Reconstruction of single olivocerebellar axons in the rat cerebellar cortex

Reconstruction of single olivocerebellar axons in the rat cerebellar cortex

s171 CORRELATION BETWEEN TEMPORAL SIMPLE-SPIKE RATE OF THE FLOCCULAR MIDDLE ZONE AND EYE MOVEMENTS DURING OPTOKINETIC RESPONSES IN CATS. 318 TOSHIH...

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s171

CORRELATION BETWEEN TEMPORAL SIMPLE-SPIKE RATE OF THE FLOCCULAR MIDDLE ZONE AND EYE MOVEMENTS DURING OPTOKINETIC RESPONSES IN CATS.

318

TOSHIHIRO KITAMA’, AKIHITO MIZUKOSHI’. TAKEHIKO and YU SATO’ ‘Dept. of Physiology and ‘Dept. of Otolaryngology, 409-3898, Japan

UENO’, LIJAN HONG-GE’

Yamanashi-Medical

Univ., Tamaho, Yamanashi

It has been shown that the floccular middle zone of the cat controls eye movements plane.

We studied relationship between

and the eye movement

parameters(acceleration,velocity

using a multiple linear regression

postion coefficients

SS activities represent

319

were large whereas acceleration

SS firing preceded

were negative.

an inverse-dynamics

of eye movements

Y.Kobayashi3,4,

A.Takemura4,5,

K.Kawano4,S

responses

by the linear sum of the

coefficients

were small, and

The results suggest that

the eye movements.

A CEREBELLAR-PLASTICITY-BASED SIMULATION OF OCULAR FOLLOWING RESPONSES

K.Yamamotol.2,

cells in the middle zone

and position) during optokinetic

SS fuing was well reconstructed

method.

Velocity coefficients

motor parameters.

simple spike(SS) activities ofpurkinje

in the horizontal

during optokinetic response. OF THE ACQUISITION

OF THE PROPERTIES

and M.Kawatol

lATR human info. Proc. Res. Labs,, Kyoto 2Niigata Univ. school of med. 3Natl. Inst. Physiol. SElectrotechnical Lab., Ibaraki, Japan

Sci., Aichi 4CREST,

JST

Using a realistic model which reconstructs simple and complex spikes, we propose a simulation model to reproduce the acqutsition of OFR properties in adult animals and behavioral data during adaptive changes of OFR. In this model, learning sites are placed at the synapses between parallel fibers or inhibitory cells and Purkinje cells. Climbing fiber inputs to Purkinje cells were assumed to prefer upward or contraversive stimulus motion at birth. Preferred directions of the parallel fiber and inhibitory cell inputs were set so as to cover 360 degrees in total. The efficacy of the parallel fiber and inhibitory cell inputs on the Purkinje cells was changed plastically by LTD. LTP, and rebound potentiation. After the repetition of the standard velocity step of the large field visual stimulus in various directions, those Purkinje cells that received climbing fiber inputs preferring upward motion, increased their firing rate for downward stimuli and decreased it for upward stimuli. Those Purkinje cells that received climbing fiber inputs preferring con&aversive motion, increased their firing rate for ipsiversive stimuli and decreased it for contraversive stimuli. Even when the visual stimulus moved, the eyes did not move before the repetition of the stimuli; eye movements started following the visual stimulus only after the repetition. Using the same model, repeated exposure to speed steps involving abrupt increases or decreases in speed resulted in increases or decreases, respectively, in the OFR elicited by the standard speed step stimulus. The synaptic transmission efficacy required changing even when the firing of the parallel liber inputs and inhibitory cell inputs preceded the complex spikes. We also discuss whether the various kinds of parallel fiber firing properties can produce the reported uniform kind of simple spike firing properties by our model RECONSTRUCTION

320 I. SUGIHARA.

Department

OF SINGLE OLIVOCEREBELLAR

AXONS

IN THE RAT CEREBELLAR

CORTEX.

H -S. WU and Y. SHINODA

of Physiology.

Tokyo Medical and Dental University School of Medicine.

I-5-45

Yushima. Bunkyo-ku.

Tokyo

I 13-8519. Japan. Single olivocerebellar

axons originating

from the rat inferior olivary

amine injected mto the nucleus. was reconstructed. which terminated as a climbing

fiber (CF).

nucleus. that were labeled with biotinylated

Each axon (n=l I so far) gave rise to 2

dextran

- I7 thick collaterals, rach of

All CFs of some single axons terminated in a single lobule. while CFs of other

single axons were separated mto two or three groups that terminated in diffet-ent lobules.

Branchings usuallv occurred in the

white matter near the cerebellar nucleus or in the deep potlion of the folial white matter and occasionally in the distal portton of the folium or in the granular layer. which was usually less than 200 pm. trees of the Purkimc iells.

All CF termmalx of a single axon aerc located in a thin longitudinal in each lobule.

Supported by CREST

This strip was approximately

and Grants-In-Aid

for Scientific

strip. the width of

parallel to the planes of the dendritic

Research.