Lesson 10_Learning, Memory+Addiction

long-term potentiation

synaptic responses are dramatically and lastingly enhanced for hours or days.

mediated by glutamate receptors specifically the NMDA receptor.

Prominent in the hipocampus and is involved in memory acquisition +storage.

Early LTP:AMPA receptor modification 1-3hrs no new protein synthesis needed.Late LTP:new protein synthesis, dendritic spine growth days-years

ionotropic responses in memory

Ions passing thru channels.

low lvls of activation, lil amount of glutamate released. Post synaptic response is controlled by AMPA receptors. The pore of NMDA receptors is blocked by Mg²⁺.

metabotropic responses in memory

secondary messenger cascade, increase in proteins and enzymes.

High lvls of glutamate release cause enough post synaptic depolarization to release Mg²⁺ block of NMDA channels, calcium enters +metabolic response occurs, potentiation of the synapse. Activation of metabotropic NMDA receptors

anterograde vs retrograde amnesia

you cant remember things after the injury(post traumatic

you cant remember things that happened prior to the injury

limbic system fuction

responds to external triggers. Complex network structure deep in the brain controling emotion, memory+survival drive.

Key components:thalamus,hypothalamus, amygdala, hippocampus

emotions+motivation/reward

Why is dopamine important

produced in dopaminergic neurons in SN(substantia nigra) and VTA(ventral tegmental) areas of the brain. Monoamine synthesis pathways and serotonin-noradrenalin is linked to dopamine synthesis

cycle for addiction

preoccupation anticipation, binge intoxication, withdrawel/negative affect, spiral distress. the addictive chemicals take the breaks off of dopamine-producing neurons.

chemicals/drugs and their addictive potential

opiods, cannabinoids, diazepam, and other drugs.

memory

declaritive:facts+events you can consciously recall ex:names, dates

Non-declarative memory:skills,habits+responses ex:fear of hot stove+bike riding

synapse+neurotransmitter activity

Ap arrives at presynaptic terminal, vescicles fuse with membrane+release glutamate into cleft, Glutamate binds AMPA receptors depolarizing postsynaptic cell

NMDA receptor

involved in memory formation

needs glutamate to bind fro presynaptic cell also needs post synaptic membrane to be sufficiently depolarized and Mg block to be dispelled.

Types of memory

immediate/short term-remember for 30sec 5-10 items

Recent memory-info undergoes consolidation occuring within a few hrs + is stored in hipocampus 3-5min

Remote/long-term: weeks-lifetime, most of our personal experience and knowledge, requires protein synthesis.

Learning+memory involve regions of cortex that process sensory info +control motor output. long memory also needs cholinergic neural system working and neuro-trophins that help preserve cholinergic neurons(acetylcholine)

Addiction stages

initial: experimentation, self-medication, peer pressure, genetic predisposition,

Early/medium: all above plus memories of pleasure, increased incentive of drug related stimuli, in neurons:synaptic plasticity in hippocampus, amygdala

Late/relapse: All above plus habit is established and unconscious. in neurons: synaptic plasticity of neocortical projections to dorsal striatum