Abstract:
Negative-going responses in sensory cortex co-vary with perceptual awareness of
sensory stimuli. Given that this awareness negativity has also been observed for
undetected stimuli, some have challenged its role for perception. To address this
question, we combined magnetoencephalography, electroencephalography, and pupillometry
to study how sustained attention and response criterion affect the auditory awareness
negativity. Participants first detected distractor sounds and denied hearing
task-irrelevant near-threshold tones, which evoked neither awareness negativity nor
pupil dilation. These same tones evoked both responses when task-relevant, stronger
for hit but also present for miss trials. Participants then rated their perception on
a six-point scale to test whether response criterion explains the presence of these
responses for miss trials. Decreasing perception ratings were associated with
gradually reduced evoked responses, consistent with signal detection theory. These
results support the concept of an awareness negativity that is modulated by attention,
but does not require a non-linear threshold mechanism.
Dataset:
The data set includes single subject raw data (M/EEG and eyetracking) and source estimates (combined M/EEG), as well as group averages for both M/EEG and the pupil dilation response. Analysis scripts are also included. Further details are provided in the readme file.