Behavioral Science chptr 5
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- What is a proband?
- How frequently a behavioral disorder or trait occurs in the relatives of the affected individual
- What do family risk studies measure?
- How frequent in relatives versus general population
- What is concordance rate?
- Disorder occurs in both twins (or relatives)
- What psychiatric disorders have genetic links?
- Schizophrenia (numerous genes on numerous chromosomes), bipolar disorder (chromosomes 12,16,18), personality disorders (twin studies)
- What neuropsychiatric disorders have strong genetic links?
- Alzheimer’s (chromosome 21 thus Down’s syndrome link), Huntington’s, Tourette’s
- What ages are considered early onset Alzheimer’s?
- Before age 60
- What role does apolipoprotein E2 allele play in the development of Alzheimer’s?
- The presence of this allele on chromosome 19 decreases the E4 allele and increases liklihood of developing Alzheimer’s especially in women
- What evidence is there that alcoholism/substance abuse has genetic associations?
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Concordance rate 2x higher in monozygotic twins than dizygotic
Adopted children in adulthood show drinking patterns of biological parents
4x more prevalent in biological children of alcoholics than nonalcoholics - What area of the brain is most closely associated with behavior?
- Cerebral cortex
- What effect would a frontal lobe dorsolateral convexity lesion have on behavior?
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Decreased motivation, concentration and attention
Disorientation
Mood disturbances - What behavior change would occur with an orbitofrontal cortex lesion?
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Disinhibition and inappropriate behavior
Poor judgment
Lack of inhibition or remorse (pseudopsychopath)
Lack of characteristic modesty - What effects on behavior would a medial cortex lesion have?
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Apathy
Decreased spontaneous movement
Gait disturbances
Incontinence - What effect on behavior would a temporal lobe lesion have?
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Impaired memory
Psychomotor seizures
Changes in aggressive behavior
Inability to understand language (Wernicke’s aphasia) - A lesion to the hippocampus would have what effect on behavior?
- Poor new learning
- A lesion in the amygdala would have what effect on behavior?
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Kluver-Bucy syndrome
Decreased conditioned fear response
Inability to recognize facial and vocal expressions of anger in others - What is Kluver-Bucy syndrome?
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Decreased aggression
Increased sexuality
Hyperorality - Lesions to the parietal lobe will result in what behavior effects?
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Impaired IQ
Impaired processing of visual-spatial information
Gerstmann’s syndrome - What is Gerstmann’s syndrome?
- Cannot name fingers, write, tell left from right, or do simple math, and impaired processing of verbal information
- A patient who had a bilateral prefrontal lobotomy would exhibit what changes in behavior?
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Perseveration
Disinhibition
Sudden outbursts of temper
Infantile sucking and rooting reflexes - What disorders are associated with decreased bilateral prefrontal cortical activity?
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Schizophrenia
Obsessive Compulsive Disorder - What portion of the frontal lobe is involved in the reward circuit and how is this circuit activated?
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Orbitofrontal
Activated in addicts exposed to drug-related cues - Which portion of the frontal lobe is involved in primarily motor activity?
- Medial region has connections to basal ganglia and accessory cortical motor areas
- What emotional issue results from damage to the left prefrontal area?
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Depression
Stress activates this area of the brain - What emotional issue results from damage to the right prefrontal area?
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Elevated mood
Positive mood activates this area of the brain - What is the primary function of the limbic system?
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Mediate between hypothalamus and cortex
Modulate ANS activity - What is the Papez circuit and what is it involved in?
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Hippocampus – fornix – mammilary body – anterior nucleus of thalamus – cingulate gyrus – amygdala
Involved in processing emotions - What areas of the brain have reduced volume in schizophrenia?
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Prefrontal cortex
Limbic structures (amygdala, hippocampus) - Name the 4 structural components of the basal ganglia.
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Striatum (caudate nucleus & putamen)
Pallidum (aka globus pallidus)
Substantia nigra
Subthalamic nucleus - What function does the basal ganglia serve?
- Translates desire to execute movement into actual movement
- Overactivity or damage to the substantia nigra results in what syndrome
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Inability to initiate movement (bradykinesia)
Parkinson’s - Underactivity of the striatum/shrinking of the caudate nucleus causes what syndrome?
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Huntington’s
Tourette’s (specifically the caudate nucleus) - Lesions of the pallidum and subthalamic nucleus result in what condition?
- Sudden uncontrolled limb movements
- Which side of the body does the L brain control?
- R side
- What structures enable communication between the cerebral hemispheres?
- Corpus callosum, anterior commissure, hippocampal commissure, habenular commissure
- Which hemisphere is associated with language function?
- Left
- Which hemisphere is associated primarily with perception and spatial relations?
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Right
Also associated with body image, recognition of faces, music, puzzle-solving, map-reading, musical/artistic ability - What are the differences between male and female brains?
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Females have larger corpus callosum and ant commissure thus better interhemispheric communication
Women use both hemispheres whereas men show activation of one hemisphere.
Men have better developed Right hemispheres (better spatial skills) - What function is the thalamus and reticular formation involved in?
- Arousal and consciousness
- What lesions can result in coma?
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Left-sided extensive cortical lesions
Small localized lesions to thalamus or reticular formation - How do you score levels of consciousness?
- Glasgow Coma scale scores 3-15
- Define persistent vegetative state
- Irreversible coma with no cognitive function
- What function is the parasympathetic NS involved in?
- Homeostasis and conservation of resources
- What behavior is the sympathetic NS involved in?
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Stress response
Coordinates emotions with visceral responses (HR, BP, peptic acid secretion) - The Sympathetic NS is involved in what disease processes?
- HTN, PUD, RA
- What functions is the hypothalamus involved with?
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Biological control of emotions mainly rage and aggression
Maintains homeostasis (body temp, drinking and eating)
Coordinates ANS with pituitary gland
Regulation of sexual activity in adulthood - Damage to the ventromedial nucleus results in what condition?
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Obesity
(VMN the satiety center)
Damage increases appetite - Damage to the lateral nucleus will result in what condition?
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Weight loss
Damage decreases appetite - What is a neurotransmitter?
- Chemical messengers that are closely involved in cellular function at all levels of the NS
- Interactions/Imbalances among neurotransmitters cause what?
- Emotions and psychopathology
- Describe the main types of NTs
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Biogenic amines (monoamines)
Amino acids - Both biogenic amines and amino acids are synthesized in presynaptic terminals
Peptides - Synthesized in neuronal cell bodies
Endocrine hormones
Other substances - What are presynaptic and postsynaptic receptors?
- Proteins present in membranes of neurons that recognize specific NTs
- What do excitatory NTs do?
- Increase the chance that a neuron will fire
- What do inhibitory NTs do?
- Decrease the chance that a neuron will fire
- After NTs are released by the presynaptic neuron, how are they removed from the cleft?
- Simple diffusion into local tissue
- How is active removal of NTs accomplished?
- Reuptake or degradation (MAO or acetylcholinesterase)
- What factors regulate neuron responsiveness?
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Lowered availability of NTs
Changes in number or affinity of receptors
Efficiency with which a NT is changed into a message - How do postsynaptic receptors alter metabolism of neurons, and give examples.
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Second messengers
Cyclic adenosine, guanosine monophosphate, diacylglycerol, Ca2+, NO - What is neuronal plasticity?
- Changes in the number or affinity of receptors for specific NTs
- Describe the monoamine theory of mood disorder
- Altered monoamine activity and related changes in monoamine receptors result in abnormalities of mood
- With what disorders or syndromes is dopamine involved?
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Parkinson’s disease
Mood disorders
Conditioned fear response
Rewarding nature of drugs of abuse
Pathophysiology of schizophrenia/psychotic disorders - How many dopamine receptor subtypes are there and what do they do?
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D1 – site of action of atypical antipsychotics (clozapine)
D2 – site of action of traditional antipsychotics
D3
D4 – site of action of atypical antipsychotics (clozapine)
D5 - What are the three main dopaminergic tracts and what effect dopamine causes?
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Nigrostriatal – regulates muscle tone and movement (blocked in parkinson’s and treatment with traditional antipsychotics)
Tuberoinfundibular – inhibits secretion of prolactin from ant pituitary (blocked by antipsychotics causes galactorrhea, breast enlargement, and sexual dysfunction)
Mesolimbic-mesocortical – psychosis manifestation role in emotion expression (hyperactivity = symptoms of schizophrenia) - What dopaminergic pathway is responsible for the rewarding and addictive nature of drugs of abuse?
- Ventral tegmental – nucleus accumbens
- What is the nucleus of origin for dopamine?
- Substantia nigra
- Where does dopamine conversion to norepinephrine occur?
- In noradrenergic neurons via β-hydroxylase
- Where are most noradrenergic neurons located?
- Locus ceruleus
- What is norepinephrine responsible for?
- Mood, anxiety, arousal, learning, memory
- Do noradrenergic neurons synthesize dopamine?
- Yes, then convert it to norepi
- What role does serotonin play?
- Mood, sleep, pain sensitivity, appetite, sexuality, impulse control
- How is serotonin synthesized?
- Tryptophan is converted to serotonin by tryptophan hydroxylase (or amino acid decarboxylase)
- Where are most serotoninergic cell bodies found?
- Dorsal raphe nucleus (upper pons and lower midbrain)
- Increased brain serotonin is associated with what effects?
- Improved mood and sleep, decreased sexual function (delayed orgasm), psychotic symptoms (high concentrations)
- What symptoms will you see with decreased serotonin availability?
- Depression of mood, poor impulse control, violent behavior, alcoholism, chronic pain syndromes, sleep disorders, anxiety disorders, OCD
- How do antidepressants work?
- Increase the availability of serotonin and other biogenic amines in the synaptic cleft
- Where is Acetylcholine used?
- Nerve-skeleton-muscle junctions
- How is acetylcholine synthesized?
- Cholinergic neurons synthesize ACh from acetyl CoA and choline via choline acetyltransferase (ChAT)
- What enzyme breaks down ACh and what are the products?
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Acetylcholinesterase (AChE)
Choline and acetate - What disorders are related to decreased production of ChAT?
- Alzheimer’s
- What are some treatments for Alzheimer’s and how do they work?
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Donepezil, rivastigmine, galanthamine
Delay progression of disease by blocking action of AChE - What disorders are related to decreased ACh availability?
- Down’s syndrome, movement disorders, sleep disorders
- Do muscarinic or nicotinic receptors play a greater role in behavior and psychoactive side effects?
- muscarinic
- What are anticholinergic side effects and what drugs cause these effects?
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Dry mouth, blurred vision, urinary hesitancy, constipation
Antipsychotics and tricyclic antidepressants - Where do most serotonin fibers arise from?
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Raphe nuclei
Basal nucleus of Meynert - What effect do psychoactive agents have on histamine?
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Increase histamine receptor blockade
Sedation and increased appetite leads to weight gain - What does GABA do?
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GABA (γ-aminobutyric acid) is the principal inhibitory NT in CNS
Associated with anxiety - How do antianxiety agents work and name some?
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They increase the affinity of GABA for its binding site, allowing Cl to enter the neuron and hyperpolarize and inhibit firing
Benzodiazepines (diazepam), barbiturates (secobarbital) - Where is glycine found and what does it do?
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Found in spinal cord
Inhibitory NT works as a regulator of excitatory NT glutamate - What conditions is glutamate associated with?
- Epilepsy, neurodegenerative illness, memory formation, cell death mechanisms, schizophrenia (primarily alterations in glutamate receptor NMDA)
- What neuropeptides produced in the brain act on behavior and what is their effect?
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Enkephalins and endorphins
Decrease pain and anxiety, role in addiction and mood - What pathways are involved in the placebo effect?
- Endogenous opioid and dopaminergic
- What other neuropeptides are associated with psychiatric disorders?
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CCK, neurotensin – schizophrenia
Somatostatin, substance P, vasopressin, oxytocin, VIP – mood disorders
Somatostatin, substance P – huntington’s
Somatostatin, VIP – dementia (Alzheimer’s)
Substance P, CCK – anxiety
Substance P – pain and aggression - What is HVA?
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Homovanillic acid
Aka dopamine - What is MHPG?
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3-methoxy-4-hydroxyphenylglycol
Norepinephrine - What is 5-HIAA?
- serotonin
- Increased blood plasma HVA is associated with what disorder?
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Parkinson’s disease
Untreated depression
Treated schizophrenia
Pheochromocytoma
Untreated schizophrenia - In untreated schizophrenia, what will be the size of ventricles, glucose utilization of frontal lobes, and size of limbic structures?
- ↑ ↓ ↓
- Patient presents with feeling “down†and lack of interest in food or other activities formerly enjoyed. What part of the brain is affected?
- Left frontal lobe
- Body fluids in a depressed patient will show:
- Decreased 5-HIAA
- With clonidine administration, withdrawal symptoms improve. What area of the brain is involved with this effect?
- Locus ceruleus
- What mechanism causes side effects (sedation, increased appetite, and weight gain) with treatment with antipsychotic meds?
- Blockade of histamine receptors
- Symptoms of Alzheimer’s (dementia) are most likely originating from what brain structures?
- Hippocampus and nucleus basalis of Meynert