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Cortical modulations increase in early sessions with brain-machine interface.

Zacksenhouse M, Lebedev MA, Carmena JM, O'Doherty JE, Henriquez C, Nicolelis MA - PLoS ONE (2007)

Bottom Line: We conclude that the enhanced modulations are related to computational tasks that are significant especially in novel motor contexts.Although the function and neuronal mechanism of the enhanced cortical modulations are open for further inquiries, we discuss their potential role in processing execution errors and representing corrective or explorative activity.These representations are expected to contribute to the formation of internal models of the external actuator and their decoding may facilitate BMI improvement.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Mechanical Engineering, Technion, Haifa, Israel. mermz@tx.technion.ac.il

ABSTRACT

Background: During planning and execution of reaching movements, the activity of cortical motor neurons is modulated by a diversity of motor, sensory, and cognitive signals. Brain-machine interfaces (BMIs) extract part of these modulations to directly control artificial actuators. However, cortical modulations that emerge in the novel context of operating the BMI are poorly understood.

Methodology/principal findings: Here we analyzed the changes in neuronal modulations that occurred in different cortical motor areas as monkeys learned to use a BMI to control reaching movements. Using spike-train analysis methods we demonstrate that the modulations of the firing-rates of cortical neurons increased abruptly after the monkeys started operating the BMI. Regression analysis revealed that these enhanced modulations were not correlated with the kinematics of the movement. The initial enhancement in firing rate modulations declined gradually with subsequent training in parallel with the improvement in behavioral performance.

Conclusions/significance: We conclude that the enhanced modulations are related to computational tasks that are significant especially in novel motor contexts. Although the function and neuronal mechanism of the enhanced cortical modulations are open for further inquiries, we discuss their potential role in processing execution errors and representing corrective or explorative activity. These representations are expected to contribute to the formation of internal models of the external actuator and their decoding may facilitate BMI improvement.

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Related in: MedlinePlus

Mean-PVM of the Nsig significantly modulated units in different cortical regions during different control modes in the same sessions as Figure 7.Full bars mark the mean values across all the 2-minute intervals in the same control mode, and error bars represent the standard deviation. M1–primary motor cortex, PMd–dorsal premotor cortex, S1–primary somatosensory cortex, SMA–supplementary motor area, PP–posterior parietal cortex (medial intraparietal).
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pone-0000619-g010: Mean-PVM of the Nsig significantly modulated units in different cortical regions during different control modes in the same sessions as Figure 7.Full bars mark the mean values across all the 2-minute intervals in the same control mode, and error bars represent the standard deviation. M1–primary motor cortex, PMd–dorsal premotor cortex, S1–primary somatosensory cortex, SMA–supplementary motor area, PP–posterior parietal cortex (medial intraparietal).

Mentions: Full bars mark the mean values across all the 2-minute intervals in the same control mode, and error bars represent the standard deviation. M1–primary motor cortex, PMd–dorsal premotor cortex, S1–primary somatosensory cortex, SMA–supplementary motor area, PP–Posterior Parietal Cortex (medial intraparietal).


Cortical modulations increase in early sessions with brain-machine interface.

Zacksenhouse M, Lebedev MA, Carmena JM, O'Doherty JE, Henriquez C, Nicolelis MA - PLoS ONE (2007)

Mean-PVM of the Nsig significantly modulated units in different cortical regions during different control modes in the same sessions as Figure 7.Full bars mark the mean values across all the 2-minute intervals in the same control mode, and error bars represent the standard deviation. M1–primary motor cortex, PMd–dorsal premotor cortex, S1–primary somatosensory cortex, SMA–supplementary motor area, PP–posterior parietal cortex (medial intraparietal).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1919433&req=5

pone-0000619-g010: Mean-PVM of the Nsig significantly modulated units in different cortical regions during different control modes in the same sessions as Figure 7.Full bars mark the mean values across all the 2-minute intervals in the same control mode, and error bars represent the standard deviation. M1–primary motor cortex, PMd–dorsal premotor cortex, S1–primary somatosensory cortex, SMA–supplementary motor area, PP–posterior parietal cortex (medial intraparietal).
Mentions: Full bars mark the mean values across all the 2-minute intervals in the same control mode, and error bars represent the standard deviation. M1–primary motor cortex, PMd–dorsal premotor cortex, S1–primary somatosensory cortex, SMA–supplementary motor area, PP–Posterior Parietal Cortex (medial intraparietal).

Bottom Line: We conclude that the enhanced modulations are related to computational tasks that are significant especially in novel motor contexts.Although the function and neuronal mechanism of the enhanced cortical modulations are open for further inquiries, we discuss their potential role in processing execution errors and representing corrective or explorative activity.These representations are expected to contribute to the formation of internal models of the external actuator and their decoding may facilitate BMI improvement.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Mechanical Engineering, Technion, Haifa, Israel. mermz@tx.technion.ac.il

ABSTRACT

Background: During planning and execution of reaching movements, the activity of cortical motor neurons is modulated by a diversity of motor, sensory, and cognitive signals. Brain-machine interfaces (BMIs) extract part of these modulations to directly control artificial actuators. However, cortical modulations that emerge in the novel context of operating the BMI are poorly understood.

Methodology/principal findings: Here we analyzed the changes in neuronal modulations that occurred in different cortical motor areas as monkeys learned to use a BMI to control reaching movements. Using spike-train analysis methods we demonstrate that the modulations of the firing-rates of cortical neurons increased abruptly after the monkeys started operating the BMI. Regression analysis revealed that these enhanced modulations were not correlated with the kinematics of the movement. The initial enhancement in firing rate modulations declined gradually with subsequent training in parallel with the improvement in behavioral performance.

Conclusions/significance: We conclude that the enhanced modulations are related to computational tasks that are significant especially in novel motor contexts. Although the function and neuronal mechanism of the enhanced cortical modulations are open for further inquiries, we discuss their potential role in processing execution errors and representing corrective or explorative activity. These representations are expected to contribute to the formation of internal models of the external actuator and their decoding may facilitate BMI improvement.

Show MeSH
Related in: MedlinePlus