title: Amygdala habituation: a reliable fMRI phenotype.
abstract: Amygdala function is of high interest for cognitive, social and psychiatric neuroscience, emphasizing the need for reliable assessments in humans. Previous work has indicated unsatisfactorily low within-subject reliability of amygdala activation fMRI measures. Based on basic science evidence for strong habituation of amygdala response to repeated stimuli, we investigated whether a quantification of habituation provides additional information beyond the usual estimate of the overall mean activity. We assessed the within-subject reliability of amygdala habituation measures during a facial emotion matching paradigm in 25 healthy subjects. We extracted the amygdala signal decrement across the course of the fMRI run for the two test-retest measurement sessions and compared reliability estimates with previous findings based on mean response amplitude. Retest-reliability of the session-wise amygdala habituation was significantly higher than the evoked amygdala mean amplitude (intraclass correlation coefficients (ICC)=0.53 vs. 0.16). To test the task-specificity of this finding, we compared the retest-reliability of amygdala habituation across two different tasks. Significant amygdala response decrement was also seen in a cognitive task (n-back working memory) that did not per se activate the amygdala, but was totally unreliable in that context (ICC~0.0), arguing for task-specificity. Together the results show that emotion-dependent amygdala habituation is a robust and considerably more reliable index than the mean amplitude, and provides a robust potential endpoint for within-subject designs including pharmaco-fMRI studies.
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany. Electronic address: Michael.Plichta@zi-mannheim.de.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Plichta
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Grimm
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Morgen
authors.affiliation: Central Institute of Mental Health, Department of Clinical Psychology, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Mier
authors.affiliation: Central Institute of Mental Health, Department of Clinical Psychology, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Sauer
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Leila
authors.initials: L
authors.lastname: Haddad
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Tost
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Esslinger
authors.affiliation: Central Institute of Mental Health, Department of Clinical Psychology, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kirsch
authors.affiliation: Imaging, Eli Lilly and Company, Indianapolis, USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Schwarz
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, University of Heidelberg/Medical Faculty Mannheim, Mannheim, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Meyer-Lindenberg
mesh_terms: D000328:Adult; D000679:Amygdala / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D010641:Phenotype; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Amygdala habituation; Emotion; Faces; Intra-class correlation coefficient (ICC); Retest reliability; fMRI