Transcript The role of the basal ganglia in habit formation

The role of the basal ganglia in habit
formation
Group 4
Youngjin Kang
Zhiheng Zhou
Baoyu Wang
21. What happens with pDMS lesions, and what
does this show us?
• pDMS lesion rats turned right on the cross maze
indicating a habituated response strategy.
• Showes the role of the DMS in flexible choice
behavior and A-O contingency.
22. Is the information represented by activity in
hippocampal place cells being compared to activity in
BG goal representation cells?
• No, they do not compete to each other.
• Hippocampus act together with dorsomedial
and ventral striatal regions to form a
functional circuit.
• Information provided by hippocampal place
cells conveyed to DMS to signal where to go to
reach the definite goal.
23. What did Baleine et al. show about how PFC
plays a role in learning?
• Lesions to the medial PFC, the prelimbic regions
which project to DMS, led to insensitive to
devaluation and degradation.
• Leisions to mediodorsal nucleus of the thalamus,
which links to both DMS and PFC, also led to the
similar result.
• Together, PFC might also plays a role in A-O
learning.
24. The authors of this article propose a model of
learning in basal ganglia and cortex. In their model,
what is a cortico-basal ganglia network?
• A fundamental motif of cerebral organization, and is the
fundamental unit of function at the level of behavior.
• Cortical, striatal and pallidal components,
• Cell groups (for example, dopaminergic)
• Associated diencephalic structures (for example, the thalamus and
the subthalamic nucleus)
• Three major levels:
•
•
•
Limbic (stimulus–outcome, S–O): appetitive Pavlovian learning
Associative (A–O): acquisition and performance of goal-directed actions
Sensorimotor (S–R) networks: S-R habits
Cortico-basal ganglia network
Cortico-basal ganglia network
25. What is wrong with this assertion: “For instance, it is often
asserted that the neocortex mediates a particular function,
whereas the striatum subserves another?”
• System neuroscience is dominated by attempts to localize
psychological functions without regard for the actual
functional circuitry of the brain.
• Not only do the psychological functions lack operational
specificity, but the anatomical entities that are said to
subserve such functions also lack the requisite circuitry.
• Using operationally defined representational structures that
can be dissociated behaviourally allows us to identify the
distributed networks that control distinct types of decisionmaking and learning.
26. Is Your Behavior Associative or Sensorimotor network ?
1.
2.
Associative Network
- “A-O”
- DMS (dorsomedial striatum), PFC
- reward expectancy, monitoring recent actions as well as anticipating their
consequences
Sensorimotor Network
- “S-R”
- DLS (dorsolateral striatum), sensorimotor cortices
- movement, discriminative stimuli
- shifts from a higher level of functional integration (associative cortico basal
ganglia network )to a lower one (the sensorimotor cortico-basal ganglia
network ).
3. Is your behavior Associative or Sensorimotor ?
- Training & Practice
- Ratio schedule or Interval schedule of reward
- Controlling over reward or not.
- Appropriate rate of reward and response has been established or not
(Fig. 4).
- “Adjusting a behavior to get expected reward , then keep it going.”
27. Drug Addiction : Classical Conditioning or Instrumental
Conditioning?
1.
Instrumental Conditioning (A-O)
- Learning reward using drugs. (dugs is better than any natural
gratification)
- Adjusting amount of drug (high enough, but avoiding overdose)
- Drug Seeking Behaviors (how to buy, do, but not being caught)
2.
Classical Conditioning (S-R)
- Drug habit formation (irresistible urge)
- Perception grown who are sellers (now just I know!)
- Environmental Cue (difficult to be clean)
“ Innocent Curiosity can Ruin your Entire Life! “