title: Evaluation of sliding window correlation performance for characterizing dynamic functional connectivity and brain states.
abstract: A promising recent development in the study of brain function is the dynamic analysis of resting-state functional MRI scans, which can enhance understanding of normal cognition and alterations that result from brain disorders. One widely used method of capturing the dynamics of functional connectivity is sliding window correlation (SWC). However, in the absence of a "gold standard" for comparison, evaluating the performance of the SWC in typical resting-state data is challenging. This study uses simulated networks (SNs) with known transitions to examine the effects of parameters such as window length, window offset, window type, noise, filtering, and sampling rate on the SWC performance. The SWC time course was calculated for all node pairs of each SN and then clustered using the k-means algorithm to determine how resulting brain states match known configurations and transitions in the SNs. The outcomes show that the detection of state transitions and durations in the SWC is most strongly influenced by the window length and offset, followed by noise and filtering parameters. The effect of the image sampling rate was relatively insignificant. Tapered windows provide less sensitivity to state transitions than rectangular windows, which could be the result of the sharp transitions in the SNs. Overall, the SWC gave poor estimates of correlation for each brain state. Clustering based on the SWC time course did not reliably reflect the underlying state transitions unless the window length was comparable to the state duration, highlighting the need for new adaptive window analysis techniques.
authors.affiliation: Georgia Institute of Technology, Electrical and Computer Engineering, Atlanta, GA, USA. Electronic address: sadia_shakil@gatech.edu.
authors.forename: Sadia
authors.initials: S
authors.lastname: Shakil
authors.affiliation: Georgia Institute of Technology, Electrical and Computer Engineering, Atlanta, GA, USA. Electronic address: chinhui.lee@ece.gatech.edu.
authors.forename: Chin-Hui
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Georgia Institute of Technology, Biomedical Engineering, Atlanta, GA, USA; Emory University, Biomedical Engineering, Atlanta, GA, USA. Electronic address: shella.keilholz@bme.gatech.edu.
authors.forename: Shella Dawn
authors.initials: SD
authors.lastname: Keilholz
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
keywords: Functional connectivity; Network dynamics; Resting-state functional MRI; Sliding window correlation; States; k-Means