Table 1.

Magnetic Resonance Imaging Terms

Term/Acronym	Meaning
Artifact	An irregularity in the magnetic field caused by head movement, bony cavities, or the presence of metal, which leads to loss of integrity of signal.
Atlas	A brain template used to define regions and/or networks, e.g., the MNI Atlas, Talairach Atlas, Yeo Atlas.
Block fMRI	Consecutive blocks of task stimuli presented in series (e.g., for 30s), interspersed with rest periods.
BOLD	Blood Oxygenation Level Dependent signal; measures magnitude of activation using contrast between oxygenated and deoxygenated blood.
Cluster	A contiguous part of a statistical brain map after some method of significance testing (e.g., “we identified a significant cluster in the left insula”).
Connectivity	Estimates of the dynamic temporal relationship between brain cells, areas, regions or networks.
Event-related	Task-based design, individual task trials interspersed with variable inter-trial interval
FWE/FDR	Family wise error/false discovery rate: multiple testing considerations to correct for the ~50,000 voxels in a brain.
GLM	General linear model - most common statistical approach for fMRI data, implemented in all major packages (FSL, AFNI, SPM).
HRF	Hemodynamic response function - the shape and lag used to model the BOLD response.
ITI	Inter-trial interval - the delay between successive task trials.
Mask	To extract signal from a discrete region or network for analysis, a mask is created, which is a 3D map of which voxels should be included in analysis.
Network	An interacting, topologically organized set of brain regions.
RF pulse	Radiofrequency pulse - the perturbational signal emitted by the scanner.
ROI	Region of interest; a predefined brain region used for analysis of discrete, usually anatomically-defined brain regions.
rsfMRI	Resting state fMRI - participant rests in the scanner with eyes open or closed.
SNR	Signal-to-noise ratio, an index of data quality; e.g., “there is low SNR in that region due to an artifact near the orbital sinus”.
Slice	A full acquisition in one plane; e.g., “36 sagittal slices”.
tesla	Unit of measurement for magnet strength; abbreviated “T” (e.g., a 3T scanner).
Time series autocorrelation	Degree of similarity in activation between two regions while accounting for the time lapse between them.
TE	Time to echo - the time between administration of the magnetic pulse and the corresponding echo from the perturbed atomic nuclei in the brain.
TR	Time to repetition - the time between magnetic pulses (typically ~2s).
Volume	A single complete acquisition (whole brain/part of the brain) (e.g., “336 volumes”).
Voxel	A 3D pixel (e.g., “the region contained 200 voxels”).