Neural correlates of intersensory processing in 5‐month‐old infants

Abstract

Two experiments assessing event-related potentials in 5-month-old infants were conducted to examine neural correlates of attentional salience and efficiency of processing of a visual event (woman speaking) paired with redundant (synchronous) speech, nonredundant (asynchronous) speech, or no speech. In Experiment 1, the Nc component associated with attentional salience was greater in amplitude following synchronous audiovisual as compared with asynchronous audiovisual and unimodal visual presentations. A block design was utilized in Experiment 2 to examine efficiency of processing of a visual event. Only infants exposed to synchronous audiovisual speech demonstrated a significant reduction in amplitude of the late slow wave associated with successful stimulus processing and recognition memory from early to late blocks of trials. These findings indicate that events that provide intersensory redundancy are associated with enhanced neural responsiveness indicative of greater attentional salience and more efficient stimulus processing as compared with the same events when they provide no intersensory redundancy in 5-month-old infants.

Behavioral and Neural Foundations of Multisensory Face-Voice Perception in Infancy

“…In 5-month olds, they observed differential attentional responses (Nc), with a greater response to faces paired with congruent emotional voices compared to faces paired with incongruent emotional voices regardless of the race of the face (African American or Caucasian). Like findings reported on above, the direction of these results is consistent with some previous work (Reynolds et al, 2014) and opposite of what others have found (Knopp, 2014;Grossmann et al, 2006;Hyde et al, 2011). In contrast, 9-month olds did not show attentional response (Nc) differences by congruency in emotion between faces and voices.…”

“…There is some evidence that the neural response of infants is greater to bimodal compared to unimodal stimulation, paralleling that observed in adults and non-human animals (e.g., Besle et al, 2004;Giard & Peronnet, 1999;Pilling, 2009;Reynolds et al, 2014;Brefczynski-Lewis et al, 2009;Wallace & Stein, 1997;Wallace, Wilkinson, & Stein 1996). Infants also appear to integrate information from different senses early during sensory processing in some contexts, as has also been documented routinely in adults (Hyde et al, 2011;Besle et al, 2009).…”

“…Like others studies reviewed, these results provide consistent evidence for early integration of auditory and visual information in sensory processing (see Besle et al, 2009 for a review). The observed pattern of attentional response (Nc) mirrors that observed by some (Grossmann et al, 2006;Hyde et al, 2011), but is the opposite of what others have observed (Reynolds et al, 2014). Uniquely, this study raises interesting questions about how the timing of processing information from different sense modalities may interact to elicit different perceptions in infants.…”

“…Some initial evidence of greater neural responses to bimodal compared to unimodal stimulation has also been observed in infants (Hyde, Jones, Porter, & Flom, 2010;Reynolds, Bahrick, Lickliter, & Guy, 2014). In one experiment, Hyde and colleagues (2010) compared event-related potentials to bimodal stimulation (i.e., a large colored circle paired with a "bong" sound and a small circle paired with a "ping" sound), unimodal auditory stimulation (i.e., the lower pitched "bong" and higher pitched "ping" sounds), and unimodal visual stimulation (i.e., the large and small colored circles) in 3-month-old infants and adults.…”

“…Greater fronto-temporal negativities were also observed in adults to the same stimuli, albeit earlier and stronger over the left hemisphere (N2) (Figure 1, panel D). Thus, even 3-month-old infants, like adults (e.g., Fort et al, 2002b;Giard & Peronnet, 1999), show greater neural responses for bimodal compared to unimodal stimulation (also see Reynolds et al, 2014). …”