Reward pathway Flashcards
Objective or Subjective?
Reward.
Subjective
Objective or Subjective?
Reinforcement
Objective
What is reinforcement?
To perform a behavior in order to obtain that stimulus
What is the ‘reward pathway’?
the mesolimbic pathway
What are the two main dopamine pathways?
Ventral tegmental area
- -> Nucelus accumbens
- ->Frontal cortex
Substantia nigra
–> Caudate
6-OHDA does what?
Destroys dopaminergic neurones
D1 and D2 antagonists do what?
Inhibit drug self administration
Drugs abused by humans usually increase synaptic concentrations of which chemical?
Dopamine
Cocain and amphetamine increase dopamine levels by…
Increasing DA release or inhibiting the re-uptake (in Nacc)
Opiates increase dopamine levels by…
Act on U-opioid receptors on GABAergic neurones.
Causes disinhibition of DA neurones in VTA
Ethanol increases dopamine levels by…
Acts directly on DA neurones in VTA
Decreases After-Hyperpolarisation (AHP)
Increases firing rate
Nicotine increases dopamine levels by…
Acts on nicotinic Ach receptors on DA neurones in VTA
Increases firing rate
Cannabis increases dopamine levels by…
Acts on cannabinoid receptors on GABAergic neurones
Causes disinhibition of DA neurones in VTA
Describe the dopamine-reward hypothesis
Natural rewards increase DA levels in Nacc
Drugs of abuse mimic natural rewards
Reward is the initial drive to take drugs (Doesn’t explain the addiction)
