2005 Fiscal Year Final Research Report Summary
Probing the cognitive brain functions with the oculomotor system
| Project/Area Number |
13854029
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
神経・脳内生理学
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| Research Institution | National Institute for Physiological Sciences (2004-2005)
Okazaki National Research Institutes (2001-2003) |
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Principal Investigator |
ISA Tadashi National Institute for Physiological Sciences, Department of Developmental Physiology, Professor, 発達生理学研究系, 教授 (20212805)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Masatoshi National Institute for Physiological Sciences, Department of Developmental Physiology, Assistant Professor, 発達生理学研究系, 助手 (30370133)
ENDO Toshiaki National Institute for Physiological Sciences, Department of Developmental Physiology, Assistant Professor, 発達生理学研究系, 助手 (30353436)
KOBAYASHI Yasushi Graduate School of Frontier Biosciences, Osaka University, Associate Professor, 大学院生命機能研究科, 助教授 (60311198)
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| Project Period (FY) |
2001 – 2005
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| Keywords | saccade / attention / motivation / cholinergic system / superior colliculus / mouse / blindsight / monkey |
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| Research Abstract |
In this study, we studied the fundamental structure of the neural circuits controlling saccades and how the activity of the circuits can be modulated in a context dependent manner.
(1)At the local circuits level, we clarified the neural mechanism of burst generation of the neurons in the deeper layer of the superior colliculus (SC). We found that the burst is generated via NMDA receptor-mediated transmission and local recurrent network. Release from GABAergic inhibition is essential for the circuit to exhibit burst.
(2)We recorded the activities of neurons in the pedunculopontine tegmental nucleus (PPTN), which is the origin of cholinergic input to the SC, during visually guided saccade task. We have found that a group of PPTN neurons showed tonic discharge while monkeys are fixating the fixation point and make saccades. When a large reward volume was expected, the neuron showed higher activity, while when small reward was predicted, the activity was low. These results suggest that these
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PPTN neurons encode predicted reward. Considering that the PPTN neurons project to the dopamine neurons in the substantia nigra, which have been shown to encode reward prediction error, activity of the PPTN neurons were supposed to be used for calculation of reward prediction error at the dopamine neurons.
(3)We investigated the saccades of monkeys with unilateral lesion of the primary visual cortex (V1) in monkeys. These monkeys with V1 lesion could perform visually guided saccades to the target presented in the blind field. These monkeys could perform memory guided saccades to the cue in the blind field and could exert top down attention to the cue in the blind field. These results suggested that the visual information through the pathway bypassing the V1 can trigger working memory and the visual processing in the pathway is under the influence of top down attention.
(4)We have established the high speed video oculography to detect saccades in mice. Saccade-like rapid eye movements could be induced by SC stimulation in mice. Thus, we have established the experimental system to study the molecular basis of cognitive functions using mice model. Less
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Research Products
(18 results)
