The site of a motor memory shifts with consolidation.
The basis for the consolidation of memory is a controversial topic, particularly in the case of motor memory. One view is that motor memory is transferred, partially or completely, to a new location during the consolidation process ("systems consolidation"). We investigated this possibility in a primitive motor system, the vestibulo-ocular reflex (VOR). In the simple circuitry of the VOR, there are relatively few possible storage sites for memory. We partially blocked excitatory neurotransmission in the cerebellar cortex of cats with the glutamate antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). If CNQX was injected immediately after 60 min of rotation under conditions that induced a learned decrease in the gain of the VOR, gain was returned to its baseline value. Expression of the new memory could also be disrupted by rotation in darkness, suggesting that consolidation had not taken place; however, after learning had continued for 3 d, expression of the learned change was diminished only slightly by blockade and was unaffected by rotation in darkness. Our interpretation of these results is that learning may take place initially in the cerebellar cortex and that during consolidation, motor memories are converted to a more distributed representation that includes the cerebellar cortex and another site.
Kassardjian
Charles D
CD
Division of Cellular and Molecular Biology, Toronto Western Research Institute, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
Tan
Yao-Fang
YF
Chung
Ji-Yeon J
JY
Heskin
Raquel
R
Peterson
Michael J
MJ
Broussard
Dianne M
DM
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D002415:Cats; D019416:Head Movements / Q000187:drug effects / Q000502:physiology; D008297:Male; D008568:Memory / Q000502:physiology*; D009048:Motor Skills / Q000187:drug effects / Q000502:physiology*; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D012027:Reflex, Vestibulo-Ocular / Q000187:drug effects / Q000502:physiology
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione