兴奋性神经元使浅层后扣带回皮层能够精确持久地编码信息。

Hyperexcitable Neurons Enable Precise and Persistent Information Encoding in the Superficial Retrosplenial Cortex.

机构信息

Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.

Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.

出版信息

Cell Rep. 2020 Feb 4;30(5):1598-1612.e8. doi: 10.1016/j.celrep.2019.12.093.

DOI:10.1016/j.celrep.2019.12.093

PMID:32023472

Abstract

The retrosplenial cortex (RSC) is essential for memory and navigation, but the neural codes underlying these functions remain largely unknown. Here, we show that the most prominent cell type in layers 2/3 (L2/3) of the mouse granular RSC is a hyperexcitable, small pyramidal cell. These cells have a low rheobase (LR), high input resistance, lack of spike frequency adaptation, and spike widths intermediate to those of neighboring fast-spiking (FS) inhibitory neurons and regular-spiking (RS) excitatory neurons. LR cells are excitatory but rarely synapse onto neighboring neurons. Instead, L2/3 is a feedforward, not feedback, inhibition-dominated network with dense connectivity between FS cells and from FS to LR neurons. Biophysical models of LR but not RS cells precisely and continuously encode sustained input from afferent postsubicular head-direction cells. Thus, the distinct intrinsic properties of LR neurons can support both the precision and persistence necessary to encode information over multiple timescales in the RSC.

摘要

后隔核（ retrosplenial cortex，RSC）对于记忆和导航至关重要，但这些功能背后的神经编码在很大程度上仍不清楚。在这里，我们表明，在颗粒后隔核的 2/3 层（L2/3）中最突出的细胞类型是兴奋性较高的小锥体神经元。这些细胞具有较低的基强度（rheobase，LR）、较高的输入电阻、缺乏频率适应性以及介于相邻快速放电（fast-spiking，FS）抑制性神经元和常规放电（regular-spiking，RS）兴奋性神经元之间的尖峰宽度。LR 细胞是兴奋性的，但很少与邻近神经元形成突触。相反，L2/3 是一个前馈而非反馈的抑制主导网络，FS 细胞之间以及 FS 到 LR 神经元之间具有密集的连接。LR 细胞而非 RS 细胞的生物物理模型可以精确且连续地编码来自传入的副海马头方向细胞的持续输入。因此，LR 神经元的独特内在特性可以支持在后隔核中对多个时间尺度的信息进行编码所必需的精度和持久性。