Frequency-Dependent Synaptic Dynamics Differentially Tune CA1 and CA2 Pyramidal Neuron Responses to Cortical Input

• DOI: 10.1523/jneurosci.0451-20.2021
• Publication Date: 2021-08-12T17:50:23Z
• Authors: Qian Sun; Eric W. Buss; Yu-Qiu Jiang; Bina Santoro; David H. Brann; Daniel A. Nicholson; Steven A. Siegelbaum
• Keywords: Entorhinal cortex

Entorhinal cortex neurons make monosynaptic connections onto distal apical dendrites of CA1 and CA2 pyramidal through the perforant path (PP) projection. Previous studies show that differences in dendritic properties synaptic input density enable PP inputs to produce a much stronger excitation compared with neurons. Here, using mice both sexes, we report difference efficacy varies substantially as function presynaptic firing rate. Although single stimulus evokes 5- 6-fold greater EPSP CA1, brief high-frequency train stimuli strongly facilitating postsynaptic response relatively little change CA2. Furthermore, demonstrate blockade NMDARs significantly reduces strong temporal summation but has impact on As result frequency- NMDAR-dependent summation, naturalistic patterns activity evoke responses distinct dynamics, differentially tuning bursts versus spikes, respectively.SIGNIFICANCE STATEMENT Recent have demonstrated abundant entorhinal cortical innervation efficient propagation hippocampal robust evoked by stimuli, CA1. Here uncovered, unexpectedly, A burst not result, displays contrasting which depends activation NMDARs. Thus, whereas responds is selectively recruited input.