Wasmuht Dante F, Pena Jose L, Gutfreund Yoram
Department of Neuroscience, The Ruth and Bruce Rappaport Faculty of Medicine and Research Institute, The Technion, Bat-Galim, Haifa, 31096, Israel.
Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA.
Eur J Neurosci. 2017 Feb;45(4):610-621. doi: 10.1111/ejn.13505. Epub 2017 Jan 17.
Whether the auditory and visual systems use a similar coding strategy to represent motion direction is an open question. We investigated this question in the barn owl's optic tectum (OT) testing stimulus-specific adaptation (SSA) to the direction of motion. SSA, the reduction of the response to a repetitive stimulus that does not generalize to other stimuli, has been well established in OT neurons. SSA suggests a separate representation of the adapted stimulus in upstream pathways. So far, only SSA to static stimuli has been studied in the OT. Here, we examined adaptation to moving auditory and visual stimuli. SSA to motion direction was examined using repeated presentations of moving stimuli, occasionally switching motion to the opposite direction. Acoustic motion was either mimicked by varying binaural spatial cues or implemented in free field using a speaker array. While OT neurons displayed SSA to motion direction in visual space, neither stimulation paradigms elicited significant SSA to auditory motion direction. These findings show a qualitative difference in how auditory and visual motion is processed in the OT and support the existence of dedicated circuitry for representing motion direction in the early stages of visual but not the auditory system.
听觉和视觉系统是否使用相似的编码策略来表示运动方向仍是一个悬而未决的问题。我们在仓鸮的视顶盖（OT）中研究了这个问题，测试了对运动方向的刺激特异性适应（SSA）。SSA是指对重复刺激的反应减弱，且不会泛化到其他刺激，这在OT神经元中已得到充分证实。SSA表明在上游通路中对适应刺激有单独的表征。到目前为止，在OT中仅研究了对静态刺激的SSA。在此，我们研究了对移动听觉和视觉刺激的适应。使用移动刺激的重复呈现来检查对运动方向的SSA，偶尔将运动切换到相反方向。声学运动要么通过改变双耳空间线索来模拟，要么在自由场中使用扬声器阵列来实现。虽然OT神经元在视觉空间中显示出对运动方向的SSA，但两种刺激范式均未引发对听觉运动方向的显著SSA。这些发现表明在OT中处理听觉和视觉运动的方式存在质的差异，并支持在视觉而非听觉系统的早期阶段存在用于表示运动方向的专用电路。
