title: Is There a Nonadditive Interaction Between Spontaneous and Evoked Activity? Phase-Dependence and Its Relation to the Temporal Structure of Scale-Free Brain Activity.
abstract: The aim of our study was to use functional magnetic resonance imaging to investigate how spontaneous activity interacts with evoked activity, as well as how the temporal structure of spontaneous activity, that is, long-range temporal correlations, relate to this interaction. Using an extremely sparse event-related design (intertrial intervals: 52-60 s), a novel blood oxygen level-dependent signal correction approach (accounting for spontaneous fluctuations using pseudotrials) and phase analysis, we provided direct evidence for a nonadditive interaction between spontaneous and evoked activity. We demonstrated the discrepancy between the present and previous observations on why a linear superposition between spontaneous and evoked activity can be seen by using co-occurring signals from homologous brain regions. Importantly, we further demonstrated that the nonadditive interaction can be characterized by phase-dependent effects of spontaneous activity, which is closely related to the degree of long-range temporal correlations in spontaneous activity as indexed by both power-law exponent and phase-amplitude coupling. Our findings not only contribute to the understanding of spontaneous brain activity and its scale-free properties, but also bear important implications for our understanding of neural activity in general.
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, ON K1Z 7K4, Canada.
authors.forename: Zirui
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou 311121, PR China.|Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou Normal University, Hangzhou 310015, PR China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors.forename: André
authors.initials: A
authors.lastname: Longtin
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, ON K1Z 7K4, Canada.|Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors.forename: Grégory
authors.initials: G
authors.lastname: Dumont
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, ON K1Z 7K4, Canada.|Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou 311121, PR China.|Brain and Consciousness Research Center, Taipei Medical University-Shuang Ho Hospital, New Taipei City 23561, Taiwan.
authors.forename: Niall W
authors.initials: NW
authors.lastname: Duncan
authors.affiliation: Department of Anthropology, University of Toronto, Toronto, ON M5S 2S2, Canada.
authors.forename: Johanna
authors.initials: J
authors.lastname: Pokorny
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, ON K1Z 7K4, Canada.|Brain and Consciousness Research Center, Taipei Medical University-Shuang Ho Hospital, New Taipei City 23561, Taiwan.
authors.forename: Pengmin
authors.initials: P
authors.lastname: Qin
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou 311121, PR China.|Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou Normal University, Hangzhou 310015, PR China.|School of Life Science, South China Normal University, Guangzhou 510613, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Dai
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, ON K1Z 7K4, Canada.
authors.forename: Francesca
authors.initials: F
authors.lastname: Ferri
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou 311121, PR China.|Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou Normal University, Hangzhou 310015, PR China.
authors.forename: Xuchu
authors.initials: X
authors.lastname: Weng
authors.affiliation: Institute of Mental Health Research, University of Ottawa, Ottawa, ON K1Z 7K4, Canada.|Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou 311121, PR China.|Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou Normal University, Hangzhou 310015, PR China.|Brain and Consciousness Research Center, Taipei Medical University-Shuang Ho Hospital, New Taipei City 23561, Taiwan.
authors.forename: Georg
authors.initials: G
authors.lastname: Northoff
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D010100:Oxygen / Q000097:blood; D011597:Psychomotor Performance / Q000502:physiology*; D011932:Reading; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: fMRI; infraslow frequency; scale-free property; spontaneous activity; trial-to-trial variability