EEG and ERP studies of low-level odor exposure in normal subjects.

Evidence from four EEG/ERP experiments is presented. Findings of these experiments consistently demonstrate the ability of low-level and undetected odors to alter neurophysiology. Behavioral and cognitive effects are also described. These data may have applicability to theories of MCS since they illustrate the possibility that low-level or undetected odors affect central nervous system activity and may precipitate or cue MCS symptoms.