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Abstract:
Rapid auditory processing has been shown to be related to
language development. We measured infant brain activation and
behavioral performance in separate sessions for complex tone-pairs
separated by 300 or 70 ms interstimulus intervals (ISI). ERPs were
recorded to 100-100 Hz standard stimuli and to 100-300 Hz deviant
stimuli (15%) in a mismatch negativity paradigm. ERP peak amplitude
and latency measures were calculated from difference waves (deviant
- standard). According to preliminary analyses (12 participants),
negative amplitudes of the difference wave, peaking at about 850 ms
for 300 ms ISI and 420 ms for 70 ms ISI, showed pre-attentive
discrimination between standard and deviant tone-pairs. Behavioral
performance was measured in a conditioned head-turn task using the
same stimuli. Eight out of 12 infants learned to associate the
deviant stimuli with visual reinforcement at 500 ms training ISI.
In these 8 infants, ERP amplitude measures were not associated to
behavioral performance. However, ERP latencies for 70 ms ISI were
inversely related to behavioral discrimination for 300 ms ISI
stimuli (r = -.70 to -.85) and a trend was found for 70 ms ISI (r =
-.63 to -.71). Significant brain-behavior associations were located
predominantly in the left fronto-central regions suggesting that,
in infants, earlier anterior activation for passive change
detection is related to better behavioral discrimination.
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