Profound impact of hippocampal output on the interpretation of tactile input patterns in SI neurons

Abstract

Due to continuous state variations in neocortical circuits, individual SI neuronsin vivodisplay a variety of intracellular response types to repeated presentations of the exact same tactile input pattern. The specific intracellular response obtained depends on a time-evolving combination of the specific input with the current neocortical state. To manipulate the internal cortical state, we here used brief electrical stimulation of the output region of the hippocampus, which preceded the delivery of specific tactile afferent input patterns to digit 2 of the anesthetized rat. We find that hippocampal output had a diversified and remarkably strong impact on the specific set of intracellular response types each SI neuron displays to each given tactile input pattern. The findings show that hippocampal output can profoundly impact the state-dependent interpretation of tactile inputs in SI neurons and hence influence their perception, potentially with affective and semantic components.

Local field potential sharp waves with diversified impact on cortical neuronal encoding of haptic input

“…We have previously reported that the exact same tactile input pattern can trigger a wide variety of responses in individual primary somatosensory (S1) cortical neurons (Norrlid et al, 2021). The response variations are due to internal state variations in the neocortical neuronal network globally, which can be demonstrated by weakly perturbing either a remote area of the cortex (Etemadi et al, 2022;Wahlbom et al, 2019) or the output of the hippocampus (Etemadi et al, 2023). These response variations in individual neurons can be explained as a consequence of subtle changes in the state of the neocortex globally, which in turn can alter the number of "open" network pathways supplying the recorded neuron with tactile information.…”