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Coordinated eye and head movements induced by stimulation of the caudate nucleus
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E F F E C T S OF D O P A M I N E D E F I C I E N C Y ON T A S K S P E C I F I C SACCADIC EYE MOVEMENTS A b ~ E R MPTP I N F U S I O N INTO THE MONKEY CAUDATE NUCLEUS. A.KORI*, N. MIYA~HITA*, ~,U~UI*, M. KATQ*, M, M A T S U M U R A * AND O. HIKOSAKA, N a t i o n a l I n s t i t u t e for Phv~iolofficol Sciences. Mvodaiii. O k a z a k i 444. J a p a n . The basal ganglia participate in the initiation of voluntary visual and memory guided saccades. Local dopamine deficiency in the eaudate nucleus was induced to investigate the influence of this n e u r o t r a n s m i t t e r on the saccade activity. Monkeys trained to perform visual and memory guided saccades received an intracaudate infusion of MPTP. Effects were more evident in the saccades made to the contralateral side of the infusion. I n the visual saccades, only latencies became slightly longer and variable after MPTP treatment. More important changes were seen in the memory guided saccades: they were hypometric, their latencies were longer and their velocities decreased. Misdirected saccades to the ipsilateral hemifield were frequently seen. These results indicate that dopamine is involved in the i n i t i a t i o n and control of saccadic eye movements, especially those memory guided.
COORDINATED EYE AND HEAD MOVEMENTS INDUCED BY STIMULATION OF THE CAUDATE NUCLEUS. TOSHIHIRO KITAMA*, TADAO OHNO, MAKI TANAKA~, HIROSHI TSUBOKAWA*, AND KAORU YOSHIDA, Department of Physiology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, lbaraki 305, lapan. Effects of stimulation of the caudate nucleus on eye and head movements were studied in alert cats. Stimulation with 0.5-1 sec pulse trains (0.2 msee pulses, 100/sec, 50-200 pA) did induce saccadic gaze shifts toward the contralateral side. When the head was restrained, the vast majority of evoked eye movements were single conjugate saccades. The amplitude of the saccade varied with the initial position of the eye, and was larger for saccades initiated from more contralateral positions. If the eyes were directed far contralaterally, no saccades were induced. When the head was freed, the same stimulation induced a sequence of contraversive gaze saccades composed of several coordinated eye and head movements. The amplitude of the eye movement in the orbit was similar to that in the head-restrained condition. However, combined with the concomitant head movement, the amplitude of the eye movement in space (i.e. the gaze shift) was significantly larger than in head-resh'ained condition. Coordinated eye and head movements were also induced in the total darkness, but the number of saccades was clearly less than that in the light. Further, the amplitude of individual gaze shifts in the dark was often very large and distributed over a wide range. These results indicate that characteristics of the saccades produced by caudate stimulation are affected by situations in which they were induced.
VISUALAND OCULOMOTORFUNCTIONSOF THE MONKEY SUBTHALAMICNUCLEUS MASARU MATSUMURA*.JUNKOJIMA*,TOMW.GARDINER*,ANDOKIHIDE HIKOSAKA,Labomtoryof .Neural Control. National Institute for Phv~il0gicalSciences. 38 Nishigonaka,Myoudaiji,Okazaki,444Jar)an. We studied singlecell activitiesin the subthalamienucleus(STN)of monkeys while they were performing visuomotor tasks. Twenty-five% of STN neurons were related to visuo-oculomotor functions. The visuo-oculomotor activities were classifiedas; saccade-related,eye fixation-related,visual, target and reward related. Activity related to saccade was a phasic excitation after the onset of saccade. The activity was selective for the directionof saccade, mostly contralateralto the recordingsite. Activity related to visual stimuli was also excitatory.The receptive fields were on the contralateralside. Activityrelated to eye locationwas a sustained discharge while the animal was locating on the target point, which ceased abruptly when the target went off and the animal made a saccade. Activity related to target and reward was similar to the Vocation-relatedactivity which, however, was apparent only when the monkey was expecting a reward that would be delivered after its dimming.Visuo-occulomotor-relatedneurons were located mostly at the ventral half of STN. In contrast, skeletomotor-relatedneurons were located mostly at its dorsal half. We hypothesizethat the activity of STN may act to maintainfixation (locationactivity)and to stabilizeeye position after saccade (saccade activity) by sending excitatory signals to the substantianigra pars reticulata.
E F F E C T S OF D O P A M I N E D E F I C I E N C Y ON T A S K S P E C I F I C SACCADIC EYE MOVEMENTS A b ~ E R MPTP I N F U S I O N INTO THE MONKEY CAUDATE NUCLEUS. A.KORI*, N. MIYA~HITA*, ~,U~UI*, M. KATQ*, M, M A T S U M U R A * AND O. HIKOSAKA, N a t i o n a l I n s t i t u t e for Phv~iolofficol Sciences. Mvodaiii. O k a z a k i 444. J a p a n . The basal ganglia participate in the initiation of voluntary visual and memory guided saccades. Local dopamine deficiency in the eaudate nucleus was induced to investigate the influence of this n e u r o t r a n s m i t t e r on the saccade activity. Monkeys trained to perform visual and memory guided saccades received an intracaudate infusion of MPTP. Effects were more evident in the saccades made to the contralateral side of the infusion. I n the visual saccades, only latencies became slightly longer and variable after MPTP treatment. More important changes were seen in the memory guided saccades: they were hypometric, their latencies were longer and their velocities decreased. Misdirected saccades to the ipsilateral hemifield were frequently seen. These results indicate that dopamine is involved in the i n i t i a t i o n and control of saccadic eye movements, especially those memory guided.
COORDINATED EYE AND HEAD MOVEMENTS INDUCED BY STIMULATION OF THE CAUDATE NUCLEUS. TOSHIHIRO KITAMA*, TADAO OHNO, MAKI TANAKA~, HIROSHI TSUBOKAWA*, AND KAORU YOSHIDA, Department of Physiology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, lbaraki 305, lapan. Effects of stimulation of the caudate nucleus on eye and head movements were studied in alert cats. Stimulation with 0.5-1 sec pulse trains (0.2 msee pulses, 100/sec, 50-200 pA) did induce saccadic gaze shifts toward the contralateral side. When the head was restrained, the vast majority of evoked eye movements were single conjugate saccades. The amplitude of the saccade varied with the initial position of the eye, and was larger for saccades initiated from more contralateral positions. If the eyes were directed far contralaterally, no saccades were induced. When the head was freed, the same stimulation induced a sequence of contraversive gaze saccades composed of several coordinated eye and head movements. The amplitude of the eye movement in the orbit was similar to that in the head-restrained condition. However, combined with the concomitant head movement, the amplitude of the eye movement in space (i.e. the gaze shift) was significantly larger than in head-resh'ained condition. Coordinated eye and head movements were also induced in the total darkness, but the number of saccades was clearly less than that in the light. Further, the amplitude of individual gaze shifts in the dark was often very large and distributed over a wide range. These results indicate that characteristics of the saccades produced by caudate stimulation are affected by situations in which they were induced.
VISUALAND OCULOMOTORFUNCTIONSOF THE MONKEY SUBTHALAMICNUCLEUS MASARU MATSUMURA*.JUNKOJIMA*,TOMW.GARDINER*,ANDOKIHIDE HIKOSAKA,Labomtoryof .Neural Control. National Institute for Phv~il0gicalSciences. 38 Nishigonaka,Myoudaiji,Okazaki,444Jar)an. We studied singlecell activitiesin the subthalamienucleus(STN)of monkeys while they were performing visuomotor tasks. Twenty-five% of STN neurons were related to visuo-oculomotor functions. The visuo-oculomotor activities were classifiedas; saccade-related,eye fixation-related,visual, target and reward related. Activity related to saccade was a phasic excitation after the onset of saccade. The activity was selective for the directionof saccade, mostly contralateralto the recordingsite. Activity related to visual stimuli was also excitatory.The receptive fields were on the contralateralside. Activityrelated to eye locationwas a sustained discharge while the animal was locating on the target point, which ceased abruptly when the target went off and the animal made a saccade. Activity related to target and reward was similar to the Vocation-relatedactivity which, however, was apparent only when the monkey was expecting a reward that would be delivered after its dimming.Visuo-occulomotor-relatedneurons were located mostly at the ventral half of STN. In contrast, skeletomotor-relatedneurons were located mostly at its dorsal half. We hypothesizethat the activity of STN may act to maintainfixation (locationactivity)and to stabilizeeye position after saccade (saccade activity) by sending excitatory signals to the substantianigra pars reticulata.