<論文・報告>Effects of Luminance Contrast on the Looming-sensitive Neuron of the Praying Mantis Tenodera aridifolia

Abstract

Responses of the looming-sensitive neurons to visual stimuli were recorded extracellularly from the cervical connective of the mantis Tenodera aridifolia. Responses to looming stimuli were affected by the contrast polarity between objects and background. Although the looming-sensitive neuron responded to looming objects both darker and lighter than the background, the maximum spike frequency during the presentation of a white looming circle on black background was significantly lower than that of a black-on-white looming circle. On the checkerboard background, which had the similar average luminance to gray, the maximum spike frequencies in response to a white looming circle were significantly smaller than that to black and gray looming circles. Finally, responses to black and gray looming circles on checkerboard background appeared to be similar: there was no significant difference in the maximum spike frequency between them.

オオカマキリの腹髄から衝突検出ニューロンの応答を細胞外記録した. 衝突検出ニューロンの応答は物体と背景の間のコントラストの方向に影響された. 衝突検出ニューロンは背景よりも明るい接近刺激と暗い接近刺激ともに応答したが, 黒背景白図形の接近刺激を提示した時の最大スパイク頻度は白背景黒図形のものに比べて有意に低かった. 平均の明るさが灰色とほとんど等しい市松模様を背景にした場合, 白色の接近刺激に対する応答の最大スパイク頻度は, 黒色・灰色の接近刺激に対するものと比べて有意に低かった. 市松模様背景における黒色と灰色の接近刺激に対する応答は似ており, 最大スパイク頻度の間には有意差が見られなかった.