环绕调制已经在几个哺乳动物的大脑区域进行了大量的研究,包括初级视觉皮层,外侧膝状核,和上丘(SC),但鸟类视神经顶盖缺乏系统分析(OT,与哺乳动物SC同源)。这里,多单位是从鸽子(哥伦巴利维亚)OT记录的,以及对不同大小的移动的反应,闪烁的正方形,和酒吧进行了比较。统计结果表明,在移动和闪烁的范式中,大多数大脑皮层神经元对较大的刺激都表现出抑制反应,当刺激中心越过近经典感受场(CRF)中心时,闪烁的正方形引起的抑制与移动的正方形相当,这与完整的周围条件相对应。相应地,当刺激中心越过CRF边界时,抑制变得越来越弱,相当于部分周围的条件。同样,由周围的闪烁方块引起的抑制比部分周围的闪烁方块更强烈。这些结果表明,对顶盖神经元的抑制作用似乎是完全围绕而不是局部横向的。这项研究丰富了对禽顶盖神经元周围调制特性的理解,并提供了有关其他核抑制排列的可能假设,这两者对于阐明由禽类进行的针对杂波背景的目标检测的机制都很重要。
Surround modulation has been abundantly studied in several mammalian brain areas, including the primary visual cortex, lateral geniculate nucleus, and superior colliculus (SC), but systematic analysis is lacking in the avian optic tectum (OT, homologous to mammal SC). Here, multi-units were recorded from pigeon (Columba livia) OT, and responses to different sizes of moving, flashed squares, and bars were compared. The statistical results showed that most tectal neurons presented suppressed responses to larger stimuli in both moving and flashed paradigms, and suppression induced by flashed squares was comparable with moving ones when the stimuli center crossed the near classical receptive field (CRF) center, which corresponded to the full surrounding condition. Correspondingly, the suppression grew weaker when the stimuli center moved across the CRF border, equivalent to partially surrounding conditions. Similarly, suppression induced by full surrounding flashed squares was more intense than by partially surrounding flashed bars. These results suggest that inhibitions performed on tectal neurons appear to be full surrounding rather than locally lateral. This study enriches the understanding of surround modulation properties of avian tectum neurons and provides possible hypotheses about the arrangement of inhibitions from other nuclei, both of which are important for clarifying the mechanism of target detection against clutter background performed by avians.