Classical eyeblink conditioning in glutamate receptor subunit delta 2 mutant mice is impaired in the delay paradigm but not in the trace paradigm

Eur J Neurosci. 2001 Mar;13(6):1249-53. doi: 10.1046/j.0953-816x.2001.01488.x.


In mice lacking glutamate receptor subunit delta 2 (GluR delta 2(-/-_ mice), cerebellar long-term depression (LTD) at the parallel fibre-Purkinje cell synapses is disrupted. Unlike the cerebellar LTD-deficient mice previously used for eyeblink conditioning, however, the abnormalities of the GluR delta 2(-/-) mice are restricted to the cerebellar cortex. In delay eyeblink conditionings (interstimulus interval of 252 and 852 ms), in which the conditioned stimulus (CS) overlaps temporally with a coterminating unconditioned stimulus (US), GluR delta 2(-/-) mice are severely impaired in learning, strongly supporting the hypothesis that cerebellar cortical LTD is essential for delay conditioning. In the trace paradigm, in which a stimulus-free trace interval of 500 ms intervened between the CS and US, GluR delta 2(-/-) mice learned as successfully as wild-type mice, indicating that cerebellar LTD is not necessary for trace conditioning. Thus, the present study has revealed a cerebellar LTD-independent learning in eyeblink conditioning.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blinking / physiology*
  • Conditioning, Classical / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains / genetics
  • Receptors, Glutamate / deficiency
  • Receptors, Glutamate / genetics
  • Receptors, Glutamate / physiology*
  • Time Factors


  • Receptors, Glutamate
  • glutamate receptor delta 2