Spatiotemporal distribution of location and object effects in the electromyographic activity of upper extremity muscles during reach-to-grasp

Rouse, Adam G.; Schieber, Marc H.

doi:10.1152/jn.00008.2016

Cited by 11 publications

(5 citation statements)

References 39 publications

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“…Although reaching and grasping traditionally have been considered to be mediated through independent channels ( Jeannerod, 1984 ), considerable evidence suggests that under appropriate conditions, variation in reaching affects grasping and vice versa ( Wallace and Weeks, 1988 ; Paulignan et al, 1991 ; Hoff and Arbib, 1993 ; Haggard and Wing, 1998 ; Connolly and Goodale, 1999 ). Our previous studies of the present RGM movements have shown that location-related variance predominates early and object-related variance later, not only in the activity of individual M1 neurons ( Rouse and Schieber, 2016a ) but also in the EMG activity of individual muscles ( Rouse and Schieber, 2016b ) and in the kinematics of individual joints ( Rouse and Schieber, 2015 ). Our findings here that a similar population of neurons in the motor cortex is related both to reach location and to the object grasped and manipulated—but with progressively shifting neural dimen-sions of activity—may provide a framework to better understand these observations.…”

Section: Discussionmentioning

confidence: 67%

Condition-Dependent Neural Dimensions Progressively Shift during Reach to Grasp

Rouse

Schieber

2018

Cell Reports

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SUMMARY Neural population space analysis was performed to assess the dimensionality and dynamics of the neural population in the primary motor cortex (M1) during a reach-grasp-manipulation task in which both the reach location and the object being grasped were varied. We partitioned neural activity into three components: (1) general task-related activity independent of location and object, (2) location- and/or object-related activity, and (3) noise. Neural modulation related to location and/or object was only one-third the size of either general task modulation or noise. The neural dimensions of location and/or object-related activity overlapped with both the general task and noise dimensions. Rather than large amplitude modulation in a fixed set of dimensions, the active dimensions of location and/or object modulation shifted progressively over the time course of a trial.

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Section: Discussionmentioning

confidence: 67%

Condition-Dependent Neural Dimensions Progressively Shift during Reach to Grasp

Rouse

Schieber

2018

Cell Reports

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“…For further selection, we calculated from the spike shapes of each neuron the signal-to-noise ratio (SNR), defined as the amplitude, i.e., the mean of the trough-to-peak voltage, divided by twice the standard deviation of the entire signal (Hatsopoulos et al, 2004 ). For this study we selected only single neurons with SNR values >2.5 to guarantee good sorting quality (see also Rouse and Schieber, 2016 ). The distributions of the SNR values of all neurons are shown in Figure 1E .…”

Section: Methodsmentioning

confidence: 99%

Behavioral Context Determines Network State and Variability Dynamics in Monkey Motor Cortex

Riehle

Brochier

Nawrot

et al. 2018

Front. Neural Circuits

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Variability of spiking activity is ubiquitous throughout the brain but little is known about its contextual dependance. Trial-to-trial spike count variability, estimated by the Fano Factor (FF), and within-trial spike time irregularity, quantified by the coefficient of variation (CV), reflect variability on long and short time scales, respectively. We co-analyzed FF and the local coefficient of variation (CV2) in monkey motor cortex comparing two behavioral contexts, movement preparation (wait) and execution (movement). We find that the FF significantly decreases from wait to movement, while the CV2 increases. The more regular firing (expressed by a low CV2) during wait is related to an increased power of local field potential (LFP) beta oscillations and phase locking of spikes to these oscillations. In renewal processes, a widely used model for spiking activity under stationary input conditions, both measures are related as FF ≈ CV2. This expectation was met during movement, but not during wait where FF ≫ CV22. Our interpretation is that during movement preparation, ongoing brain processes result in changing network states and thus in high trial-to-trial variability (expressed by a high FF). During movement execution, the network is recruited for performing the stereotyped motor task, resulting in reliable single neuron output. Our interpretation is in the light of recent computational models that generate non-stationary network conditions.

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“…Because we chose to study relatively naturalistic movements, the reach, grasp, and manipulation components were not performed separately, but rather in a continuous fluid motion during the movement epoch of the task sequence (Figure 2B). In previous studies of a version of this task without separate instruction or delay epochs, we have shown that joint kinematics, EMG activity, and neuron activity in the primary motor cortex, all vary throughout the movement epoch in relation to both reach location and object, with location predominating early in the movement epoch and object predominating later (Rouse and Schieber, 2015, 2016b, a). Our task thus did not dissociate the reach, the hand shape used to grasp the object, and the manipulation performed on the object.…”

Section: Resultsmentioning

confidence: 88%

“…The monkey then reached to, grasped, and manipulated the remembered target object: turning a sphere, pushing a button, pulling a coaxial cylinder (coax), or pulling a perpendicular cylinder (perp). The reach, grasp, manipulate sequence was performed as a single, uninterrupted, fluid movement of the entire upper extremity (Rouse and Schieber, 2015, 2016b, a). Once the instructed object had been manipulated, a ring of green LEDs around the object illuminated (indicating successful manipulation of the object) and the ring of blue LEDs for that object also illuminated (indicating correct object).…”

Section: Methodsmentioning

confidence: 99%

Progressively shifting patterns of co-modulation among premotor cortex neurons carry dynamically similar signals during action execution and observation

Zhao,

Schieber

2023

Preprint

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Many neurons in the premotor cortex show firing rate modulation whether the subject performs an action or observes another individual performing the same action. Although such “mirror neurons” have been thought to have highly congruent discharge during execution and observation, many if not most show non-congruent activity. Studies of such neuronal populations have shown that the most prevalent patterns of co-modulation—captured as neural trajectories—pass through subspaces which are shared in part, but in part are visited exclusively during either execution or observation. These studies focused on reaching movements for which the neural trajectories show comparatively simple dynamical motifs. But the neural dynamics of hand movements are more complex. We developed a novel approach to examine prevalent patterns of co-modulation during execution and observation of a task that involved reaching, grasping and manipulation. Rather than following neural trajectories in subspaces that contain their entire time course, we identified time series of instantaneous subspaces, sampled trajectory segments at the times of selected behavioral events, and projected each segment into the series of instantaneous subspaces. We found that instantaneous neural subspaces were partially shared between execution and observation in only one of three monkeys and were otherwise exclusive to one context or the other. Nevertheless, the patterns during execution and observation could be aligned with canonical correlation, indicating that though distinct, neural representations during execution and observation show dynamical similarity that may enable the nervous system to recognize particular actions whether performed by the subject or by another individual.

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Spatiotemporal distribution of location and object effects in the electromyographic activity of upper extremity muscles during reach-to-grasp

Abstract: Rouse AG, Schieber MH. Spatiotemporal distribution of location and object effects in the electromyographic activity of upper extremity muscles during reach-to-grasp.

Cited by 11 publications

References 39 publications

Condition-Dependent Neural Dimensions Progressively Shift during Reach to Grasp

Condition-Dependent Neural Dimensions Progressively Shift during Reach to Grasp

Behavioral Context Determines Network State and Variability Dynamics in Monkey Motor Cortex

Progressively shifting patterns of co-modulation among premotor cortex neurons carry dynamically similar signals during action execution and observation

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