title: Decoding negative affect personality trait from patterns of brain activation to threat stimuli.
abstract: Pattern recognition analysis (PRA) applied to functional magnetic resonance imaging (fMRI) has been used to decode cognitive processes and identify possible biomarkers for mental illness. In the present study, we investigated whether the positive affect (PA) or negative affect (NA) personality traits could be decoded from patterns of brain activation in response to a human threat using a healthy sample.
  
  
  
  fMRI data from 34 volunteers (15 women) were acquired during a simple motor task while the volunteers viewed a set of threat stimuli that were directed either toward them or away from them and matched neutral pictures. For each participant, contrast images from a General Linear Model (GLM) between the threat versus neutral stimuli defined the spatial patterns used as input to the regression model. We applied a multiple kernel learning (MKL) regression combining information from different brain regions hierarchically in a whole brain model to decode the NA and PA from patterns of brain activation in response to threat stimuli.
  
  
  
  The MKL model was able to decode NA but not PA from the contrast images between threat stimuli directed away versus neutral with a significance above chance. The correlation and the mean squared error (MSE) between predicted and actual NA were 0.52 (p-value=0.01) and 24.43 (p-value=0.01), respectively. The MKL pattern regression model identified a network with 37 regions that contributed to the predictions. Some of the regions were related to perception (e.g., occipital and temporal regions) while others were related to emotional evaluation (e.g., caudate and prefrontal regions).
  
  
  
  These results suggest that there was an interaction between the individuals' NA and the brain response to the threat stimuli directed away, which enabled the MKL model to decode NA from the brain patterns. To our knowledge, this is the first evidence that PRA can be used to decode a personality trait from patterns of brain activation during emotional contexts.
authors.affiliation: Department of Physiology and Pharmacology, Laboratory of Neurophysiology of Behaviour, Biomedical Institute, Federal Fluminense University, Niterói, RJ, Brazil. Electronic address: ofernandesjr@vm.uff.br.
authors.forename: Orlando
authors.initials: O
authors.lastname: Fernandes
authors.affiliation: Department of Physiology and Pharmacology, Laboratory of Neurophysiology of Behaviour, Biomedical Institute, Federal Fluminense University, Niterói, RJ, Brazil.
authors.forename: Liana C L
authors.initials: LCL
authors.lastname: Portugal
authors.affiliation: Department of Physiology and Pharmacology, Laboratory of Neurophysiology of Behaviour, Biomedical Institute, Federal Fluminense University, Niterói, RJ, Brazil.
authors.forename: Rita de Cássia S
authors.initials: RCS
authors.lastname: Alves
authors.affiliation: Department of Radiology, Faculty of Medicine, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Tiago
authors.initials: T
authors.lastname: Arruda-Sanchez
authors.affiliation: Department of Computer Science, Centre for Computational Statistics and Machine Learning, University College London, London, UK.
authors.forename: Anil
authors.initials: A
authors.lastname: Rao
authors.affiliation: Laboratory of Neurobiology II, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Eliane
authors.initials: E
authors.lastname: Volchan
authors.affiliation: Department of Physiology and Pharmacology, Laboratory of Neurophysiology of Behaviour, Biomedical Institute, Federal Fluminense University, Niterói, RJ, Brazil.
authors.forename: Mirtes
authors.initials: M
authors.lastname: Pereira
authors.affiliation: Department of Physiology and Pharmacology, Laboratory of Neurophysiology of Behaviour, Biomedical Institute, Federal Fluminense University, Niterói, RJ, Brazil.
authors.forename: Letícia
authors.initials: L
authors.lastname: Oliveira
authors.affiliation: Department of Computer Science, Centre for Computational Statistics and Machine Learning, University College London, London, UK; Max Planck University College London Centre for Computational Psychiatry and Ageing Research, University College London, London, UK.
authors.forename: Janaina
authors.initials: J
authors.lastname: Mourao-Miranda
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect / Q000502:physiology*; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology; D001931:Brain Mapping / Q000379:methods*; D005239:Fear / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010363:Pattern Recognition, Automated / Q000379:methods*; D010551:Personality / Q000502:physiology*; D055815:Young Adult
keywords: Decode; Functional magnetic resonance imaging; Multi-kernel learning; Negative affect trait; Pattern recognition analyses; Threat stimuli