Cortical mapping of human action perception during infancy: A functional Near Infrared Spectroscopy investigation

The ability to identify cues from motion, such as eye gaze shifts, emotional expression, articulation of the mouth and manual gestures, provides the foundation of social perception and allows us to comprehend and interpret the intentions, language, emotions and desires of others. The cortical mapping of human action perception in the infant brain is poorly understood, largely due to the limitations of available neuroimaging methods. The research presented in this talk investigated cortical activation to facial and manual human actions using functional near infrared spectroscopy (fNIRS). fNIRS provides an elegant solution to bridge this methodological gap, and is an emerging new technology for investigating developmental cognitive neuroscience. Over a series of experiments, four to six-month-old infants watched life-size videos of adult actors moving their hand, their mouth, or their eyes, while haemodynamic responses were recorded over the frontal and temporal cortices. The data presented in Study 1 and 2 suggests that a localised superior temporal region of the cortex is responsive to the observation of complex social human actions, and not to non-human mechanical actions. Study 3 reveals localised cortical responses to differing dynamic facial and manual human action cues in regions of the frontal and temporal cortex with partially separable localised responses evident to different types of human movements. Finally Study 4, which investigated these effects further, presents optical data alongside concurrent eye-tracking data and additional behavioural measures of manual dexterity. These preliminary findings suggest that infant’s own fine motor abilities may be correlated with cortical activation to the perception of another’s hand movements. Taken together, this work illuminates hitherto undocumented maps of cortical activation to human action perception in the early developing brain, and demonstrate the potential that fNIRS offers for developmental research.