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 neurons in vivo display 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.