Random change in cortical load representation suggests distinct control of posture and movement

Kurtzer, Isaac; Herter, Troy M.; Scott, Stephen H.

doi:10.1038/nn1420

Cited by 177 publications

(167 citation statements)

References 42 publications

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“…Moreover, by recording from many neurons, the BMI will be able to select a subpopulation of neurons with the greatest contribution to achieve optimal task performance in the control of a prosthetic device at a given moment. Consistent with the results reported here, Kurtzer et al (2005) reported random shifts in load representation during behavioral tasks that involved control of posture and reaching movement. The authors argue that current BMI approaches that assume fixed correlation between neuronal activity and motor output may be suboptimal.…”

Section: Discussionsupporting

confidence: 90%

Stable Ensemble Performance with Single-Neuron Variability during Reaching Movements in Primates

Carmena¹,

Lebedev²,

Henriquez³

et al. 2005

J. Neurosci.

147

127

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Significant variability in firing properties of individual neurons was observed while two monkeys, chronically implanted with multielectrode arrays in frontal and parietal cortical areas, performed a continuous arm movement task. Although the degree of correlation between the firing of single neurons and movement parameters was nonstationary, stable predictions of arm movements could be obtained from the activity of neuronal ensembles. This result adds support to the idea that movement parameters are redundantly encoded in the motor cortex, such that brain networks can achieve the same behavioral goals through different patterns and relative contribution of individual neuron activity. This has important implications for neural prosthetics, suggesting that accurate operation of a brain-machine interface requires recording from large neuronal ensembles to minimize the effect of variability and ensuring stable performance over long periods of time.

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Section: Discussionsupporting

confidence: 90%

Stable Ensemble Performance with Single-Neuron Variability during Reaching Movements in Primates

Carmena¹,

Lebedev²,

Henriquez³

et al. 2005

J. Neurosci.

147

127

View full text Add to dashboard Cite

show abstract

“…In contrast, other cells, the activity of which varied with trajectory loads did not show variations with postural loads. Cells that showed variation with both posture and movement indicated independent tuning functions for each type of load (Kurtzer et al, 2005). These results provide strong support to the idea that trajectory and posture are independently coded and controlled in the CNS.…”

Section: Differential Control Of Trajectory and Positionsupporting

confidence: 70%

“…Scott and colleagues (Kurtzer, Herter, & Scott, 2005) have reported primate motor cortex cells whose activities vary with loads applied during either the postural or trajectory phases of movement. Importantly, many cells showed activities that varied with posture, but were not sensitive to loads applied during movement.…”

Section: Differential Control Of Trajectory and Positionmentioning

confidence: 99%

Control of velocity and position in single joint movements

Mutha

Sainburg

2007

Human Movement Science

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Previous research on single joint movements has lead to the development of models of control that propose that movement speed and distance are controlled through an initial pulsatile signal that can be modified in both amplitude and duration. However, the manner in which the amplitude and duration are modulated during the control of movement speed and distance remains controversial. We now report two studies that were designed to test and refine the pulse-step model of movement control. In our first study, participants move at a series of speeds to a single spatial target. In this task, acceleration duration (pulse-width) varied substantially across targets, and was negatively correlated with peak acceleration (pulse-height). In a second experiment, we removed the spatial target, but required movements at three speeds similar to those used in the first study. In this task, acceleration amplitude varied extensively across the speed targets, while acceleration duration remained constant across the three speeds. Taken together, our current findings demonstrate that pulse-width measures can be modulated independently from pulse-height measures, and that a positive correlation between such measures is not obligatory, even when sampled across a range of movement speeds. In addition, our findings suggest that pulse-height modulation plays a primary role in controlling movement speed and specifying target distance, whereas pulse-width mechanisms are employed to correct errors in pulse-height control, as required to achieve spatial precision in final limb position.

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“…The selection of these groups is due, in part, to known differences in how parts of the sensorimotor circuit contribute to visually guided reaching. Control processes for posture and movement are somewhat distinct [61], and certain neurological disorders can affect one or the other [62]. Difficulties responding to a visual stimuli may not reflect a motor problem, such as in someone with hemianopsia.…”

Section: Robots For Upper-limb Motor Assessmentmentioning

confidence: 99%

Potential of robots as next-generation technology for clinical assessment of neurological disorders and upper-limb therapy

Scott¹,

Dukelow²

2011

JRRD

161

118

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Abstract-Robotic technologies have profoundly affected the identification of fundamental properties of brain function. This success is attributable to robots being able to control the position of or forces applied to limbs, and their inherent ability to easily, objectively, and reliably quantify sensorimotor behavior. Our general hypothesis is that these same attributes make robotic technologies ideal for clinically assessing sensory, motor, and cognitive impairments in stroke and other neurological disorders. Further, they provide opportunities for novel therapeutic strategies. The present opinionated review describes how robotic technologies combined with virtual/augmented reality systems can support a broad range of behavioral tasks to objectively quantify brain function. This information could potentially be used to provide more accurate diagnostic and prognostic information than is available from current clinical assessment techniques. The review also highlights the potential benefits of robots to provide upper-limb therapy. Although the capital cost of these technologies is substantial, it pales in comparison with the potential cost reductions to the overall healthcare system that improved assessment and therapeutic interventions offer.

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Random change in cortical load representation suggests distinct control of posture and movement

Cited by 177 publications

References 42 publications

Stable Ensemble Performance with Single-Neuron Variability during Reaching Movements in Primates

Stable Ensemble Performance with Single-Neuron Variability during Reaching Movements in Primates

Control of velocity and position in single joint movements

Potential of robots as next-generation technology for clinical assessment of neurological disorders and upper-limb therapy

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