Abstract
Movement decoders exploit the tuning of neural activity to various movement parameters with the ultimate goal of controlling end-effector action. Invasive approaches, typically relying on spiking activity, have demonstrated feasibility. Results of recent functional neuroimaging studies suggest that information about movement parameters is even accessible non-invasively in the form of low-frequency brain signals. However, their spatiotemporal tuning characteristics to single movement parameters are still unclear. Here, we extend the current understanding of low-frequency electroencephalography (EEG) tuning to position and velocity signals. We recorded EEG from 15 healthy participants while they performed visuomotor and oculomotor pursuit tracking tasks. Linear decoders, fitted to EEG signals in the frequency range of the tracking movements, predicted positions and velocities with moderate correlations (0.2–0.4; above chance level) in both tasks. Predictive activity in terms of decoder patterns was significant in superior parietal and parieto-occipital areas in both tasks. By contrasting the two tracking tasks, we found that predictive activity in contralateral primary sensorimotor and premotor areas exhibited significantly larger tuning to end-effector velocity when the visuomotor tracking task was performed.
Highlights
Access to neural activity through various recording modalities allowed us to study its tuning characteristics in upper-limb movements from microscale up to macroscale levels
To exploit the tuning of neural activity over multiple lags, we extended the feature set by using multiple samples in the sliding window, linear regression approach
We have presented a novel paradigm, which was tailored to study the tuning characteristics of human, low-frequency EEG to target and cursor positions and velocities in the presence of eye movements
Summary
Access to neural activity through various recording modalities allowed us to study its tuning characteristics in upper-limb movements from microscale up to macroscale levels. Neural spiking activity in primary motor[1] and premotor[2] as well as posterior parietal[3] areas is tuned to reach direction among other movement parameters[4]. By exploiting these tuning characteristics, non-human primates[4,5] and selected humans[6] with spinal cord injuries have been able to control artificial end-effectors in a 3D world. In the other condition (VM task), upper-limb movement is involved in the tracking By contrasting these conditions, it should be possible to infer whether low-frequency EEG carries more information about end-effector positions and velocities during the performance of the VM or OM task, and to identify where the differences are expressed at the cortical level. Primary motor and premotor areas carry more information about end-effector positions and velocities when the VM task is being performed, and that activity in areas related to the reaching and oculomotor networks is tuned to positions and velocities in both tasks
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