Involvement of the ipsilateral and contralateral cerebellum in the acquisition of unilateral classical eyeblink conditioning in guinea pigs.
OBJECTIVE
The aim of this study was to evaluate the relative contributions of the ipsilateral and contralateral cerebellum to the acquisition of unilateral classical eyeblink conditioning (EBCC).


METHODS
The unilateral EBCC was achieved using a binaural tone conditioned stimulus (CS) paired with a left airpuff unconditioned stimulus (US). A high-resolution potentiometer was used to monitor eyeblink responses. Guinea pigs received one CS-US session followed by three CS-US sessions (sessions 2 to 4), during which microinjections of muscimol, a GABA(A) receptor agonist, were performed to reversibly inactivate the cerebellum unilaterally prior to training. To test whether any learning had occurred during these inactivation sessions, training was continued for six more CS-US sessions (sessions 5 to 10) without any inactivation.


RESULTS
Animals with inactivation of the left cerebellum had no signs of left conditioned response (CR) during sessions 2 to 4, and their CR acquisition during sessions 5 to 10 was not distinguishable from that of control animals during sessions 2 to 7. In contrast, animals with inactivation of the right cerebellum acquired left CRs during sessions 2 to 4, although their CR acquisition was significantly retarded during session 2. In addition, microinjections of muscimol into the right cerebellum did not affect left neuro-behavioral activity. Finally, microinjections of muscimol into either the left or the right cerebellum did not affect the performance of tone-airpuff evoked unconditioned response (UR).


CONCLUSIONS
In contrast to the essential role of the ipsilateral cerebellum, the contralateral cerebellum is potentially involved in the acquisition of unilateral EBCC during the early stage of training.
Hu
Bo
B
Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, China.
Lin
Xi
X
Huang
Lü-Shuai
LS
Yang
Li
L
Feng
Hua
H
Sui
Jian-Feng
JF
D000818:Animals; D001767:Blinking; D002531:Cerebellum / Q000033:anatomy & histology* / Q000187:drug effects / Q000502:physiology*; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D004594:Electrophysiology; D018755:GABA Agonists / Q000494:pharmacology; D006168:Guinea Pigs; D008297:Male; D008845:Microinjections; D009118:Muscimol / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism
D018755:GABA Agonists; D009118:Muscimol