INFORMATION PROCESSING IN CEREBELLAR FLOCCULUS FUNCTIONAL ZONE

Research Project

Project/Area Number	08680885
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	神経・脳内生理学
Research Institution	YAMANASHI MEDICAL UNIVERSITY
Principal Investigator	SATO Yu YAMANASHI MEDICAL UNIVERSITY,PHYSIOLOGY,PROFESSOR, 医学部, 教授 (60111746)
Project Period (FY)	1996 – 1998
Project Status	Completed (Fiscal Year 1998)
Budget Amount *help	¥2,600,000 (Direct Cost: ¥2,600,000) Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 1996: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	CEREBELLUM / EYE MOVEMENT / OPTOKINETIC RESPONESE / MOTOR CONTROL / NEUROPHYSIOLOGY / モジュール / プルキンエ細胞
Research Abstract	We investigated correlation between the eye movement and temporal simple-spike (SS) frequency of the Purkinje cell in the cerebellar flocculus middle-zone during optokinetic response (OKR) in alert cats. Time course of the temporal SS-rate at a given time delay (mean, 11 ins) was well reconstructed with coefficient of determination > 0.7 by a linear weighted superposition of the eye acceleration (mean coefficient, 0.076 spikes/s per deg/s2), velocity (5.19 spikes/s per deg/s), position (-2.89 spikes/s per deg), and bias (mean, 35.8 spikes/s), Magnitude of the contribution of each component to the regression was estimated, and three cell types were found : Velocity-Position-Acceleration (VPA) type (n=19), contribution of velocity, position, and acceleration components is significant (P < 0.05) ; Velocity-Position (VP) type (n=9), velocity and position components are significant ; Velocity-Acceleration (VA) type (n=2), velocity and acceleration components are significant. Using a single set of the coefficients for 5 deg/s stimulus velocity, the SS rate during higher (10, 20, and 40 deg/s) stimulus velocities were successfully reconstructed, suggesting generality of the model. The eye-position information encoded in SS-firing during OKR is relative but not absolute in the sense that the magnitude of the position shift contributes to the firing-rate change regardless of the initial eye-position. It is concluded that 1) the temporal SS-firing frequency in the cat middle-zone encodes the velocity and acceleration information for controlling the viscosity- and inertia-forces, respectively, during short-duration horizontal OKR and 2) the position information encoded in the SS-firing is not sufficient for controlling the elastic force during] OKR.