An adaptive‐filter model of cerebellar zone c3 as a basis for safe limb control?
Published online on July 12, 2013
Abstract
Abstract The review asks how the adaptive‐filter model of the cerebellum might be relevant to experimental work on zone C3, one of the most extensively studied regions of cerebellar cortex. As far as features of the cerebellar microcircuit are concerned, the model appears to fit very well with electrophysiological discoveries concerning the importance of molecular layer interneurons and their plasticity, the significance of LTP, and the striking number of silent parallel‐fibre synapses. Regarding external connectivity and functionality, a key feature of the adaptive‐filter model is its use of the decorrelation algorithm, which renders it uniquely suited to problems of sensory noise‐cancellation. However, this capacity can be extended to the avoidance of sensory interference, by appropriate movements of e.g. the eyes in the vestibulo‐ocular reflex. Avoidance becomes particularly important when painful signals are involved, and since the climbing‐fibre input to zone C3 is extremely responsive to nociceptive stimuli, it is proposed that one function of this zone is the avoidance of pain, by for example adjusting movements of the body to avoid self‐harm. This hypothesis appears consistent with evidence from humans and animals concerning the role of the intermediate cerebellum in classically conditioned withdrawal reflexes, but further experiments focussing on conditioned avoidance are required to test the hypothesis more stringently. The proposed architecture may also be useful for automatic self‐adjusting damage‐avoidance in robots, an important consideration for next generation ‘soft’ robots designed to interact with people.
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