Poster #: 4
Topic: Attention and distraction
Wednesday, Sep 9, 2015
P3a evidence of consciousness following acoustic change during REM sleep
Psychology, University of Ottawa, Ottawa, Canada
Certain potentially-relevant auditory stimuli occurring outside the focus of attention can trigger an attention switch from the task-at-hand to the distracting auditory event. Such attention capture may result in an “intrusion into consciousness”, eliciting a positive-going event-related potential, P3a. This is thought to reflect processes related to the switching of attention and the subsequent conscious awareness of the auditory event. This study examines these processes during an unconscious state, natural sleep. Certain deviants can elicit a P3a, some during REM sleep. These studies employ oddball paradigms with lengthy testing times due to rarely occurring deviants. An “optimal” paradigm allows for time-efficient data collection (during REM sleep). The present study examines the processing of six deviants using the optimal paradigm. During wakefulness, only white noise and environmental sounds elicited a significant P3a. During stages N2 and N3, a small amplitude positive-component around the time of P3a was apparent following these stimuli. During REM, white noise and environmental sounds elicited a large amplitude positivity occurring around the same latency and amplitude as the waking-P3a. The scalp distribution maps of these positivities was however different. In waking, it was maximum over centro-frontal scalp sites. During REM, the positivity was more widespread. Deviants not eliciting P3a in waking also did not elicit this positivity during REM. This suggests that processes related to the possible intrusion into consciousness remain active during REM, which may be crucial for survival. The brain regions activated by these highly relevant stimuli do however appear to be different in REM.