EEG alpha activity reflects motor preparation rather than the mode of action selection

Abstract

Alpha-band activity (8–13 Hz) is not only suppressed by sensory stimulation and movements, but also modulated by attention, working memory and mental tasks, and could be sensitive to higher motor control functions. The aim of the present study was to examine alpha oscillatory activity during the preparation of simple left or right finger movements, contrasting the external and internal mode of action selection. Three preparation conditions were examined using a precueing paradigm with S1 as the preparatory and S2 as the imperative cue: Full, laterality instructed by S1; Free, laterality freely selected and None, laterality instructed by S2. Time-frequency (TF) analysis was performed in the alpha frequency range during the S1–S2 interval, and alpha motor-related amplitude asymmetries (MRAA) were also calculated. The significant MRAA during the Full and Free conditions indicated effective external and internal motor response preparation. In the absence of specific motor preparation (None), a posterior alpha event-related desynchronization (ERD) dominated, reflecting the main engagement of attentional resources. In Full and Free motor preparation, posterior alpha ERD was accompanied by a midparietal alpha event-related synchronization (ERS), suggesting a concomitant inhibition of task-irrelevant visual activity. In both Full and Free motor preparation, analysis of alpha power according to MRAA amplitude revealed two types of functional activation patterns: (1) a motor alpha pattern, with predominantly midparietal alpha ERS and large MRAA corresponding to lateralized motor activation/visual inhibition and (2) an attentional alpha pattern, with dominating right posterior alpha ERD and small MRAA reflecting visuospatial attention. The present results suggest that alpha oscillatory patterns do not resolve the selection mode of action, but rather distinguish separate functional strategies of motor preparation.

The roles of alpha oscillation in working memory retention

“…Thus, the long‐lasting ERD increase may be explained with preparation for the movement required for a response, and this preparation seems to begin immediately with the beginning of the stimulus sequence as much as 10 s before actual movement execution. Alpha ERD during movement preparation has been reported previously and was interpreted as preparing for a motor task but does not reflect processing for the specific task itself (Deiber et al, ). The alpha ERD in the sensorimotor system may support the concept of a preparatory role of alpha ERD.…”

Auditory event-related potentials and alpha oscillations in the psychosis prodrome: Neuronal generator patterns during a novelty oddball task

“…Interestingly, Kayser et al (2010a) found that the FRN-related source asymmetry linked to manual response versus silent count of target tones was reduced in schizophrenia. Predominant right parieto-occipital alpha ERD has also been reported for right-handed healthy adults during the anticipatory S1-S2 interval of a cued motor response task, particularly for participants with weak lateralization of sensorimotor alpha activity, suggesting distinct alpha asymmetry patterns associated with motor or attentional processes (Deiber et al, 2012). However, more research is required to clarify the mechanisms underlying these alpha ERD effects.…”

Experienced stress produces inhibitory deficits in old adults’ Flanker task performance: First evidence for lifetime stress effects beyond memory

“…With respect to sensorimotor involvement, alpha ERS is thought to indicate an inhibited or deactivated motor region while ERD is thought to reflect an active brain region engaged in motor execution (Neuper, Woertz & Pfurtscheller, 2006;Deiber et al, 2012). In terms of attentional control, alpha ERS is linked to the successful inhibition of brain regions not necessary for stimulus processing or maintenance (Cooper et al, 2003;Klimesch, 2012), thereby facilitating the reduction of potentially distracting information (Sauseng et al, 2009).…”