alcohol 2 Flashcards
explain how alcohol interferes with memory
- interferes with the encoding of new information into long-term declarative memory
- can range from little memory lapses to partial or complete black outs
what does cocktail party memory deficits refer to?
- little memory lapses induced from alcohol intake
define binging
- consuming large amounts of alcohol rapidly
what % of students who had ever consumed alcohol answered YES to being asked
“Have you ever awoken after a night of drinking not able to remember things that you did or places that you went?”
51%
define declarative memory
memory that we can declare/are conscious of
- consists of episodic memory (memories of events)
- consists of semantic memory (memories about facts)
what are the two main possible mechanisms of alcohol induced amnesia?
1/ state dependence
2/ selective interference with hippocampal memory mechanisms
(by disrupting the physiological mechanisms of memory, weakening LTP)
what is state dependence?
- idea that information that is encoded or learned in a drugged state = remembered better if tested in same drugged state
outline study that looks into state-dependence and memory
had 4 groups experience two conditions
- AA group = encoded info whilst under alcohol, retrieved info whilst under alcohol
- SS group = encoded info whilst sober, retrieved info whilst sober
- AS group = encoded info whilst under alcohol, retrieved info whilst sober
- SA group = encoded info whilst sober, retrieved info whilst under alcohol
PROCEDURE:
- day 1 = learning phase -> asked to respond to 10 words with first 10 words that comes to mind
- day 2 = recall phase -> cued with words and asked to respond with words from day 1
FINDINGS:
- recall is better in group AA than in group AS
- explains state-dependence as ppts able to recall words when in same state as when recalling words
what does state-dependence account for mainly?
- little memory lapses
- blackouts seem to be due to other mechanisms
explain how selective interference with hippocampal memory mechanisms
- alcohol interferes with encoding of new declarative memory
- this is similar to damage to the hippocampus
- interference with hippocampal synaptic mechanisms may contribute to alcohol-induced amnesia
identify an example of selective interference with hippocampal memory
- alcohol disrupting the induction of hippocampal long-term potentiation
- LTP = process involving constant strengthening of synapses, leads to long-lasting increase in signal transmission between neurones
- LTP = key physiological mechanism of memory
what are most of the effect of alcohol?
negative
give examples of unpleasant effects of alcohol
- hangover
- arguments
- damage property
- get injured
- miss class
- behind in school
why do lots of people consume alcohol despite the negative effects?
alcohol directly stimulates the brain’s reward system
experience alcohol as rewarding
what is the brain’s reward system known as?
meso-corticolimbic dopamine system
what does the meso-corticolimbic dopamine system do?
- located in ventral tegmental area in midbrain
- this sends dopaminergic projections into several parts of the brain
- this includes the nucleus accumbens, ventral striatum (important for reward system)
- the release of dopamine within nucleus accumbens -> signals rewarding stimuli
- evidence that drugs of abuse stimulates dopamine release within nucleus accumbens
- alcohol disinhibits reward system
- leads to more dopamine release
explain how you use intracerebral microdialysis to measure neurotransmitters
- insert microdialysis probe into brain region of interest
- probe has semi-permeable membrane
- this comes in contact with extracellular space of brain
- flush liquid past membrane
- collect perfused at other end
- whilst perfused passes membrane, dopamine and other content of extracellular fluid move into perfusate
- this is in proportion to extracellular concentration through osmosis
- level of dopamine you have in perfusate reflects concentration of dopamine in extracellular fluid of brain
what about drugs of abuse, including alcohol, gets us hooked?
- drugs of abuse (incl. alcohol) drives dopamine/reward system
- keeps us wanting more
how can chronic excessive alcohol use lead to alcohol dependence?
- long-term compensatory changes in neural mechanisms
- leads to tolerance
- chronic psychological changes when sober
what is withdrawal hyperexcitability?
(long-term compensatory change)
- refers to out of balance between excitatory and inhibitory neurotransmission
- in response to chronic alcohol
- decreases GABA-A receptor functions
this compensates for acute GABA enhancing effects of acute alcohol - increases glutamate receptor stimulation
this compensates for decreased glutamate release
what are the possible effects of withdrawal hyperexcitability?
- withdrawal symptoms: seizures, tremors, withdrawal anxiety, alcohol craving
- excitotoxic brain damage (long-term cognitive deficits)
this is where neurones get too excited for too long, they die
what is the name of the syndrome associated with severe cognitive impairments and brain shrinkage due to chronic excessive alcohol consumption?
Wernicke-Korsakoff syndrome
explain Wernicke-Korsakoff syndrome
- caused by thiamine (vitamin B) deficiency
- commonly associated with alcoholism
- characterised by ophtalmoplegia (paralysis of eye muscles), confusion, ataxia (loss of full bodily control)
what is Korsakoff amnesia?
- what remains after treatment of acute Wernicke syndrome if thiamine deficiency lasted too long
- impairment of forming new declarative memory
- severe brain shrinkage
- striking degeneration of mammillary bodies (part of hypothalamus)
what does uncomplicated alcoholics refer to?
- alcoholics that are dependent on alcohol
- don’t show Wernicke-Korsakoff syndrome
