title: Low-frequency fluctuation in continuous real-time feedback of finger force: a new paradigm for sustained attention.
abstract: OBJECTIVE
  Behavioral studies have suggested a low-frequency (0.05 Hz) fluctuation of sustained attention on the basis of the intra-individual variability of reaction-time. Conventional task designs for functional magnetic resonance imaging (fMRI) studies are not appropriate for frequency analysis. The present study aimed to propose a new paradigm, real-time finger force feedback (RT-FFF), to study the brain mechanisms of sustained attention and neurofeedback.
  
  
  METHODS
  We compared the low-frequency fluctuations in both behavioral and fMRI data from 38 healthy adults (19 males; mean age, 22.3 years). Two fMRI sessions, in RT-FFF and sham finger force feedback (S-FFF) states, were acquired (TR 2 s, Siemens Trio 3-Tesla scanner, 8 min each, counter-balanced). Behavioral data of finger force were obtained simultaneously at a sampling rate of 250 Hz.
  
  
  RESULTS
  Frequency analysis of the behavioral data showed lower amplitude in the low-frequency band (0.004-0.104 Hz) but higher amplitude in the high-frequency band (27.02-125 Hz) in the RT-FFF than the S-FFF states. The mean finger force was not significantly different between the two states. fMRI data analysis showed higher fractional amplitude of low-frequency fluctuation (fALFF) in the S-FFF than in the RT-FFF state in the visual cortex, but higher fALFF in RT-FFF than S-FFF in the middle frontal gyrus, the superior frontal gyrus, and the default mode network.
  
  
  CONCLUSIONS
  The behavioral results suggest that the proposed paradigm may provide a new approach to studies of sustained attention. The fMRI results suggest that a distributed network including visual, motor, attentional, and default mode networks may be involved in sustained attention and/or real-time feedback. This paradigm may be helpful for future studies on deficits of attention, such as attention deficit hyperactivity disorder and mild traumatic brain injury.
authors: National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China.
authors: Zhang-Ye
authors: ZY
authors: Dong
authors: Dong-Qiang
authors: DQ
authors: Liu
authors: Jue
authors: J
authors: Wang
authors: Zhao
authors: Z
authors: Qing
authors: Zhen-Xiang
authors: ZX
authors: Zang
authors: Chao-Gan
authors: CG
authors: Yan
authors: Yu-Feng
authors: YF
authors: Zang
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005246:Feedback; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time; D012146:Rest / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult