Developmental changes in point-light walker processing during childhood: a two-year follow-up ERP study

Abstract

Event-related potentials were measured in twenty-four children aged 6-15 years, at one-year intervals for two years, to investigate developmental changes in each subject's neural response to a point-light walker (PLW) and a scrambled PLW (sPLW) stimulus. One positive peak (P1) and two negative peaks (N1 and N2) were observed in both occipitotemporal regions at approximately 130, 200, and 300-400ms. The amplitude and latency of the P1 component measured by the occipital electrode decreased during development over the first one-year period. Negative amplitudes of both N1 and N2, induced by the PLW stimulus, were significantly larger than those induced by the sPLW stimulus. Moreover, for the P1-N1 amplitude, the values for the eight-year-old children were significantly larger than those for the twelve-year-old children. N1 and N2 latency at certain electrodes decreased with age, but no consistent changes were observed. These results suggest that enhanced electrophysiological responses to PLW can be observed in all age groups, and that the early components were changed even over the course of a single year at the age of twelve.

Fig. 1

Grand-averaged ERPs at four electrodes (O1, O2, T5′, T6′) in response to (A) PLW and (B) sPLW stimuli displayed to subjects in three age groups. Each color indicates a stimulus condition in the first or second year. (PLW condition in the first year (blue) and the second year (aqua), and the sPLW condition in the first year (red) and the second year (pink).) Three prominent components, P1, N1 and N2, were observed at around 130, 200 and 300–400 ms after the stimulus onset, respectively. The P1 component was observed at the O1/O2 electrodes, and its amplitude decreased significantly with development. The latency of the P1 component at the O1/O2 electrodes was not modulated by development. The N1 and N2 components were mainly observed at the T5′/T6′ electrodes. Both negative amplitudes induced by the PLW stimulus were significantly larger than those induced by the sPLW stimulus. The N1 latency decreased significantly with development, but the N2 latency did not.

Fig. 2

The averaged amplitude of the P1 component. (A) O1/O2 electrodes and (B) T5′/T6′ electrodes. The error bars indicate the standard errors (SEs) of the mean.

Fig. 3

The averaged latency of the P1 component. (A) O1/O2 electrodes and (B) T5′/T6′ electrodes. The error bars indicate the standard errors (SEs) of the mean.

Fig. 4

The averaged amplitude of the N1 component. (A) O1/O2 electrodes and (B) T5′/T6′ electrodes. The error bars indicate the standard errors (SEs) of the mean.

Fig. 5

The averaged latency of the N1 component. (A) O1/O2 electrodes and (B) T5′/T6′ electrodes. The error bars indicate the standard errors (SEs) of the mean.

Fig. 6

The averaged P1–N1 amplitude. (A) O1/O2 electrodes and (B) T5′/T6′ electrodes. The error bars indicate the standard error (SE) of the mean.

Fig. 7

The averaged amplitude and latency of the N2 component at the T5′/T6′ electrodes. The error bars indicate the standard errors (SEs) of the mean.