Cerebellar posterior interpositus nucleus as an enhancer of classically conditioned eyelid responses in alert cats.
Cerebellar posterior interpositus neurons were recorded in cats during delayed and trace conditioning of eyeblinks. Type A neurons increased their firing in the time interval between conditioned and unconditioned stimulus presentations for both paradigms, while type B neurons decreased it. The discharge of different type A neurons recorded across successive conditioning sessions increased, with slopes of 0.061-0.078 spikes/s/trial. Both types of neurons modified their firing several trials in advance of the appearance of eyelid conditioned responses, but for each conditioned stimulus presentation their response started after conditioned response onset. Interpositus microstimulation evoked eyelid responses similar in amplitude and profiles to conditioned responses, and microinjection of muscimol decreased conditioned response amplitude. It is proposed that the interpositus nucleus is an enhancer, but not the initiator, of eyelid conditioned responses.
Gruart
A
A
División de Neurociencias, Laboratorio Andaluz de Biología, Universidad Pablo de Olavide, 41013 Sevilla, Spain.
Guillazo-Blanch
G
G
Fernández-Mas
R
R
Jiménez-Díaz
L
L
Delgado-García
J M
JM
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001143:Arousal; D002415:Cats; D002529:Cerebellar Nuclei / Q000166:cytology / Q000502:physiology*; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology; D003215:Conditioning, Eyelid / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D004576:Electromyography; D004594:Electrophysiology; D018755:GABA Agonists / Q000494:pharmacology; D009046:Motor Neurons / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
D018755:GABA Agonists; D009118:Muscimol