前頭眼野 : 視覚入力・眼球運動出力に関する体制化
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概要
- 論文の詳細を見る
The frontal eye field (FEF) is topographically organized in terms of sensory input from the environmental space as well as oculomotor output. Many visual neurons are located in the FEF. Those located in the lateral part of the FEF have the visual receptive field in the foveal region of the contralateral visual field, while those in the medial part have the visual receptive field in the eccentric region from the fovea. Many oculomotor neurons are also found in the FEF, the activation of which elicits saccadic eye movements of a particular amplitude and direction, depending on their location in the FEF: activation in the lateral part of the FEF induces a saccade with a small amplitude, while activation in the medial part induces a large saccade. The destination of the saccades is always in the contralateral visual hemifield. The visual and oculomotor neurons located at a given part of the FEF area related. A saccade elicited by activation of the oculomotor neurons is generally directed to the most responsive area in the receptive field of the visual neurons, suggesting that a transfer of neuronal activities from the sensory neurons to the motor neurons induces visually-guided eye movements. In addition, the FEF exhibits an inhibitory effect on oculomotor initiation and holds the image of the visual object to the foveal region. Activation of FEF neurons representing the foveal region suppresses saccade generation. Furthermore, this suppressive effect of the lateral part of the FEF functions even when a visual object is moving. Electrical activation of this area elicits slow eye movement resembling a smooth pursuit eye movement. Spike activities are also seen in neurons in this area during smooth pursuit eye movements. Based on these facilitatory and inhibitory functions, the FEF may contribute to the generation of normal orientation behavior, which is composed of selecting a particular object in the environmental space, visual fixation on the object for an appropriate duration, and shifting from the object to other objects in proper time.
- 日本めまい平衡医学会の論文
- 1998-10-01