Cerebellar aminergic neuromodulation: towards a functional understanding.
Although a number of neuromodulators influence the cerebellar circuitry, their functions remain largely unknown. By reviewing and combining results from data-driven and theory-driven studies, we attempt to provide an integrated systems view of cerebellar neuromodulation. First, we review the short- and long-term effects of neuromodulators on the cerebellar circuitry. Second, we review recent theories of the cerebellum and show that a number of modulatory signals are needed for powerful cerebellar learning and control. Finally, we attempt to match each theoretically derived modulatory signal with a specific neuromodulator. In particular, we propose that serotonin controls the 'responsibility' of each cerebellar unit (or microcomplex) in cerebellar learning and control; norepinephrine gates unsupervised learning in the cerebellar cortex; dopamine enhances goal-oriented cerebellar learning; and, finally, acetylcholine controls the speed of supervised learning in Purkinje cells.
CREST, Japan Science and Technology Agency, ATR, 2-2-2, Hikaridai, Keihanna Science City, Kyoto 619-0288, Japan. nicolas@atr.co.jp
Nicolas
N
Schweighofer
Kenji
K
Doya
Shinya
S
Kuroda
D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism / Q000502:physiology*; D002531:Cerebellum / Q000378:metabolism*; D006801:Humans; D007858:Learning / Q000502:physiology; D009415:Nerve Net / Q000378:metabolism / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000502:physiology*
D001679:Biogenic Amines; D018377:Neurotransmitter Agents