Occurrence of long-term depression in the cerebellar flocculus during adaptation of optokinetic response

Elife. 2018 Mar 27;7:e36209. doi: 10.7554/eLife.36209.

Abstract

Long-term depression (LTD) at parallel fiber (PF) to Purkinje cell (PC) synapses has been considered as a main cellular mechanism for motor learning. However, the necessity of LTD for motor learning was challenged by demonstration of normal motor learning in the LTD-defective animals. Here, we addressed possible involvement of LTD in motor learning by examining whether LTD occurs during motor learning in the wild-type mice. As a model of motor learning, adaptation of optokinetic response (OKR) was used. OKR is a type of reflex eye movement to suppress blur of visual image during animal motion. OKR shows adaptive change during continuous optokinetic stimulation, which is regulated by the cerebellar flocculus. After OKR adaptation, amplitudes of quantal excitatory postsynaptic currents at PF-PC synapses were decreased, and induction of LTD was suppressed in the flocculus. These results suggest that LTD occurs at PF-PC synapses during OKR adaptation.

Keywords: Cerebellum; Long-term depression; Motor learning; Optokinetic response; Parallel fiber; Purkinje cell; mouse; neuroscience.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Animals
  • Cerebellum / physiology
  • Eye Movements*
  • Learning*
  • Long-Term Synaptic Depression*
  • Mice
  • Psychomotor Performance*

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.