Left hemisphere dominance for bilateral kinematic encoding in the human brain

Abstract:

Neurophysiological studies in humans and nonhuman primates have revealed movement representations in both the contralateral and ipsilateral hemispheres. Inspired by clinical observations, we ask if this bilateral representation differs for the left and right hemispheres. Electrocorticography was recorded in human participants during an instructed-delay reaching task, with movements produced with either the contralateral or ipsilateral arm. Using a cross-validated kinematic encoding model, we found stronger bilateral encoding in the left hemisphere, an effect that was present during preparation and was amplified during execution. Consistent with this asymmetry, we also observed better across-arm generalization in the left hemisphere, indicating similar neural representations for right and left arm movements. Notably, these left hemisphere electrodes were centered over premotor and parietal regions. The more extensive bilateral encoding in the left hemisphere adds a new perspective to the pervasive neuropsychological finding that the left hemisphere plays a dominant role in praxis.

authors:

• Christina M Merrick

• Tanner C Dixon

• Assaf Breska

• Jack Lin

• Edward F Chang

• David King-Stephens

• Kenneth D Laxer

• Peter B Weber

• Jose Carmena

• Robert Thomas Knight

• Richard B Ivry

Date: 2022

DOI: : https://doi.org/10.7554/eLife.69977

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Left hemisphere dominance for bilateral kinematic encoding in the human brain

Abstract:

Neurophysiological studies in humans and nonhuman primates have revealed movement representations in both the contralateral and ipsilateral hemispheres. Inspired by clinical observations, we ask if this bilateral representation differs for the left and right hemispheres. Electrocorticography was recorded in human participants during an instructed-delay reaching task, with movements produced with either the contralateral or ipsilateral arm. Using a cross-validated kinematic encoding model, we found stronger bilateral encoding in the left hemisphere, an effect that was present during preparation and was amplified during execution. Consistent with this asymmetry, we also observed better across-arm generalization in the left hemisphere, indicating similar neural representations for right and left arm movements. Notably, these left hemisphere electrodes were centered over premotor and parietal regions. The more extensive bilateral encoding in the left hemisphere adds a new perspective to the pervasive neuropsychological finding that the left hemisphere plays a dominant role in praxis.

Authors:

• Christina M Merrick

• Tanner C Dixon

• Assaf Breska

• Jack Lin

• Edward F Chang

• David King-Stephens

• Kenneth D Laxer

• Peter B Weber

• Jose Carmena

• Robert Thomas Knight

• Richard B Ivry

Date: 2022

DOI: : https://doi.org/10.7554/eLife.69977

View PDF

Neural entrainment and network resonance in support of top-down guided attention

Abstract:

Which neural mechanisms provide the functional basis of top-down guided cognitive control? Here we review recent evidence that suggest that the neural basis of attention is inherently rhythmic. In particular, we discuss two physical properties of self-sustained networks, namely entrainment and resonance, and how these shape the timescale of attentional control. Several recent findings revealed theta-band (3-8 Hz) dynamics in top-down guided behavior. These reports were paralleled by intracranial recordings, which implicated theta oscillations in the organization of functional attention networks. We discuss how the intrinsic network architecture shapes covert attentional sampling as well as overt behavior. Taken together, we posit that theta rhythmicity is an inherent feature of the attention network in support of top-down guided goal-directed behavior.

Authors:

• Randolph F Helfrich

• Assaf Breska

• Robert T Knight

Date: 2019

DOI: 10.1016/j.copsyc.2018.12.016

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Neural entrainment and network resonance in support of top-down guided attention

ABSTRACT

Which neural mechanisms provide the functional basis of top-down guided cognitive control? Here, we review recent evidence that suggest that the neural basis of attention is inherently rhythmic. In particular, we discuss two physical properties of self-sustained networks, namely entrainment and resonance, and how these shape the timescale of attentional control. Several recent findings revealed theta-band (3–8 Hz) dynamics in top-down guided behavior. These reports were paralleled by intracranial recordings, which implicated theta oscillations in the organization of functional attention networks. We discuss how the intrinsic network architecture shapes covert attentional sampling as well as overt behavior. Taken together, we posit that theta rhythmicity is an inherent feature of the attention network in support of top-down guided goal-directed behavior.

AUTHORS

• Randolph F. Helfrich

• Assaf Breska

• Robert T. Knight

Date: 2019

DOI: 10.1016/j.copsyc.2018.12.016

View PDF