PSB3002 Exam 2

List the contributions of various cortical regions to motor learning.

The primary motor cortex is responsible for executing motor behaviors, and input from the premotor area and supplementary motor area help to refine motor learning.

Identify some possible functions of REM sleep.

The functions of REM sleep are less understood than those of slow-wave sleep. REM sleep may promote brain development and facilitate changes responsible for learning that occur throughout the lifespan.

Describe evidence in support of emotional expressions as innate responses.

Darwin believed that expressions of emotion were innate -- that these muscular movements were inherited behavioral patterns. Ekman and his colleagues performed cross-cultural studies. Their results supported Darwin's hypothesis. The facial expressions of young blind and sighted children are very similar providing additional support for the idea of innate and universal expressions of emotion.

Evaluate the roles of heredity and serotonin in human aggression

Low CSF levels of 5-HIAA are correlated with increased risk-taking and aggressive behavior in humans. Genetic factors play a role in people's level of aggression and antisocial behavior.

Describe the components of the visual pathway.

1. Axons of the retinal ganglion cells bundle together to form the optic nerve 2. Optic nerves join together at base of the brain to form the optic chiasm 2. Axons cross the X shaped chiasm to a part of the thalamas called the dorsal lateral geniculate nucleus (LGN) on opposite sides of the brain 3. neurons in LGN send axons through optic radiations to the primary visual cortex (V1) in occipital lobe (AKA striate cortex bc of dark staining layer of cells) 4. visual info sent to visual association cortex (V2), AKA extrastriate cortex bc region surrounds striate cortex, then projects to inferior temporal cortex

Summarize the process of transduction.

1. Photopigment is exposed to light broken into its two parts (opsin and retinal) 2. Stimuli either hyperpolarizes sensory receptors or depolarizes (light = hyperpolarization; dark = depolarization) 3. Depolarization increases release of glutamate by bipolar cell which then excites the ganglion cell

Identify the events required for LTP to occur.

A circuit of neurons passes from the etorhinal cortex through the hippocampal formation. High-frequency stimulation of the axons in this circuit strengthens synapses; it leads to an increase in the size of the EPSPs in the dendritic spines of the postsynaptic neurons. The only requirement for LTP is that the postsynaptic membrane be depolarized at the same time that the synapses are active. The perforant pathwat must be depolarized either by exposure to stimuli in the environment or by delivery of a burst or pulses.

Describe how AMPA receptors contribute to LTP.

AMPA receptors are ionotropic receptors present on the postsynaptic membrane and help to depolarize the cell by controlling a sodium ion channel. AMPA receptors are also required for LTP. When glutamate binds to the AMPA receptor, the resulting depolarization removes the Mg2+ ion from the NMDA receptors, allowing Ca2+ to enter the cell. A result of calcium signaling is the insertion of additional AMPA receptors in the postsynaptic membrane, strengthening depolarization of the membrane. This enhanced depolarization of the membrane. This enhanced depolarization is responsible for strengthening the synapses involved in LTP.

Explain how adenosine contributes to regulating sleep.

Adenosine is released when neurons used glycogen, and it serves as the link between increased brain metabolism and the necessity of sleep. When neurons are active, glycogen is depleted, and adenosine accumulates. Accumulating adenosine binds to adenosine receptors and serves as a sleep-promoting signal. Glycogen is replenished during slow-wave sleep, and adenosine levels decrease.

Distinguish the roles of serotonin and neural circuitry in animal models of aggression and predation.

Aggressive behaviors are species-typical and serve useful functions most of the time. The Periaqueductal Gray Matter (PAG) appears to be involved in defensive behavior and predation. These mechanisms are modulated by the hypothalamus and amygdala. The activity of serotonergic neurons appears to inhibit risk-taking behaviors, including aggression. Destruction of serotonergic axons in the forebrain enhances aggression, and administration of drugs that facilitate serotonergic transmission reduces it. Low CSF levels of 5-HIAA (a metabolite of serotonin) are correlated with increased risk-taking and aggressive behavior in monkeys. High levels of brain serotonin and 5-HIAA in rats and silver foxes are associates with reduced aggression.

Describe the role of extrastriate cortex in perceiving movement.

Area V5 of the extrastriate cortex (area MT) contains neurons that respond to movement. Bilateral damage to the human brain that includes area V5 produces akinetopsia. MST neurons receive info from V5 and respond to complex patterns of movement, including radial, circular, and spiral motion. More specifically, MSTd neurons analyze optic flow. Movements of different body parts activate cells in the extrastriate body.

Compare the roles of slow-wave and REM sleep in learning.

Both REM sleep and slow-wave sleep promote learning: REM sleep facilitates nondeclarative learning, and slow-wave sleep facilitates declarative learning.

Contrast the location and function of rods and cones.

Cones: Responsible for daytime vision; provide us with info about small features in our environment and are the source of vision of the highest sharpness (fovea in retina only contains cones); responsible for color vision; provide info about hue; central retina; sensitive to moderate to high levels of light Rods: Way more than cones; more sensitive to low levels light; night vision; poor acuity; peripheral retina; provides only monochromatic info

Describe the symptoms, treatment, and biological basis of bedwetting, sleepwalking, and night terrors.

During slow-wave sleep some people experience bedwetting (nocturnal enuresis), sleepwalking (somnambulism), or night terrors (pavor nocturnus). These problems are most common in children, who usually outgrow them. People with sleep-related eating disorder seek and consume food while sleepwalking. Treatments include training for bed wetting, dopamine agonists, or topiramate for sleep eating. Many children eventually outgrow problems associated with slow-wave sleep.

Critique evidence for the facial feedback hypothesis.

Ekman and his colleagues have shown that even stimulating an emotional expression causes changes in the activity of the autonomic nervous system. Perhaps feedback from these changes explains why an emotion can be "contagious": We see someone smile with pleasure, we ourselves imitate the smile, and the internal feedback makes us feel at least somewhat happier. The tendency to mimic the facial expression of others appears to be a consequence of activity in the brain's system of mirror neurons; however, it is not clear when this pattern of activity develops. Many researchers have failed to replicate infant imitation, calling into questions whether this is an innate emotional behavior.

List examples of circadian rhythms and zeitgebers.

Examples of circadian rhythms include the: sleep/wake cycle, cycles of physical activity and body temperature. Examples of zeitgebers include the presence of illumination, clocks, or other time clues.

Describe how neurochemical systems help regulate arousal.

Five systems of neurons appear to be important for maintaining arousal. The acetylcholinergic system of the pons and the basal forebrain is involved with cortical activation. (high during waking and REM) The noradrenergic system of the locus coeruleus is involved with vigilance. (high during wakefulness and almost 0 during REM) The serotonergic system of the raphe nuclei is involved with activation of automatic behaviors such as locomotion and grooming. (high during waking, almost zero at REM, but temporarily became active again after period of REM ended) The histaminergic neurons of the tuberomammillary nucleus are involved in maintaining wakefulness. (high in waking) The orexinergic system of the lateral hypothalamus is involved in maintaining wakefulness. (high in waking, almost zero in others)

Summarize the evidence for and against the James-Lange theory of emotion.

From the earliest times, people recognized that emotions were accompanied by feelings that seemed to come from inside the body, which probably provided the impetus for developing physiological theories of emotion. James and Lange suggested that emotions were primarily responses to situations. Feedback from the physiological and behavioral reactions to emotion-producing situations gave rise to the feelings of emotion; feelings are the results, not the causes, of emotional reactions. Hohman's study of people with spinal cord damage supported the James-Lange thoery; people who could no longer feel the reactions from most of their body reported that they no longer experienced intense emotional states. Cannon proposed that the body could not respond quickly enough to account for feedback and feelings of emotion; however, this was not supported by subsequent research.

Describe the roles of the amygdala and ventromedial prefrontal cortex in human emotion.

Functional-imaging and lesion studies with humans indicate that the amygdala is involved in emotional conditioning and emotional memory in our species, too. However, many of our conditioned emotional responses are acquired by observing the responses of other people or even through verbal instruction. The vmPFC plays an important role in extinction of a conditioned emotional response.

Compare features of the eye involved in central and peripheral vision.

Ganglion cells in the fovea receive input from a smaller number of photoreceptors than those in periphery and provide more acute visual information. At the periphery of the retina many individual receptors converge on a single ganglion cell, bringing information from a relatively large area of the retina, hence a large area of the visual field

Summarize factors involved in regulating transitions between sleep and waking.

Homeostatic control of sleep maintains the balance of sleep/waking at an optimal level. Sleep can also be regulated by allosteric control, which responds to environmental stressors to override homeostatic control when needed. Circadian factors entrain periods of sleep to particular portions of the light/dark cycle. Slow-wave sleep occurs when neurons in the ventrolateral preoptic area (vlPOA) become active. These neurons inhibit the systems of neurons that promote wakefulness. In turn the vlPOA in inhibited by these same wakefulness-promoting regions to create a flip-flop circuit that keeps up either awake or asleep. The accumulation of adenosine promotes sleep by inhibiting wakefulness-promoting regions and activating the sleep-promoting neurons of the vlPOA. Activity of the orexinergic neurons of the lateral hypothalamus keeps the flip-flop that controls sleep and waking in the "waking" state. (can be activated by hunger or satiety arousal stimuli)

Describe three perceptual dimensions of light.

Hue: The dominant wavelength Saturation: purity of the light that is being perceived Brightness: intensity (proportional with brightness)

Describe the structure of the lateral geniculate nucleus.

Layers 1, 4, 6 receive input from the contralateral eye Layers 2, 3, 5 receive input from the ipsilateral eye Magnocellular layers: first two innermost and largest layers that transmits information necessary for perception of form, movement, depth, and small differences in brightness to V1 Parvocellular layers: four outer layers that transmits info necessary for perception of color and fine details to the primary visual cortex Koniocellular sublayers: located underneath each layer and transmits information from short wavelength cones to V1

Describe the role of the striate and extrastriate cortex in color perception.

In the striate cortex, the parvocellular system receives info from "red" and "green" cones. Additional info from "blue" cones in transmitted through the koniocellular system and relayed to the extrastriate cortex. Extrastriate cortex region V4 adds complexity to the color processing begun in the striate cortex and is likely involved in the analysis of form as well as color. Area TEO in the primate extrastriate cortex is resposible for additional color and shape perception. Research with human volunteers revealed a region for color perception, V8, that is analogous to TEO. Damage to this region results in achromotopsia. Damage to other regions of the extrastriate cortex can selectively impair form recognition, leaving the ability to discriminate between color intact.

Identify the functions and organization of the striate cortex.

Koniocellular input is received by sublayers 2 &3 whereas magnocellular input is received by sublayer 4Ca and parvocellular input is received by sublayer 4Cb V1 has many modules which each have CO blobs and interblob regions. CO blobs (which project into thin strips in V2) receive info concerning color, whereas interblob areas (which project into thick and pale strips in V2) receive info about orientation, spatial frequency, movement, and retinal disparity

List the synaptic changes that accompany LTP.

LTP may involve presynaptic changes in existing synapses, such as an increase in the amount of glutamate that is released by the terminal button. Presynaptic changes may be signaled from the postsynaptic cell via retrograde messengers. The establishment of LTP includes changes in the size and shape of postsynaptic dendritic spines into fatter, mushroom-shaped spines. Long-lasting LTP requires protein synthesis. The genes that codes fro the production of the enzyme PKM-zeta is constantly produced in the nucleus and transported to dendritic spines, where its translation is blocked by the action of another enzyme, Pin1.

Describe the role of the striate and extrastriate cortex in perceiving spatial location.

Most neurons in the striate cortex are binocular and contribute to depth perception via retinal disparity. The disparity-sensitive neurons found in the dorsal stream, which is involved in spatial perception, respond to large, extended visual surfaces, whereas those found in the ventral pathway, which is involved in object perception, respond to the contours of 3D objects. Damage to regions of the dorsal stream can impair 3D spatial perception, producing "flat vision". The dorsal stream of the extrastriate cortex terminates in the parietal cortex, which is involved in spatial and somatosensory perception. The parietal cortex receives visual, auditory, somatosensory, and vestibular info to perform these tasks. Single-unit studies with monkeys and functional-imaging studies with humans indicate that neurons in the intraparietal sulcus (IPS) are involved in visual attention and control of saccadic eye movements (LIP and VIP), visual control of reaching and pointing (VIP and MIP), visual control of grasping and manipulating hand movements (AIP), and perceiving depth from stereopsis (CIP).

Explain the role of the striate cortex in perceiving orientation.

Most neurons in the striate cortex are sensitive to orientation and respond by increasing their rate of firing action potentials when a line is in a particular position in their receptive field.

Compare the relationship between NMDA and AMPA receptors in LTP.

NMDA and AMPA receptors are present on the postsynaptic membrane and are required to establish LTP. NMDA and AMPA receptors are both ionotropic receptors that respond to glutamate and are found in the hippocampus. NMDA receptors are blocked by an ion of magnesium at rest, and require depolarization to remove the Mg2+ ion. AMPA receptors contribute to this local depolarization to facilitate removal of the Mg2+ ion. Once open, NMDA receptors allow Ca2+ ions to enter the cell, triggering intracellular events responsible for LTP and the recruitment of additional AMPA receptors to the terminal membrane.

Describe the symptoms, treatment, and biological basis of narcolepsy.

Narcolepsy is characterized by sleep (or some of its components) at inappropriate times. The symptoms of narcolepsy include sleep attacks, cataplexy, sleep paralysis, and hypnagogic hallucinations. Narcolepsy is associated with mutations of a gene in chromosome 6 for the orexin receptor or lack of orexin. Some patients develop narcolepsy after an autoimmune attack of orexin neurons. Narcolepsy is treated with stimulants, antidepressants, or modafinil.

Suggest some possible functions of slow-wave sleep.

One important function of slow-wave sleep seems to be to lower the brain's metabolism and permit it to rest. In support of this hypothesis, research has shown that slow-wave sleep reduces the brain's metabolic rate and increased mental activity (the surprise, fun-day-out experiment) can cause an increase in slow-wave sleep the next night.

Compare the activity of retinal ganglion cells in perceiving light and dark.

ON, OFF, and ON/OFF retinal ganglion cells contain center and surround portions of their receptive fields. In ON cells, light stimulation the center (but not the surround) portion of the receptive field results in a burst of action potentials. In OFF cells, light stimulating the surround (but not the center) portion of the receptive field results in a burst of action potentials. ON/OFF cells respond when the light goes on and again when it goes off. These cells project mainly to the superior colliculus, which is involved in visual reflexes in response to moving or suddenly appearing stimuli

Outline the neural mechanisms of operant conditioning.

Operant conditioning involves strengthening connections between neural circuits that detect stimuli and neural circuits that produce responses. One of the locations of these changes appears to be the basal ganglia, especially in the changes responsible for learning of automated and routine behaviors, The basal ganglia receive sensory info and info about plans for movement from the neocortex. The mesolimbic and mesocortical pathways are responsible for reinforcement in operant conditioning. The prefrontal cortex may be involved in activating the mesolimbic pathway to achieve goals.

Describe the perceptual learning ability of patients with hippocampal damage.

Patents with hippocampal damage display perceptual learning. They do not have awareness that learning has occurred. The hippocampus is not required for perceptual learning.

Describe the motor learning ability of patients with hippocampal damage.

Patients with hippocampal damage display motor learning. They do not have awareness that learning has occurred. The hippocampus is not required for motor learning.

Describe the stimulus-response learning ability of patients with hippocampal damage.

Patients with hippocampal damage display stimulus-response learning, but do not have an awareness that the learning has occurred. The hippocampus is not required for stimulus-response learning.

Contrast the roles of cortical regions in retaining perceptual information in short-term memory.

Perceptual short-term memory involves sustained activity of neurons in the sensory association cortex. Functional-imaging studies have shown that retention of specific types of short-term visual memories involves activity of specific regions of the extrastriate cortex. Transcranial magnetic stimulation of various regions of the human extrastriate cortex disrupts short-term perceptual memories. The prefrontal cortex is also involved in short-term memory. This region encodes info pertaining to the stimulus that must be remembered and is involved in manipulating and organizing info in short-term memory. Successful retention of info in short-term memory requires filtering out irrelevant info, which involves the left basal ganglia, and maintaining relevant info, which involves the right prefrontal cortex.

Describe the symptoms, treatment, and biological basis of REM sleep behavior disorder.

REM sleep behavior disorder is caused by a neurodegenerative disease that damages brain mechanisms that produce paralysis during REM sleep. As a result, the patient acts out his or her dreams. REM behavior disorder can be treated with benzodiazepine.

Describe the symptoms, treatment, and biological basis of insomnia.

Primary insomnia is characterized as difficulty falling asleep after going to bed or after awakening during the night. Secondary insomnia is an inability to sleep due to another mental or physical condition, such as pain, substance use, or a psychological or neurological condition. Insomnia treatments include cognitive behavior therapy (CBT), progressive relaxation techniques, changes in sleep hygiene, as well as hypnotic, benzodiazepine, and antihistamine drugs. Research has found no difference in time spent sleeping between people with and without insomnia. Insomnia can be caused by sleep apnea, and be treated with surgery or a medical device to keep the airway open.

Describe the role of flip-flop circuits controlling transitions to REM.

REM sleep is controlled by another flip-flop circuit. The sublaterodorsal nucleus (SLD) serves as the REM-ON region, and the ventrolateral periaqueductal gray region (vlPAG) serves as the REM-OFF region. This flip-flop is controlled by the sleep/waking flip-flop. Only when the sleep/waking flip-flop is in the "sleeping" state can the REM flip-flop switch to the REM state. The muscular paralysis that prevents us from acting out our dreams is produced by connections between neurons in the SLD that excite inhibitory interneurons in the spinal cord. Rapid eye movements and genital activity in REM are produced by indirect connections with the REM-ON region.

Summarize the neural basis of emotional recognition, including laterality, direction of gaze, imitation, and disgust.

Recognition of other people's emotional expressions involves the right hemisphere more than the left. Studies show that recognition of particular faces involved neural circuits different from those needed to recognize facial expressions of emotions. The amygdala plays a role in recognition of emotional expression; lesions of the amygdala disrupt the ability to recognize facial expressions of fearfulness. One of the reasons that bilateral amygdala damage impairs recognition of fearful facial expressions appears to be failure to look at people's eyes. Neurons in the superior temporal suculus are sensitive to direction of gaze and transmit this info to other parts of the brain, including the amygdala. Mirror neurons in the ventral premotor cortex receive visual info concerning the facial expression of other people that activate the neural circuits responsible for these expressions. Feedback from this activity, which may be transmitted to the somatosensory cortex, helps us to comprehend the emotional intentions of other people. Damage to the basal ganglia and insular cortex disrupts recognition of facial expressions of disgust, and functional-imaging studies show increased activity in the insular cortex (which contains primary gustatory cortex) when people smell disgusting odors or see faces displaying disgust. Damage to the right somatosensory cortex results in impaired facial emotion recognition and is thought to be due to impaired ability to imitate the emotion.

Describe the roles of the ventral stream and fusiform face area in perceiving form.

Recognizing visual patterns and identifying particular objects take place in the inferior temporal cortex (part of the ventral stream) in primates. It is here that analyses of form and color are put together, and perceptions of three-dimensional objects and backgrounds are achieved. Damage to the human extrastriate cortex can cause a category of deficits known as visual agnosia, a failure to recognize familiar objects or categories of objects, including faces. The fusiform face area is specifically devoted to facial recognition. Development of this region may be a result of extensive experience looking at faces; expertise with other complex stimuli such as artificial creatures causes the development of circuits devoted to the perception of these stimuli as well. Development of the fusiform face area may be involved in symptoms of ASD, possibly related to developing experience in recognizing faces.

Organize the structures and functions of the eye involved in visual processing.

Retina: the neural tissue and photoreceptive cells located on the inner surface of the posterior part of the eye; plays a role in the messages sent through the optic nerve to the brain; where rods and cones are located (photoreceptors) Sclera: white outer coat of the eye to hold it in place and help with movement Conjunctiva: hides the muscles behind the eyes so we can't see them Iris: muscles that control size of the pupil Lens: transparent, onion-like layers that can change in shape (by contraction of ciliary muscles) to permit the eye to focus on images of near or distant objects on the retina (accommodation)

Describe the role of the cortex in semantic memory.

Semantic memories appear to be stored in the anterolateral temporal lobe.

Differentiate sensation and perception.

Sensation is the process in which specialized cells of the nervous system detect environmental stimuli and transduce their energy into receptor potentials (bottom up) Perceptions is the conscious experience and interpretation of this information from the senses and involves neurons in the central nervous system (top down)

Contrast characteristics of sensory, short-term, and long-term memory.

Sensory memory is very brief and involves remembering an initial sensation. A small fraction of info from sensory memory passes on to short-term memory, which last seconds or minutes and is limited to a few items. Short-term memory capacity can be extended with rehearsal or chunking. Long-term memory is relatively permanent, and memories can be retrieved throughout a lifetime and strengthened with increased retrieval. Long-term memory includes declarative and nondeclarative memory.

Explain the role of serotonin in impulse control regulation.

Serotonergic input to the prefrontal cortex inhibits amygdala and suppresses aggressive and impulsive behavior. Increasing serotonergic activity reduces impulsive behavior. The vmPFC of people with impulsive aggression contains less dense serotonergic input

Suggest why shift work and jet lag result in changes in circadian rhythms.

Shift work and jet lag result in changes in circadian rhythms because of desynchronization between the SCN and zeitgebers in the external environment.

Suggest some possible general functions of sleep.

Sleep is evolutionarily conserved and is present in all animals studied so far. Sleep is essential to long-term survival, as well as maintaining physical health and cognitive function, suggesting that it has several broad functions

Describe the progression, behaviors, and EEG characteristics of the stages of sleep.

Sleep stages generally progress through stages 1-3, followed by REM, and are defined by changed in physiology, behavior, and EEG activity. In the EEG, waking alertness consists of desynchronized beta activity (13-30 Hz) while relaxation and drowsiness consist of alpha activity (8-12 Hz). Muscle tone decreases throughout the stages resulting in deepest relaxation and paralysis in REM sleep. Step 1 sleep consists of alternating periods of alpha activity, irregular fast activity, and theta activity, along with decreasing muscle tone. The EEG of stage 2 sleep contains sleep spindles (short periods of 12-14 Hz activity) and occasional K complexes. Stage 3 sleep primarily consists of delta activity (< 3.5 Hz). REM sleep consists of theta and beta activity.

Outline the benefit of neural circuits that analyze spatial frequency in the striate cortex.

Small objects, details within a large object, and large objects with sharp edges provide a signal rich in high frequencies, whereas large areas of light and dark are represented by low frequencies. Possessing neural circuits that can differentiate between these types of stimuli is beneficial in filtering noise from a visual stimulus, making the image more clear in the human visual system, and allowing an individual to perceive the underlying form.

Compare characteristics of stimulus-response, motor, perceptual, and relational learning.

Stimulus-response learning, including classical and operant conditioning, consists of connections between perceptual and motor systems. Classical conditioning occurs when a neutral stimulus elicits an unconditioned response (UR). After this pairing, the neutral stimulus becomes a conditioned stimulus (CS); it now elicits the response by itself, which we refer to as the conditioned response (CR). Operant conditioning occurs when a response is followed by a reinforcing or punishing stimulus. Motor learning, although it may primarily involve changes within neural circuits that control movement, is guided by sensory stimuli and is a form of stimulus-response learning. Perceptual learning consists primarily of changes in perceptual systems that make it possible for us to recognize stimuli so that we can respond to them appropriately. Relational learning, the most complex form of learning, includes the ability to recognize objects through more than one sensory modality, to recognize the relative location of objects in the environment, and to remember the sequence in which events occurred during particular episodes.

Critique the role of hormones in aggression

Testosterone functions to increase behaviors related to obtaining and maintaining social status. Under conditions of threat, testosterone increases aggression. Under conditions in which generosity would increase social status, testosterone can increase generosity. When it does increase aggression, testosterone may do so through disinhibition. Androgens primarily affect offensive attack. They are not necessary for defensive behaviors, which are shown by females as well as males. Research suggests that the primary effect of androgens may be to increase motivation to achieve dominance and that increased aggression may be secondary to this effect. It is not clear whether high androgen levels promote dominance or whether successful dominance increases androgen levels.

Describe the relationship between the pineal gland and melatonin.

The SCN and the pineal gland control annual rhythms. During the night the SCN signals the pineal gland to secrete melatonin. Prolonged melatonin secretion, which occurs during the winter, causes animals to enter the winter phase of their annual cycle. Melatonin also appears to be involved in synchronizing circadian rhythms: the hormone can help people adjust to the effects of shift work or jet lag and even synchronize the daily rhythms of blind people for whom light cannot serve as a zeitgeber.

Explain how the suprachiasmatic nucleus regulates circadian rhythms.

The SCN is responsible for circadian regulation of sleep, but not homeostatic regulation. After receiving light info from the eyes, info from the SCN is conveyed via the subparaventricular zone and the dorsomedial nucleus of the hypothalamus to regions of the brain involved in sleep and waking. Individual neurons, rather than circuits of neurons, are responsible for the "ticking". Each tick, approximately 24 hours long, consists of the production and breakdown of a series of proteins in two interlocking loops that act back on the genes responsible for their own production.

Provide evidence for a developmental factor in impulse control.

The amygdala is a part of a circuit involved in anger and violence and matures before the prefrontal cortex, which suppresses violent behavior. Research found that aggressive behavior during adolescence was positively related to the volume of the amygdala and negatively related to the relative volume of the right medial prefrontal cortex.

Outline evidence for the roles of the amygdala and ventromedial prefrontal cortex in animal models of emotion.

The amygdala organizes behavioral, autonomic, and hormonal responses to a variety of situations, including those that produce fear, anger or disgust. It receives inputs from the olfactory system, the association cortex of the temporal lobe, hypothalamus, hippocampal formation, and brain stem nuclei that control autonomic functions and some species-typical behaviors. Electrical recordings of single neurons in the amygdala indicate that some of them respond when the animal perceives particular stimuli with emotional significance. Stimulating the amygdala leads to emotional responses, and destroying it disrupts them. Pairing neutral stimuli with those that elicit emotional responses results in classically conditioned emotional responses. Learning these responses takes place primarily in the amygdala. Extinction of conditioned emotional responses involved inhibitory control of amygdala activity by the vmPFC.

Summarize the neural basis of emotional expression, including laterality, laughter, and humor.

The anterior cingulate gyrus appears to play a role in the motor aspects of laughter, while the appreciation of humor appears to involve the right vmPFC. Genuine expressions of emotion are controlled by special neural circuits. The best evidence for this assertion comes from the complementary syndromes of emotional volitional facial paresis. People with emotional facial paresis can move their facial muscles voluntarily but not in response to an emotion, whereas people with volitional facial paresis show the opposite symptoms. In addition, the left halves of people's faces -- the faces of monkeys -- tend to be more expressive than the right halves.

Explain the role of the basal ganglia in motor learning.

The basal ganglia are responsible for learning automatic motor behaviors, such as in stimulus-response paradigms.

Describe the three components of an emotional response.

The behavioral component consists of muscular movements that are appropriate to the situation that elicits them Autonomic responses facilitate the behaviors and provide quick mobilization of energy for vigorous movement Hormonal responses reinforce the autonomic responses

Describe the role of the hippocampus in relational learning.

The hippocampal formation -- especially the right posterior hippocampus -- is involved in spatial memory. Functional-imaging studies have shown that performance of spatial tasks increases activity in this region. Studies with laboratory animals indicate that damage to the hippocampal formation disrupts the ability to learn spatial relations. The hippocampal formation contains place cells -- neurons that respond when the animal is in a particular location, which implied that the hippocampus contains neural networks that keep track of the relationships among stimuli in the environment that define the animal's location. Neurons in the hippocampal formation reflect where an animal "thinks" it is. Topographical information reaches field CA1 of the hippocampus from the parietal lobe by means of the entorhinal cortex. Place cells encode more than space; they include info about the response that the animal with perform next. Besides place cells, the hippocampal region also contains grid cells, head-direction cells, and border cells, which play a role in spatial perception and memory.

Compare the role of the hippocampus in memory consolidation and retrieval.

The hippocampal formation receives info from other regions of the brain, processes this info, and then, through its efferent connections with these regions, modifies the memories that are being consolidated there, linking them together in ways that will permit us to remember the relationships among the elements of memories. The hippocampal formation transfers memories into permanent storage in other areas of the brain. Before this transfer is complete, the hippocampal formation is required for the retrieval of these memories. Later, retrieval of these memories can be accomplished even if the hippocampal formation has been damaged.

Describe the role of the hippocampus in relational learning.

The hippocampus receives info about what is going on from sensory and motor association cortexes and from some subcortical regions, such as the basal ganglia and amygdala. It processes this information and then, through its efferent connections with these regions, modifies the memories that are being consolidated there, linking them together in ways that will permit us to remember the relationships among the elements of memories -- for example, the order in which events occurred, the context in which we perceived a particular item, and so on. WIthout the hippocampal formation, we would be left with individual, isolated memories without the linkage that makes it possible to remember -- and think about -- episodes and contexts. Similarly, deactivation of the dorsal hippocampus prevents consolidation if it occurs 1 day after the animal learns a Morris water maze task but has no effect if it occurs 30 days later. In contrast, deactivation of regions in the cerebral cortex disrupts performance if it occurs 30 days after training but has no effect if it occurs 1 day after training, suggesting that these cortical regions are involved in the storage of the memory of the task. The dentate gyrus is one of the two places in the brain where adult stem cells can divide and give rise to new neurons. These neurons establish connections with neurons in the hippocampus and appear to participate in learning. Evidence indicates that thee neurons play a role in the formation of new memories.

Explain the patterns of brain activity present during REM and slow-wave sleep.

The rate of cerebral blood flow during REM sleep is high in the extrastriate cortex but low in the striate cortex and the prefrontal cortex. This activity reflects a lack of visual input in REM (little or no activation in the striate cortex), but the presence of active visual hallucinations during dreaming (activation in the extrastriate cortex). Lack of prefrontal cortex activity likely reflects the lack of organization and planning that occur in dreams. Regional cerebral blood flow during slow-wave sleep is generally decreased throughout the brain compared to waking. However, localized increases in the visual and auditory cortexes are hypothesized to be the neural basis for the dreamlike imagery experienced during slow-wave sleep. Blood flow to the thalamus and cerebellumis decreased in slow-wave sleep.

Identify the retina's contributions to perceiving spatial location.

The retina contributes to perspective, relative retinal size, loss of detail through the effects of atmospheric haze, and relative apparent movement of retinal image as we move our heads as monocular features that contribute perception of depth and spatial location. Binocular vision provides a vivid perception of depth through the process of stereopsis involving information from both retinas.

Differentiate between the trichromatic and opponent-color system theories.

The trichromatic theory explains that the eye detects different colors because it contains three types of receptors, each sensitive to a single hue (blue, green, or red). The opponent-color system theory explains that each color is represented in the visual system as opponent colors: red versus green and yellow versus blue. Research has revealed that cones are sensitive to blue, green, and red light, in support of the trichromatic theory and that retinal ganglion cells respond specifically to pairs of colors, with red opposing green and blue opposing yellow, in support of the opponent-color system theory

Describe the brain regions involved in emotional aspects of moral decision making involving impulse control.

The vmPFC is involved in making moral judgments. When people make judgments that involve confilicts between utlilitarian judgments and personal moral judgments, the vmPFC is activated. People with damage to the vmPFC display utilitarian moral judgments.

Describe the role of the ventromedial prefrontal cortex in impulse control.

The vmPFC plays an important role in emotional reactions. This regions communicates with the dorsomedial thalamus, temporal cortex, ventral tegmental area, olfactory system, amygdala, cingulate cortex, lateral hypothalamus, and other regions of the frontal cortex, including the dorsolateral prefrontal cortex. People with vmPFC lesions throw impulsive behavior and often display outbursts of inappropriate anger. They are able to explain the implications of complex social situations but often respond inappropriately when they find themselves in these situations. Decreased prefrontal activity and increased subcortical activity are associated with impulsive, violent behavior. People with antisocial personality disorder have reduced gray matter volume in the prefrontal cortex. The activity of the vmPFC increases when people show courageous behavior (impulse control) -- letting a snake approach them even though they fear snakes.

Describe the structures and functions of the pathways of the extrastriate cortex.

V2 analyze info and pass results on to higher regions (such as V3) for further analysis Pathways diverge after V2: Ventral stream: begins with neurons in pale and thin stripes in V2 and continues to area V4, and projects to a variety of subareas of the inferior temporal cortex; provides info about size, shape, color, and texture of objects Dorsal stream: begins with the neurons in the thick strips of area V2 and ascends into regions of the posterior parietal cortex; provides info that guides navigation and skilled movements directed towards objects

Explain the roles of cortical regions in perceptual learning.

Visual recognition occurs in circuits in the dorsal and ventral streams. Perceptual learning occurs as a result of changes in synaptic connections within the sensory association cortex. Damage to the inferior temporal cortex -- the highest level of the ventral stream -- disrupts visual perceptual learning. Functional-imaging studies with humans have shown that retrieval of memories of pictures, sounds, movements, or spatial locations activates the appropriate regions of the sensory association cortex.

Describe the roles of the amygdala, AMPA receptors, and NMDA receptors in classical conditioning.

When a stimulus (CS) is paired with a shock (US), the two types of info converge in the lateral nucleus of the amygdala. Classical conditioning changes the response of neurons to the CS in the lateral nucleus of the amygdala. The mechanism of synaptic plasticity in this system appears to be NMDA-mediated long-term potentiation. LTP is accomplished through the activation of NMDA receptors and the subsequent insertion of additional AMPA receptors into the postsynaptic membrane. Blocking aspects of LTP in the lateral nucleus prevents establishing conditioned emotional responses.

List functions of other retinal pathways.

coordination of eye movements, controlling the muscles of the iris and the ciliary muscles which control the lens