Neural correlates of action perception at the onset of functional grasping.

Event-related potentials were recorded while infants observe congruent or incongruent grasping actions at the age when organized grasping first emerges (4-6 months of age). We demonstrate that the event-related potential component P400 encodes the congruency of power grasps at the age of 6 months (Experiment 1) and in 5-month-old infants that have developed the ability to use power grasps (Experiment 2). This effect does not extend to precision grasps, which infants cannot perform (Experiment 3). Our findings suggest that infants' encoding of the relationship between an object and a grasping hand (the action-perception link) is highly specialized to actions and manual configurations of actions that infants are able to perform.

Infants' mu suppression during the observation of real and mimicked goal-directed actions.

Since their discovery in the early 1990s, mirror neurons have been proposed to be related to many social-communicative abilities, such as imitation. However, research into the early manifestations of the putative neural mirroring system and its role in early social development is still inconclusive. In the current EEG study, mu suppression, generally thought to reflect activity in neural mirroring systems was investigated in 18- to 30-month-olds during the observation of object manipulations as well as mimicked actions. EEG power data recorded from frontal, central, and parietal electrodes were analysed. As predicted, based on previous research, mu wave suppression was found over central electrodes during action observation and execution. In addition, a similar suppression was found during the observation of intransitive, mimicked hand movements. To a lesser extent, the results also showed mu suppression at parietal electrode sites, over all three conditions. Mu wave suppression during the observation of hand movements and during the execution of actions was significantly correlated with quality of imitation, but not with age or language level.

Influence of eye gaze on spoken word processing: an ERP study with infants.

Eye gaze is an important communicative signal, both as mutual eye contact and as referential gaze to objects. To examine whether attention to speech versus nonspeech stimuli in 4- to 5-month-olds (n=15) varies as a function of eye gaze, event-related brain potentials were used. Faces with mutual or averted gaze were presented in combination with forward- or backward-spoken words. Infants rapidly processed gaze and spoken words in combination. A late Slow Wave suggests an interaction of the 2 factors, separating backward-spoken word+direct gaze from all other conditions. An additional experiment (n=15) extended the results to referential gaze. The current findings suggest that interactions between visual and auditory cues are present early in infancy.

Processing faces in dyadic and triadic contexts.

In a series of four experiments we assessed whether functional properties of the human face, such as signaling an object through eye gaze, influence face processing in 3- and 4-month-old infants. Infants viewed canonical and scrambled faces. We found that 4- but not 3-month-old infants' ERP showed an enhanced face-sensitive N170 component for the scrambled stimulus. Furthermore, when canonical and scrambled faces were gazing toward an object, 4-month-olds displayed an enhanced Negative central (Nc) component, related to attentional processes, for the scrambled face. Three-month-olds did not display any of these effects. These results point to important transition in the first months of infancy and show that triadic cues influence the processing of the human face.

Looking at eye gaze processing and its neural correlates in infancy-implications for social development and autism spectrum disorder.

The importance of eye gaze as a means of communication is indisputable. However, there is debate about whether there is a dedicated neural module, which functions as an eye gaze detector and when infants are able to use eye gaze cues in a referential way. The application of neuroscience methodologies to developmental psychology has provided new insights into early social cognitive development. This review integrates findings on the development of eye gaze processing with research on the neural mechanisms underlying infant and adult social cognition. This research shows how a cognitive neuroscience approach can improve our understanding of social development and autism spectrum disorder.