Neural Correlates of Individual Differences in Infant Visual Attention and Recognition Memory

Abstract

Past studies have identified individual differences in infant visual attention based upon peak look duration during initial exposure to a stimulus. Colombo and colleagues (e.g., Colombo & Mitchell, 1990) found that infants that demonstrate brief visual fixations (i.e., short lookers) during familiarization are more likely to demonstrate evidence of recognition memory during subsequent stimulus exposure than infants that demonstrate long visual fixations (i.e., long lookers). The current study utilized event-related potentials to examine possible neural mechanisms associated with individual differences in visual attention and recognition memory for 6- and 7.5-month-old infants. Short- and long-looking infants viewed images of familiar and novel objects during ERP testing. There was a stimulus type by looker type interaction at temporal and frontal electrodes on the late slow wave (LSW). Short lookers demonstrated a LSW that was significantly greater in amplitude in response to novel stimulus presentations. No significant differences in LSW amplitude were found based on stimulus type for long lookers. These results indicate deeper processing and recognition memory of the familiar stimulus for short lookers.

Figure 1

Layout of the EGI 128-channel sensor net, the electrode clusters that demonstrated significant experimental effects are indicated. The grand average waveforms for these electrode clusters are shown to the right. The Y-axis indicates change in amplitude from baseline and the X-axis indicates time following stimulus onset.

Figure 2

Mean amplitude of the late slow wave by looker type and stimulus type at TemporalR. The Y-axis represents change in amplitude from baseline and the X-axis represents time following stimulus onset following familiar (thin line) and novel (bold line) stimulus presentations. The shaded area indicates the portion of the waveform examined in the LSW analysis from 1 to 2 s following stimulus onset.

Figure 3

Mean amplitude of the late slow wave by looker type and stimulus type at FrontalZ. The Y-axis represents change in amplitude from baseline and the X-axis represents time following stimulus onset following familiar (thin line) and novel (bold line) stimulus presentations. The shaded area indicates the portion of the waveform examined in the LSW analysis from 1 to 2 s following stimulus onset.