| |
Abstract:
Abstract: We investigated the neural substrates of
audiospatial attention using two selected set designs and virtual
auditory space technology (VAST). We asked whether 1) VAST stimuli
elicit attentional modulation of electrophysiological and
behavioral measures, 2) mixed and blocked cue designs involve
different neural systems and 3) these differences are manifested at
the behavioral level. Behavioral and event-related potential (ERP)
data were collected simultaneously using both mixed and blocked cue
designs, each involving the presentation of a central arrow and an
auditory target. Targets were broadband noises pre-convolved with
head-related impulse responses from a standard subject and
presented over headphones. Four virtual locations were used: upper
and lower, left of midline; upper and lower, right of midline.
Subjects were directed to covertly attend to the side specified by
the central arrow. Subjects determined whether the target was below
or above the horizontal plane and indicated their judgement with a
button press. We found that reaction times were lower for validly
than for invalidly cued targets in both designs. Peak negativity
between 50-150 ms (i.e., N100) was significantly greater for
validly than for invalidly cued targets. We found no
design-dependent differences in ERPs or reaction times. Subjects
showing the largest behavioral validity effects also showed larger
effects in ERPs compared to subjects having no behavioral validity
effect. Supported by grants from the NIDCD (DC00128) and the NIGMS
(5-T32-GM07257).
|
