Inactivation of brainstem motor nuclei blocks expression but not acquisition of the rabbit's classically conditioned eyeblink response.
Rabbits were eyeblink conditioned while their accessory abducens nucleus (ACC), facial nucleus (FN), and surrounding reticular formation (RF) were temporarily inactivated with microinjections of muscimol to determine whether these structures are critically involved in acquisition of the conditioned eyeblink response (CR). Rabbits performed no CRs or unconditioned responses (URs) during inactivation training. Training was continued without inactivation and rabbits performed the CR at asymptotic levels from the start of training without inactivation. They had fully learned the CR while their ACC, FN, and RF were inactivated, despite performing no CRs or URs at all during inactivation. These results rule out any critical role for neurons within the ACC, FN, or surrounding RF in acquisition of the classically conditioned eyeblink response.
Krupa
D J
DJ
Department of Biology, University of Iowa, Neurosciences Program, University of Southern California, Los Angeles 90089-2520, USA.
Weng
J
J
Thompson
R F
RF
D000010:Abducens Nerve / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology; D001931:Brain Mapping; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology*; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D003215:Conditioning, Eyelid / Q000187:drug effects / Q000502:physiology*; D005143:Eyelids / Q000294:innervation; D005152:Facial Muscles / Q000294:innervation; D005154:Facial Nerve / Q000187:drug effects / Q000502:physiology*; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology; D008845:Microinjections; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012154:Reticular Formation / Q000187:drug effects / Q000502:physiology
D009118:Muscimol