lecture 32: what happens when the brain misbehaves

Question 1

2 types of behavioral effects

Answer 1

specific: coup or countrecoup
generalized: widespread throughout brain ex. diffuse axonal shearing

Question 2

imparimed cognitive functions

Answer 2

mental speed, concentration. efficiency, behavioral,
- memory, social skills and personality show poorest recovery
recovery may take 2-3 yeras or longer (most in 6-9 months)

Question 3

stroke

Answer 3

interuption of blood flow from blockage (ischemic) or bleeding (hemorrhagic) of vessel

Question 4

ischemia

Answer 4

lack of blood to brain from blocked vessel

- cascade of cellular events that cause damage to site and surrounding area

Question 5

5 effects of stroke

Answer 5

1. release of glutamate = prolonged opening of calcium channels
2. toxic levels of calcium produce toxicity and instigate second messange rpathways and protein production
3. brain inflammation theratens neurons far from site
4. neural shock (diaschisis) causes areas distant from damage to depress
5. changes in metabolism of injured hemisphere, glucose can persist for days

Question 6

treatments for stroke

Answer 6

clot busting drugs (3-5 hours)
neuroprotectant: block cascade of events
therapies (speech/physical) used to facilitate plastic changes in brain

Question 7

epilepsy & causes

Answer 7

recurrent seizures (highly synchronized but abnormal EEG waves)
causes:
- genetic from known genetic defect
- structural from brain malformation/tumor, stroke/trauma, infection
- unkown

Question 8

types: focal seizure

Answer 8

synchronous hyperactive activity in local brain region

• motor. sensory and behavioral features
• focail aware or focal imparied aware

Question 9

types: generalized seizure

Answer 9

start focally then spread to distributed networks
- normal EEG before, onset and tonic phase stiffens body, clonic phase makes rhythmic movements in time with discharges, depressed period after seizure

Question 10

treating epilepsy

Answer 10

main goal to raise seizure thresholds by enhancing GABA

• intractable epilepsy in 30-40%
• most common treatment for intractable epilepsy is surgical resection of tissue

Question 11

parkinsons disease

Answer 11

related to degeneration of substantia nigra and loss of dopamine in striatum
symptoms: can take 10-20 years, resemble normal changes in motor activity with aging

Question 12

parkinsons positive symptoms

Answer 12

appearance of abnormal behaviors:

• tremor at rest
• muscular rigidity: cogwheel
• involuntary movements: akathesia or cruel restlessness

Question 13

parkinsons negative symptoms

Answer 13

loss of normal behavior:

• posture (fixation and equilibrium)
• righting: standing in supine position
• locomotion: initiating stepping
• speech disturbances: abscence of prosody
• hypokinesia: poverty or slowness of movement

Question 14

parkinsons treatment

Answer 14

pharmacological: increase activity in dopamine symptoms with L-dopa
neurosurgical: lesion GPi to reduce rigidity and tremor and DBS to reduce hyperactivity of GPi

Question 15

alzheimers disease

Answer 15

unkown cause = 65% of dementia
amyloid plaques: clumps of waste protein in cerebral cortex
neurofibrillary tangles: found in cerebral cortex and hippocampus

Question 16

cortical degeneration in alzheimers

Answer 16

part due to cell death and part due to loss of dendritic arborization

Question 17

diagnosing schizophrenia

Answer 17

delusions, hallucinations, disorganized speech and behavior, catatonic behavior, blunted emotions or loss of interest

Question 18

schizphrenia

Answer 18

genetics: high concordance in identical twins (50%)
development: young adulthood diagnosis but begins earlier, envionmental factors through epigenetic mechanisms
correlates: ventricle larger and cortex thinner in MT and frontal, changes of neuron fiber and compositions, dendritic field abnormality

Question 19

dopamine theory of schizophrenia

Answer 19

dopamine agonists can produce psychotic symptoms, neuroleptics are dopamine antagonists
- but also many other neuochemical anormalities associated with schizophrenia ex. glutamate, GABA

Question 20

mood disorders

Answer 20

major depression: prolonged feelings of worthlessness, sleep disturbances, suicide. slowing of behavior

mania: exessive euphoria and hyperactive
bipolar: alternating periods of depression and mania

Question 21

causes and treatments of mood disorders

Answer 21

causes: many predisposing factors ex. social failure, vitamin deficiencies, pregnancy, brain injury, childhood abuse
treatmentsL drugs increase NE and serotonin, CBT

Question 22

anxiety disorders

Answer 22

characterized by excessive anxiety or fear reactivity

• imaging shows increased activation in cingulate cortex and parahippocampal gyrus
• enhanced amygdala and pFC
• excessive excitatory NT may enhance
• GABAergic drugs reduce anxiety

Question 23

anxiety treatments

Answer 23

pharamcological: benzodiazepines, SSRIs
cognitive behavioral therapy: as effective as medication
exposure therapy for phobias