LECT 1 | Pierce Flashcards
What is the name of the system that is central to pleasure, reward and addiction?
Mesolimbic System
Does _ activity in the nucleus accumbens activate or inhibit pleasure?
Inhibit pleasure
Does _ activity in the ventral tegmental area (VTA) activate or inhibit pleasure?
Activate pleasure
Which neurotransmitter is released by the nucleus accumbens (NA) to the prefrontal cortex?
GABA
Which neurotransmitter is released by the ventral tegmemtal area (VTA) to the nucleus accumbens?
Dopamine
Which neurotransmitters do the prefrontal cortex and lateral hypothalamic nucleus release to _ the VTA, repectively?
PFC_ EAA LHN_ orexin (from fooooood)
Describe the negative feedback loop between the NA and VTA.
GABA and dynorphin from NA released back to VTA_ _ further DA release from VTA
Describe the dopamine hypothesis of reward.
Dependence-producing drugs _ the mesolimbic DA system_ pleasure
Explain an example of how a reward can be induced by dopamine-independent mechanisms.
Endogenous opioids also _ VTA via disinhibition of GABAergic neurons locally through -receptors _ DA from VTA_ _ NA_ pleasure
Which neurons encode the discrepancy between reward predictions vs. actual reward?
Dopaminergic
Describe the results of the following on the reward system: 1. Unpredicted reward 2. Fully predicted reward 3. Lack of predicted reward
- Activation (positive prediction error) 2. No response 3. Depression (negative prediction error)
Define long-term potentiation (LTP).
A persistent _ in synaptic strength following high-frequency stimulation of a chemical synapse
What is the effect of CREB (cAMP response elements) in the nucleus accumbens?
Targets dynorphin
Describe the mechanism of physical dependency.
CREB-dependent upregulation of target genes in locus coeruleus (LC)_ excessive noradrenergic output
Do CREB-dependent mechanisms result in short-term or long-term changes?
Short-term changes
List a couple things that activate _FosB.
Stress Drugs of abuse
Activation of _FosB leads to _ expression of what (3)?
- EAA receptors (AMPA/NMDA) 2. Elements of cell signaling 3. Factors promoting drug seeking, motivation, and locomotion
Do _FosB-dependent mechanisms result in short-term or long-term changes?
Long-term (structural) changes
Describe the role of NF-_B in terms of drug addiction.
Induced within NA and promotes growth of dendritic spines_ _ drug rewards
Describe the effect of associative learning (conditioning) on dopamine firing in the VTA.
_ Phasic DA firing in the VTA_ fast, short-lived _ of DA in the NA, reflecting expectation of reward
Describe the difference between natural rewards vs. drugs of abuse in regards to phasic dopamine firing in the VTA.
Natural reinforcers (food, sex, exercise): cease phasic DA firing when the event concludes Drugs of abuse: continue increasing DA release
