Separate contributions of enhanced and suppressed sensitivity to the auditory attentional filter.
Three experiments used a probe-signal method to determine the extent to which exposure-related changes in sensitivity result from an immediate effect of stimulation and from a cumulative effect of repeated stimulation. In the first experiment, a fixed-frequency cue was followed by a same-frequency target (on 75% of trials) or a different-frequency probe (on 25% of trials). In the second experiment, a cue frequency selected randomly from a set of five was followed by a same-frequency target, or one of four different-frequency probes. Targets and probes were randomly selected independently of the cue frequency and all were equiprobable (20%). Target detection showed an average 3.4 dB advantage over probe detection. In the third experiment, tones with a randomly selected frequency were detected better when cued by a tone of the same-frequency than when presented without a prior cue. The cued tones showed an average 2.6 dB advantage over the uncued tones. Together, these results suggest that two mechanisms contribute to changes in sensitivity following auditory stimulation: first, an immediate enhancement of target detection produced by an auditory cue and second, a suppression of non-target frequencies caused by the expectation of a target.
The Auditory Laboratory, Physiology, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, WA 6009, Australia. tanm01@tartarus.uwa.edu.au
Michael N
MN
Tan
Donald
D
Robertson
Geoffrey R
GR
Hammond
D000161:Acoustic Stimulation; D001288:Attention; D001306:Auditory Pathways / Q000502:physiology*; D001307:Auditory Perception; D001309:Auditory Threshold; D017626:Cochlear Nucleus / Q000502:physiology; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D009847:Olivary Nucleus / Q000502:physiology; D010470:Perceptual Masking; D011571:Psychoacoustics