Departamento de Neurociencias Integrativas y Computacionales, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
PLoS One. 2024 Sep 20;19(9):e0308146. doi: 10.1371/journal.pone.0308146. eCollection 2024.
Packet information encoding of neural signals was proposed for vision about 50 years ago and has recently been revived as a plausible strategy generalizable to natural and artificial sensory systems. It involves discrete image segmentation controlled by feedback and the ability to store and compare packets of information. This article shows that neurons of the cerebellum-like electrosensory lobe (EL) of the electric fish Gymnotus omarorum use spike-count and spike-timing distribution as constitutive variables of packets of information that encode one-by-one the electrosensory images generated by a self-timed series of electric organ discharges (EODs). To evaluate this hypothesis, extracellular unitary activity was recorded from the centro-medial map of the EL. Units recorded in high-decerebrate preparations were classified into six types using hierarchical cluster analysis of post-EOD spiking histograms. Cross-correlation analysis indicated that each EOD strongly influences the unit firing probability within the next inter-EOD interval. Units of the same type were similarly located in the laminar organization of the EL and showed similar stimulus-specific changes in spike count and spike timing after the EOD when a metal object was moved close by, along the fish's body parallel to the skin, or when the longitudinal impedance of a static cylindrical probe placed at the center of the receptive field was incremented in a stepwise manner in repetitive trials. These last experiments showed that spike-counts and the relative entropy, expressing a comparative measure of information before and after the step, were systematically increased with respect to a control in all unit types. The post-EOD spike-timing probability distribution and the relatively independent contribution of spike-timing and number to the content of information in the transmitted packet suggest that these are the constitutive image-encoding variables of the packets. Comparative analysis suggests that packet information transmission is a general principle for processing superposition images in cerebellum-like networks.
神经信号的包信息编码大约在 50 年前被提出，最近作为一种可行的策略重新出现，可推广到自然和人工感觉系统。它涉及由反馈控制的离散图像分割，以及存储和比较信息包的能力。本文表明，电鱼 Gymnotus omarorum 的类似小脑的电感觉叶（EL）的神经元使用尖峰计数和尖峰时间分布作为信息包的组成变量，该信息包逐个地对由自定时的一系列电器官放电（EOD）产生的电感觉图像进行编码。为了评估这个假设，从 EL 的中-内侧图中记录了细胞外单位活动。使用 EOD 后尖峰直方图的层次聚类分析，将在高去大脑制备中记录的单元分为六种类型。互相关分析表明，每个 EOD 强烈影响下一个 EOD 间隔内的单元发射概率。具有相同类型的单元在 EL 的层状组织中类似地定位，并在金属物体靠近时，或当放置在感受野中心的静态圆柱探针的纵向阻抗在重复试验中以逐步方式增加时，在 EOD 后表现出类似的刺激特异性尖峰计数和尖峰时间变化。最后这些实验表明，尖峰计数和相对熵（表示步前和步后的信息的比较度量）在所有单元类型中均相对于对照系统地增加。EOD 后尖峰时间概率分布以及尖峰时间和数量对传输包中信息内容的相对独立贡献表明，这些是包中图像编码变量的组成部分。比较分析表明，包信息传输是类似小脑网络中处理叠加图像的一般原则。
