Being an agent or an observer: Different spectral dynamics revealed by MEG

Abstract

14Several neuroimaging studies reported that a common set of regions are recruited during 15 action observation and execution and it has been proposed that the modulation of the µ rhythm, 16 in terms of oscillations in the alpha and beta bands might represent the electrophysiological 17 correlate of the underlying brain mechanisms. However, the specific functional role of these bands 18 within the µ rhythm is still unclear. Here, we used magnetoencephalography (MEG) to analyze the 19 spectral and temporal properties of the alpha and beta bands in healthy subjects during an action 20 observation and execution task. 21We associated the modulation of the alpha and beta power to a broad action observation 22 network comprising several parieto--frontal areas previously detected in fMRI studies. Of note, we 23 observed a dissociation between alpha and beta bands with a slow--down of beta oscillations 24 ACCEPTED FOR PUBLICATION -NEUROIMAGE2 compared to alpha during action observation. We hypothesize that this segregation is linked to a 25 different sequence of information processing and we interpret these modulations in terms of 26 internal models (forward and inverse). In fact, these processes showed opposite temporal 27 sequences of occurrence: anterior--posterior during action (both in alpha and beta bands) and 28 roughly posterior--anterior during observation (in the alpha band). The observed differentiation 29 between alpha and beta suggests that these two bands might pursue different functions in the 30 action observation and execution processes. 32Keywords: action observation and execution, alpha and beta rhythms, Event--Related 33Desynchronization (ERD), magnetoencephalography (MEG), internal models 34 35 36 INTRODUCTION 37Several studies report that our sensorimotor system is activated when we observe an 38 action performed by other people. This putative mirror--like activity in humans was found in the 39 precentral gyrus (vPM), the inferior frontal gyrus (IFG), the inferior parietal lobule (IPL), and 40 regions within the intraparietal sulcus (for a review see Rizzolatti and Sinigaglia, 2010). In addition 41 to this limited number of regions, neuroimaging studies observed a broader action observation 42 network (AON) which seems to be involved during action observation (OBS) and execution (EXE) 43 (Avenanti et al., 2012;Buccino et al., 2004;Gazzola and Keysers, 2009). A proposed theoretical 44 framework postulates that such AON implements forward and inverse internal models (Wolpert 45 and Ghahramani, 2000), which should be engaged during EXE and OBS. The internal models can 46 account both for how we link our actions to sensory consequences and how others' actions match 47 our own actions and sensations (Gazzola and Keysers, 2009;Iacoboni, 2005). It has been proposed 48 that the fronto--parietal AON has a predictive nature and according to this hypothesis, during 49 action observation the inverse and forward models are integrated to achieve a prediction of 50 ACCEPTED FOR PUBLICATION -NEUROIMA...

Play along: effects of music and social interaction on word learning

“…Instead, the presence of music overrules contextual diversity, as participants maintain the same pattern of coordination independently from the characteristics of a word presentation. This result is somehow in-between the two opposing accounts of the adult learner, one suggesting that adults are entirely self-sufficient learners ( Pickering and Garrod, 2004 ; Stephens et al, 2010 ) and the other suggesting a critical role for others in shaping cognitive activity ( Schilbach et al, 2013 ; Ciaramidaro et al, 2014 ; Schilbach, 2014 ; Sebastiani et al, 2014 ); indeed, these results suggest that the presence of another person is used when needed . While our results indeed confirm that music and social interaction may drive attention in different ways, the question remains open as to which strategy may be more relevant to successfully learning new words.…”

The plasticity of the mirror system: How reward learning modulates cortical motor simulation of others

“… Cochin et al, 1999 ; Muthukumaraswamy et al, 2004 ). However, a recent study reported that beta-mu ERD during action observation showed a peculiar spatiotemporal pattern that could reflect its role in evaluating the accuracy of the simulated motor plan ( Sebastiani et al, 2014 ). Based on this, we speculate that such assessment has to be more accurate for socially relevant stimuli (i.e.…”

Language–motor interference reflected in MEG beta oscillations

“…Taken together, the role of beta oscillations in embodied language processing makes it a feasible candidate for a functional mechanism of language-motor interference. Similarly, alpha band (8-13 Hz) oscillations have been associated with action execution (Salmelin et al, 1995;Sebastiani et al, 2014), observation (Caetano et al, 2007;Avanzini et al, 2012), motor imagery (Pfurtscheller et al, 2006;de Lange et al, 2008), spoken language processing (Strauß et al, 2014), and action language processing (Alemanno et al, 2012;Fargier et al, 2012). Since alpha band oscillations may be more related to sensory than motor processing (Salmelin et al, 1995;Brinkman et al, 2014;Sebastiani et al, 2014;Coll et al, 2015), the focus in the current study is on the beta band, but alpha oscillations are also investigated.…”