Biopsychology Exam 3 Study Guide PDF

**CHAPTER 8** **WAKEFULNESS AND SLEEP** **Chapter Outline** I. **Rhythms of Waking and Sleep** A. Endogenous Rhythms 1. **Endogenous circannual rhythm**: An internal calendar that prepares a species for annual seasonal changes. 2. **Endogenous circadian rhythm**: Internal rhythms that...

**CHAPTER 8** **WAKEFULNESS AND SLEEP** **Chapter Outline** I. **Rhythms of Waking and Sleep** A. Endogenous Rhythms 1. **Endogenous circannual rhythm**: An internal calendar that prepares a species for annual seasonal changes. 2. **Endogenous circadian rhythm**: Internal rhythms that last about a day (e.g., wakefulness and sleepiness). 3. In humans, the circadian rhythm has a self-generated duration of about 24 hours. 4. **Circadian rhythms are also present in eating, drinking, urination, secretion of hormone, sensitivity to drugs, and other variables. Body temperature also fluctuates (36.7°C at night and 37.2°C in the late afternoon).** 5. **Circadian rhythms also affect mood. On average, teenagers showed an increase in positive mood from waking until late afternoon, then a slight decline from then to bedtime. Most people report their most pleasant mood around 5 [p.m.]{.smallcaps} and their least pleasant mood around 5 [a.m]{.smallcaps}.** B. Setting and Resetting the Biological Clock 1. **Zeitgeber**: Stimulus that is necessary for resetting the circadian rhythm. Light is the dominant zeitgeber for land animals. 2. **Astronauts exposed to 45-minute intervals of light and dark are never fully alert during their wakeful periods and they sleep poorly during their rest periods.** 3. **Most people are ill-rested and inefficient for days after the shift to daylight savings time.** 4. **Blind people sometimes use other zeitbegers (noise, temperature, meals, etc.) but individuals not sensitive enough to these secondary zeitbegers often experience insomnia at night and sleepiness during the day.** 3. Jet Lag a. **Jet lag**: A disruption of our biological rhythms due to crossing time zones. b. *Phase-delay*: What happens to our circadian rhythms when we travel west, as we stay awake late and awaken the next day already partly adjusted to the new schedule. c. *Phase-advance*: What happens to our circadian rhythms when we travel east, as we tend to sleep and awaken earlier than usual. d. Recent studies have indicated that repeated adjustments of the circadian rhythm can increase levels of *cortisol*, which can damage the hippocampus and cause memory loss. 4. Shift Work e. Night shift workers often have difficulty adjusting to their wake/sleep cycle (e.g., waking up groggy, not sleeping well during the day, etc.). Working under lights comparable to noonday may help shift the circadian rhythms. They should also try to sleep in a very dark room. f. Even after years of a night shift schedule, workers continue to feel groggy on the job and sleep poorly during the day. Their body temperature continues to peak when they are sleeping in the day instead of while they are working at night. 5. **One's natural circadian rhythm predisposes them to be either "larks" (early risers) or "owls" (evening people). This rhythm may change with age.** C. Mechanisms of the Biological Clock 1. **The Suprachiasmatic Nucleus** (**SCN**) a. Nucleus located above the optic chiasm in the hypothalamus. The SCN controls the rhythms for sleep and temperature. The neurons of the SCN generate impulses that follow a circadian rhythm. b. There is a genetic mutation in hamsters that causes the SCN to generate a 20-hour circadian rhythm. When the SCN of these hamsters with a 20-hour rhythm was transplanted into adult hamsters, the adults produced a 20-hour rhythm. 2. How Light Resets the SCN a. The SCN is reset by the retinohypothalamic path that extends directly from the retina to the SCN. b. The retinal ganglion cells that reset the SCN are different from the ganglion cells that contribute to vision and have their own photopigment called **melanopsin** that responds to slow changes in overall duration of light. c. These special ganglion cells are located near the nose, not evenly throughout the retina. This way, blind people have enough input to the melanopsin-containing ganglion cells to entrain their waking and sleeping cycle to the local pattern of sunlight. 3. The Biochemistry of the Circadian Rhythm a. In flies, the SCN regulates the circadian rhythms through the regulation of two genes, period (*per*) and timeless (*tim*). The *per* and *tim* genes code for the proteins PER and TIM, respectively. Early in the morning, the concentration of both PER and TIM is low and increases during the day. In the evening, protein concentrations are high and result in sleepiness. During the night, the genes stop producing the proteins. b. When PER and TIM levels are high, they feed back to inhibit the genes that produce the messenger RNA molecules. When levels are low, the result is wakefulness. c. Analyzing the mechanism in flies leads to research on humans. Mammals have three versions of PER and several versions of TIM. d. In humans, mutations in genes producing PER cause alterations in sleep schedules. 2. Melatonin d. SCN regulates waking and sleeping by controlling the **pineal gland** which releases the hormone **melatonin,** which increases sleepiness. Melatonin release usually starts 2 or 3 hours before bedtime. e. Melatonin stimulates receptors in the SCN to reset the biological clock. II. **Stages of Sleep and Brain Mechanisms** A. Sleep and Other Interruptions of Consciousness 1. **Sleep**: A state that the brain actively produces, characterized by decreased response to stimuli. 2. **Coma**: An extended period of unconsciousness caused by head trauma, stroke, or disease. Characterized by low brain activity throughout the day and little or no response to stimuli, including pain. 3. **Vegetative State**: A person alternates between periods of sleep and moderate arousal, although they show no awareness of their surroundings. 4. **Minimally Conscious State**: A person shows occasional, brief periods of purposeful actions and limited speech comprehension. 5. **Brain Death**: No sign of brain activity and no response to stimulation. In this case, physicians generally wait 24 hours before pronouncing death. B. The Stages of Sleep 1. The electroencephalograph (EEG) records gross electrical potentials in an area of the brain through electrodes attached to the scalp. 2. **Polysomnograph**: A combination of EEG and eye-movement records. 3. **Alpha waves** have a frequency of about 8 to 12 brain waves per second; these waves are typical of a relaxed state of consciousness. 4. Stage 1 sleep is a stage of light sleep noted by the presence of irregular, jagged, and low-voltage waves. 5. Stage 2 sleep is characterized by **sleep spindles** (a burst of 12--14 Hz waves that last approximately 0.5 second) and **K-complexes** (sharp, high-amplitude waves followed by a smaller, positive wave). 6. Stages 3 and 4 are known as **slow-wave sleep** (**SWS**), which comprises slow, large-amplitude waves. 1. **Paradoxical sleep**: Sleep stage discovered in cats in which the brain is very active but muscles are completely relaxed. Named "paradoxical" because it is deep sleep in some ways and light in others. 2. **Rapid eye movement** (**REM**) **sleep**: Same as paradoxical sleep. Researchers discovered that repeated eye movements were associated with paradoxical sleep. Also characterized by fast low-voltage brain waves, plus breathing and heart rates similar to stage 1 sleep. Paradoxical sleep is synonymous with REM sleep, except that some animal species lack eye movements. 3. **Non**-**REM (NREM) sleep**: The stages of sleep other than REM. 4. When people fall asleep, they enter stage 1, followed by stages 2, 3, and 4, in that order. Then, they cycle back from stage 4 through stages 3, 2, and then enter rapid eye movement (REM) sleep. 5. After entering REM sleep, the sleep cycle sequence repeats, with each complete cycle lasting 90 minutes. 6. Early in the night, stages 3 and 4 predominate, but toward morning, stage 4 grows shorter and REM grows longer. 7. REM sleep is associated with dreaming, but dreams can happen in **non-REM sleep**. 1. Brain Structures of Arousal and Attention a. **Reticular formation**: A structure that extends from the medulla into the forebrain. Lesions through the reticular formation decrease arousal. b. **Pontomesencephalon**: A part of the reticular formation that contributes to cortical arousal. Stimulation of the pontomesencephalon awakens a sleeping individual or increases alertness in someone already awake. c. **Locus coeruleus**: A structure in the pons that is inactive at most times but emits impulses, releasing norepinephrine, in response to meaningful events. The locus coeruleus is also important for storing information. The locus coeruleus is usually silent during sleep. d. Certain areas of the hypothalamus stimulate arousal by releasing the neurotransmitter *histamine,* which produces excitatory effects throughout the brain. Antihistamine drugs produce drowsiness if they cross the blood-brain barrier. e. A different group of axons from the hypothalamus (primarily the lateral nucleus of the hypothalamus) releases the peptide neurotransmitter **orexin** (also called **hypocretin**). Orexin is necessary for staying awake. f. **Basal forebrain**: An area just anterior and dorsal to the hypothalamus. Some of the axons from the basal forebrain release GABA and are essential for sleep. These neurons receive input from the anterior and preoptic areas of the hypothalamus. Another set of axons in the basal forebrain release acetylcholine. 2. Sleep and the Inhibition of Brain Activity g. During sleep, body temperature and metabolic rate decrease slightly. h. Sleep depends on GABA-mediated inhibition. While spontaneously active neurons continue to fire at a normal rate, we are unconscious because GABA inhibits synaptic activity. i. Sleep can be localized. Sleepwalking is possible because a sleepwalker is awake in one part of the brain and asleep in another part. 1. During REM sleep, activity increases in the pons, the limbic system, and the parietal and temporal cortex of the brain. Activity decreases in the primary visual cortex, the motor cortex, and the dorsolateral prefrontal cortex. 2. **PGO** (pons-geniculate-occipital) **waves**: A distinctive pattern of high-amplitude electrical potentials associated with REM sleep. The waves are detected first in the pons, shortly afterward in the lateral geniculate nucleus of the thalamus, and then in the occipital cortex. 3. REM sleep depends on both serotonin and acetylcholine activity for its onset and continuation. Stimulation of acetylcholine synapses quickly moves a sleeper into REM, and serotonin interrupts or shortens REM sleep. Norepinephrine from the locus coeruleus also blocks REM sleep. 1. **Insomnia**: Inadequate sleep characterized by how one feels the following day. 2. Insomnia can result from a number of causes, including noise, uncomfortable temperatures, stress, pain, diet, and medications. 3. Insomnia may be due to shifts in circadian rhythms (e.g., trying to sleep while body temperature rises). a. *Phase delayed*: shift in rhythm where someone has trouble falling asleep at the usual time. b. *Phase advanced*: shift in rhythm where someone falls asleep easily but awakens early. 4. Paradoxically, the use of tranquilizers, such as sleeping pills, can lead to insomnia. 5. **Sleep** Apnea a. Inability to breathe during sleep. b. Symptoms include sleepiness during the day, impaired attention, depression, and sometime heart problems. c. People with sleep apnea have many brain areas that appear to have lost neurons. They consequently show deficiencies of learning, reasoning, attention, and impulse control. d. Research with mice suggests that sleep apnea leads to the aforementioned deficiencies (not the other way around) because of the deprivation of oxygen. e. Genetics, hormones, and obesity are all causes of this disorder. 6. **Narcolepsy** a. A disorder characterized by frequent unexpected periods of sleepiness during the day. b. Symptoms include gradual or sudden attacks of sleepiness, occasional **cataplexy** (attack of muscle weakness while awake), sleep paralysis (inability to move while asleep), and *hypnagogic hallucination* (dreamlike experiences occurring at the onset of sleep). c. Each of the symptoms of narcolepsy is interpreted as REM sleep intruding into wakefulness. d. People with narcolepsy lack the hypothalamic cells that produce and release orexin. e. Narcolepsy is currently treated with stimulant drugs such as methylphenidate (Ritalin). 7. **Periodic limb movement disorder**: **Repeated** involuntary movements of the legs and arms that can cause insomnia. The limb movements occur mostly during NREM sleep. Often treated with tranquilizers. 8. **REM behavior disorder**: Disorder where people move around vigorously during their REM periods apparently acting out their dreams. Likely due to the inability of the pons to inhibit spinal motor neurons. 9. Night Terrors and Sleepwalking a. **Night terrors**: An abrupt, anxious awakening from NREM sleep; this disorder is more common in children than adults. b. **Sleepwalking**: Usually occurs during stages 3 or 4 early in the night; more common in children than adults; usually runs in families; more common when people are sleep deprived or under unusual stress. c. **Sleep sex or "sexsomnia": An analogous condition in which sleeping people engage in sexual behavior either with a partner or by masturbation.** III. **Why Sleep? Why REM? Why Dreams?** A. Functions of Sleep 1. **Sleep and Energy Conservation** a. Sleep may have evolved to serve different purposes that it did in the distant past. b. For most animals, sleep conserves energy during times when the animal is inefficient. Animals also increase sleep during food shortages (i.e., hibernation). c. Animal species vary in their sleep habits in accordance with how many hours per day they devote to finding food, how safe they are from predators while they sleep, and other aspects of their way of life. d. Some species that are efficient at all hours of the day and night have evolved to never sleep (e.g., some fish species, dolphins after giving birth, some bird species). 2. Sleep and Memory a. Another function of sleep is improved memory. Young adults deprived of a night's sleep show deficits on memory tasks. In contrast, if someone learns something and then goes to sleep, even for a short time, memory after sleeping is improved. b. Research shows that the patterns that occur in the brain during sleep resembled those that occurred during learning, yet were more rapid during sleep. This suggests that the brain replays its daily experiences during sleep and reinforces the learning through repetition. c. Sleep strengthen memory selectively by reinforcing certain synaptic connections and weakening others to prevent over-activity of the brain. d. During sleep, the brain also exhibits spindle activities of sleep spindles, which increase in number after new learning. B. 1. 2. 3. 4. 2. **Neurocognitive Hypothesis**: Either internal or external stimulation activates parts of the parietal, occipital, and temporal cortex. No visual information overrides the stimulation and no criticism of the prefrontal cortex censors it, so it develops into hallucinatory perceptions. **Learning Objectives**  1. Define and describe endogenous rhythms. 2. Explain the mechanisms that set and reset the biological clock. 3. List and characterize the stages of sleep. 4. Describe the brain mechanisms of waking and sleeping. 5. Discuss several consequences of thinking of sleep as a localized phenomenon. 6. List several sleep disorders with their causes. 7. Evaluate possible explanations of the functions of sleep. 8. Describe possible explanations of dreaming. **Key Terms** - activation-synthesis hypothesis - alpha waves - basal forebrain - brain death - coma - endogenous circadian rhythm - endogenous circannual rhythm - insomnia - jet lag - K-complex - locus coeruleus - melatonin - minimally conscious state - narcolepsy - neurocognitive hypothesis - night terrors - non-REM (NREM) sleep - orexin (or hypocretin) - paradoxical sleep - periodic limb movement disorder - PGO waves - pineal gland - polysomnograph - pontomesencephalon - rapid eye movement (REM) sleep - REM behavior disorder - reticular formation - sleep apnea - sleep spindle - slow-wave sleep (SWS) - suprachiasmatic nucleus (SCN) - vegetative state - zeitgeber **CHAPTER 12** **THE BIOLOGY OF LEARNING AND MEMORY** **Chapter Outline**  I. **Learning, Memory, and Amnesia** A. Your memory is almost synonymous with your sense of self. B. Localized Representations of Memory 1. **Classical Conditioning**: After repeated presentations (although a strong stimulus will work with only one pairing) of a **conditioned stimulus** (**CS**), which initially elicits no response, with an **unconditioned stimulus** (**UCS**), which automatically elicits an **unconditioned response** (**UCR**), the subject begins responding (**conditioned response, CR**) to the CS because they have come to associate it with the UCS. For example, Pavlov classically conditioned a dog to respond to have a salivating response to a bell after continuously pairing the bell with the dog's food. 2. **Instrumental Conditioning (Operant Conditioning)**: Behavior is followed by a **reinforcer** (which increases the future probability of a response) or **punishment** (which suppresses the frequency of a response). 3. Lashley's Search for the Engram a. **Engram**: Physical representation of learning. b. Karl Lashley's work on learning (using cortical lesions in varying locations within the brains of rats) led him to propose two principles about the nervous system. c. Lashley's work was based on the assumption that the cerebral cortex was the best place to search for an engram and that all memories are physiologically the same. Researchers that followed found neither assumption was necessary true. d. Years later, Richard F. Thompson located an engram of memory in the cerebellum. B. Types of Memory 1. Short-Term and Long-Term Memory a. **Short-term memory**: Memory of events that have just occurred. b. **Long-term memory**: Memory of events from previous times. c. **Short-term and long-term memories differ in capacity. Short-term memory holds no more than seven items, while long-term memory is vast and more difficult to estimate.** d. Short-term memory depends on rehearsal and long-term memory does not. e. With short-term memory, once you forget something, it is lost. Long-term memories may be recalled with hints and reconstructed. f. Information initially entered into short-term storage can be **consolidated** into long-term memory. 2. Our Changing Views of Consolidation a. Many short-term memories are not simply temporary stores on their way to being long-term memories. Once something changes (like the score to a hockey game), it doesn't turn into a long-term memory. b. The time needed for consolidation varies enormously. Memorizing interesting facts will take less time than memorizing boring ones. Emotionally significant memories form quickly. Small to moderate amount of epinephrine and cortisol activate the amygdala and hippocampus, where they enhance the storage and consolidation of recent experiences. Emotional experiences activate the locus coeruleus, which increases norepinephrine release throughout the cortex and dopamine release in the hippocampus. c. It was previously thought that once formed, long-term memories were permanent. However, it is now clear that consolidated memories are not always permanent. They can change, fade, and vary in detail. d. If a reminder is followed by a similar experience, the memory is **reconsolidated**. New experiences during the reconsolidation process can modify the memory. 3. Working Memory a. **Working memory**: Temporary storage of memories about a task that one is attending to at the moment. b. **Delayed response task**: Memory task in which a subject is given a signal to which it must give a learned response after a delay. A common test for working memory. c. **Damage to the prefrontal cortex impairs performance on working memory tasks, and the deficit can be amazingly precise**. d. Older people have impairments of working memory, probably because of changes in the prefrontal cortex. C. Memory Loss 1. **Amnesia**: Memory loss. Damage to the hippocampus produces a powerful kind of amnesia. Amnesia is also the result of several disorders---Korsakoff's syndrome and Alzheimer's disease. 2. Korsakoff's Syndrome a. b. c. d. 3. Alzheimer's Disease e. f. g. h. i. 4. Infant Amnesia j. k. l. m. n. II. A. Brain damage can result in amnesia---and much of what we have learned about memory has been from patients with localized brain damage. B. Memory Loss after Damage to the Hippocampus 1. Patient H. M. had his hippocampus and surrounding brain tissue removed from both hemispheres in 1953 to treat his severe epilepsy. Afterward, H. M. had great difficulty forming new long-term memories although his short-term/working memory remained intact. 2. Anterograde and Retrograde Amnesia a. H. M. suffered moderate **retrograde amnesia** (loss of memory for events that occurred shortly before brain damage) and severe **anterograde amnesia** (loss of long-term memories for events that happened after brain damage) as a result of the bilateral hippocampal removal. 3. Intact Working Memory a. H. M.'s short-term memory or working memory remained intact. b. Was able to remember a number after 15 minutes without distraction. When distracted, memory was gone in seconds. 4. Impaired Storage of Long-Term Memory a. The surgery severely impaired H. M.'s ability to form long-term memories. Even newer words to the English language, like Jacuzzi and granola, were regarded as nonsense. b. When distracted, he would underestimate his own age by 10 years or more. c. He did not recognize himself in a photo, but could recognize himself in a mirror. 5. Severe Impairment of Episodic Memory a. He showed no ability to form **episodic memories** (memories of personal events). He could describe facts that he learned before the operation but could not recount personal events. b. He did retain the ability to weakly retain **semantic (factual) memories**. Memory loss also affected his ability to describe the future. 6. Better Implicit than Explicit Memory a. Nearly all patients with amnesia show better **implicit memory** (influence of a recent experience on behavior, even if one does not realize that he or she is using memory at all) than **explicit memory or declarative memory** (deliberate recall of information that one recognizes as a memory). b. As an experiment, three hospital workers agreed to act in special ways toward a patient with amnesia (not H. M.). One worker was as pleasant as possible. The second was neutral. The third was stern, refused all requests, and made the patient perform boring tasks. a. After 5 days, the patient was asked to look at photos of the three workers and try to identify them or say anything he knew about them. He said he did not recognize any of them. b. He told researchers that he preferred the friendly nurse and never selected that he preferred the stern nurse. He could not say why he chose or avoided a particular nurse. 7. Intact Procedural Memory a. **Procedural memory**: the development of motor skills and habits; a special kind of implicit memory. H. M. acquired new skills without apparent difficulty. b. People with amnesia usually have normal working memory, severe anterograde amnesia for declarative memory, some retrograde amnesia, better implicit than explicit memory, and nearly intact procedural memory. 8. Theories of the Function of the Hippocampus a. i. People with hippocampal damage acquire new skills but have enormous trouble learning new facts. This leads researchers to believe that the hippocampus is critical for declarative memory, especially episodic memory. ii. **Delayed matching-to-sample task**: Task used to measure declarative memory in animals. In this procedure, animals see an object (the sample) and after a delay get to choose between two objects, one of which matches the sample. iii. **Delayed nonmatching-to-sample task**: The procedure is the same except that the animal must choose the object that is different from the sample. iv. Hippocampal damage impairs performance on both delayed matching-to-sample and delayed nonmatching-to-sample tasks. C. Navigation 1. In rats, many hippocampal neurons are tuned to particular spatial locations. In human cab drivers, imaging data have shown that the hippocampus is activated when answering spatial questions and they have a larger than normal posterior hippocampus. 2. **Radial Maze**: Maze with eight or more arms used to test spatial memory in animals. Damage to the hippocampus impairs performance on this task. 3. **Morris Water Maze**: Procedure where an animal has to find a hidden platform, usually under murky water. This procedure is used to test spatial memory in animals and, like the radial maze, performance is negatively affected by hippocampal damage. 4. In certain closely related species of birds, the larger the hippocampus, the better their performance on spatial memory tasks. 5. Cells Responsible for Spatial Memory a. May-Britt Moser, Edvard Moser, and John O'Keefe shared the 2014 Nobel Prize in Physiology or Medicine for their discovery of the cells responsible for spatial memory. b. **Place cells**: Hippocampal neurons tuned to particular spatial locations, responding best when an animal is in a particular place and looking in a particular direction. c. **Time cells**: Some place cells also function as time cells that respond at a particular point in a sequence of time. d. Place cells receive input from cells in the entorhinal cortex. Recorded cells in the entorhinal cortex became active at locations separated from one another in a hexagonal grid. The cells are called **grid cells**. At a given level within the entorhinal cortex, different cells respond to different sets of locations, but always in a hexagon. D. The Striatum 1. Episodic memory, dependent on the hippocampus, develops after a single experience. However, to learn habits or learning what will or will not likely happen under a set of circumstances relies on part of the basal ganglia, specifically the caudate nucleus and the putamen, which are together known as the **striatum.** 2. "Will it Rain?" Example a. Multiple strategies for guessing yes or no with different probabilities of being correct. b. With more trials, you would likely get more accurate---even if you couldn't describe your "strategy". c. Gradual, probabilistic learning depends on the basal ganglia. 3. Results suggest a division of labor between the striatum and other brain areas that include the hippocampus and cerebral cortex. However, most tasks activate both systems. Hippocampal learning at the beginning of a task, but once the task becomes "habitual" or "automatic", more emphasis on striatum. E. Other Brain Areas and Memory 1. 2. 3. 4. 5. III. A. **Blind Alleys and Abandoned Mines** 1. a. b. c. B. Learning and the Hebbian Synapse 2. C. *Single-Cell Mechanisms of Invertebrate Behavior Change* 3. a. 4. a. 5. b. D. Long-Term Potentiation in Vertebrates 1. a. b. c. 2. 3. a. i. ii. iii. iv. v. vi. vii. Calcium enhances the responsiveness to glutamate by activating a protein called CaMKII, leading to the following effects: - The dendrite may build more AMPA receptors or move them into a better position. - Neurons make more NMDA receptors. - The dendrite may make more branches, thus forming additional synapses with the same axon. - The AMPA receptors become more responsive than before. viii. The effects of CaMKII and CREB are magnified by BDNF, a neurotrophin similar to nerve growth factor. ix. Once LTP has been established, it no longer depends on NMDA synapses. Drugs that block NMDA prevent the establishment of LTP, but they do not interfere with the maintenance of LTP. b. Presynpatic Changes i. LTP causes presynaptic changes through the release of a **retrograde neurotransmitter** from the postsynaptic cell. These changes include reduced threshold for producing action potentials, increased neurotransmitter release, expanded size of the presynaptic axonal membrane, and release of neurotransmitter from more sites on the axon. E. Improving Memory 1. The relationship between LTP and learning is unknown at this time, but studying the biochemistry of LTP has improved our understanding of what could impair or improve memory. 2. LTP depends on production of several proteins, and enhancing production of these proteins enhances memory in rodents. 3. Moderate doses of stimulant drugs enhance learning by increasing arousal. Caffeine and methylphenidate are both examples. 4. Altering gene expression is being studied in mice. Improvements come with a cost: generally impair a different type of memory. 5. Behavioral methods best way to improve memory: study, rehearse, test yourself, get good sleep, and reduce stress. IV. A. Intelligence includes learning, memory, reasoning, and problem solving,ntelligenceion is being studied in mice. riendly nurse and never selected that he preferred the stern nurse. but it is actually a difficult concept to define. B. One of the first discoveries from psychological research was Charles Spearman's (1904) report that, as a rule, all measures of cognitive performance correlate positively with one another. 1. Many psychologists have therefore assumed that all the skills share a single underlying factor of general intelligence, known as ***g***. 2. One can discuss general intelligence as one would general athletic ability, but we should also remember that some people are intelligent in one way and not so much in another, just as people can excel in one athletic skill and not another. C. Brain Size and Intelligence 1. A bigger brain does not mean "smarter" 2. All mammalian brains have the same organization, but they differ greatly in size. i. Within a family (e.g., rodents), larger species, which have proportionately larger brains, learn faster and retain their learning better than smaller species. ii. This is not true if you compare species (e.g., human vs. whale). 3. The species humans regard as most intelligent---ourselves---have larger brains in proportion to body size than do species we consider less impressive, such as frogs. 4. Body to Brain Ratio i. Doesn't make sense for certain species (e.g., Chihuahuas, squirrel monkeys, and marmosets). ii. And because of the increasing prevalence of human obesity, our brain-to-body ratio is declining. 5. Total Number of Neurons i. Humans do lead in one aspect, by a considerable margin: total number of neurons. ii. Total number of neurons may be a reasonable correlate of intelligence. iii. Whales and elephants have larger brains than humans, their neurons are larger and more spread out. iv. Marmosets have a greater brain-to-body ratio than humans, but their bodies are smaller, and therefore their brains and neuron number are smaller. 6. Human Data i. Moderate correlation between brain size and IQ. Intelligence correlates with surface area of the cerebral cortex in the frontal and parietal lobes as well as with the caudate nucleus. ii. Intelligence correlates with white matter implying that BOTH neurons and the connections among neurons are important. iii. Limitations with the Human Data: Men have larger brains but equal IQs. Overall, males and females have equal intelligence. iv. Hypotheses: Women have more and deeper sulci on the cortex---surface area almost equal to men. Another hypothesis: Male and female brains organized differently possibly as an evolutionary mechanism to keep intelligence the same despite the relative size v. The correlation is not high enough to justify using brain measurements to make any decisions about an individual. D. Genetics and Intelligence 1. Monozygotic twins resemble more alike than dizygotic twins on tests of overall intelligence, specific cognitive abilities, and brain volume. They resemble each other even when reared in separate homes. 2. Heritability increases as people grow older, presumably because high-performing people gravitate toward educational opportunities and challenging activities that facilitate whatever genetic predispositions were present. 3. Heritability of intellectual performance is lower; however, for people who grow up in impoverished conditions and children who attend lower-quality schools. Evidently genetic variations influence how well someone can take advantage of opportunities, but if the opportunities are sparse, a genetic advantage goes to waste. 4. The same pattern holds for so much of psychology: Significant heritability, contributions from many genes, but no common gene with a major effect. E. Brain Evolution 1. Except for the specializations related to language, human brains are organized the same way as those of other mammals, especially other primates. 2. How did we manage to evolve such a large brain? The brain is a metabolically expensive organ. The human brain constitutes 2 percent of the body's mass, but consumes 20 percent of its fuel. 3. For our remote ancestors to evolve such large brains, they needed to get a great deal of nutrition, but they also needed to reduce the energy spent on other functions. i. Walking upright---saves time and energy ii. Cooking food---smaller digestive tract needed iii. Hunting in groups versus alone iv. Glucose transport genetic differences---More for the brain, less for the muscles therefore we spend more energy for brains instead of strength. v. Hunting in groups, tools, weapons become important. vi. Reduce energy for reproduction vii. Fewer babies, more care viii. Our lifespan is unusually long ix. Cooperation is common x. Social groups help with rearing of young---male/female pair bonds, family groups **Learning Objectives** 1. Distinguish among types of memory. 2. Define *engram*, and describe research to localize an engram. 3. Discuss types of amnesia. 4. Contrast the functions of the hippocampus and the striatum. 5. Define Hebbian synapses. 6. Explain the mechanism of long-term potentiation. 7. Discuss the relationships among brain anatomy, genetics, and intelligence. **Key Terms**  - **Alzheimer's disease** - **amnesia** - **AMPA receptor** - **amyloid-β** - **anterograde amnesia** - **associativity** - **BDNF** - **classical conditioning** - **conditioned response(CR)** - **conditioned stimulus (CS)** - **confabulation** - **consolidate** - **cooperativity** - **declarative memory** - **delayed matching-to-sample task** - **delayed nonmatching-to-sample task** - **delayed response task** - **engram** - **episodic memory** - **equipotentiality** - **explicit memory** - ***g*** - **grid cells** - **habituation** - **Hebbian synapse** - **implicit memory** - **infant amnesia** - **instrumental conditioning** - **Korsakoff's syndrome** - **lateral interpositus nucleus (LIP)** - **long-term depression (LTD)** - **long-term memory** - **long-term potentiation (LTP)** - **mass action** - **Morris water maze** - **NMDA receptor** - **place cells** - **procedural memory** - **punishment** - **radial maze** - **reinforcer** - **retrograde amnesia** - **retrograde transmitter** - **semantic dementia** - **semantic memories** - **sensitization** - **short-term memory** - **specificity** - **striatum** - **tau protein** - **time cells** - **unconditioned response (UCR)** - **unconditioned stimulus (UCS)** - **working memory** **CHAPTER 13** **Cognitive Functions** **Chapter Outline** I. **Lateralization and Language** A. The Left and Right Hemispheres 1. The brain has two hemispheres; each hemisphere controls the contralateral (opposite) side of the body. For example, the right hemisphere is connected to sensory receptors and muscles mainly on the left half of the body (the opposite holds true for the left hemisphere). Both hemispheres control the trunk muscles and facial muscles. Taste and smell are uncrossed (each hemisphere gets taste information from its own side of the tongue. According to fMRI data and other methods, the left hemisphere is dominant for speech production in more than 95 percent of right-handers and nearly 80 percent of left-handers. 2. **Lateralization**: Refers to the behaviors and cognitive abilities that each hemisphere specializes in. For example, language ability is primarily localized in the left hemisphere. 3. **Corpus Callosum**: A set of axons that allows the two hemispheres to exchange information with one another. The anterior commissure, the hippocampal commissure, and a couple of other small commissures also help in the exchange of interformation. 4. One section of the temporal cortex, **planum temporal**, is larger in the left side for 65 percent of people. This difference is seen even in infants. Other small differences exist between the hemispheres. Smaller but still significant differences are found between left and right hemispheres of chimpanzees, bonobos, and gorillas (Hopkins, 2006). Many primates also show a preference for using either their right or left hand. B. Visual and Auditory Connections to the Hemispheres 1. Light from the right **visual field** (what is visible at a particular moment) shines onto the left half of both retinas; this information is then relayed to the left hemisphere. The right half of each retina connects to the right hemisphere, which sees the left visual field. 2. **Optic chiasm**: Point where half of the axons from each eye cross to the opposite side of the brain. 3. Each ear receives sound waves from one side of the head, but each sends the information to both sides of the brain. If the two ears receive different information, each hemisphere pays more attention to the ear on the opposite side. 1. Severing the corpus callosum prevents the sharing of information between the two brain hemispheres. 2. **Epilepsy**: Condition characterized by repeated episodes of excessive synchronized neural activity (i.e., seizure). Most people with epilepsy (90%) use drugs to suppress their seizure activity. 3. If seizure activity is not controlled by drug therapy, some people have surgery to remove the **focus** (point of origin of the seizure). Alternatively, epileptics sometimes have their corpus callosum severed to prevent seizure activity from crossing from one hemisphere to the other. 4. Evidently, epileptic activity rebounds back and forth between the hemispheres and prolongs seizures. Without the bounce back effect, a seizure may not develop at all. These individuals are often referred to as **split-brain people**. 5. Split-brain people can point to objects with their left hand (but not with their right hand) if visual information is presented from the left visual field to their right hemisphere. Information presented in the right visual field (thus going to the left hemisphere) allows patients to name or describe what they see. 6. The two hemispheres of a split-brain person can process information independently of each other. This allows split-brain people to do tasks that some find difficult, like drawing circles with both hands simultaneously with one hand going slightly faster than the other. 7. Split Hemispheres: Competition and Cooperation a. In the first weeks after surgery, split-brain people find that the hemispheres act like separate people sharing one body. For example, one person repeatedly took items from the grocery shelf with one hand and returned them with the other. b. Later, the brain eventually learns to use smaller connections between the left and right hemispheres to avoid conflicts between them. c. Sometimes, the hemispheres learn to cooperate. This is tested using words that are flashed simultaneously on both sides of the visual field. Some split-brain people will combine the two words into one concept. a. The right hemisphere is better than the left at perceiving the emotions in people's gestures and tone of voice. b. People with right-hemisphere damage speak with less inflection and expression, plus they often have trouble interpreting the emotions that other people express through their tone of voice. c. Research findings suggest that the right hemisphere is more adept than the left at comprehending spatial relationships. d. The left hemisphere is more focused on details and the right hemisphere is better at perceiving overall patterns. a. Research on hemisphere dominance should not be over-emphasized. b. One should not conclude from this research that they are not good at certain things because they are either "left-brained" or "right-brained". It is doubtful that any individual habitually relies mostly on one hemisphere. 1. Human language stands out from others because of its **productivity**, its ability to produce new signals to represent new ideas. 1. Nonhuman Precursors of Language a. Common chimpanzees cannot learn to talk, but can learn some language skills using American Sign Language or other visual systems. Their use of language- related symbols differs from human language in many ways. b. They vocalize while breathing in (instead of out like humans). c. The chimpanzees seldom used the symbols in new original combinations. They lack *productivity.* The chimpanzees used their symbols almost always to make a request, only rarely to describe. Chimpanzees show moderate understanding and can answer "What" and "Who" questions accurately. a. Bonobos (*Pan paniscus*) given language training used symbols in several ways that more resemble humans than common chimpanzees. i. ii. iii. iv. v. b. The reason for the better language skills in the bonobos is unknown, but three reasons have been suggested: i. ii. iii. 4. Nonprimates a. Alex, an African gray parrot, could say a variety of words in conjunction with specific objects. Alex's language abilities caused many to rethink some assumptions about what sort of brain development is necessary for language. b. Dogs can learn to respond to many human words. They have activity in the left hemisphere when responding to meaningful words and right hemisphere when responding to intonation. c. These studies indicate that human language evolved from precursors present in other species. They give insights on how best to teach language to those who do not learn it easily. Also, they illustrate the ambiguity of our concept of language and suggest that we need a more precise definition. E. How Did Humans Evolve Language? 1. Language may have evolved from communication by gestures. Most theories fall into two categories: a. The first is that we evolved it as a by-product of overall brain development. b. The second is that we evolved it as a specialization. 2. Language: By-product of Intelligence, or Specialized Adaptation? c. People with Normal Intelligence but Impaired Language i. ii. d. People Relatively Spared Language but Low Overall Intelligence iii. e. Language as a Specialization iv. v. 3. A Sensitive Period for Language Learning f. While testing the hypothesis that there is a sensitive period for language acquisition early in life, researchers found that adults are better than children at memorizing the vocabulary of a second language. However, children have a great advantage on learning the pronunciation and grammar. g. Research shows that the younger language acquisition starts, the better. People who start learning a second language beyond age 12 or so almost never reach the level of a true native speaker. This is similar for deaf children. It they began sign language while young learned much better than those who started later. h. Those who grow up in a bilingual home show substantial bilateral brain activity during speech, for both languages. In addition, their temporal and frontal cortex grow thicker than average. i. Language has a critical period; if you don't learn language when you are young, you will forever be language-disadvantaged. D. Brain Damage and Language 1. Broca's Aphasia (Nonfluent Aphasia) a. **Aphasia**: Severe language impairment. b. **Broca's area**: Small part of the frontal lobe of the left cerebral cortex that when damaged, leads to language impairments. c. **Broca's aphasia** or **nonfluent aphasia**: A language impairment whose most prominent symptom is a deficit in language production. Caused by damage to Broca's area and surrounding areas. d. Patients suffering from Broca's aphasia speak meaningfully, but omit pronouns, prepositions, conjunctions, and qualifiers from their own speech; they also have trouble understanding these same kinds of words. e. Difficulty in Language Production i. Broca's aphasia relates to language, not just vocal muscles. English speakers with Broca's aphasia speak most pronouns, prepositions, conjunctions, auxiliary verbs, quantifiers, and tense and number endings. ii. The problem seems to be with word meanings, not just pronunciation. f. Problems in Comprehending Grammatical Words and Devices iii. People with Broca's aphasia have trouble understanding the same kinds of words that they omit when speaking. They also misunderstand complex sentences. iv. However, they generally recognize when something is wrong in a sentence and have some knowledge of grammar. 2. Wernicke's Aphasia (Fluent Aphasia) a. **Wernicke's aphasia** or **fluent aphasia**: Damage to Wernicke's Area, near the auditory part of the temporal cortex, leads to difficulty in comprehending the verbal and written communications of others. Although patients can still speak smoothly, their speech content is often nonsensical. They also have **anomia** (difficulty recalling the names of objects). b. **Typical characteristics of Wernicke's aphasia are articular speech, difficulty finding the right word, and poor language comprehension.** c. **People with Wernicke's aphasia have anomia, difficulty recalling names of objects.** d. Language requires the activation of many different areas other than the frontal cortex (Broca's area and surrounding regions) and the temporal cortex (Wernicke's area). E. Dyslexia 1. **Dyslexia**: Inability to read despite adequate vision and intelligence. Dyslexia is more common in boys than girls and has been linked to at least four genes that produce deficits in hearing or cognition. 2. People with dyslexia more likely to have abnormalities in the left hemisphere. Many also have parts of the right temporal cortex larger than left. 3. Different researchers have hypothesized different explanations for dyslexia including: a. Dyslexia reflects a subtle hearing impairment. b. Dyslexia is caused by a problem detecting the temporal order of sounds. c. Dyslexia is caused by a problem converting vision to sound or vice versa, as if one part of the brain were poorly connected to another. d. Dyslexia is a function of attentional differences. II. A. The Mind-Brain Relationship 1. The mind-brain problem: What is the relationship between the mind and the brain? 2. The most widespread view among nonscientists is **dualism**, the belief that mind and body are different kinds of substances that exist independently. 3. The alternative is **monism**, the belief that the universe consists of only one kind of substance. 4. Various types of monism are: a. **Materialism**: the view that everything that exists is material, or physical. b. **Mentalism**: the view that only the mind really exists and that the physical world could not exist unless some mind were aware of it. c. **Identity position**: the view that mental processes and certain kinds of brain processes are the same thing. B. Consciousness of a Stimulus 1. If a cooperative person reports the presence of one stimulus, but not of a second, they were **conscious** of the first but not the second. 2. Consciousness is roughly equivalent to attention. 3. Can be driven by features of the stimulus, such as brightness, motion, or size, or due to "top-down" processes. 1. Researchers use the operational definition: If a cooperative person reports awareness of one stimulus and not another, then he or she was **conscious** of the first and not the second. 2. The next step is to present a given stimulus under two conditions. For example, in "**flash suppression**," you may be unable to see a stationary dot while other dots are flashing around it. 3. Experiments using Masking d. **Masking**: a brief visual stimulus is preceded and followed by longer interfering stimuli. e. **Backward masking**: the same method as above but only the later stimulus is presented. f. Data on masking studies show that consciousness of a stimuli depends on the amount and spread of brain activity. 4. Experiments Using Binocular Rivalry a. **Binocular rivalry**: Gradual changes in perception when two different stimuli are presented to the two eyes. b. Consciousness seems to be all or none; you cannot be partially conscious of a stimulus. 5. The Fate of an Unattended Stimulus a. Brain must identify a stimulus as meaningful before you become conscious of it. Much of brain activity is unconscious and can influence behavior. b. Brain attends to some things even if you are not conscious of the stimulus. 6. Consciousness as a Threshold Phenomenon a. One study suggests that consciousness is a yes/no phenomenon. When shown blurry words on a screen, participants almost never said they were partly conscious of something. They always rated words as 0 or 100 in terms of how conscious they were of it. 7. The Timing of Consciousness a. **Phi phenomenon**: If you see a dot in one position alternating with a similar dot nearby, it will seem that the dot is moving back and forth. 4. Later perceptions alter earlier perceptions. C. Conscious and Unconscious People 5. Studies followed people as they lost consciousness under anesthesia and then regained it as the drug effects wore off. Loss of consciousness was marked by decreased overall activity and especially by decreased connectivity between the cerebral cortex and subcortical areas such as the thalamus, hypothalamus, and basal ganglia. Initial recovery of consciousness depended on increased connectivity between subcortical and cortical areas, and later increases in alertness depended on increased activity in the cortex. 6. Researchers used fMRI images to record brain activity in a young woman who was in a persistent vegetative state. When she was told to imagine playing tennis, the fMRI showed increased activity in motor areas of her cortex, similar to that of healthy volunteers. 7. One problem in solving the mind-body problem is we cannot observe consciousness. D. Attention 1. Attention is closely aligned with consciousness. 2. **Inattentional blindness** or change blindness: If something in a complex scene changes slowly, you probably will not notice it unless you are paying attention to the particular item that changes. 3. Brain Areas Controlling Attention a. Bottom-up process: a reaction to a stimulus b. Top-down process: intentional. For example, when you look for someone in a crowd. c. **Stroop effect**: the difficulty of ignoring words and saying the color of ink 4. Unilateral Neglect d. **Spatial neglect**: a tendency to ignore the left side of the body and its surroundings, including visual, auditory, and touch stimuli after damage to the right hemisphere. g. If the damage to the right hemisphere is to the inferior part of the parietal cortex, the person tends to neglect everything to the left of their own body. People with damage to the superior temporal cortex neglect the left side of objects, regardless of their location. h. Spatial neglect can be reduced by doing manipulations to increase attention to the left side, such as giving instructions to attend to the left side or having the person look left while at the same time feeling something with the left hand. III. A. Perceptual Decisions 1. 2. a. Within part the prefrontal cortex called the frontal orienting fields, adjacent to the motor cortex, one set of cells responded when the left side was ahead, and a different set responded when the right side was ahead. That is, responses in the posterior parietal cortex are graded, but responses in the frontal cortex produce an all-or-none outcome, like a scorekeeper who announces which team has won the game b. 3. B. Decisions Based on Values 1. 2. a. People with damage seem less sensitive to the possible rewards at the moment. b. The ventromedial prefrontal cortex also seems to monitor confidence in one's decisions. 3. C. 1. 2. 3. a. b. c. d. e. D. 1. 2. 3. 1. In a moral dilemma, they are more likely to kill one person to save 5 (Ch. 11). 2. Show little interest in how others perceive them and don't show embarrassment. **Learning Objectives**  1. Identify the primary functions of the left and right hemispheres. 2. Describe the behavioral results from split-brain surgery. 3. Describe the attempts to teach language to nonhumans. 4. Explain why increased overall intelligence does not explain how humans evolved language. 5. Contrast Broca's aphasia with Wernicke's aphasia. 6. Discuss the biological basis for dyslexia. 7. Explain why nearly all neuroscientists and philosophers favor some version of monism with regard to the mind-brain relationship. 8. Describe what brain activities differentiate between conscious and unconscious processing, and the types of research leading to these conclusions. 9. Describe research on the brain mechanisms of making decisions. 10. List some key findings about biological influences on social behavior. **\ Key Terms** - anomia - aphasia - backward masking - binocular rivalry - Broca's aphasia - (nonfluent aphasia) - Broca's area - conscious - corpus callosum - dualism - dyslexia - empathy - flash suppression - frontotemporal dementia - hard problem - identity position - inattentional blindness - interpreter - language acquisition device - lateralization - masking - materialism - mentalism - mind-brain problem - monism - nonfluent aphasia - optic chiasm - orbitofrontal cortex - oxytocin - phi phenomenon - planum temporale - productivity - social neuroscience - spatial neglect - split-brain people - Stroop effect - ventromedial prefrontal cortex - visual field - Wernicke's aphasia (fluent aphasia) - Wernicke's area - Williams syndrome