title: Differential sensory fMRI signatures in autism and schizophrenia: Analysis of amplitude and trial-to-trial variability.
abstract: Autism and schizophrenia share multiple phenotypic and genotypic markers, and there is ongoing debate regarding the relationship of these two disorders. To examine whether cortical dynamics are similar across these disorders, we directly compared fMRI responses to visual, somatosensory and auditory stimuli in adults with autism (N=15), with schizophrenia (N=15), and matched controls (N=15). All participants completed a one-back letter detection task presented at fixation (to control attention) while task-irrelevant sensory stimulation was delivered to the different modalities. We focused specifically on the response amplitudes and the variability in sensory fMRI responses of the two groups, given the evidence of greater trial-to-trial variability in adults with autism. Both autism and schizophrenia individuals showed weaker signal-to-noise ratios (SNR) in sensory-evoked responses compared to controls (d>0.42), but for different reasons. For the autism group, the fMRI response amplitudes were indistinguishable from controls but were more variable trial-to-trial (d=0.47). For the schizophrenia group, response amplitudes were smaller compared to autism (d=0.44) and control groups (d=0.74), but were not significantly more variable (d<0.29). These differential group profiles suggest (1) that greater trial-to-trial variability in cortical responses may be specific to autism and is not a defining characteristic of schizophrenia, and (2) that blunted response amplitudes may be characteristic of schizophrenia. The relationship between the amplitude and the variability of cortical activity might serve as a specific signature differentiating these neurodevelopmental disorders. Identifying the neural basis of these responses and their relationship to the underlying genetic bases may substantially enlighten the understanding of both disorders.
authors.affiliation: Department of Psychology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA. Electronic address: haighsm@upmc.edu.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Haigh
authors.affiliation: Department of Psychology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
authors.forename: Akshat
authors.initials: A
authors.lastname: Gupta
authors.affiliation: School of Social Work, University of Pittsburgh, 2117 Cathedral of Learning, Pittsburgh, PA 15260, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Barb
authors.affiliation: School of Social Work, University of Pittsburgh, 2117 Cathedral of Learning, Pittsburgh, PA 15260, USA.
authors.forename: Summer A F
authors.initials: SAF
authors.lastname: Glass
authors.affiliation: Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Minshew
authors.affiliation: Psychology Department, Ben-Gurion University of the Negev, 653, Beer-Sheva, 84105, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Dinstein
authors.affiliation: Department of Psychology and Center for Neural Science, New York University, 6 Washington Place, New York, NY 10003, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Heeger
authors.affiliation: School of Social Work, University of Pittsburgh, 2117 Cathedral of Learning, Pittsburgh, PA 15260, USA; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA.
authors.forename: Shaun M
authors.initials: SM
authors.lastname: Eack
authors.affiliation: Department of Psychology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
authors.forename: Marlene
authors.initials: M
authors.lastname: Behrmann
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001321:Autistic Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D010465:Perception / Q000502:physiology*; D010812:Physical Stimulation; D011618:Psychotic Disorders / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D011930:Reaction Time; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D055815:Young Adult
keywords: Autism; Schizophrenia; Sensory perception; Variability; fMRI