •Two-point discrimination •Stereognosis •Graphesthesia •Weight discrimination •Perception of simultaneous stimuli •Perception of texture •Sporadic activity in S1 can cause perception of missing limb •In homunculus, face area and hand area are adjacent •Missing arm à hand area of cortex no longer gets "direct" stimulation à fibers that normally go to "face cortex" sprout collaterals to "hand cortex" à stimulation of those hand cortex cells makes amputee perceive hand stimulation The sensory homunculus is a map along the cerebral cortex of where each part of the body is processed. The sensations occur all along the body. The impulses from the body will be sent into the spinal cord and eventually back to the brain to be processed. cortical sensory homunculus is located in the postcentral gyrus and provides a representation of the body to the brain. Somatotopic mapping is analogous to retinotopic mapping in vision and tonotopic mapping in hearing. Somatotopy is the point-for-point correspondence of an area of the body to a specific point on the central nervous system. Typically, the area of the body corresponds to a point on the primary somatosensory cortex (postcentral gyrus). ... Areas such as the viscera do not have sensory locations on the post central gyrus.

•What are the 4 main tactile receptors? How do they differ in terms of adaptation and receptive field size? What tactile functions do they subserve? What does it mean that they are mechanoreceptors?

The four major types of tactile mechanoreceptors include: Merkel's disks, Meissner's corpuscles, Ruffini endings, and Pacinian corpuscles. Merkel's disk are slow-adapting, unencapsulated nerve endings that respond to light touch; they are present in the upper layers of skin that has hair or is glabrous. if doesnt mean above *** Mechanoreceptors, thermoreceptors, chemoreceptors, categories within those Note that the two deepest types of receptors (Ruffini and Pacinian) have the largest receptive fields and the two shallowest types of receptors (Merkel and Meissner) have the smallest receptive fields. Left: the types of fibers found in hairy skin, including A-delta fibers specifically associated with down hair; skin layers are also identified. Right: the fibers found in glabrous skin, with the mechanoreceptors identified. Additional A-delta fibers found within the epidermis of both hairy and glabrous skin are not illustrated receptive fields: Very sensitive area of body = small and densely packed receptive fields = more cortical area processing touch from that area Onion-like outer membrane provides mechanical support so it is resistant to gradual or constant pressure...so rapidly adapting. BTW, the other rapidly adapting receptor, Meissner's corpuscle, works in a similar way. Mechanoreceptors are a type of somatosensory receptors which relay extracellular stimulus to intracellular signal transduction through mechanically gated ion channels. The external stimuli are usually in the form of touch, pressure, stretching, sound waves, and motion. slide 11 somato

•What is the Gate Theory of Pain?

The gate control theory of pain asserts that non-painful input closes the nerve "gates" to painful input, which prevents pain sensation from traveling to the central nervous system. ie: When you bang your shin on a chair or table, for example, you might stop to rub the injured spot for a few moments. The increase in normal touch sensory information helps inhibit pain fiber activity, therefore reducing the perception of pain. In times of anxiety or stress, descending messages from the brain may actually amplify the pain signal at the nerve gate as it moves up the spinal cord. Alternatively, impulses from the brain can "close" the nerve gate, preventing the pain signal from reaching the brain and being experienced as pain.

•For what primary tastes do humans show "specific hungers"? What is some evidence for these? What is necessary for something to be able to cause a specific hunger?

The need for a nutrient causes the body to crave it: "body wisdom" •Limited only to sweet and salty...doesn't work for vitamins (rats and B12 story). -Nutrient needs to be obviously associated with sensory cue...doesn't work if the nutrient doesn't have a taste. •3 ½ year old boy craved salt, salt-restricted during hospital stay, died, adrenal gland tumor had caused body to lose sodium...his craving for salty foods had kept him alive. •Insulin injections increase craving for sweets

•What is the pathway (names and all the stops along the way) for touch info to get to the brain? What part of the spinal cord does it enter? When/where does it cross to the other side of the brain? What part of thalamus does it use? If that touch is on the face or head, what cranial nerve is involved?

Touch sensations can travel ~2 meters from the skin of feet to the brain stem! •Information must pass through spinal cord *******The pathway responsible for touch and proprioception is called the lemniscal pathway. The first axon in this pathway runs along the dorsal root of the spinal nerve and up the dorsal column of the spinal cord.********** USES THALAMUS/CEREBRAL CORTEX •Axons of various tactile receptors combine into single nerve trunks •Labeled lines: Each fiber type from the skin codes a particular touch sensation. •Labeled lines become interconnected in spinal cord, allowing complex patterns to emerge. Axons from touch fibers enter the spinal cord in the dorsal horn. -Dorsal horn is organized into multiple layers, or laminae. -Inputs to spinal cord organized somatotopically—adjacent areas of the skin project to adjacent areas in the spinal cord. A-alpha fibers: Wide-diameter, myelinated sensory nerve fibers that transmit signals from proprioceptive receptors in muscles and tendons. A-beta fibers: Wide-diameter, myelinated sensory nerve fibers that transmit signals from mechanical stimulation A-delta fibers: Intermediate-sized, myelinated sensory nerve fibers that transmit pain and temperature signals C fibers: Narrow-diameter, unmyelinated sensory nerve fibers that transmit pain and temperature signals Two major pathways from spinal cord to brain -Dorsal column-medial lemniscal (DCML) pathway: Carries signals from skin, muscles, tendons, and joints (faster). -Spinothalamic pathway: Carries most of the information about skin temperature and pain (slower). (It makes sense for the DCML pathway to be faster since you need to constantly sense your body's position in space so that you adjust accordingly. For instance, walking on an uneven surface will require quick adjustments to maintain your balance and footing.) Somatosensory Info from Face and Head(Cranial Nerve V) •Trigeminal nerve (CN V) •Different fibers/nuclei involved in general sensory versus pain and temperature •Joins medial lemniscus/spinothalamic pathway •Also conveys information from stretch receptors from chewing muscles

•Anatomy of the olfactory system: What are turbinates? What is the olfactory epithelium (and what types of cells does it contain)? Olfactory bulb? Cribriform plate? Glomeruli? Olfactory nerve? Understand the anatomy of the olfactory receptor cells (in olfactory epithelium...cilia (dendrites) extend into mucosa and contain receptors, axon travels thru cribriform plate as part of olfactory nerve and ends in olfactory bulb). How is the olfactory information organized in the olfactory bulb, especially with regard to glomeruli? What is the projection neuron within the glomerulus that receives info from the olfactory nerve and sends info to the cortex? What parts of cortex get olfactory info? Where else in the brain does olfactory information go, and what are the roles of each of those regions?

Turbinates Ridges that add turbulence to incoming air to send some thru the olfactory cleft and onto the olfactory epithelium Olfactory information is transmitted from the olfactory bulb to the primary olfactory cortex comprising the amygdala-hippocampal complex of the limbic system in the first stages of olfactory processing. The orbitofrontal cortex is considered to be the secondary olfactory cortex and is responsible for conscious odor perception. •OSNs in nasal epithelium •Axons go thru cribriform plate (bony plate) and end in olfactory bulb - ipsilateral projection all the way to cortex! The olfactory epithelium contains three types of cells: olfactory sensory neurons (OSNs) •Small neurons with cilia •Receptor proteins are on the cilia •Die and are replaced every month or so •Project to glomeruli (clusters of neurons) in olfactory bulb , basal cells, and sustentacular cells. The OSNs are located within a watery mucous layer on the epithelium; the hairlike olfactory cilia of the OSN dendrites project into the mucus and within them are the receptor sites for odorant molecules. The different colors of the OSNs in this illustration indicate the glomeruli onto which they converge. All blue OSNs connect to blue glomeruli, all purple to purple, and so on. This schematic illustrates the fact that different OSNs expressing the same receptors converge on the same type of glomerulus, no matter where they are in the olfactory epithelium. Olfactory sensory neurons: •~20 mil (humans) •Small neurons w/ cilia •Receptor proteins are on the cilia -Each OSN expresses 1 type of receptor protein (next slide) •Project through cribriform plate to glomeruli (clusters of synapses) in olfactory bulb -These axons constitute the olfactory nerve (CNI). -Ipsilateral projection

•How/why do olfactory thresholds increase with age?

Your sense of smell can also diminish, especially after age 70. This may be related to a loss of nerve endings and less mucus production in the nose. Mucus helps odors stay in the nose long enough to be detected by the nerve endings. It also helps clear odors from the nerve endings.

•What is evidence that a placebo drug can decrease pain perception by working through opiate receptors in the PAG?

fMRI scans of subjects that reported decreased pain following placebo administration show increased activity in the periaquaductual gray (PAG; left) and in the dorsolateral-prefrontal cortex (right) Placebo + naloxone (opioid receptor antagonist) à no reported analgesia (so effect is thru opioid receptors) It is the central nervous system that makes the decision to create the experience of pain, not the stimulus!

•Why does gently rubbing an injured area seem to make it hurt a little less?

ie: When you bang your shin on a chair or table, for example, you might stop to rub the injured spot for a few moments. The increase in normal touch sensory information helps inhibit pain fiber activity, therefore reducing the perception of pain. In times of anxiety or stress, descending messages from the brain may actually amplify the pain signal at the nerve gate as it moves up the spinal cord. Alternatively, impulses from the brain can "close" the nerve gate, preventing the pain signal from reaching the brain and being experienced as pain.

•In action for perception, what types of exploratory procedures do we use to give us info about an object, and what type of info do those procedures yield?

lateral motion= texture pressure = hardness contact = temperature holding= weight enclosure, global shape= volume contour following = exact shape

•What do you know about the link between olfaction, emotion and memory? What neural substrates underlie the connection between olfaction, emotion and memory?

•1st experience sometimes determines emotional association of the odor...wow, so we must encode it in memory quickly and easily • •Specific, explicit memory, or non-specific memory like an emotional association (implicit memory) • •Study done in mid-'60s in Britain, again in late '70s in US: Brits give wintergreen one of lowest pleasantness ratings; Americans rate it high -Candy to Americans -Added to analgesics during WWII for Brits. •Odors are not better than other senses at evoking memories in general, but are really good at evoking emotional memories. -People list more emotions associated with olfactory memories than with any other sensory modality cue -Emotions have greater intensity -Feel more "transported to the original time" -Memories are not necessarily more accurate (or specific) Amygdala: axons from OB synapse directly in amygdala •Amygdala: emotional processing, including emotional memories •Amygdala is activated by smell of a perfume that elicits a personal memory, but not by the sight of that perfume or by the scent of a different perfume

•What are the 3 main roles of pheromones? What is some evidence for pheromonal communication in humans?

•AND (androstadienone) -Made in adrenal glands and gonads as part of step for making testosterone and estrogens -Increases alertness and positive mood in women -Decreases positive mood in men -Hypothalamus activation in women and homosexual men; not hetero men •EST (estratetraene) activates hypothalamus in men, not women •Major histocompatibility complex (MHC) -Large gene family (chromosome 6 in humans) -Genes make the molecules that enable immune system to recognize invaders -More diverse MHC of parents à stronger immune system of offspring -Women prefer odor of men with dissimilar MHCs to own. •Preference reversed if taking oral contraceptives. •Preference seen in male mice and fish, too • •Humans have no functional VNO or AOB, so if there is pheromonal communication between humans, it is unclear how it is occurring...perhaps thru main olfactory system.

•What is the pathway that noxious stimuli takes to the brain? How does the pathway to cortex differ from that of the dorsal columns/medial lemniscal system? Where else in the brain does the info go, and what purpose does that serve?

•Action potential in primary afferent •Synapse in dorsal horn of spinal cord -Substantia gelatinosa -Glutamate or glutamate and substance P -Secondary afferent crosses midline immediately (very different from DC/ML) •Goes to thalamus (VP), then cortex The thalamus is one of the structures that receives projections from multiple ascending pain pathways. The structure is not merely a relay centre but is involved in processing nociceptive information before transmitting the information to various parts of the cortex.

•What are adaptation and cross-adaptation? What did the essay on water tastes teach you?

•Adaptation: the loss of taste (or any stimulus) with constant stimulation -This is why your saliva doesn't taste salty •Soak tongue in lemon juice, then vinegar...the vinegar isn't as sour -Why?? Sour receptors have been fatigued by lemon juice. -BUT, taste of something sweet or salty is not affected...no cross-adaptation (reduced response to one primary taste after exposure to another) -Dessert then lemonade: dessert adapted (fatigued) sweet receptors, so lemonade tastes more sour than sweet •The adaptation here is still within a primary taste...

•What is "analgesia"? What things modulate pain and how do those work (i.e., act as analgesics)?

•Analgesia: decreasing pain perception during a conscious experience -Psychological factors -Non-Rx drugs (NSAIDs) •Non-steroidal anti-inflammatory drugs (aspirin, ibuprofen, etc.) •Block synthesis of prostaglandins •Only suitable for mild or moderate pain •Can be combined with opioids in combination therapy (e.g., low dose of codeine + NSAID produces same effect as moderate dose of codeine) -Local anesthetics •Types of drugs: the 'caines (lidocaine, procaine, novacaine, etc.; most often encountered with the dentist or if you're getting stitches) •Block the conduction of nerve impulses in a localized/discrete area (sodium channel blocker) •Fun fact: the duration of local anesthetics varies on a circadian rhythm -Rx drugs (opioids) •Variety of compounds (morphine, codeine, etc.) •Activate opioid receptors (mostly mu-subtype) within CNS -So mu-opioid receptor agonist •Reduce transmission of nerve impulses by modulating activity in periaqueductal gray (PAG) of midbrain and dorsal horn of SC -TENS •Transcutaneous Electric Nerve Stimulation -Stimulates afferent myelinated (A-beta) fibers -Activates inhibitory circuits in SC -Nerve impulse transmission reduced -Decreased perception of pain -Consistent with Gate theory of pain -Compare this to rubbing or holding an injured area of the body -Religious belief / prayer -Excitement -Interpersonal influences •PET on women receiving electric shock while holding husband's hand, an unknown man's hand, or no hand... these below could make it worse -Prior experience -Anticipation -Social influences

•What is anosmia, and what can cause it? What is specific anosmia, and what is its most common cause?

•Anosmia: Inability to smell •Whip-lash type accident à sheer axons of olfactory receptor cells...grow back -If cribriform plate is fractured by blow to head, it could scar and axons cannot regrow •Connection with mental health! -Lose sense of smell à more likely to go into clinical depression -People who are depressed report altered sense of smell -Croy et al (2014) Olfaction as a marker for depression in humans. J Affective Disorders 160: 80-86 Nasal congestion from a cold, allergy, sinus infection, or poor air quality is the most common cause of anosmia. Other anosmia causes include: Nasal polyps -- small noncancerous growths in the nose and sinuses that block the nasal passage. Injury to the nose and smell nerves from surgery or head trauma. Exposure to toxic chemicals, such as pesticides or solvents SPECIFIC ANOSMIA •The inability to smell a specific compound amid otherwise normal smell perception. •Usually to steroidal musk compounds •Usually genetic •5 - 31 specific anosmias have been identified in humans (the number depends on the strength of the data).

•Do we use labeled-line or cross fiber patterning to identify odors? Understand why!

•Brain knows from what glomerulus axons have traveled, which helps brain determine smell (like labeled-line, right?) •But an odorant activates a pattern of OSNs = so pattern of glomeruli (so really cross-fiber patterning) -Glomeruli pattern of activation differs based on experience & preference for the odorant

•Salt: what can affect salt preference and perception?

•Salt preference is affected by early learning -No salt preference (indifferent or aversion to high concentrations) until ~6 months old -Cl- or Na+ deficiency in infancy à increased Na+ preference in adulthood -Bad morning sickness à offspring have increased Na+ preference -Infants fed starchy foods (likely high in salt) à increased salt preference •Salt perception changes -Low Na+ diet à increase in perceived intensity of saltiness (good for people on a low-salt diet!)

•How can suggestion affect odor perception?

•Distilled water on cotton ball...tell class is has novel odor...ask when people begin to smell it... •Tell people on radio and TV that a certain frequency noise will generate a smell perception of wintergreen...people report smelling it •Give subjects odors to evaluate...use names that are positive or negative ("vomit")... dramatically affected evaluation of odor •Affects adaptation too: -think something is benign, adapt -think it's harmful, sensitize Also, odors are invisible, and somewhat disconnected from language, so we look for cues anywhere.

•What do you know about haptic search? What features of an object hat you are touching "pop out" and what features do not?

•Do some material properties "pop out"? -Yes: Rough among smooth, hard among soft, cool among warm, edged surfaces among smooth surfaces -No: Horizontal lines among vertical lines Long story short: you can detect before using selective attention to identify a particular feature...this is called preattentive feature detection. -No need to compare in order to detect; some features just "pop-out" •Works for texture (rough vs. smooth), temperature, hard/soft •Doesn't work for horizontal vs. vertical lines -Haptic recognition relies on material properties, not object contours -Good for handling objects to identify them... -Bad for feeling raised contours of a drawing of the object -This is opposite visual system, which would be good at horizontal vs. vertical

•What aspects of taste are probably coded using labeled-line and which ones are probably coded using cross-fiber patterning?

•Each fiber coming from a taste receptor cell has a "favorite" stimulus (salt or sweet etc.) -Compare this to the characteristic frequency of auditory nerve fibers •But no fiber is tuned exclusively to one taste, so we rarely taste a "pure taste" •Closer to labeled line for identification of primary taste •Closer to cross-fiber patterning for id of type within a primary (kind of sweet, kind of salt, etc.). -most tastants stimulate more than one type of receptor, so the brain uses the activation across many types to identify the tastant

•What cranial nerves innervate the tongue? What brain regions (in order) get info about taste? What are the roles of the insular cortex and the orbitofrontal cortex?

•Each fiber coming from a taste receptor cell has a "favorite" stimulus (salt or sweet etc.) -Compare this to the characteristic frequency of auditory nerve fibers •But no fiber is tuned exclusively to one taste, so we rarely taste a "pure taste" •Closer to labeled line for identification of primary taste •Closer to cross-fiber patterning for id of type within a primary (kind of sweet, kind of salt, etc.). -most tastants stimulate more than one type of receptor, so the brain uses the activation across many types to identify the tastant 1. The hypoglossal nerve (CN XII) provides motor innervation to all of the intrinsic and extrinsic muscles of the tongue except for the palatoglossus muscle, which is innervated by the vagus nerve (CN X) 2. A message of taste moves from the taste buds in the tongue to the brain through cranial nerves. The signal is first received by areas in the brainstem, which connects the spinal cord with the rest of the brain. The signal then moves to the thalamus in the brain. The primary gustatory cortex is a brain structure responsible for the perception of taste. It consists of two substructures: the anterior insula on the insular lobe and the frontal operculum on the inferior frontal gyrus of the frontal lobe. 3. The insula reciprocally connects with frontal brain regions such as the anterior cingulate, the orbitofrontal, and the medial prefrontal cortices, which are implicated in cognitive, emotional and executive functions, and projects to parts of the brain implicated in motivation and reward Orbitofrontal Cortex (association cortex; cells are multimodal) -Temperature, touch, smell, taste, etc. -So good for flavor (next slide) Another important factor: S1 for somatosensation Insular Cortex (primary taste cortex): gustotopic in mammals (humans?) Neural signals from the taste buds in the papillae are transmitted via cranial nerves VII, IX, and X to the brain. Circumvallate, Foliate, and Fungiform papillae contribute to taste because they have taste buds embedded within them. Filiform papillae do not have taste buds.

•What are endorphins and enkephalins? What releases them?

•Endorphins: enkephalins (methionine "met" and leucine "leu") and β-endorphin -inhibitory -Released by inescapable "pain", sex, "runner's high" and even very enjoyable music (!!) -Act at opioid receptors enkephalins= either of two compounds that occur naturally in the brain. They are peptides related to the endorphins, with similar physiological effects. Since endorphins act on the opiate receptors in our brains, they reduce pain and boost pleasure, resulting in a feeling of well-being. Endorphins are released in response to pain or stress, but they're also released during other activities, like eating, exercise, or sex.

•What is flavor? How does the brain differentiate between tasting or smelling something?

•Flavor is metasensation created by brain based on taste and smell •Chew and swallow food à molecules released into air outside mouth and forced up behind palate in nasal cavity (stimulate olfactory receptors)...retronasal olfactory sensations

•What are hyperalgesia and allodynia? Why do they occur?

•Hyperalgesia -damage has occurred to tissue à site is more sensitive...triggers feeling of pain easier than before •Allodynia -normally innocuous stimulus becomes painful •More sensitive because chemicals in damaged or inflamed tissue increase the number of Na+ channels in nearby receptors, including free-nerve endings (nociceptors), so magnify activation of those receptors

•In what major brain region is the periaqueductal gray (PAG), and what seems to be its role in gating info about noxious stimuli?

•Large role in processing pain •Some fibers from ALS •Contains many opiate receptors...maybe production of analgesia here -Stimulate in rats = enough analgesia to do surgery! -Stimulate in humans to ameliorate intractable pain PAG = raphe magnus and more medullary reticular formation à posterior/dorsal horn...more on this with reticular formation. The periaqueductal gray, or PAG, is an area of gray matter found in the midbrain. The PAG surrounds the cerebral aqueduct (hence the name periaqueductal) and occupies a column of brainstem that stretches about 14 mm long.a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. PAG is also the primary control center for descending pain modulation.

•What are thermoreceptors, and what kinds are there? What type of channel do they use? Understand that these are free nerve endings (know what that means) with ThermoTRP receptors in the membrane.

•Sensory receptors that signal information about changes in skin temperature Thermoreceptors respond when you make contact with an object warmer or colder than your skin Also ruffini corpuscles sense warmth and krause's end bulbs sense cold. •ThermoTRP channels (thermally sensitive transient receptor potential ion channel)...non-selective cation channels in cell membrane of sensory neurons •To detect such a large range of temps, probably need more than one...turns out we have several different TRP channels for temp, all tuned to specific range of temperature •Some thermoreceptors also respond to chemicals •Warmth fibers and cold fibers 2 TYPES OF THERMO Free nerve endings (likenociceptors Free nerve endings are the most abundant type of nerve endings. ... Free nerve endings are formed by branching terminations of sensory fibers in the skin. The endings are slightly thickened. Although mechanoreceptors, thermoreceptors, and nociceptors are all examples of free endings, nociceptors are the most common type.

•Know the disorders of taste we discussed. Also know the terms ageusia, hypogeusia and dysgeusia. Why can altered taste perception be so bad for overall health?

•Many causes, leading to altered taste perception: -Ageusia (total loss of taste) -Hypogeusia (decrease in taste, of all or specific primaries/tastants) -Dysgeusia (distorted taste) Xerostomia •Dry mouth due to dysfunction of salivatory glands -Saliva liquifies tastants, providing vehicle for them to affect taste receptor cells -Saliva contains salt, and salt affects the perception of the other primary tastes -Dry mouths are more acidic, affecting sweet and sour tastes Burning Mouth Syndrome •Burning pain, usually affecting tongue, hard palate, and/or lips •Usually spontaneous, but sometimes after dental work or trauma •Sometimes with xerostomia and dysgeusia •Often associated with poor quality of life, depression, anxiety •Prevalence: 0.7-15% -More common in women compared to men (33:1) •Often perimenopausal or postmenopausal •Can coexist with other chronic pain syndromes •Treatment: -Pharmacotherapy (often antidepressants) and CBT -Often resolves spontaneously after years Phantom Tastes •"Phantageusia" •Most common taste disorder •Lingering, often unpleasant taste, with nothing in the mouth •Can be initiated by strong tastes (coffee, garlic) in patients

•Bitter: usually means poisonous. How many genes for bitter receptors are there and what does that tell us? Do we differentiate between bitters? Why or why not? How do bitter and sweet interact with each other? How does the perception of bitter change across the lifespan of women?

•Multigene family: 25 bitter receptors on 3 different chromosomes -Certain bitter stimuli excite certain receptors -But, each type of bitter receptor doesn't necessarily have own projection neuron...so hard to distinguish between bitters (no labeled line within)...just avoid all! -Multitude of bitter receptors allows for a variety of responses to bitter compounds between individuals within a species (in other words, different genetic make-up means that you and I might have different bitter experiences). •Quinine, tonic water, aspirin, coffee, unsweet chocolate, etc. -BTW sweet and bitter inhibit each other. Tonic water is high in quinine and sugar. •Often things that taste bitter are poisonous... this is biological function: avoid bitter tastes! •Sometimes they are very healthy (veggies!) -Compound (AMP) that inhibits some bitter sensations is naturally present in mother's milk (which has some bitter elements...babies avoid bitter tastes from birth). In women, sensitivity to bitter intensifies with pregnancy and diminishes after menopause

•What is the purpose of each of the 4 primary tastes (i.e., what important info do they give us that is necessary for our survival)?

•Needs -Ions/basic elements (salt) •For proper nerve and muscle function... die without it. -Energy •Carbohydrates (sweet) -Building blocks for proteins •Amino acids (umami) •Dangers -Poisons •Bacteria/Spoiled food (sour) •Toxic chemicals (bitter)

•What do you know about how pain is processed in different people or as the result of different noxious stimuli?

•Pain can occur without a noxious stimulus. -Chronic pain conditions •Pain can fail to occur when a noxious stimulus is occurring •For the 'same' type of pain, the areas that are engaged in one individual's brain may differ from those in other individuals. •Patterns of activation may differ when s/he is healthy versus ill. The experience of pain changes across the lifespan

•Understand the anatomy of the taste system: know the names of the different types of papillae; what/where are the taste buds, and taste cells; what is the taste pore; where do fibers of the taste cranial nerves synapse with taste cells

•Papillae: ridges on tongue fillform pappilae folliate papillae fungiform pap circumvallate pap •Filiform -Anterior part of tongue -No taste function -Different shapes in different species •Fungiform -Look like little mushrooms -Anterior part of tongue -Vary in diameter -About 6 buds per fungiform papilla -Some people have more, others less...functional significance •Foliate -Rear, sides of tongue, where it attaches -Look like folds; taste buds buried in the folds •Circumvallate -Large and circular, like islands with motes -Taste buds buried in the motes -4 types; 3 with taste function •Taste buds embedded in papillae •Taste buds made of taste cells •Receptor proteins on taste cells •Chew food à broken down into molecules, dissolved in saliva •Molecules in saliva go into taste pore to get to taste bud •Remember: taste buds made up of taste cells and found in papillae •Each taste receptor cell responds to a limited number of molecules -"Responds": initiates AP along nerve (VII, IX, or X) to brain •Bud = cluster of long cells •Tips end in microvilli •Some (not all) receptor cells synapse on nerve fibers -3 separate cranial nerves •Fungiform papillae: Some fibers branch, so >1 cell per fiber and >1 fiber per cell (M:M) •Taste receptor cells live for about 10 days, then die and are replaced. •Receptor cells innervated by same fiber respond to same tastants. -Important for fiber to convey same message to brain even when cell it innervates changes (dies and is replaced) •How do molecules stimulate taste receptor cells? -Depends on the molecule

•What are the arguments for and against umami being a primary taste?

•Primary taste? -Yes: •signals protein, therefore plays important role in nutrition •"hot spot" for it in insula (also hot spots for the 4 classical primary tastes) -No: •imperceptible in many protein-rich foods; •some people like it and others don't (a basic taste, by definition, is responded to in the same way by most people)

•What are the roles of the cingulate cortex and the prefrontal cortex in processing pain?

•Procedure -Subjects hypnotized and hands put in very hot water -Subjects were told the unpleasantness from the water was increasing or decreasing -PET scan the whole time -Subjects report perceived unpleasantness decreased, while intensity remained high -S1 and S2 activated by hot water; no effect of suggestion -ACC decreased activity with suggestion that unpleasantness was decreasing •Conclusions -ACC involved in emotional processing of response to pain (perceived unpleasantness) •In another example: -Painful stimulation of skin activates cingulate cortex... -... but direct electrical stimulation of cingulate (same part) sometimes elicits pain, other times no pain but a distressed mood •PREFRONTAL CORTEX involved in executive functioning, working memory, cognition in general •Secondary pain affect -Reflects influence of cognition -Emotional response associated w/ long-term suffering that occurs when painful events are imagined or remembered -Cancer patient facing another round of chemo

•How do we perceive proteins and fat? What is the importance of the gut? How do we choose foods?

•So if the glutamate receptor is found in the gut, what could be its function? -Most proteins are too big to be sensed by receptors in the tongue... -Proteins are broken down to amino acids in gut... -Glutamate is amino acid...so when it stimulates the gut receptors it signals the brain that you have ingested a protein. -Prove it! Novel-flavored soup with MSG (1) held in mouth or (2) actually ingested: •Former doesn't create food preference; latter does •Fat receptor in the gut too... -Fats are too big to bind to taste receptors •Whole fat molecules do activate trigeminal nerve in mouth à oily, viscous, creamy, etc. -Some fat molecules partially digested in mouth à fatty acids stimulate fatty acid receptors (at least in rats...us, too?) -Fat is broken down further in gut and binds to receptors there à gut signals brain to prefer the sensory properties of the food containing the fat Whole fat molecules do activate trigeminal nerve in mouth à oily, viscous, creamy, etc People who swallow novel soup with msg prefer it more than those who just hold it in their mouths and spit it out similarities: •Both probably stimulate receptors to a small degree in the mouth -Glutamate receptors for protein (umami) -Fatty acid receptors for fats -These have been found in rat papillae at least... •Both also stimulate receptors in the gut -Even more so than tongue, because more broken down by then •Gut sends signal back to brain, via vagus nerve, to like the sensory properties of that food. how we choose foods: •Hard-wired taste preferences -Based on evolutionary needs -Facial expressions of newborns to primary tastes is universal/stereotypical •Even in anencephalic babies (no cortex), so mediated by primitive parts of brain (brainstem) •Learned responses to food flavors -Signals back from gut: liking foods that provide important nutrients Learned taste aversions

What are somatosensation, kinesthesis and proprioception?

•Somatosensation: A collective term for sensory signals from the body -Touch, pain, temp, proprioception •Kinesthesis: The perception of the position and movement of our limbs in space -Proprioception: Perception mediated by kinesthetic and vestibular receptors Proprioception, also referred to as kinaesthesia, is the sense of self-movement and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons located within muscles, tendons, and joints.

•What test is used to identify olfactory thresholds? What test is used to study the ability to discriminate between odorants?

•Staircase method -Similar to method of limits in audition -Odor presented in increasing concentration increments, then decreasing, multiple times •Triangle test -To determine if a person can discriminate between odorants -One of these things is not like the other

•What is adaptation? Physiologically speaking, why does it occur? Is there a psychological effect on adaptation?

•Stop perceiving an odorant while still in its presence •Enables us to filter out "background" odors •Average: 10-15 minutes of continuous exposure, but can happen faster •Takes longer to adapt to higher concentrations •Psychological effects: expose people to an odorant...tell half of them it is healthful, and half it is hazardous... result??? •Peripheral mechanism: Receptor recycling: molecule binds to receptor à receptor is internalized into cell (comes uncoupled from molecule) = emerges on membrane minutes later •Peripheral mechanism: receptor recycling -molecule binds to receptor à -receptor is internalized into cell (comes uncoupled from molecule) à -emerges on membrane minutes later Olfactory receptors are G-protein coupled receptors, which all do receptor recycling Result: the half that thought it was healthful adapted at a normal rate; the half that thought it was hazardous didn't adapt in that time

•What are some functional consequences of the ipsilateral projection of the olfactory system together with the lateralization of language and emotion?

•The brain is lateralized: -Right side is stronger in emotion -Left side is stronger in language •Smell goes to ipsilateral side of brain Binaural Rivalry and Extensions to Other Sensory Modalities •If present one odor to one nostril and different odor to other nostril (roses and sharpies), go back and forth between perceiving one then the other -If mix them, still go back and forth •Same is true for audition and vision -a different sound presented to each ear -a different image presented to each eye olfaction,memory, emotion

•What is the function of olfaction?

•The first receptor was probably a chemoreceptor...chemicals are detected in 2 ways: floating in the air (olfaction) and in solution (for gustation) •Similar to Taste in Function -Approach/Avoidance -Additional 'Social' Role (pheromones)

•What is tactile agnosia?

•The inability to identify objects by touch •Caused by lesions to the parietal lobe Patient documented by Reed and Caselli (1994): Tactile agnosia with right hand but not left hand. Could not recognize objects such as a key chain in right hand but could with left hand or visually. Rules out a general loss of knowledge about objects. Other sensory abilities were normal in both hands

•What are some differences between men and women in olfaction?

•Women detect odors more readily than men -Women detect odors at lower thresholds than men, especially when ovulating. -Brain responses to odors are stronger in women. -Occurs in all age groups and cultures (tested) •Women of child-bearing age sensitize to odors until they smell them in very faint amounts -Prepubescent women, post-menopausal women, and men don't. •Odor more important to women than men in choosing partners.