Alpha suppression during prehension indicates neural motor drive inhibition

Changes in alpha band activity (8-12 Hz) have been shown to indicate the inhibition of engagement of brain regions during cognitive tasks, reflecting real-time cognitive load. Despite this, its feasibility to be used in a more dynamic environment with ongoing motor corrections has not been studied. This research used electroencephalography (EEG) to explore how different brain regions are engaged during a simple grasp and lift task where unexpected changes to the objects properties are introduced. To our knowledge, this is the first study to show alpha activity changes related to motor error correction occur only in motor-related areas (i.e. central areas), but not in error processing areas (ie. fronto-parietal network). This suggests that oscillations over motor areas could reflect inhibition of motor drive related to motor error correction, thus being a potential cortical electrophysiological biomarker for the process, and not solely as a proxy for cognitive demands. This observation is particularly relevant in scenarios where these signals are used to evaluate high cognitive demands co-occurring with high levels of motor errors and corrections, such as prosthesis use. The establishment of electrophysiological biomarkers of mental resource allocation during movement and cognition can help identify indicators of mental workload and motor drive, which may be useful for improving brain-machine interfaces. New and NoteworthyThis research expands on previous fMRI literature by demonstrating that alpha band suppression, an EEG metric with high temporal resolution, occurs over the primary sensorimotor area during error correction of hand movements. This furthers our understanding of alpha suppression beyond processes related to cognitive demands by highlighting how motor control also influences this frequency band. Recognizing that alpha band activity is modulated by both motor and cognitive processes is important in situations where high cognitive demands can lead to a high level of movement errors. Interpretations of such modulation are often attributed only to cognitive demands, whereas a motor process may also play a factor. Furthermore, alpha suppression could be used as a biomarker for error correction with applications in human machine interfaces, such as neuroprostheses.