PSB 2000 - Final Exam

Chapter 12 What is the incidence of psychiatric illness? At what stage of life does schizophrenia usually appear?

Incidence refers to the occurrence of an illness. Symptoms usually appear in the late teens and early 20s.

Also called atypical neuroleptic. An antipsychotic drug that has primary actions other than or in addition to the dopamine D2 receptor antagonism that characterizes the typical antipsychotics.

atypical antipsychotic

A ventral region in the forebrain that has been implicated in sleep.

basal forebrain

Any of a class of anti-anxiety drugs that are agonists of GABA receptors in the CNS.

benzos

CH. 10 A regular fluctuation in any living process.

biological rhythm

A psychiatric disorder characterized by periods of depression that alternate with excessive, expansive moods.

bipolar disorder

Sudden loss of muscle tone, leading to collapse of the body without loss of consciousness.

cataplexy

What happens when brainstem systems to inhibit movement during REM sleep are damages?

forebrain system: no longer will get SWS brainstem system: brain wont activate to wakefulness hypothalamic system: nothing would coordinate pontine system: no REM sleep (paralyzed)

Referring to a rhythm of behavior shown by an animal deprived of external cues about time of day.

free-running

A drug that renders an individual unconscious.

general anesthetic

The idea that schizophrenia may be caused, in part, by under-stimulation of glutamate receptors.

glutamate hypothesis

Also called angle dust. An anesthetic agent that is also a psychedelic drug. PCP makes many people feel dissociated from themselves and their environment.

phencyclidine (PCP)

In psychiatry, an abnormal behavioral state. Examples include hallucinations, delusions, and excited motor behavior.

positive symptom

A bout of depression that afflicts a woman either immediately before or after giving birth.

postpartum depression

A drug that induces a state of resembling schizophrenia.

psychotomimetic

A noninvasive treatment in which repeated pulses of focused magnetic energy are sued to stimulate the cortex through the scalp.

repetitive transcranial magnetic stimulation (rTMS)

An extensive region of the brainstem that is involved in arousal.

reticular formation

The route by which retinal ganglion cells send their axons to the SCN.

retinohypothalamic pathway

A severe psychopathological disorder characterized by negative symptoms such as emotional withdrawal and flat affect, and by positive symptoms such as hallucinations and delusions.

schizophrenia

Bed-wetting.

sleep enuresis

A state, during the transition to or from sleep, in which the ability to move or talk is temporarily lost.

sleep paralysis

The process of sleeping more than normally after a period of sleep deprivation, as though in compensation.

sleep recovery

A characteristic 14-18 Hz wave in the EEG of a person said to be in stage 2 sleep.

sleep spindle

somnambulism

sleepwalking

The initial sleep of non-REM sleep, which is characterized by small-amplitude EEG waves of irregular frequency, slow heart rate, and reduced muscle tension.

stage 1 sleep

A stage of sleep that is defined by bursts of regular 14-18 Hz EEG waves called sleep spindles.

stage 2 sleep

Slow wave sleep (SWS). A stage of non-REM sleep that is defined by the presence of large-amplitude, slow delta waves.

stage 3 sleep

An exaggerated "rebound" psychosis that may emerge when doses of antipsychotic medication is reduced.

supersensitivity psychosis

A small region of the hypothalamus above the optic chiasm that is the locaiton of a circadian clock.

suprachiasmatic nucleus (SCN)

A disorder associated with typical antipsychotic use, and characterized by involuntary movements, especially of the face and mouth.

tardive dyskinesia

What happens when we are deprived of sleep?

the brain tries to catch up the next night, it can be fatal, bacteria builds up, sleep helps with our immune system.

A region of the basal hypothalamus, near the pituitary stalk, that plays a told in generating slow wave sleep.

tuberomammillary nucleus

Also called typical neuroleptic. An anti-schizophrenic drug that shows antagonist activity at dopamine D2 receptors.

typical antipsychotic

Referring to a rhythmic biological event with a period shorter than a day, usually from several minutes to several hours long.

ultradian

Give some examples of ultradian and infradian rhythms.

ultradian: hunger or thirst; snacking, hormone release infradian: menstrual cycle, breeding season; behavioral disorders

A sharp-wave EEG pattern that is seen during stage 1 sleep.

vertex spike

"Time giver." The stimulus that entrains circadian rhythms.

zeitgeber

A shift in the activity of a biological rhythm, typically provided by a synchronizing environmental stimulus.

phase shift

An inherited disorder in which humans sleep normally at the beginning of their life but in midlife stop sleeping and, 7-24 months later, die.

fatal familial insomnia

What are the four major categories of symptoms in schizophrenia? Provide some examples of each symptom category. What do we mean by positive and negative symptoms of schizophrenia?

-psychosis (positive symptoms): examples: hallucinations, emotional outbursts, paranoia, delusions, disorganized speech and thought -emotional dysregulation: (negative symptoms): examples: depression, flat affect, reduced emotional expression -motivational impairment: -cognitive impairment (neuro-cognitive impairment: examples: changes in memory, attention, and social perception Positive symptoms put things out into the world. Negative symptoms withhold them and have a flat affect.

What sorts of physical damage can occur to the brain in a traumatic brain injury (TBI)? Understand coup-countercoup.

-seizures -fluid buildup in brain -infections -blood vessel damage -headaches -veritgo -see powerpoint coup-countercoup: coup injury occurs under the site of impact with an object, and a contrecoup injury occurs on the side opposite the area that was hit. Coup and contrecoup injuries are associated with cerebral contusions, a type of traumatic brain injury in which the brain is bruised.

What are the symptoms of depression, and how does depression differ from simple sadness?

-unhappy mood -loss of interests -reduced energy -changes in appetite -sleep patterns -loss of pleasure in most things -difficulty in concentration -restless agitation or torpor -dwells on thoughts of death -contemplates suicide Simple sadness usually occurs and then person moves on to a happier state of mind, or gets back into the groove they had. Depression is an unhappy mood state and is more than just a sad day or two.

Describe the four brain systems that control different stages of sleep-waking cycle, discussing the experiments that revealed each.

1. A forebrain system generates SWS, this was found by Fredric Bremer. He called it the isolated brain. When bremer made the transection higher along the brainstem in the midbrain, a very different result was seen. Bremer referred to such a preparations as an isolated forebrain, and he found that the EEG from the brain in front of the cut displayed constant SWS 2. A brainstem system that activates the sleeping forebrain into wakefulness. In the late 1940s, scientists found that they could wake sleeping animals by electrically stimulating an extensive region of the brainstem known as reticular formation. This is a diffuse group of cells whose axons and dendrites course in many directions, extending from the medulla through the thalamus. 3. A pontine system that triggers REM sleep. Several experiments indicated that a region of the pons is important for REM sleep. Lesions of the region just ventral to the locus coeruleus abolish REM sleep. Cats with such lesions seem to act out their dreams. They either enter SWS as they normally would, but when they begin to display the EEG signs of REM sleep, instead of becoming completely limp as normal cats do, these cats stagger to their feet 4. A hypothalamic system that coordinates the other three brain regions to determine which state we're in. this was revealed through a study of narcolepsy. Several strains of dogs exhibits narcolepsy, complete with sudden collapse and very rapid sleep onset. They have an abnormal gene for production of hypocretin, which influences activity in the hypothalamus.

Describe the four most prominent theories about the function of sleep and the evidence to support them.

1. Energy conservation- sleep conserves energy. We use less energy when we sleep than when we are awake. For example, SWS is marked by reduced muscular tension, lowered heart rate, reduced blood pressure, reduced body temperature, and slower respiration. Also organisms with higher metabolism (use more energy) tend to sleep more 2. Niche adaptation- almost all animals are either nocturnal or diurnal. This specialization for either night time or daytime activity is part of each speches ecological niche, that unique assortment of environmental opportunities and challenges to which each organism is adapted 3. Body restoration- sleep rebuilds or restoration of materials used during waking, such as proteins. Some of these are only produced during sleep. Sleep is so crucial that deprivation of it can lead to death 4. Memory consolidation- studies have shown that sleep is important for learning. Suggesting that if given a verbal learning task before bed helps you remember them better. Also researchers have proposed the question that the brain refuses to store anything that happened in REM sleep, because why waste memory storage on something that never happened?

What is bipolar disorder, and how does it compare with unipolar depression and with schizophrenia? How is it treated?

A psychiatric disorder characterized by periods of depression that alternate with excessive, expansive moods. The observed pattern of changes in the brain and behavior of people has led to a recognition that bipolar disorder has more in common with schizophrenia than with unipolar depression. commonly: self-aggrandizing ideas and extreme talkativeness of people delusions disorientated thinking -treated with lithium

What treatments for depression arose in the twentieth century, and which is used most often today?

ECT was originally deployed during the 1930s in a desperate and unsuccessful attempt to relieve the symptoms of schizophrenia. ECT is the intentional induction of a large-scale seizure. The treatment that is most commonly used today is the use of drugs that affect the monoamine transmitters: norepinephrine, dopamine, and serotonin. Antidepressants are the modern treatment for the depressed today. SSRIs are the most used. They up the levels of serotonin in the brain.

The recording of gross electrical activity of the brain via large electrodes placed on the scalp.

EEG

A form of classical conditioning in which fear comes to be associated with previously neutral stimuli.

fear conditioning

What class of drugs is the most common anxiolytic, and what effect do these drugs have on transmitter systems?

Benzodiazepines are the most common anxiolytic, including Xanax, halcion, and Ativan. Anxiolytic benzo's bind to GABA receptors, where they act a non-competitive agnostics. GABA is the most inhibitory transmitter in the brain. When GABA is released from a presynaptic terminal and activates postsynaptic receptors, it hyperpolarizes the target neuron and therefore inhibits it from firing. Benzo's alone have little affect on the GABA receptor, but in the presence of GABA they markedly enhance the GABA- provoked hyperpolarization. Benzo's boost GABA mediated postsynaptic inhibition

Psychotherapy aimed at correcting negative thinking and consciously changing behaviors as a way of changing feelings.

CBT

What is chronic traumatic encephalopathy? Who is at risk? What protein is involved? What are the symptoms?

Chronic traumatic encephalopathy (CTE) is a brain condition associated with repeated blows to the head. athletes and those who get repetitive brain trauma abnormal protein memory loss, confusion, impaired judgement, impulse control, depression, aggression, and progressive dementia

CH. 10 What are circadian rhythms, and how can they be studied and manipulated in lab animals?

Circadian rhythm is a pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period. Animals show circadian rhythms of activity that can be entrained by light. These rhythms synchronize behavior to changes in the environment. In constant dim light, animals free-run, displaying a period of about 24 hours. They can be studied and manipulated by animals by studying rodents on running wheels. (comments) When lighting in the lab is kept at a constant dim level, organisms show a consistent circadian rhythm, which suggests an internal biological clock. Also, if the light/dark cycle in the lab is changed, organisms' circadian rhythms entrain to the external environmental cue.

How does information about day and night reach the mammalian brain?

Diurnal is active during the light periods of the day and nocturnal is active during the dark periods of the daily cycle. These circadian activities are extraordinarily precise: the beginning of activity may only vary a few minutes from one day to another. Animals use a built in biological clock. (comments) Some cells in the retina contain a light sensitive photopigment called melonopsin. The axons of ganglion cells that synapse with these receptors for the retinohypothalamic pathway, which influence activity in the SCN

Give evidence that describes that heredity plays a role in schizophrenia.

Family Studies: parents and siblings of people with schizophrenia have a higher risk of becoming schizophrenic than individuals in the general population Adoption Studies: studies of adopted people confirm a strong genetic factor in schizophrenia. The biological parents of adoptees who suffer from schizophrenia are far more likely to have suffered from this disorder than are adopting parents Twin Studies: in identical twins, if one twin develops schizophrenia, the other twin has a 50% of developing also. Fraternal twins both together have a 50% chance of developing it. Individual genes: genetic analyses suggest that genes influencing the development of schizophrenia are scattered across many different human chromosomes.

What are the main types of anxiety disorders?

Generalized Anxiety Disorder: persistent, excessive anxiety and worry are experienced for months Obsessive-Compulsive Disorder: characterized by unreasonable thoughts and fears (obsessions) that lead to compulsive behaviors. Phobic Disorders: intense, irrational fears that become centered on a specific object, activity, or situation that the person feels compelled to avoid Panic Disorder: characterized by recurrent transient attacks of intense fearfulness PTSD: a disorder in which a person has difficulty recovering after experiencing or witnessing a terrifying event.

How are concussions classified (graded)?

Grade 1: symptoms last <15 minutes; no loss of consciousness. Grade 2: symptoms last >15 minutes; no loss of consciousness Grade 3: loss of consciousness, sometimes just for a few seconds.

Describe how sleep changes as we grow up and grow old.

Half of sleep in the first two weeks of life is REM sleep. Infants can move directly from an awake state to REM sleep. The REM sleep of infants is quite active. The importance of REM sleep early in life suggests that it is essential the maturation of the nervous system. Infants also spend more time in SWS. The character of sleep changes more slowly in old age than in early development. The total amount of sleep declines, while the number of awakenings increases. The most dramatic decline is in stage 3 sleep

Describe the two types of stroke. Define penumbra and diaschisis. Define thrombus and embolus.

Ischemic stroke: occurs when a vessel supplying blood to the brain is obstructed Hemorrhagic stroke: when blood from an artery begins bleeding into the brain. This happens when a weakened blood vessel bursts and bleeds into the surrounding brain. Pressure from the leaked blood damages brains cells, and, as a result, the damaged area is unable to function properly. penumbra: a rim of mild to moderately ischemic tissue lying between tissue that is normally perfused and the area in which infarction is evolving diaschisis: is a sudden loss of function in a portion of the brain connected to, but at a remote distance away from, a damaged area thrombus: collection of blood cells that accumulates in vasculature embolus: a blood clot, air bubble, piece of fatty deposit, or other object which has been carried in the bloodstream to lodge in a vessel and cause an embolism. pieces of thrombus that break off

What can we conclude about the function of sleep when we consider people who sleep very little?

It is differnt for different people

During what stage of sleep does sleepwalking tend to happen? During what time of night?

It occurs during the stage 3 of SWS, and are more common in the first half of the night when that stage predominates.

A sharp, negative EEG potential that is seen in stage 2 sleep.

K complex

Understand the MPTP model for PD. How are they induced? How is it alike and different from the human disease it is modeling?

MPTP was accidentally produced by MPPP. It could illicit Parkinson's like symptoms in animal models. alike: rats and mice are resisitant to MPTTP like humans different: causation and no lewy bodies

What is narcolepsy, and what brain systems seen to be responsible for this disorder?

Narcolepsy is a disorder that involves frequent, intense episode of sleep, which last from 5 to 30 minutes and can occur anytime a component of narcoleptic attacks. hypothalamus which is responsible for the orexin that is important for switching sleep on and off. The hypocretin system in the hypothalamus is responsible Narcolepsy is a genetic disorder, and is caused by a deficiency in the production of a neuropeptide (known as hypocretin or orexin) by a part of the brain called the hypothalamus. The main characteristic of narcolepsy is excessive and overwhelming daytime sleepiness, even after adequate nighttime sleep.

An anxiety disorder in which the affected individual experiences recurrent unwanted thoughts and engages in repetitive behaviors without reason or the ability to stop.

OCD

What is OCD, and what treatments are available to combat it?

OCD is an anxiety disorder in which the affected individual experiences recurrent unwanted thoughts and engages in repetitive behaviors without reason or the ability to stop. treatments: -cognitive-behavioral therapy -prozac -luvox -anafanil -ssris

Which drugs can induce a psychosis resembling schizophrenia? What receptor(s) do these drugs act on?

PCP, also called angel dust, is an anesthetic agent that is also a psychedelic drug. PCP makes many people feel dissociated from themselves and their environment. Psychotomimetic is a drug that induces a state resembling schizophrenia. PCP acts as an NMDA receptor antagonist. PCP blocks the NMDA receptor's central calcium channel, thereby preventing the endogenous ligand-glutamate- from having its usual effects.

A disorder in which memories of an unpleasant episode repeatedly plague the victim.

PTSD

Describe PTSD and the hypothesis that the disorder is a special case of fear conditioning.

PTSD is a disorder in which memories of an unpleasant episode repeatedly plague the victim. Fear conditioning is the memory for a stimulus that the animal has learned to associate with a negative event. The persistence of fear and memory in PTSD may depend on the failure of the mechanism to forget.

What brain regions are affect in Huntington's disease and Parkinson's disease? What do they have in common? (I'll give you this one: basal ganglia, motor disorder)? Symptoms of each? Causes of each?

Parkinsons: loss of substantia nigra symptoms: resting tremors, muscular rigidity, slowness of movement, difficulty initiating movement, and mask-like face no single causes: risk factors: toxins, TBI, stroke, tumor Huntington's: loss of basal ganglia (caudate and putamen) symptoms: uncontrollable jerky movements of limbs cognitive and emotional effects csaus common: basal ganglia and neurodegenerative diseases

Paradoxical sleep. A stage of sleep characterized by small-amplitude, fast EEG waves, no postural tension, and rapid eye movement.

REM

Describe the REM behavioral disorder.

Rapid eye movement (REM) sleep behavior disorder is a sleep disorder in which you physically act out vivid, often unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM sleep — sometimes called dream-enacting behavior. REM behavior disorder is characterized by organized behavior—such as fighting an imaginary foe, eating a meal, or acting like a wild animal—from a person who appears to be asleep. Sometimes the person remembers a dream that fits well with his behavior. This disorder usually begins after the age if 50 and is more common in men than women.

What happens to our muscles during the sleep stage characterized by the most vivid dreams?

Rapid eye movement, voluntary muscles become paralyzed

An antidepressant drug that blocks the re-uptake of transmitter at serotonergic synapses.

SSRIs

Summarize the evidence for and against the use of SSRIs in depression. Why is the use of SSRIs controversial?

SSRIs act to increase serotonin levels in the brain. However, it takes several weeks of SSRIs for patients to feel better. Research shows that SSRIs are only useful to people are have higher cases of depression, and that low cases respond better to placebos.

What is the evidence that stress can affect whether a person will develop schizophrenia?

Schizophrenia usually appears during a time in life that many people find stressful. Examples include: living in a city, general stress, substance abuse, poverty, moving at a young age.

Also called neuroleptic. Any of a class of drugs that alleviate symptoms of schizophrenia, typically by blocking dopamine receptors.

antipsychotic

What are the different types of insomnia, and why are sleeping pills an imperfect long-term solution?

Sleep-onset insomnia: difficulty falling asleep Sleep-maintenance insomnia: difficulty staying asleep Sleep apnea: respiration slows or stops periodically, waking the patient. Excessive day-time sleepiness results from the frequent nocturnal awakening Sudden infant death syndrome: crib death. the sudden, unexpected death of an apparently healthy human infant who simply stops breathing, usually during sleep Sleep state misperception: commonly, a person's perception that he has not been asleep when in fact he was. it typically occurs at the start of a sleep episode They do not provide a normal night of sleep in terms of the stages. The pills lose their effectiveness and decline the ability to inducing sleep often leads to doses that are dangerous. They produce marked changes in the pattern of sleep, both while the drug is being used and for days afterward. I can lead to persistent sleep drunkenness, which impairs walking activity, or memory gaps about the daily activity

Describe one way that certain species manage to remain active around the clock and still sleep.

Some mammals put their hemispheres to sleep manually. Unihemispheric slow-wave sleep (USWS) is sleep where one half of the brain rests while the other half remains alert. This is in contrast to normal sleep where both eyes are shut and both halves of the brain show unconsciousness.

DR. TOWNES QUESTIONS Describe the neurological features and symptoms of stroke, traumatic brain injury (TBI), chronic traumatic encephalopathy (CTE), Parkinson's Disease, and Huntington's Disease.

Stroke: disruption of blood flow to the brain symptoms: trouble with speaking and standing, paralysis or numbness of face, arm, or leg, trouble with seeing in one or both eyes, headache, trouble with walking TBI: Brain dysfunction caused by an outside force, usually a violent blow to the head symptoms: see powerpoint

Any of a class of psychological disorders that includes recurrent panic states, generalized persistent anxiety disorders, and post-traumatic stress disorder.

anxiety disorder

A substance that is used to combat anxiety.

anxiolytic

What are the different stages of sleep, and what measures define them?

The beginning of non-REM sleep, called stage 1 sleep which is accompanied by slowing of the heart rate and relaxation of the muscles, in addition, under the closed eyelids the eyes may roll about slowly. stage 1 usually lasts several minutes and gives way to stage 2 sleep, which is defined by sleep waves of 12-14 hx called sleep spindles and by K complexes. if awakened during these stages, ppl may deny that they ever went asleep. stage 2 leads to stage 3, which is defined by the appearance of large amplitude, also known as SWS. as night progesses delta waves become more prominent. then REM sleep.

Describe the evidence supporting the dopamine hypothesis of schizophrenia, and contrast it with the evidence casting doubt on this hypothesis.

The dopamine hypothesis includes chlorpromazine and other antipsychotic drugs that came along a litter later were able to find this specific action, that they block postsynaptic dopamine receptors, particularly dopamine D2 receptors because all of the earliest antipsychotic drugs blocked dopamine D2 receptors, researchers proposed the dopamine hypothesis, that people with schizophrenia suffer from an excess of either dopamine release of dopamine receptors. Dopamine receptors are blocked faster than symptoms disappear. Atypical neuroleptics influence serotonin and may increase levels of dopamine Support for the dopamine hypothesis came from another source, people who were abusing drugs. Some daily users of amphetamine reach the point of taking astonishingly high doses. This produced doubt because support from their hypotheses came from those who had been abusing drugs

A disorder involving heightened sensitivity to sensory stimuli that may be accompanied by verbal or physical tics.

Tourette's syndrome

What distinguishes typical antipsychotics from atypical antipsychotics?

Typical antipsychotic drugs act on the dopaminergic system, blocking the dopamine type 2 (D2) receptors. Atypical antipsychotics have lower affinity and occupancy for the dopaminergic receptors, and a high degree of occupancy of the serotoninergic receptors 5-HT2A

What are some of the ways in which the brains of people with schizophrenia differ from the brains of people without schizophrenia?

Ventricular abnormalities: enlarged cerebral ventricles as well as lateral ventricles. Cortical abnormalities: accelerated loss of gray matter at adolescence in schizophrenia patients and cortical thinning. The frontal lobes are also different. Differences in brain activity: impaired on neuropsychological tests that are sensitive to front cortical lesions. Frontal cortex activity is abnormal in schizophrenia. Also, have a reduced metabolic activity in frontal lobes relative to other regions of the brain. The frontal lobes are underactive.

Describe the outcome of Randy Gardener's famous self-study.

World record for sleep deprivation, 11 days for a science fair project. his test performance was impaired,but he could still hold conversation, he showed no signs of insanity was just insanely tired. in recovery his stage 3 was the most different, involved more rapid eye movement

What is excitotoxicity, and how is it related to stroke?

a term used to describe cell death induced by high levels of Glutamate in the synaptic cleft 1.) Disruption of blood flow 2.) Decrease in oxygen and glucose to neurons 3.) slowing of sodium-potassium pumps, then depolarization 4.) excess glutamate release and even more depolarization which speeds to other neurons and causes excitotoxic cell death 5.) causes disruption to BBB

A brain potential of 8-12 Hz that occurs during relaxed wakefulnedd.

alpha rhythm

An early antipsychotic drug that revolutionized the treatment of schizophrenia.

chlorpromazine

A pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour-pd.

circadian rhythm

an atypical antipsychotic

clozapine

Sharing of characteristics by both individuals of a pair of twins.

concordance

Mild electrical stimulation through an electrode that is surgically implanted deep in the brain.

deep brain stimulation (DBS)

The slowest type of EEG wave, characteristic of stage 3 sleep

delta wave

VOCAB A false belief that is strongly held in spite of contrary evidence.

deluision

A psychiatric condition characterized by such symptoms as an unhappy mood; loss of interests, energy, and appetite; and difficulty concentrating.

depression

Beta-activity. A pattern of EEG activity comprising a mix of many different high frequencies wit low amplitude.

desynchronized EEG

The idea that schizophrenia results from either excessive levels of synaptic dopamine or excessive postsynaptic sensitivity to dopamine.

dopamine hypothesis

Difficulty of distortion in voluntary movement.

dyskinesia

The unique assortment of environmental opportunities and challenges to which each organism is adapted.

ecological niche

A last-resort treatment for unmanageable depression, in which a strong electrical current is passed through the brain, causing a seizure.

electroconvulsive shock therapy (ECT)

The process of synchronizing a biological rhythm to an environmental stimulus.

entrainment

Describe experiments that established which parts of the brain control circadian rhythms.

hamster

The idea that schizophrenia may reflect under-activation of the frontal lobes.

hypofrontality hypothesis

Referring to a rhythmic biological event with a larger period longer than a day.

infradian

An experimental preparation in which an animal's brainstem has been separated from the spinal cord by a cut below the medulla.

isolated brain

An experimental preparation in which an animal's nervous system has been cut in the upper midbrain, dividing the forebrain from the brainstem.

isolated forebrain

A dissociative anesthetic drug, similar to PCP, that acts as an NMDA receptor antagonist.

ketamine

A learning paradigm in which individuals are subjected to inescapable, unpleasant conditions.

learned helplessness

An element that, administered to patients, often relieves the symptoms of bipolar disorder.

lithium

The surgical separation of a portion of the frontal lobes from the rest of the brain, once used as a treatment for schizophrenia and many other ailments.

lobotomy

A small nucleus in the brainstem whose neurons produce norepinephrine and modulate large areas of the forebrain.

locus coeruleus

What groups are at high risk for such an injury?

males 15-24 substance abusers infants elderly those who have already had a prior injury

A photopigment found in those retinal ganglion cells that project to the SCN.

melanopsin

An amine hormone that is secreted by the pineal gland at night, thereby signaling day length to the brain.

melatonin

The interval of time between two similar points of successive cycles, such as sunrise to sunset.

period

A type of quantitative review of field of research, in which the results of multiple previous studies are combined in order to identify overall patterns that are consistent across studies.

meta-analysis

An enzyme that breaks down monoamine neurotransmitters, thereby inactivating monoamine transmitters.

monoamine oxidase (MAO)

A disorder that involves frequent, intense episodes of sleep, which lasts 5-30 mins and can occur anytime during the usual waking hours.

narcolepsy

In psychiatry, an abnormality that reflects insufficient functioning. Examples include emotional and social withdrawal, and blunted affect.

negative symptom

A sudden arousal from stage 3 sleep that is marked by intense fear and autonomic activation.

night terror

A long, frightening dream that awakens the sleeper from REM sleep.

nightmare

Sleep, divided into stage 1-3, that is defined by the presence of distinctive EEG activity that differs from that seen in REM sleep.

non-REM sleep

A neuropeptide produced in the hypothalamus that is involved in switching between sleep states, in narcolepsy, and in the control of appetite.

orexin