Normal motor learning during pharmacological prevention of Purkinje cell long-term depression.
Systemic delivery of (1R-1-benzo thiophen-5-yl-2[2-diethylamino)-ethoxy] ethanol hydrochloride (T-588) prevented long-term depression (LTD) of the parallel fiber (PF)-Purkinje cell (PC) synapse induced by conjunctive climbing fiber and PF stimulation in vivo. However, similar concentrations of T-588 in the brains of behaving mice and rats affected neither motor learning in the rotorod test nor the learning of motor timing during classical conditioning of the eyeblink reflex. Rats given doses of T-588 that prevented PF-PC LTD were as proficient as controls in learning to adapt the timing of their conditioned eyeblink response to a 150- or 350-ms change in the timing of the paradigm. The experiment indicates that PF-PC LTD under control of the climbing fibers is not required for general motor adaptation or the learning of response timing in two common models of motor learning for which the cerebellum has been implicated. Alternative mechanisms for motor timing and possible functions for LTD in protection from excitotoxicity are discussed.
Welsh
John P
JP
Neurological Sciences Institute, Oregon Health and Science University, Beaverton, OR 97006, USA.
Yamaguchi
Hidetoshi
H
Zeng
Xiao-Hui
XH
Kojo
Masanobu
M
Nakada
Yasushi
Y
Takagi
Akiko
A
Sugimori
Mutsuyuki
M
Llinás
Rodolfo R
RR
D000818:Animals; D001767:Blinking / Q000187:drug effects / Q000502:physiology; D004048:Diethylamines / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects* / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009433:Neural Inhibition / Q000187:drug effects* / Q000502:physiology; D011689:Purkinje Cells / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013876:Thiophenes / Q000494:pharmacology*
D004048:Diethylamines; D013876:Thiophenes; C082372:T 588