Spatio-temporal characteristics of population responses evoked by microstimulation in the barrel cortex

Shany Nivinsky Margalit,Hamutal Slovin

doi:10.1038/s41598-018-32148-0

Shany Nivinsky Margalit, Hamutal Slovin

Open Access

https://doi.org/10.1038/s41598-018-32148-0

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Journal: Scientific Reports	Publication Date: Sep 17, 2018
Citations: 12	License type: open-access

Affiliation: Bar-Ilan University

Abstract

Intra-cortical microstimulation (ICMS) is a widely used technique to artificially stimulate cortical tissue. This method revealed functional maps and provided causal links between neuronal activity and cognitive, sensory or motor functions. The effects of ICMS on neural activity depend on stimulation parameters. Past studies investigated the effects of stimulation frequency mainly at the behavioral or motor level. Therefore the direct effect of frequency stimulation on the evoked spatio-temporal patterns of cortical activity is largely unknown. To study this question we used voltage-sensitive dye imaging to measure the population response in the barrel cortex of anesthetized rats evoked by high frequency stimulation (HFS), a lower frequency stimulation (LFS) of the same duration or a single pulse stimulation. We found that single pulse and short trains of ICMS induced cortical activity extending over few mm. HFS evoked a lower population response during the sustained response and showed a smaller activation across time and space compared with LFS. Finally the evoked population response started near the electrode site and spread horizontally at a propagation velocity in accordance with horizontal connections. In summary, HFS was less effective in cortical activation compared to LFS although HFS had 5 fold more energy than LFS.

Highlights

Electrical stimulation has long been an important tool for exploring the organization and function of the nervous system as well as an important communication channel for brain machine interfaces (BMI)
Our results show that low frequency electrical stimulation (LFS) and high-frequency stimulation (HFS) evoked population responses with distinct spatio-temporal characteristics
We found that Intra-cortical microstimulation (ICMS) at LFS was more effective in cortical activation compared with ICMS at HFS: cortical activation extended over a larger region and evoked higher neural response

Summary

Introduction

Electrical stimulation has long been an important tool for exploring the organization and function of the nervous system as well as an important communication channel for brain machine interfaces (BMI). Intra-cortical microstimulation (ICMS) is a widely used electrical stimulation technique where short pulses of relatively low amplitude currents (in the range of μA) are delivered to the cortical tissue via a small microelectrode tip and induce the excitation of nearby cell bodies and axons[6,7] This method has played a central role in experimental neuroscience and helped providing a causal link between neuronal activity and cognitive or motor functions[8,9] and it was used for functional mapping of various brain areas, e.g. the motor cortex[10,11,12], frontal eye field area[13,14] etc. Using voltage-sensitive dye imaging (VSDI) we imaged the population responses in the stimulated area at high spatial (mesoscale) and temporal resolution (Shoham et al, 1999; Slovin et al, 2002)

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Results

Conclusion