網膜における情報処理と逃避行動(視覚情報の処理過程-その基礎研究と障害への応用,第28回大会 特別講演(公開))
2010 年 29 巻 1 号 p. 31-35
詳細
2010 年 29 巻 1 号 p. 31-35
Various aspects of visual information are analyzed by parallel circuits in the retina. The outputs are sent through optic fibres, which consist mostly of the axons of retinal ganglion cells, to multiple visual centres in the brain. At present we do not know how visual information is coded by spike trains in retinal ganglion cells. It has been reported that oscillatory synchronized activities are generated among visual neurons in a manner which depends on certain key features of light stimulation. Although these activities are assumed to play an important role in perceptual integration, their functional significance has yet to be elucidated. Using frogs we performed multi-electrode recordings from isolated retinas and behavioral tests. An expanding dark spot evoked oscillatory synchronized activities among dimming detectors (OFF-sustained ganglion cells), and elicited escape behavior. Intraocular injection of GABA_A and GABA_C receptor antagonists suppressed and enhanced escape behavior, respectively. The behavioral modification correlated only with the change in oscillatory synchronized activities among dimming detectors. These activities are likely to encode escape-related information in frogs.
