concept

BOLD signal

Also known as: BOLD signal, BOLD activation, blood-oxygen-level-dependent signal, BOLD activity, BOLD signals

Facts (14)

Sources

A Synergistic Workspace for Human Consciousness Revealed by ... elifesciences.org eLife 6 facts

procedureThe researchers computed integrated information between each pair of BOLD signal timeseries for each subject, resulting in a 454-by-454 matrix of integrated information between brain regions.

procedureFunctional MRI preprocessing includes linear detrending and band-pass filtering of the subject-specific denoised BOLD signal timeseries to retain temporal frequencies between 0.008 and 0.09 Hz, eliminating low-frequency drift and high-frequency noise.

procedureThe researchers of 'A Synergistic Workspace for Human Consciousness Revealed by...' deconvolved the hemodynamic response function from regional BOLD signal timeseries prior to analysis using a dedicated toolbox.

procedureThe authors used the Gaussian solver implemented in the JIDT toolbox to calculate TDMI, synergy, and redundancy between pairs of brain regions using HRF-deconvolved BOLD signal timeseries.

perspectiveThe authors do not claim that ΦR and synergy, as measured via regional BOLD signals, are the direct cause of or identical to consciousness; rather, they view these measures as theoretically grounded macroscale indicators whose empirical relationship to consciousness may point toward underlying neural phenomena.

claimFunctional MRI (fMRI) BOLD signals serve as an indirect proxy for underlying neuronal activity but possess limited temporal resolution.

Adversarial testing of global neuronal workspace and ... - Nature nature.com Nature Apr 30, 2025 6 facts

referenceThe paper 'Deconvolving BOLD activation in event-related designs for multivoxel pattern classification analyses' by O., Ashby, F. G., and Poldrack, R. A. was published in NeuroImage, volume 59, pages 2636–2643, in 2012.

procedureThe fMRI decoding strategy utilized a multivariate pattern analysis approach on the pattern of BOLD activity over voxels, similar to the strategy used for iEEG and MEG data.

procedureThe researchers modeled BOLD signal responses to experimental variables by fitting a voxel-wise general linear model (GLM) to each run using FSL FEAT. The model included 12 regressors of interest (targets, task-relevant, and task-irrelevant stimuli for faces, objects, letters, and false fonts) convolved with a double gamma haemodynamic response function, along with 24 motion regressors and cerebrospinal fluid (CSF) and white matter (WM) tissue regressors.

measurementThe fMRI experimental protocol utilized a mean inter-trial interval of 3 s (range 2.5–10 s) and a trial length of approximately 5.5 s to avoid non-linearities in the BOLD signal that could affect fMRI decoding.

claimThe study focused on high-gamma power in iEEG analysis because it closely correlates with neural spiking activity and the BOLD signal.

formulaThe conjunction defining areas responsive to task goals was defined as [TaskRelTar > bsl] and [(TaskRelNonTar = bsl) and (TaskIrrel = bsl)], capturing areas showing increased BOLD signal for targets but not for other stimuli.

Self-awareness, self-regulation, and self-transcendence (S-ART) frontiersin.org Frontiers in Human Neuroscience 2 facts

claimSamatha-vipassana practitioners with 5,000 to over 10,000 hours of practice demonstrate increased BOLD activation in the rostral anterior cingulate cortex (ACC) and dorsomedial prefrontal cortex (DMPFC) during focused attention (FA) meditation, according to studies by Holzel et al. (2007) and Manna et al. (2010).

referenceLutz, A., Greischar, L. L., Perlman, D. M., and Davidson, R. J. (2009) published 'BOLD signal in insula is differentially related to cardiac function during compassion meditation in experts vs. novices' in Neuroimage, volume 47, pages 1038–1046, finding that BOLD signals in the insula relate differently to cardiac function in expert meditators compared to novices.