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1516 Visuomotor and motor type saccade related purkinje cells in the cerebellar hemisphere of the monkey
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VISUOMOTOR AND MOTOR TYPE SACCADE RELATED PURKlNJE CELLS IN THE CEREBELLAR HEMISPHERE OF THE MONKEY Dept. of Neurophysiol., Tokyo Metropolitan Institute for Neuroscience, Musashidai 2-6, Fuchu-shi, Tokyo 183, Japan NORIICHI MANO, YUMI ITO, HIDETOSHI SHIBUTANI We found visuomotor type saccade-related Purkinje cells in the posterior cerebellar hemisphere of the monkey, in addition to the motor type saccade-related Purkinje cells which we have already reported. The visuomotor type Purkinje cells have two component of discharges: the one is the visual component which responded with constant latency of 60 milliseconds to the jump of a fixation light spot from a center to either 20 degrees up, down, left or right directions. The other is the motor component which shows the same discharge characteristics as the discharges of motor type Purkinje cells, i.e., the discharge rate begins t.o change 80 to 20 milliseconds prior and time-locked to the onset of saccades. The visuomotor type Purkinje cells were found in the posterior region of Crus IIa, intermingled with the motor type Purkinje cells.
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EFFECTS OF GAZE ON NEURONAL ACTIVITIES IN THE VENTRAL PREMOTOR CORTEX AND THE PRIMARY MOTOR CORTEX Dept. Physiol. Tohoku Univ. School of Medicine, Sendai, 980, Japan’, PREST, JST2
PART OF
Hajime Mushiake ’ *2, Yasuyuki Tanatsugu l, Jun Tanjil We compared neuronal activity of the ventral part of premotor cortex(PMv) and the primary motor cortex(M1) in the premovement period while the monkey reached the target with its eyes fixating on either a left or right fixation target. Our data demonstrated that about half of the movement-related activity in the PMv was modulated by the direction of gaze. In contrast, a vast majority of the activity of MI neurons and about half of PMv neurons were not influenced by the direction of gaze.
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Functional dissociation within the cerebellum: motor execution and sensori-motor readiness Dept. Physiol. Juntendo Univ. School of Medicine, 2-l-l Hongo, Bunkyo-ku, Tokyo, Japanl, Communications Res. Lab. 4-2-l Nukui kita-machi, Koganei-shi, Tokyo, Japan2 KATSUYUKI SAKAI’, RYOUSUKE TAKIN02, SATORU MIYAUCH12, OKIHIDE HIKOSAKA’ Cerebellar activation was measured using functional MRI, while the seven normal subjects pressed a button paced by tone sequences with a constant (ISI=500ms) or random intervals (ISI=300~700ms). Under the constant tone condition, the reaction time fell within -50~50ms, suggesting that the subject made self-paced response, and only the ipsilateral anterior lobe of the cerebellum was activated. In contrast, under the random tone condition, most of the reaction time fell within 250~350ms, suggesting that the response was externally triggered by the tone, and the bilateral posterior lobes, especially the lateral part of ansiform lobules as well as the ipsilateral anterior lobe were activated. Based on these findings, we conclude that the anterior lobe subserves motor execution, while the ansiform lobule subserves readiness for the stimuli presented with unpredictable timing.
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VISUOMOTOR AND MOTOR TYPE SACCADE RELATED PURKlNJE CELLS IN THE CEREBELLAR HEMISPHERE OF THE MONKEY Dept. of Neurophysiol., Tokyo Metropolitan Institute for Neuroscience, Musashidai 2-6, Fuchu-shi, Tokyo 183, Japan NORIICHI MANO, YUMI ITO, HIDETOSHI SHIBUTANI We found visuomotor type saccade-related Purkinje cells in the posterior cerebellar hemisphere of the monkey, in addition to the motor type saccade-related Purkinje cells which we have already reported. The visuomotor type Purkinje cells have two component of discharges: the one is the visual component which responded with constant latency of 60 milliseconds to the jump of a fixation light spot from a center to either 20 degrees up, down, left or right directions. The other is the motor component which shows the same discharge characteristics as the discharges of motor type Purkinje cells, i.e., the discharge rate begins t.o change 80 to 20 milliseconds prior and time-locked to the onset of saccades. The visuomotor type Purkinje cells were found in the posterior region of Crus IIa, intermingled with the motor type Purkinje cells.
1517
EFFECTS OF GAZE ON NEURONAL ACTIVITIES IN THE VENTRAL PREMOTOR CORTEX AND THE PRIMARY MOTOR CORTEX Dept. Physiol. Tohoku Univ. School of Medicine, Sendai, 980, Japan’, PREST, JST2
PART OF
Hajime Mushiake ’ *2, Yasuyuki Tanatsugu l, Jun Tanjil We compared neuronal activity of the ventral part of premotor cortex(PMv) and the primary motor cortex(M1) in the premovement period while the monkey reached the target with its eyes fixating on either a left or right fixation target. Our data demonstrated that about half of the movement-related activity in the PMv was modulated by the direction of gaze. In contrast, a vast majority of the activity of MI neurons and about half of PMv neurons were not influenced by the direction of gaze.
1518
Functional dissociation within the cerebellum: motor execution and sensori-motor readiness Dept. Physiol. Juntendo Univ. School of Medicine, 2-l-l Hongo, Bunkyo-ku, Tokyo, Japanl, Communications Res. Lab. 4-2-l Nukui kita-machi, Koganei-shi, Tokyo, Japan2 KATSUYUKI SAKAI’, RYOUSUKE TAKIN02, SATORU MIYAUCH12, OKIHIDE HIKOSAKA’ Cerebellar activation was measured using functional MRI, while the seven normal subjects pressed a button paced by tone sequences with a constant (ISI=500ms) or random intervals (ISI=300~700ms). Under the constant tone condition, the reaction time fell within -50~50ms, suggesting that the subject made self-paced response, and only the ipsilateral anterior lobe of the cerebellum was activated. In contrast, under the random tone condition, most of the reaction time fell within 250~350ms, suggesting that the response was externally triggered by the tone, and the bilateral posterior lobes, especially the lateral part of ansiform lobules as well as the ipsilateral anterior lobe were activated. Based on these findings, we conclude that the anterior lobe subserves motor execution, while the ansiform lobule subserves readiness for the stimuli presented with unpredictable timing.