title: Proneness to social anxiety modulates neural complexity in the absence of exposure: A resting state fMRI study using Hurst exponent.
abstract: To test the hypothesis that brain activity is modulated by trait social anxiety, we measured the Hurst Exponent (HE), an index of complexity in time series, in healthy individuals at rest in the absence of any social trigger. Functional magnetic resonance imaging (fMRI) time series were recorded in 36 subjects at rest. All volunteers were healthy without any psychiatric, medical or neurological disorder. Subjects completed the Liebowitz Social Anxiety Scale (LSAS) and the Brief Fear of Negative Evaluation (BFNE) to assess social anxiety and thoughts in social contexts. We also obtained the fractional Amplitude of Low Frequency Fluctuations (fALFF) of the BOLD signal as an independent control measure for HE data. BFNE scores correlated positively with HE in the posterior cingulate/precuneus, while LSAS scores correlated positively with HE in the precuneus, in the inferior parietal sulci and in the parahippocamus. Results from fALFF were highly consistent with those obtained using LSAS and BFNE to predict HE. Overall our data indicate that spontaneous brain activity is influenced by the degree of social anxiety, on a continuum and in the absence of social stimuli. These findings suggest that social anxiety is a trait characteristic that shapes brain activity and predisposes to different reactions in social contexts.
authors.affiliation: Clinical Psychology Branch, Department of Neuroscience, Pisa University Hospital, Via Roma. 67, Pisa, Italy; Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Via Paradisa 10, Pisa, Italy. Electronic address: claudio.gentili@med.unipi.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Gentili
authors.affiliation: Department of Information Engineering, University of Pisa, Via Diotisalvi 10, Pisa, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Vanello
authors.affiliation: Clinical Psychology Branch, Department of Neuroscience, Pisa University Hospital, Via Roma. 67, Pisa, Italy; Department of Clinical Psychology and Psychotherapy, University Babes-Bolyai, Republicii str. 37, Cluj-Napoca, Romania.
authors.forename: Ioana
authors.initials: I
authors.lastname: Cristea
authors.affiliation: Department of Clinical Psychology and Psychotherapy, University Babes-Bolyai, Republicii str. 37, Cluj-Napoca, Romania; Department of Oncological Sciences, Mount Sinai School of Medicine, 1428 Madison Ave New York, NY, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: David
authors.affiliation: Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Via Paradisa 10, Pisa, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Ricciardi
authors.affiliation: Clinical Psychology Branch, Department of Neuroscience, Pisa University Hospital, Via Roma. 67, Pisa, Italy; Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Via Paradisa 10, Pisa, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Pietrini
mesh_terms: D000328:Adult; D001007:Anxiety / Q000378:metabolism* / Q000523:psychology*; D001921:Brain / Q000378:metabolism*; D005239:Fear / Q000502:physiology / Q000523:psychology; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012146:Rest / Q000502:physiology / Q000523:psychology*; D055815:Young Adult
keywords: Default mode network; Hurst exponent; Resting state; Social anxiety; Social phobia; fALFF; fMRI