RECORDING IN ALERT ANIMALS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们在提出的项目的具体目标1和4方面取得了进展：比较MT细胞对全局刺激的响应与基于细胞平均输入属性的预测。我们做了这些实验，发现我们可以预测MT细胞对快速和中速刺激的反应，但不能预测慢速刺激的反应。这表示在低速下的非线性或整流抑制。这种抑制在相互作用图中表现为延迟的非定向抑制。这项工作已写好并提交出版。我们也开始观察MT细胞中速度调节的对比度依赖性，并意识到响应的时间过程作为对比度的函数可能解释了北冈昭吉发现的强大的运动错觉。我们确实在V1和MT中发现了静态对杆的反应与运动错觉之间的相关性。这项研究最近发表在《神经科学》杂志上。探索末端停止在提取正确的全局运动方向中的作用：沿着扩展轮廓的运动方向在局部是模糊的，因此关于物体真实运动方向的最准确信息是在其角落或末端。我们想问MT细胞提取物体运动真实方向的能力是否与局部运动检测器中的末端停止相关，或者与更复杂的计算相关，即加权末端停止和非末端停止输入的相对贡献。我们开始了这些实验，发现结束停止似乎与解决正确运动方向的能力有关。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have made progress on Specific Aims 1 and 4 of the proposed project: Compare responses of MT cells to global stimuli with predictions based on the properties of the cell¿s average input. We did these experiments and found that we could predict responses of MT cells to fast and moderate speed stimuli, but not the slow stimuli. This indicates a non-linear or rectified suppression at slow speeds. This suppression is apparent as a delayed non-directional suppression in the interaction maps. This work has been written up and submitted for publication. We also began looking at the contrast dependence of speed tuning in MT cells, and realized that the time-course of the response as a function of contrast might explain the powerful motion illusion discovered by Akiyoshi Kitaoka. We did find in both V1 and MT a correlation between responses to static pair of bars and the motion illusion. This work was recently published in J. Neurosci. Explore the role of end-stopping in extracting the correct direction of global motion: Motion direction along extended contours is locally ambiguous, so the most accurate information about an object¿s true direction of motion is at its corners or ends. We propose to ask whether MT cells¿ ability to extract the true direction of object motion is correlated with end-stopping in its local-motion detectors or to a more complicated calculation that weights the relative contributions of end-stopped and non-end-stopped inputs. We began these experiments and found that end stopping does appear to be correlated with the ability to resolve the correct direction of motion.