Predictive motor activation during action observation in human infants

Abstract

Certain regions of the human brain are activated both during action execution and action observation. This so-called 'mirror neuron system' has been proposed to enable an observer to understand an action through a process of internal motor simulation. Although there has been much speculation about the existence of such a system from early in life, to date there is little direct evidence that young infants recruit brain areas involved in action production during action observation. To address this question, we identified the individual frequency range in which sensorimotor alpha-band activity was attenuated in nine-month-old infants' electroencephalographs (EEGs) during elicited reaching for objects, and measured whether activity in this frequency range was also modulated by observing others' actions. We found that observing a grasping action resulted in motor activation in the infant brain, but that this activity began prior to observation of the action, once it could be anticipated. These results demonstrate not only that infants, like adults, display overlapping neural activity during execution and observation of actions, but that this activation, rather than being directly induced by the visual input, is driven by infants' understanding of a forthcoming action. These results provide support for theories implicating the motor system in action prediction.

EEG imaging of toddlers during dyadic turn-taking: Mu-rhythm modulation while producing or observing social actions

“…Several prior studies (Southgate et al, 2009;Marshall et al, 2011;Saby et al, 2013) also reported mu-suppression in toddlers during action observation. The current study goes further not only by employing a socially interactive paradigm and by precisely quantifying and controlling for toddlers' motor activity, but also by (1) locking toddlers' EEG to the onset and offset of their own or their mother's actions; (2) identifying mu suppression using multiple criteria including ERSP, PSD, scalp maps and source locations; and (3) comparing EEG power profiles across a wide range of frequencies and channel locations.…”

Neural mirroring during the observation of live and video actions in infants

“…Previous infant studies investigated neural mirroring during the observation of live (e.g., Nyström et al, 2010;Southgate et al, 2009) or video actions (e.g., Nyström, 2008van Elk et al, 2008). The majority of the researchers used live stimuli reasoning that live stimuli provide a more realistic view on brain processing because these stimuli are efficiently processed due to their similarity with the real world (Carver et al, 2006).…”

Developmental correspondence between action prediction and motor ability in early infancy

“…Neuro physiological [1][2][3][4][5][6][7] and brainimaging [8][9][10][11] studies indicate that others' actions are understood through a direct match ing process of a mirror neuron system (MNS), where an observed action is mapped onto the observer's own motor representation of that action 12,13 . In fact, several recent neurophysiological studies with infants over the age of 6 months have shown MNS function ing when the infants observed others' actions [14][15][16][17][18][19] . In spite of this correlation, compelling evidence of the direct matching process in early infancy is rare.…”

“…Recent neurophysiological studies found that motor activation in areas associated with the MNS occurred immediately prior to the onset of observed actions in adults 20 and 9montholds 17 . Moreover, recent behavioural studies showed that adults 21 and 12monthold infants 22 manifest proactive goaldirected eye movements while observing the manipulating actions of others.…”

“…Furthermore, many developmental studies that have relied upon grasping responses have used various groups of infants with ages less than 9 months 15,[17][18][19]32 . Accordingly, we used grasping as a type of action for which young infants are likely to have a motor representation and are capable of performing.…”