Poster D90, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Source localization of mismatch responses at 7 and 12 months in a multifeature auditory paradigm
Katherine Wolfert1, Silvia Ortiz-Mantilla1, Teresa Realpe-Bonilla1, April A. Benasich1; 1Rutgers University-Newark
The multifeature paradigm (MFP) is useful for quickly testing multiple stimulus types within one electroencephalography (EEG) session. Few studies have examined the utility of this paradigm with infants under 12-months-of-age, a population that would benefit from shorter experiment times. To characterize how the infant brain responds to tone stimuli presented in a MFP, dense-array EEG was recorded from cross-sectional groups of 7 and 12-month-olds. Infants were exposed to a standard stimulus and four deviant types: frequency, duration, silent gap, and frequency sweep. Source localization analysis using age-appropriate brain templates revealed dipoles in the auditory cortices and two components (P1 and N2) were examined within the source waveforms. The P1 was defined as the first positivity that could be analyzed for each stimulus type; the N2 was defined as a negativity approximately 370-400ms after stimulus onset. Comparisons of the source waveforms between groups revealed morphological differences typical of auditory development at these ages, including smaller amplitudes, bifurcation of the first positivity, and faster P1 latencies for a subset of stimuli at 12 months. At 7 months, the standard N2 was of greater magnitude than the deviant N2, while the opposite was true at 12 months. This switch might represent a transition from a positive to a negative mismatch response. Group differences and variations in responses to each deviant can shed light on how the sound representation of each stimulus type develops, and further, confirms that responses to multiple deviants can be assessed with the MFP at 7 and 12 months.
Topic Area: PERCEPTION & ACTION: Development & aging