Department of Biology, Wesleyan University, Middletown, CT 06459, USA; Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
Cell Rep. 2022 Mar 29;38(13):110605. doi: 10.1016/j.celrep.2022.110605.
The latency of spikes relative to a stimulus conveys sensory information across modalities. However, in most cases, it remains unclear whether and how such latency codes are utilized by postsynaptic neurons. In the active electrosensory system of mormyrid fish, a latency code for stimulus amplitude in electroreceptor afferent nerve fibers (EAs) is hypothesized to be read out by a central reference provided by motor corollary discharge (CD). Here, we demonstrate that CD enhances sensory responses in postsynaptic granular cells of the electrosensory lobe but is not required for reading out EA input. Instead, diverse latency and spike count tuning across the EA population give rise to graded information about stimulus amplitude that can be read out by standard integration of converging excitatory synaptic inputs. Inhibitory control over the temporal window of integration renders two granular cell subclasses differentially sensitive to information derived from relative spike latency versus spike count.
尖峰相对于刺激的潜伏期在不同感觉模式之间传递感觉信息。然而，在大多数情况下，尚不清楚突触后神经元是否以及如何利用这种潜伏期编码。在电鳗鱼的主动电感觉系统中，假设电感觉传入神经纤维（EAs）的刺激幅度的潜伏期编码是由运动副放电（CD）提供的中央参考读出的。在这里，我们证明 CD 增强了电感觉叶中突触后颗粒细胞的感觉反应，但对于读出 EA 输入不是必需的。相反，EA 群体中不同的潜伏期和尖峰计数调谐产生了关于刺激幅度的分级信息，这些信息可以通过会聚兴奋性突触输入的标准整合来读出。对整合时间窗口的抑制控制使两个颗粒细胞子类对源自相对尖峰潜伏期与尖峰计数的信息具有不同的敏感性。
