Authors: Julia Moser, Franziska Schleger & Hubert Preissl
Neurophysiological correlates of consciousness are used in normal and diseased populations. One possible approach is the application of an auditory “localglobal” mismatch paradigm. Based on a learned global rule the global deviant elicits a mismatch response – in addition to the local mismatch – which is related to conscious processing. All studies using the “local-global” paradigm use different instructions on how subjects should behave with respect to the stimuli. The present study therefore uses no task with the aim to investigate the suitability of this paradigm for fetal MEG studies where instructions are not possible. MEG was recorded from sixteen healthy adults with sequences of pure 500Hz and 750Hz tones as stimuli. Each experimental block had an initial learning phase and a testing phase where the global deviant appeared in one fourth of trials. Cluster based permutation testing was used for analysis. Significant early mismatch responses were detected in a time window between 90–150ms after onset of a local deviant. Global mismatch responses were found in later time windows ranging from 150 to 500ms. Additionally, a modulation of the early mismatch response was identified, depending on the global standard. Both, global effect and early modulation indicate conscious processing of the stimuli even if subjects were not instructed to attend to the stimuli. Our results create a solid basis for a fetal study, even if the explanatory power of event related responses in the search for consciousness can be discussed.
Reference: Moser, J., Schleger, F., & Preissl, H. (2017, December). MAGNETOENCEPHALOGRAPHIC SIGNATURES OF CONSCIOUS PROCESSING DURING AN AUDITORY LOCAL-GLOBAL PARADIGM WITHOUT A TASK. In PSYCHOPHYSIOLOGY (Vol. 54, pp. S58-S58). 111 RIVER ST, HOBOKEN 07030-5774, NJ USA: WILEY.