PMID-16271465[] The basal ganglia: Learning new tricks and loving it
- learning-related changes occur significantly earlier in the striatum than the cortex in a cue-reversal task. she says that this is because the basal ganglia instruct the cortex. I rather think that they select output dimensions from that variance-generator, the cortex.
- dopamine agonist treatment improves learning with positive reinforcers but not learning with negative reinforcers.
- there is a strong hyperkinetic pathway that projects directly to the subthalamic nucleus from the motor cortex. this controls output of the inhibitor pathway (GPi)
- GABA input from the GPi to the thalamus can induce rebound spikes with precise timing. (the outputs are therefore not only inhibitory).
- striatal neurons have up and down states. recommended action: simultaneous on-line recording of dopamine release and spike activity.
- interesting generalization: cerebellum = supervised learning, striatum = reinforcement learning. yet yet! the cerebellum has a strong disynaptic projection to the putamen. of course, there is a continuous gradient between fully-supervised and fully-reinforcement models. the question is how to formulate both in a stable loop.
- striosomal = striatum to the SNc
- http://en.wikipedia.org/wiki/Substantia_nigra SNc is not an disorganized mass: the dopamergic neurons from the pars compacta project to the cortex in a topological map, dopaminergic neurons of the fringes (the lowest) go to the sensorimotor striatum and the highest to the associative striatum
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