Facial affect processing inbipolar disorder: a magnetoencephalography study

Stefanie Hassel, Gulshan B. Sharma, Lucia Castellanos, Anto Bagic, Robert E. Kass, Mary L. Phillips

Research output: Contribution to journalConference abstract

Abstract

Background: Identifying biological markers to aid diagnosis of bipolar disorder (BD) is critically important. To be considered a possible biological marker, neural patterns in BD should be discriminant from those in healthy individuals (HI). We examined patterns of neuromagnetic responses revealed by magnetoencephalography (MEG) during implicit emotion-processing using emotional (happy, fearful, sad) and neutral facial expressions, in sixteen BD and sixteen age- and gender-matched healthy individuals.
Methods: Neuromagnetic data were recorded using a 306-channel whole-head MEG ELEKTA Neuromag System, and preprocessed using Signal Space Separation as implemented in MaxFilter (ELEKTA). Custom Matlab programs removed EOG and ECG signals from filtered MEG data, and computed means of epoched data (0-250ms, 250-500ms, 500-750ms). A generalized linear model with three factors (individual, emotion intensity and time) compared BD and HI. A principal component analysis of normalized mean channel data in selected brain regions identified principal components that explained 95% of data variation. These components were used in a quadratic support vector machine (SVM) pattern classifier. SVM classifier performance was assessed using the leave-one-out approach.
Results: BD and HI showed significantly different patterns of activation for 0-250ms within both left occipital and temporal regions, specifically for neutral facial expressions. PCA analysis revealed significant differences between BD and HI for mild fearful, happy, and sad facial expressions within 250-500ms. SVM quadratic classifier showed greatest accuracy (84%) and sensitivity (92%) for neutral faces, in left occipital regions within 500-750ms.
Conclusions: MEG responses may be used in the search for disease specific neural markers.
Original languageEnglish
Article number1051
Pages (from-to)382S
Number of pages1
JournalBiological Psychiatry
Volume77
Issue number9 Supp.1
Early online date3 Apr 2015
DOIs
Publication statusPublished - 1 May 2015
Event70th Annual Scientific Meeting of the Society of Biological Psychiatry on Stress, Emotion, Neurodevelopment and Psychopathology - Toronto, Canada
Duration: 14 May 201516 May 2015

Bibliographical note

Saturday abstracts: 70th Annual Scientific Meeting of the Society of Biological Psychiatry on Stress, Emotion, Neurodevelopment and Psychopathology, 14-16 May 2015, Toronto (CA).

Keywords

  • bipolar disorder
  • facial expression
  • emotion recognition
  • pattern classification
  • magnetoencephalography

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