MEG Correlates of Subliminal vs Supraliminal Face Processing
-
1
Medical Research Council (MRC), Cognition and Brain Sciences Unit, United States
In previous EEG[1] and fMRI[2] studies, we reported evidence of unconscious face processing using a paradigm in which behavioural and neural responses to a target face are modified by whether an immediately preceding “prime” face is of the same or a different person, even though objective evidence shows that the prime is rendered invisible to participants via its brief-presentation and sandwiching between a forward and backward pattern mask. In the present study, we repeat this paradigm with MEG, in order to try to relate the two temporal priming effects (observed with EEG) to the spatial priming effects (observed with fMRI). Furthermore, we added a condition in which the masks were removed, in order to compare subliminal with supraliminal priming. MEG data were acquired with a 275-channel CTF axial gradiometer system. The MEG data replicated the previous EEG temporal effects, with an “early” repetition priming effect from 100-200ms post-target onset and a “later” effect from 370-540ms. Neither effect differed reliably for masked vs unmasked conditions (or for known vs unfamiliar faces), suggesting that they reflect fairly automatic neural responses independent of awareness of the prime. Preliminary distributed source analysis in SPM8 localised the early effect to right anterior temporal and mid-fusiform regions (surviving correction for multiple comparisons over source space with the 12 participants). Planned analysis of the effective connectivity between these regions (using Dynamic Causal Modelling), further informed by the previous fMRI data, will hopefully reveal whether these effects reflect changes in “first-pass” or “re-entrant” connectivity[3] within the ventral-stream, face-processing network.
References
1. Henson et al. (2008). Neuroimage, 40, 884-895.
2. Kouider et al (2009). Cerebral Cortex, 19, 13-23.
3. Henson (2003). Progress in Neurobiology, 70, 53-81.
Conference:
Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010.
Presentation Type:
Poster Presentation
Topic:
Neurocognition and Functional Connectivity
Citation:
Henson
R
(2010). MEG Correlates of Subliminal vs Supraliminal Face Processing.
Front. Neurosci.
Conference Abstract:
Biomag 2010 - 17th International Conference on Biomagnetism .
doi: 10.3389/conf.fnins.2010.06.00222
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
30 Mar 2010;
Published Online:
30 Mar 2010.
*
Correspondence:
Richard Henson, Medical Research Council (MRC), Cognition and Brain Sciences Unit, Cambridge, United States, rik.henson@mrc-cbu.cam.ac.uk