Glossary Terms  Home

Field of View (FOV)

The total extent of an image along a spatial dimension.

Fixed-effects Analysis

Intersubject analysis that assumes that the effect of the experimental manipulation is fixed across subjects, with differences between subjects caused by random noise.

Filling k-space

The process of collecting samples from throughout k-space in order to collect data sufficient for image formation.

Flat map

An unfolded and flattened representation of the cortical sheet to allow viewing of topographic changes over cortical space.  Flat maps are most commonly used in fMRI to illustrate the organization of the visual cortex.

Flip Angle

The change in the precession angle of the net magnetization during an excitation pulse.

Flux

A measure of strength of a magnetic field over an area of space.

Fourier transform

A mathematical technique for converting a signal (i.e., changes in intensity over time) into its power spectrum.

Frequency Domain

The expression of a signal in terms of its power at different frequencies.

Frequency-Encoding Gradient

A gradient turned on during the data acquisition period, so that the frequency of spin precession changes over space.

Functional Contrast

A type of contrast that provides information about a physiological correlate of brain function, such as changes in blood oxygenation.

Functional Magnetic Resonance Imagining (fMRI)

A neuroimaging technique that uses standard MRI scanners to investigate changes in brain function over time.

Functional Neuroimaging

A class of research techniques that create images of the functional organization of the brain. Common functional neuroimaging techniques include fMRI, PET, SPECT (single-photon emission computerized tomography) and optical imaging.

Functional Resolution

The ability to map measured physiological variation to underlying mental processes.

Functional ROI

The region of interest that is chosen based on functional criteria, such as the output of a voxelwise analysis.