Electrophysiological evidence for the critical band in humans: Middle-latency responses

Abstract

Electrophysiological evidence for the critical band phenomenon in humans using event-related potentials has been sought for many years with conflicting results. Components Na and Pa of the middle-latency response (MLR) and wave V of the auditory brain-stem response (ABR) were simultaneously recorded in response to a two-tone complex varying in bandwidth from 76 Hz to 1012 Hz, centered at 2 kHz, and presented at an overall level of 85 dB SPL, in ten normal female subjects. Only the amplitude of Na showed an abrupt increase as bandwidth changed from 268 to 330 Hz, yielding an estimate of critical bandwidth in good agreement with previous behavioral estimates.

Complex tone processing and critical band in the human auditory cortex

“…Thus, N1m amplitudes show CB-like behavior. These findings that are based on AEF responses corroborate the results of both investigations of CB representations in the A1 of animals (Ehret and Schreiner, 1997;Fishman et al, 2000) and human studies demonstrating CB-like increases in the amplitudes of AEP and AEF components (Zerlin, 1986;Burrows and Barry, 1990;Soeta et al, 2005a).…”

“…However, there was no significant change in the peak (N1-P2) amplitude regardless of the frequency separation of a two-tone complex or the bandwidth of a bandpass noise. Burrows and Barry (1990) investigated the Na and Pa components of the middle-latency response (MLR) and wave V of the brainstem AEP in response to a twotone complex varying in frequency separation from 76 to 1012 Hz at the center frequency of 2 kHz. They found that the amplitude of Na only rapidly increased as the frequency separation changed from 268 to 330 Hz.…”

Effects of the critical band on auditory-evoked magnetic fields

“…Skinner and Antinoro [12], however, failed to find a significant change in the peak (N1-P2) amplitude of cortical auditory-evoked potentials (AEPs) regardless of the bandwidth of either a two-tone complex or bandpass noise. Burrows and Barry [13] reported the existence of critical band-like behavior reflected in the amplitude of the middle-latency response component Na; however, no similar effect was found for either wave V of the auditory brainstem response or component Pa of the middle-latency response. Few reports have documented cortical responses to critical band-like behavior; however, considerable disagreement exists.…”

Effects of the binaural auditory filter in the human brain

“…Zerlin [4] reported an abrupt increase in the amplitude of wave V of the brainstem AEP responses when the bandwidth of a two-tone complex approximated the CBW. Burrows and Barry [5] reported that the amplitude of Na of the AEP rapidly increased when the frequency separation of a two-tone complex increased beyond the CBW. Soeta et al [6,7] found that the N1m amplitudes of AEFs increased with increasing bandwidth when the bandwidth of bandpass noise or the frequency separation of a two-tone complex increased beyond the CBW.…”