The event-related brain potentials to uncorrelated fragment of noise
ACOUSTICAL SOCIETY OF AMERICA
wo correlated waveforms of broadband noise presented to the left and right ear simultaneously or with a short delay are often perceptually fused into one sound image. However, when an uncorrelated noise fragment (UCNF) is inserted in a long duration sound, listeners report hearing a transient burst of noise. The detection of the UCNF is dependent on the duration of the UCNF and the binaural delays. Here, we recorded event-related brain potentials (ERPs) to 100-ms UCFN and varied the binaural delay (0, 3, 10, and 20 ms) from trial to trial. The likelihood of detecting the UCNF decreased with increasing binaural delay. At 0 delay, the UCNF elicited negative and positive waves peaking at about 100 and 200 ms after UCNF onset (N1-P2 complex), which was present even when the stimuli were ignored. The conscious detection of the UCNF elicited an additional positive wave between 250 and 450 ms at parietal and occipital sites (P3b). The P3b latency was longer and its amplitude larger for binaural delay of 3 than 0 ms. Our results show that the detection of UCF involved both automatic and attention-dependent processes especially when a binaural delay is introduced between two source of correlated noises.
Huang J., Wu X.-.H., He Y., Qi J.G., Alain C., Schneider B.A. & Li L.
The 149th meeting of the Acoustical Society of America
Vancouver, BC, Canada (May 16-20, 2005)