Remote cortical perturbation dynamically changes the network solutions to given tactile inputs in neocortical neurons

Leila Etemadi,Jonas M.D Enander,Henrik Jörntell

doi:10.1016/j.isci.2021.103557

Abstract

SummaryThe neocortex has a globally encompassing network structure, which for each given input constrains the possible combinations of neuronal activations across it. Hence, its network contains solutions. But in addition, the cortex has an ever-changing multidimensional internal state, causing each given input to result in a wide range of specific neuronal activations. Here we use intracellular recordings in somatosensory cortex (SI) neurons of anesthetized rats to show that remote, subthreshold intracortical electrical perturbation can impact such constraints on the responses to a set of spatiotemporal tactile input patterns. Whereas each given input pattern normally induces a wide set of preferred response states, when combined with cortical perturbation response states that did not otherwise occur were induced and consequently made other response states less likely. The findings indicate that the physiological network structure can dynamically change as the state of any given cortical region changes, thereby enabling a rich, multifactorial, perceptual capability.

Highlights

We delivered a set of eight spatiotemporal tactile afferent activation (TA) patterns, or input patterns, each repeated in the order of 50–100 times, in random order
If such pathways would be partly responsible for mediating the tactile information to the recorded neuron, there would for each given tactile input pattern be multiple alternative response types that could arise in the recorded neuron depending on the combined transmission states of all pathways impacting the neuron
The several different response states observed for each input, even as we explored input merely from distal digit 2 combined with remote CX stimulation, indicate that the cortex is potentially capable of an extremely high number of input–output solutions that probably are under dynamic control of the internal, global cortical state

Summary

Introduction

Several studies have reported a wide distribution of cortical activity in response to input from a variety of modalities, indicating that the neocortex is in principle a globally interconnected network (Ferezou et al, 2007; Frostig et al, 2008; Fu et al, 2003; Ghazanfar and Schroeder, 2006; Hihara et al, 2015; Keller et al, 2012; Olcese et al, 2013; Rancz et al, 2015; Saleem et al, 2013). That would mean that for a given tactile input pattern, for example, which is delivered randomly in relation to the current cortical state, there would be a tendency to form specific clusters of response types, or network solutions. This is, possible to observe (Norrlid et al, 2021). The second hypothesis tested was that the CXTA stimulation condition created a set of responses that were separated (‘‘Separated’’ in Figure 1B) from the TA responses, even though the TA input pattern component was identical between the ll iScience 25, 103557, January 21, 2022 3

Results

Discussion

Conclusion