We tested whether spontaneous activity in the human somatomotor cortex is modulated by visual stimuli that display hands vs. non-hand stimuli and by the use/action they represent. In the left somatomotor cortex, we observed a stronger (multivoxel) spatial correlation between resting-state activity and natural hand picture patterns compared to other stimuli. We conclude that spontaneous activity patterns in somatomotor brain regions code for the visual representation of human hands and their use. This study is under review (El Rassi et al., Scientific Reports). In a second fMRI study in preparation (Perciballi et al.,), we showed that mere observation of everyday hand gestures are highly represented in spontaneous activity patterns across the association cortex as compared to those evoked by uncommon hand grasps. Same sample and paradigms were used to conduct an high-density EEG study (in preparation). These findings suggest that statistical regularities of the hand movement resonate in spontaneous activity. In a third study in preparation (Ramundo et al., ) we investigated the brain mechanisms of distinguishing between one's own and others' movements in the absence of aesthetic or morphological features. This is a preliminary step to understand whether the recognition of their own gesture is already encoded in the spontaneous activity. Intransitive actions were significantly more recognizable than transitive ones. fMRI results confirmed dissociable neural correlates of observing intransitive versus transitive actions. Our results show that the idiosyncrasies in the kinematics of self-generated actions, fundamental for the recognition of one’s own gesture, elicit the activation of action-related structures that participate in the distinction self/other.
In a MEG study, we tested whether hand dexterity is already encoded in spontaneous activity. Results have already been published in the peer-reviewed and high-impact factor The Journal of Neuroscience (Maddaluno et al., 2024). By using kinematics, we performed a characterization of the hand states and dynamics occurring in participants throughout an ecological setting. Results of this finding have been published in the peer-reviewed and high-impact factor journal, Scientific Reports (Sili et al., 2023). Based on this study, we are now studying whether the spatiotemporal architecture of manual behavior is already encoded in the spontaneous activity, by performing an high-density EEG study. We firstly conducted a methodological study to define the regularization parameter for estimating the functional connectivity during resting-state. Results of this finding are in revision (Neuroimage).
Using an implicit measure of embodiment and a motor task, across four experiments, we consistently show that the virtual grafting of a bionic tool elicits a sense of embodiment similar to or even stronger than its natural counterpart. This study has been accepted for publication in iScience (Marucci-Maddaluno et al., 2024). A similar paradigm was also employed in upper-limb amputees, using a 4-weeks long training using virtual reality. Before and after it, participants performed a fMRI study to study the functional brain organization, studied using measures of brain activity, connectivity, graph analysis, during resting-state and task-evoked activity. Results of these experiments were in preparation.
