Puller Christian, Manookin Michael B, Neitz Jay, Rieke Fred, Neitz Maureen
Department of Ophthalmology,
Department of Ophthalmology.
J Neurosci. 2015 Apr 1;35(13):5397-408. doi: 10.1523/JNEUROSCI.4369-14.2015.
Functional analyses exist only for a few of the morphologically described primate ganglion cell types, and their correlates in other mammalian species remain elusive. Here, we recorded light responses of broad thorny cells in the whole-mounted macaque retina. They showed ON-OFF-center light responses that were strongly suppressed by stimulation of the receptive field surround. Spike responses were delayed compared with parasol ganglion cells and other ON-OFF cells, including recursive bistratified ganglion cells and A1 amacrine cells. The receptive field structure was shaped by direct excitatory synaptic input and strong presynaptic and postsynaptic inhibition in both ON and OFF pathways. The cells responded strongly to dark or bright stimuli moving either in or out of the receptive field, independent of the direction of motion. However, they did not show a maintained spike response either to a uniform background or to a drifting plaid pattern. These properties could be ideally suited for guiding movements involved in visual pursuit. The functional characteristics reported here permit the first direct cross-species comparison of putative homologous ganglion cell types. Based on morphological similarities, broad thorny ganglion cells have been proposed to be homologs of rabbit local edge detector ganglion cells, but we now show that the two cells have quite distinct physiological properties. Thus, our data argue against broad thorny cells as the homologs of local edge detector cells.
目前仅对少数几种已在形态学上描述的灵长类神经节细胞类型进行了功能分析，而它们在其他哺乳动物物种中的对应类型仍不清楚。在此，我们记录了整装猕猴视网膜中宽棘细胞的光反应。它们表现出开-关中心光反应，这种反应在刺激感受野周边时会受到强烈抑制。与伞状神经节细胞以及其他开-关细胞（包括递归双分层神经节细胞和A1无长突细胞）相比，其动作电位反应延迟。感受野结构是由开和关通路中直接的兴奋性突触输入以及强烈的突触前和突触后抑制所形成的。这些细胞对在感受野内或外移动的暗或亮刺激有强烈反应，与运动方向无关。然而，它们对均匀背景或漂移的方格图案均未表现出持续的动作电位反应。这些特性可能非常适合指导视觉追踪中涉及的运动。此处报道的功能特征首次允许对假定的同源神经节细胞类型进行直接的跨物种比较。基于形态学上的相似性，宽棘神经节细胞被认为是兔局部边缘检测神经节细胞的同源物，但我们现在表明这两种细胞具有相当不同的生理特性。因此，我们的数据反对将宽棘细胞视为局部边缘检测细胞的同源物。
