Coherent spontaneous activity accounts for trial-to-trial variability in human evoked brain responses.
Trial-to-trial variability in the blood oxygen level-dependent (BOLD) response of functional magnetic resonance imaging has been shown to be relevant to human perception and behavior, but the sources of this variability remain unknown. We demonstrate that coherent spontaneous fluctuations in human brain activity account for a significant fraction of the variability in measured event-related BOLD responses and that spontaneous and task-related activity are linearly superimposed in the human brain.
Fox
Michael D
MD
Department of Radiology, Washington University in St. Louis, St. Louis, Missouri 63110, USA. foxm@npg.wustl.edu
Snyder
Abraham Z
AZ
Zacks
Jeffrey M
JM
Raichle
Marcus E
ME
D001921:Brain / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D015203:Reproducibility of Results
D010100:Oxygen