A high-density EEG study of looming related brain activity in young infants

As infants get more mobile from the second half of the first year of life the ability to perceive and efficiently respond to colliding objects becomes increasingly important. It is suggested that this ability develops as part of a specialization process as infants get more experienced with self-produced locomotion. The aim of this study was to investigate brain electrical activity in infants aged 5-6 months, 8-9 months and 10-11 months. The infants were presented with a looming stimulus approaching on a direct collision course under three different accelerations. Brain electrical activity was investigated by source analysis. A threedipole model of the visual areas O1, Oz and O2 was fitted around peak looming VEP activity at these sites, providing source waveforms (SWF) as a measure of activity in these areas. Start time, duration and amplitudes of the source waveforms were analyzed on a trial by trial basis. The infants seemed not to distinguish between the three looming conditions. There were significant differences between the three dipoles for start time, duration and amplitudes, indicating that the looming stimuli were processed differently in these areas. Visual Cortex radial Left (VCrL) and Visual Cortex radial Right (VCrR) showed the most prominent activity, with activity in these dipoles starting first and lasting for the longest period of time. Also, amplitudes were higher in these dipoles, indicating more cortical activity. However, a pattern of decreasing processing time with age was observed for VCrL and VCrR, which supports earlier findings of a developmental trend for decreasing processing time within the first year of life. Presumably this is due to better control over self-produced locomotion and increased specialization in the developing infant brain. Whether this decreasing brain activity in infants’ perception of looming correlates with behavioural changes should be investigated to get a better understanding of the developing brain and behaviour