Behavioral Neuroscience Exam 3

Epidemiology

• studies pattern of diseases in a population

  • Branch of medicine which deals with the incidence, distribution, and possible control of diseases and other factors relating to health

Schizophrenia

A psychiatric disorder affecting 1-1.5% of the population, characterized by psychosis and symptoms such as hallucinations, delusions, and deficits in emotional and intellectual functioning.

Psychosis

• Loss of contact with reality

• Inability to function in life

• Perceptual, emotional, intellectual deficits

• Other symptoms include auditory hallucinations, personalized delusions, changes in affect

Positive symptoms

• abnormal behaviors that are gained

  • Hallucinations

    • Perceptual experience without external stimulus, sees/hears something that is not actually there

    • Most common type is auditory hallucinations

  • Delusions

    • Disorganized, irrational thinking contrary to disconfirming evidence

      • Persecutory 

      • Grandeur

  • Excited motor behavior

Hallucinations

• Perceptual experience without external stimulus, sees/hears something that is not actually there

• Most common type is auditory hallucinations

Delusions

• Disorganized, irrational thinking contrary to disconfirming evidence

  • Persecutory 

  • Grandeur

Negative symptoms

• loss of functions

  • Slow thought and speech (alogia)

  • Emotional and social withdrawal (asociality)

  • Blunted affect or emotional expression

  • Loss of pleasure (anhedonia)

Alogia

Slow thought and speech

Asociality

Emotional and social withdrawal

Anhedonia

Loss of pleasure

Concordant

both twins have disease

50%

For identical twins, the concordance rate for schizophrenia is

Environmental influences for schizophrenia

• Direct brain damage or injury during early years

• Prenatal complications

• Starvation during pregnancy

• Paternal age

• Taking psychoactive or psychotropic drugs during teenage years & adulthood

• Stress

• Leads to developmental difficulties, such as low birth weight and impairs motor coordination

DISC1

Gene suspected involvement in schizophrenia

Paternal, ventricles, hippocampus & amygdala, pyramidal

• _________ age is epigenetic factor -> older fathers are more likely to have a child with schizophrenia

• __________ appear larger in affected individuals

• _______ & ________ are smaller

  • Areas like frontal cortex may also shrink

• ________ cells of hippocampus have disorganized arrangement

  • Most likely occurs during early cell development

• Selected cortical layers are atrophied (shrinking)

• Many areas show shrinking of dendritic trees that would lead to connectivity failures

Atrophy

shrinking

Prefrontal, hypo

• Functional abnormalities

  • Reduced function of _______ cortex called ____frontality

  • Reduced blood flow, less glucose use, less active brain

    • Evident during cognitive tasks and seen on PET scan

Wisconsin Card Sorting Test

• they have a hard time shifting and displaying flexibility in thinking as goal of task changes

  • Given set of stimulus cards, first instruction is match that card (you decide by whatever quality of it), when told it is incorrect they need to be able to decide to categorize by a different quality, when there are struggles with prefrontal cortex it takes them a much longer time to decide what to do

Lobotomies

• frontal lobes detached from rest of brain

  • Psychosurgery is now very rare, involves smaller lesions, and is a last resort for disorders like epilepsy

Chlorpromazine (thorazine)

• first generation antipsychotic

Dopamine hypothesis

• schizophrenia results from excess synaptic dopamine or dopamine receptors

  • Supported by amphetamine psychosis because amphetamine promotes release of dopamine and prolongs its action by blocking dopamine reuptake

D2

• Typical antipsychotics are __ receptor antagonists

  • Clinically effective dose of a typical antipsychotic is predicted from its affinity for __ receptors

  • Haloperidol has a great affinity for D2 receptors and is now used widely

Dyskinesia

• distortion in voluntary movement

Tardive dyskinesia

•  repetitive movements involving face, mouth, lips, and tongue

Atypical antipsychotics

_________ __________ do not support the dopamine hypothesis (type of drug)

Clozapine

• blocks serotonin (5HT2A) receptors as well as D2 receptors, AcH receptors, and some others

  • Some increase dopamine levels in frontal cortex

  • The more receptors affected, the more side effects produced

Phencyclidine

• (PCP, angel dust) = psychotomimetic, produces positive and negative symptoms

  • PCP acts NMDA receptor agonist like ketamine and prevents glutamate from acting normally

  • Glutamate hypothesis = cause by underactivation of glutamate receptors (not this simple, hypothesis more complex)

Glutamate hypothesis

• cause by underactivation of glutamate receptors (not this simple, hypothesis more complex)

Bipolar

• characterized by periods of depression alternating with expansive mood (mania)

  • ____ I, II, & cyclothymic

• Rate of cycling varies but consists of 4 or more cycles in one year

  • Some individuals may cycle several times in one day

Cyclothymia

• milder but chronic form of bipolar, cycle between dysthymia (mild depression) & hypomania (increased energy), rapid repetitive state of cycling

Lithium

• mood-stabilizing drug used to treat bipolar

  • Widespread actions in brain

  • Interacts with circadian clock

  • Boosts BDNF (brain derived neurotropin factors) activity (neuro-protective factor)

Bipolar I

• defined by mania

Bipolar II

•  defined by less extreme mania & depression, goes to hypomania

Depression

• most prevalent mood disorder

  • Unhappy mood, loss of interests, low energy & appetite, difficulty concentrating, restless agitation

  • Severely depressed feel unworthy & strong feelings of guilt, people who suffer from major affective disorder have high risk of suicide

  • Strong hereditary links

  • Focus of research on diffusing modulatory systems (neurotransmitter systems) -> NE, DA, 5HT

  • Recently the focus is on the disruption of the hypothalamic-pituitary-axis focusing on neuronal cell death & replacement

  • PET scans = show increased/decreased blood flow in prefrontal cortex & amygdala (increased & mediates fear), this persists even after depression is treated

    • Decreased blood flood in parietal & posterior temporal cortex & anterior cingulate (implicated in attention)

PET scans

___ ___ for depression shows increased/decreased blood flow in prefrontal cortex & amygdala (increased & mediates fear), this persists even after depression is treated

• Decreased blood flood in parietal & posterior temporal cortex & anterior cingulate (implicated in attention)

MAO inhibitors

• for norepinephrine & serotonin increase in synapse by inhibiting its enzyme

  • Older antidepressant that increases the amount of ____ neurotransmitter in synapse by inhibiting its enzyme

  • Tyramine controlled diet is necessary

SSRIs

Prevent the reuptake of serotonin from the synapse, increasing its availability, can take 6+ weeks to see full effects

Tricyclic antidepressants

• Older antidepressants named after rings of atoms in molecular structure

• Work by preventing the reuptake of various neurotransmitters, primarily norepinephrine & serotonin

Anxiety disorder

• unlike emotion, it is inappropriate expression of fear that does not go away over time & interferes with daily life

  • Types

    • Specific phobias

    • Social anxiety

    • Panic

    • Agoraphobia

    • Generalized anxiety

Agoraphobia

fear of unfamiliar locations and loss of control

Phobias

Most common type of anxiety disorder

• Commonly occur along with other mental or physical illnesses, which may mask anxiety symptoms or make them worse

Depression

Anxiety is affected by the same neurotransmitters & areas of the brain as ______

Benzodiazepines

• are anxiolytic (anxiety reducing), like Xanax or Valium

  • Bind to GABA receptors & enhance inhibitory actions using Cl- ions into cells

  • Serotonin agonists & SSRIs are also used

PTSD

• combat fatigue, war neurosiss, shell shock, unpleasant memories repeatedly plague the victim

  • Shows changes in memory like amnesia, flashbacks, deficits in short-term memory, heightened arousal

  • Have decreased volume in right hippocampus (in combat related PTSD)

  • Paradoxical long-term reduction in cortisol levels, some research indicates cortisol is higher

    • HPA axis is exhausted or lower cortisol levels to begin with

Hippocampus, HPA axis

• Have decreased volume in right __________ (in combat related PTSD)

• Paradoxical long-term reduction in cortisol levels, some research indicates cortisol is higher

  • _____ a_____ is exhausted or lower cortisol levels to begin with

OCD

• obsessions (recurrent thoughts or impulses) and compulsions (repetitive behaviors or mental acts that are performed to reduce anxiety surrounding obsessions)

  • Often comorbid with depressions

  • Responds to SSRIs in most cases

    • Prozac, Luvox, Anafil (TCA not SSRI)

  • Cingulotomy benefitted ⅓ of severely disabled OCD patients (last resort)

    • Cingulate cortex

  • Perinatal events and infection can trigger

  • OCD & tourettes comorbid

Tourette’s

one type of tic disorder (involuntary, repetitive movements & vocalizations, Diagnosed early at 6-7 years old, may also have ADHD or OCD

Dopamine

______ D2 receptors are denser in the caudate nucleus of a Tourette’s sufferer, as seen in twin studies

Communication

• transmission of information between individuals

  • Verbal

  • Sign

  • Writing

  • Important social behaviors

  • Made cultural evolution possible

  • Enabled discoveries to be cumulative

Language

• highly specialized arbitrary symbols or behaviors are assembled and reassembled, almost infinite variety, associated with a vast range of things, actions, & concepts

Grammar

• all of the rules for usage of a language

Lateralization

• “going to one side,” hemispheres of brain serve some different functions

  • Verbal abilities (speech & language) are associated with left hemisphere, spatial abilities (navigation) are associated with the right

  • Things that examine this: split brain experiment, PET scans, fMRI

Contralateral functioning

• Left brain controls right motor movement & right visual field processing, vice verse for right brain & functions on the left

Corpus callosum

• band of axons connecting hemispheres of brain for communication

  • Split brain studies involve cutting this

Left, right

• Sperry’s studies tested language function in each hemisphere of split-brain individuals

  • Words presented to either visual field only showed language ability if information reached _____ hemisphere

  • ______ hemisphere is specialized for processing the emotional tone of language, controlling attention, and spatial processing, including face perception

  • Can draw, just not verbalize what is being shown

Dichotic presentation

• delivered different stimuli to each ear at the same time

  • Participant may hear a particular speech sound in one ear & at the same time, a different vowel consonant for word in the other ear

  • Task is for participant to identify or recall both sounds

  • Right ear advantage -> believed to be perceived through verbal side faster

    • Right handed persons identify verbal stimuli delivered to the right ear more accurately than verbal stimuli delivered to the left

      • Handedness part not fully tested because most people are right handed, right ear goes to left brain quicker

      • 50% of left-handed individuals have a left-ear advantage

        • Have more both hemisphere behavior than right handed people

Right ear advantage

• believed to be perceived through verbal side faster

  • Right handed persons identify verbal stimuli delivered to the right ear more accurately than verbal stimuli delivered to the left

    • Handedness part not fully tested because most people are right handed, right ear goes to left brain quicker

    • 50% of left-handed individuals have a left-ear advantage

      • Have more both hemisphere behavior than right handed people

left hemisphere’s

____ ____  specialization for verbal language (brooches and vernices)

Advantage is only evident in simultaneous presentations & is restricted to consonants

Left, right, right

• ______ ear words result in stronger stimulation of right auditory cortex & left for speech productions

  • _____ ear results in stronger input to left hemisphere, immediate speech production

  • When delivered simultaneously to both ears, _____ ear is usually perceived because it has more direct pathway to left hemisphere for speech production

Tachistoscope

• measures visual perception of linguistic stimuli

  • Briefly presented to left or right visual fields

    • Left hemisphere shows better recognition of words/letters

    • Right hemisphere shows better recognition of faces/geometric forms

Planum temporale

• superior surface of the temporal lobe is larger in the left hemisphere in 65% of brains studied

  • Difference is evident before substantial experience with speech

Auditory, right

• _______ areas of ________ hemisphere play major role in emotional tone of voice aspects, prosody (patterns of rhythm), musical perception

  • Music activates right hemisphere more than left

  • Only damage to both hemispheres can abolish music perception

brain lateralization

• Handedness is associated with ____ _________

  • Left handedness is 10-15% of population

  • Left handers may have less distinct lateralization

  • Do not differ in cognitive performance

  • Handedness may have genetic or in utero components

Wada test

• tests lateralization by anesthetizing each hemisphere separately using sodium amytal

  • Most people have left hemispheric dominance for language regardless of handedness

Aphasia

• impairment in language ability caused by brain injury, usually to left hemisphere

  • Broca’s or wernicke’s

  • Primary symptom of 25-50% of people who have a stroke

  • 90-95% are due to left cerebral hemisphere

Common symptoms of Broca’s

• Lesions in left inferior frontal region, head of caudate nucleus, thalamus

• Nonfluent, labored, hesitant speech

• Anomia = inability to name persons

• Utters automatic or overlearned speech

• Agrammatism = difficulty with function vs content words

• Comprehension relatively intact

• Hemiplegia = partial paralysis of one side of body

• If extensive, not much recovery over time

Anomia

•  inability to name persons

Agrammatism

difficulty with function vs content words

Hemiplegia

partial paralysis of one side of body

Common symptoms of Wernicke’s

• Lesions in posterior part of left superior temporal gyrus, extending to adjacent parietal cortex

• Poor comprehension

• Unaware of their deficit

• Callened fluent aphasia (fluent but meaningless speech)

• Can use function but not content words

• Contains many paraphasias

• Syntactical but empty sentences

• Cannot repeat words or sentences

• Usually, no partial paralysis

Paraphasia

• less severe damage to left hemisphere, insertion of incorrect sounds or words

Agraphia

• inability to write

Alexia

 inability to read

Apraxia

motor impairment in ability to execute movements

Neologisms

entirely novel nonsense words

Nonfluent speech

• talking with considerable effort, in short sentence, without the usual melodic character of conversational speech

Broca’s area

• region of inferior left frontal lobe critical for articulation of speech/speech production

Wernicke-geschwind model

• explains how language is produced

  • Broca’s area, arcuate fasciculus (fiber tract of axons covered in myelin sheath), angular gyrus (connects visual projection to auditory & visual association areas), visual cortex, motor cortex

  • When receiving an auditory stimulus, information hits the primary auditory cortex -> words are interpreted & given meaning by Wernicke’s -> passed to Broca’s area by arcuate fasciculus -> Broca’s neurons used for articulation & information is sent to primary motor cortex -> primary motor cortex is complex muscle coordination, so appropriate language reply can be voiced, facial area is where it is given vocalization, output to lips, tongue, larynx

Conduction aphasia

•  impairment in ability to correctly repeat words they have heard, lesions of arcuate fasciculus

Broca’s aphasia

•  slow, laborious, nonfluent speech

Wernicke’s aphasia

• fluent speech but unintelligible, gibberish

Global aphasia

 total loss of language

Conduction aphasia

repetition aphasia

Electrical

________ stimulation helps neurosurgeons locate cortical regions devoted to critical functions like language

Phonemes

• basic speech sounds

Electrical stimulation

Penfield and Roberts' _____ ________ studies during epilepsy surgery (with patients under local anesthesia) helped to map cortical regions devoted to critical functions like language

Stimulation of language areas could produce errors in misnaming, impaired retention, and speech arrest

Morphemes

• simple units of meaning

Semantics

• meanings of words or sentences

Syntax

 grammatical rules for constructing phrases & sentences

Sensitive period

•  time when an organism can be permanently be altered by an experience or treatment

  • Heritable mutation of FOXP2 gene causes delayed speech development

  • People with mutation of FOXP2 exhibit different patterns of brain activation during a language task

Williams syndrome

• speak frequently & fluently & freely with a large vocabulary

  • May have issue with speech delays or production, stuttering

  • Missing copy of elastin gene leads to pixie like facial features

Recovery of function

• recovery of behavioral capacity, can occur following brain damage

Hemispherectomy

• removes malfunctioning brain tissue & saves life of child

  • Produces paralysis of one side, speech loss, visual impairment, if done early in life may show almost complete recovery

Constraint-induced movement therapy

• movement of the good limb is prevented (limited) to force use of the affected limb

  • 2 weeks of this therapy has been reported to restore up to 75% of use in affected limb

Chronic traumatic encephalopathy

• multiple head injuries, memory  loss, confusion, tendency to fall

  • Postmortem studies indicate that CTE is a type of tauopathy in which excess tau protein interferes with neuronal function

8 distinctive expressions

anger, sadness, happiness, fear, disgust, surprise, contempt & embarrassment

6 basic emotions

anger, sadness, happiness, fear, disgust, surprise

contempt & embarrassment

Two complex emotions

Superficial muscles

attach to facial skin, facial nerve (VII)