Direct inhibitory inputs had shorter onset delays than excitatory inputs at shared targets in selected mouse cortical slices

We compared direct excitatory and inhibitory input delays at the same recorded target cell in Allen Synaptic Physiology r2.1. We used detected connections with a passed response fit and cell-body distance at most 500 micrometres. In mouse visual cortex, 74 targets from 64 inferred animals gave a mean inhibitory minus excitatory onset delay of -0.585 ms. Its nominal 97.5% donor bootstrap interval was -0.836 to -0.351 ms. A check that kept input pairs with distance differences at most 25 micrometres gave -0.321 ms in 29 animals, with an interval of -0.576 to -0.051 ms. Human temporal cortex had 11 targets from seven inferred donors. Its estimate was 1.034 ms, with an interval of -0.167 to 2.296 ms. The human result remains uncertain. This is a comparison of direct inputs from separately stimulated sources. It does not measure a feedforward inhibitory relay or response jitter. Sparse slice samples, source cell composition, fitted onset values, and inferred donor labels limit the result.

Allen Institute · synaptic delay · shared target · excitation · inhibition · cortical slices