PSYCH MCAT

What is split-brain syndrome?

• severed corpus callosum

• prevents communication btwn hemispheres

• individuals experience a disconnect btwn info processed on right and left sides of brain

If a patient has split-brain syndrome, and information presented in the patient’s left visual field, what can or can’t happen?

• visual info processed in right hemisphere

• but without interhemispheric communication → patient can’t express what is being seen using language, but CAN draw it

What is the corpus callous?

bundle of axonal projections connecting right and left hemisphere → allowing the 2 hemispheres to communicate

What allows communication btwn right and left hemispheres of brain?

corpus callous

What is the left hemisphere specialized for?

• language function

• speech production (Broca area)

• language comprehension (Wernicke area)

What is Broca’s area?

speech production

What is Wernicke’s area?

language comprehension

What is top-down processing?

beliefs, ideas, expectations guide perception

What is bottom-up processing?

sensory input guides perception

What is parallel processing?

processing multiple sources of info that occur simultaneously

• ie. perceiving auditory & visual events tgthr when watching someone talk

Which psychophysiology concept determines how high the volume of the tone must be for the participants to detect it roughly half the time?

absolute threshold

Which psychophysiology concept refers to the strength of a stimulus at which one can detect its presence or change in intensity?

perceptual threshold

Which psychophysiology concept determines the smallest difference btwn 2 stimuli that a person can detect 50% of the time?

difference threshold / just noticeable difference

What are the principles of signal detection theory?

• how judgements or decisions are made under uncertain conditions amid “noise” (external/internal distractions)

1. correct detection: signal correctly perceived

2. false negative: signal not detected even tho it was present

3. false positive: signal is absent but perception erroneously reported'

4. correct rejection: signal accurately judged absent

What is the primary neurotransmitter for depressants?

• GABA, inhibitory NT

What is the idea of Gestalt principles?

how humans holistically perceive sensory stimuli

What are the Gestalt principles?

1. emergence

2. multistability

3. subjective contours

4. invariance

5. closure

6. similarity - group objects tgthr that share similar features (ie. shape, color)

7. proximity - physically closer things are a group (ie. letters closer tgthr are a word)

8. continuity - elements continue on a smooth path (ie. X is 2 lines crossing, not 2 Vs)

9. common fate - things moving tgthr are grouped tgthr (flock of birds in V formation perceived as unit)

What is the cerebellum for?

motor coordination + motor learning

What is the prefrontal cortex for?

executive functions

• critical thinking

• executive decision making

• problem solving

• planning

• impulse control

What is the amygdala for?

emotion processing (esp fear + anger)

What is the primary visual cortex for?

processing visual input from retinas

What is the primary motor cortex for?

initiation of voluntary movement + Broca area (speed production)

What brain region is activated with lucid dreaming?

prefrontal cortex

• involves critical analysis and executive decision making

When do dreams most commonly occur?

REM, particular REM cycles closer to waking

What are characteristics of REM sleep?

• rapid closed eye movements

• visually intense dreams

• brain activity that resembles beta waves seen in awake, alert state

• muscle paralysis

• irregular and increased cardiovascular and respiratory activities

• lowest body temp

What stage are K-complexes present?

stage 2

What stages are spikes in the release of growth hormone (GH) present in?

stages 3 + 4

What stage are sudden, jerking body movements present in?

entering stage 1 as the person is falling sleep

What is Parkinson's disease?

loss of dopaminergic neurons in substantial nigra

→ causes resting tremors, muscle rigidity, shuffling

What kind of medications are used to treat Parkinson’s disease?

dopamine agonists (mimic effects of dopamine, but too much can induce psychotic symptoms)

What is the monoamine hypothesis?

biomedical model of depression

• depletion of monoamine NT in CNS directly causes depression symptoms

• monoamines: serotonin, norepinephrine, dopamine

What is serotonin for?

positive mood, satisfaction, social dominance

What is norepinephrine for?

alertness, attention, memory formation

What is dopamine for?

pleasure, reward

What would support the monoamine hypothesis?

taking antidepressant meds that increase levels for all or some of the monoamine NT alleviates depression symptoms

Where is the substantial nigra?

basal ganglia

What is the basal ganglia for?

selection and execution of voluntary motor programs

What is the nucleus accumbens for?

part of reward pathway in brain

• includes ventral tegmental area (produces dopamine)

• DBS in here would activate reward pathway, would alleviate anhedonia

What are monoamine oxidase MAOI