The Dynamics of Sensorimotor Cortical Oscillations during the Observation of Hand Movements: An EEG Study

Abstract

BackgroundThe observation of action done by others determines a desynchronization of the rhythms recorded from cortical central regions. Here, we examined whether the observation of different types of hand movements (target directed, non-target directed, cyclic and non-cyclic) elicits different EEG cortical temporal patterns.MethodologyVideo-clips of four types of hand movements were shown to right-handed healthy participants. Two were target directed (grasping and pointing) motor acts; two were non-target directed (supinating and clenching) movements. Grasping and supinating were performed once, while pointing and clenching twice (cyclic movements). High-density EEG was recorded and analyzed by means of wavelet transform, subdividing the time course in time bins of 200 ms. The observation of all presented movements produced a desynchronization of alpha and beta rhythms in central and parietal regions. The rhythms desynchronized as soon as the hand movement started, the nadir being reached around 700 ms after movement onset. At the end of the movement, a large power rebound occurred for all bands. Target and non-target directed movements produced an alpha band desynchronization in the central electrodes at the same time, but with a stronger desynchronization and a prolonged rebound for target directed motor acts. Most interestingly, there was a clear correlation between the velocity profile of the observed movements and beta band modulation.SignificanceOur data show that the observation of motor acts determines a modulation of cortical rhythm analogous to that occurring during motor act execution. In particular, the cortical motor system closely follows the velocity of the observed movements. This finding provides strong evidence for the presence in humans of a mechanism (mirror mechanism) mapping action observation on action execution motor programs.

Brain Activity during the Observation, Imagery, and Execution of Tool Use: An fNIRS/EEG Study

“…The dorsolateral prefrontal cortex is activated when movements that match normal human movements are observed [31]. Previous studies have also shown that the mu ERD value for the sensorimotor regions increases during the observation of hand movements [32][33][34][35]. These studies indicate that during the observation of the hammer movement, the subjects were observing the footage of others performing the action while mentally simulating the same action.…”

Frequency and topography in monkey electroencephalogram during action observation: possible neural correlates of the mirror neuron system

“…In our study, we found that the 20-25 Hz band is the most sensitive in both monkeys, and the magnitude of suppression is more robust in the anterior and central electrodes. Other work in humans has shown that during action observation, frequency bands within this range show similar desynchronization [3,11,30,34,37] rstb.royalsocietypublishing.org Phil. Trans.…”

“…It is possible that with EEG recordings, the observation of biological movements devoid of the target-object, which is known to involve temporoparietal -premotor networks, could produce EEG changes similar to those reported during observation of goal-directed movements. The work in humans has shown that meaningful and meaningless movements can induce desynchronization of the alpha rhythm [3,8,10,37]. Related to this point, it would be interesting to investigate whether actions with a tool, or objects moving with a biological kinematics towards a goal, are capable of eliciting a similar desynchronization.…”

Understanding Neural Mechanisms of Action Observation for Improving Human Motor Skill Acquisition

“…Avanzini et al [25] investigated the dynamics of sensorimotor cortical oscillations during Understanding Neural Mechanisms of Action Observation for Improving Human Motor Skill... http://dx.doi.org/10.5772/intechopen.69266 5 the observation of hand movements using EEG (Figure 6). A desynchronization of alpha and beta rhythms was observed in the central and parietal regions.…”