Condition-Dependent Neural Dimensions Progressively Shift during Reach to Grasp

Rouse, Adam G.; Schieber, Marc H.

doi:10.1016/j.celrep.2018.11.057

Cited by 39 publications

(52 citation statements)

References 56 publications

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“…The changes in motor cortical maps were not accompanied by corresponding changes in the fraction of task-related and/or tuned cells, indicating that throughout the motor cortex, a large fraction of neurons (recorded from sites that controlled task-related as well as task-unrelated joints) exhibited comparable task-related activity. This pattern is consistent with the “dense” coding scheme employed in motor and premotor areas [33, 34], where many cells exhibit task related activity. This is a very different operational principle than the sparse coding scheme often ascribed to sensory cortical areas [35, 36].…”

Section: Discussionsupporting

confidence: 83%

Motor cortical plasticity in response to skill acquisition in adult monkeys

Gupta

Nashef

Israely

et al. 2020

Preprint

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13Cortical maps often undergo plastic changes during learning or in response to 14 injury. In sensory areas, these changes are thought to be triggered by alterations 15 in the pattern of converging inputs and a functional reassignment of the deprived 16 cortical region. In the motor cortex, training on a task that engages distal 17 effectors was shown to increase their cortical representation (as measured by 18 response to intracortical microstimulation). However, this expansion could be a 19 specific outcome of using a demanding dexterous task. We addressed this 20 question by measuring the long-term changes in cortical maps of monkeys that 21 were sequentially trained on two different tasks involving either proximal or distal 22 joints. We found that motor cortical remodeling in adult monkeys was symmetric 23 such that both distal and proximal movements can comparably alter motor maps 24 in a fully reversible manner according to task demands. Further, we found that 25 the change in mapping often included a switch between remote joints (e.g., a 26 finger site switched to a shoulder site) and reflected a usage-consistent 27 reorganization of the map rather than the local expansion of one representation 28 into nearby sites. Finally, although cortical maps were considerably affected by 29 the performed task, motor cortical neurons throughout the motor cortex were 30 equally likely to fire in a task-related manner independent of the task and/or the 31 recording site. These results may imply that in the motor system, enhanced 32 motor efficiency is achieved through a dynamical allocation of larger cortical 33 areas and not by specific recruitment of task-relevant cells. 34 Gupta et al. 2020 3 Introduction 35

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Section: Discussionsupporting

confidence: 83%

Motor cortical plasticity in response to skill acquisition in adult monkeys

Gupta

Nashef

Israely

et al. 2020

Preprint

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“…Condition-independent neural activity previously has been observed in motor tasks that are overtrained to be consistent across trials (Kaufman et al, 2016;Kobak et al, 2016;Rouse and Schieber, 2018). Here, in a precision center-out task with considerable trial-to-trial variability, the conditionindependent neural dynamics were observed to be similar for both initial as well as corrective movements and were cyclic.…”

Section: Similar But Smaller Condition-independent Activity For Corresupporting

confidence: 53%

“…In addition to encoded movement features, however, there is also a large condition-independent component in the firing rate of neurons in motor cortex (Kaufman et al, 2016;Rouse and Schieber, 2018). Condition-independent neural activity is the change in a neuron's firing rate from baseline that happens regardless of the instructed movement for any given trial within a given task.…”

Section: Introductionmentioning

confidence: 99%

Cyclic, condition-independent activity in primary motor cortex predicts corrective movement behavior

Rouse

Schieber

2018

Preprint

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SummaryCyclic neural activity occurred not only during initial reaching movements but also subsequent corrective movements as subjects performed a precision center-out task. The cyclic trajectories identified from the condition-independent neural activity were similar between initial and corrective movements. For both, instantaneous cycle phase predicted when contact with the target occurred, even when the subject made multiple corrective movements. Moreover, the phase of the cyclic neural activity correlated with instantaneous movement speed. Neural activity during these corrective movements thus reveals encoding of discrete sub-movements rather than smooth and continuous updating of movement towards a target.

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“…The possibility remains that dynamics are present in M1 during grasp, but that they are higherdimensional than during reach, or that they are nonlinear. Indeed, previous work analyzing neural state spaces in M1 during a reach-grasp-manipulate task found that neural activity is higher-dimensional than that observed during reach movements alone 6 . As a first test of these possibilities, we examined the relationship between movement and neural activity from the standpoint of decoding.…”

Section: Main Textmentioning

confidence: 99%