Simple-spike activity of floccular Purkinje cells responding to sinusoidal vertical rotation and optokinetic stimuli in alert cats.
To understand how the cerebellar flocculus is involved in the processing of semicircular canal signals in the vertical vestibulo-ocular reflex (VOR), we analyzed the simple-spike activity of floccular Purkinje (P) cells that was modulated by sinusoidal pitch rotation, and then analyzed their activity during presentation of sinusoidal vertical optokinetic stimuli in alert, head-fixed cats. The great majority of P cells also responded to optokinetic stimuli with peak discharge near peak stimulus velocity. Eighty percent of P cells that responded to both pitch and optokinetic stimuli showed increased activity when the directions of the resultant eye movements were the same. During rapid modification of the VOR induced by visual pattern movement, modulation amplitudes of the cells tested increased together with the eye velocity increase. Maximal activation directions of these cells studied during vertical rotation in many planes were near the vertical canal planes, similar to those in our previous studies. The remaining 20% of P cells showed increased discharge for the same direction of stimulus movement. These results suggest that the activity of the majority of pitch-responding P cells contains, at least partly, a vertical eye velocity component during presentation of vestibular or optokinetic stimuli in addition to canal inputs during pitch rotation.
Fukushima
K
K
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Chin
S
S
Fukushima
J
J
Tanaka
M
M
D000818:Animals; D002415:Cats; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology; D005133:Eye Movements / Q000502:physiology; D005260:Female; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D010812:Physical Stimulation; D011689:Purkinje Cells / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology; D012399:Rotation