fMRI (BOLD, 3T)

MRI · reads

BOLD fMRI is a magnetic resonance imaging technique that detects changes in MRI signal intensity linked to blood oxygenation: paramagnetic deoxyhemoglobin alters local magnetic fields and T2/T2* relaxation. This signal is an indirect, hemodynamic proxy for nerve-cell activity, arising from a mismatch between blood flow and oxygen use, and is variously associated with local field potentials, spikes, or both. After a brief stimulus, the response peaks about 5–6 seconds after onset and its full dynamics, including an undershoot, last about 20–30 seconds.

Spatial resolution

3.4 mm (point spread)

Temporal resolution

100 ms (sample interval)

Field of view

1.23 L (acquired volume)

Reads

T2* MR signal; blood oxygenation (deoxyhemoglobin)

Destructive?

non-destructive

Prerequisites

none beyond ordinary participation

Theoretical spatial resolution

470 µm (point spread)

Theoretical field of view

1.23 L (reachable envelope)

Description

BOLD fMRI at 1.5 T and 3 T measures MRI signal-intensity changes arising when paramagnetic deoxyhemoglobin alters local magnetic fields and T2/T2* relaxation. This is an indirect hemodynamic (metabolic) consequence of neural activity and is much slower than the neural processes: after a brief stimulus the BOLD response peaks about 5-6 s after onset with a width of about 3 s, and its full dynamics, including an undershoot, last about 20-30 s. Reported point-spread widths at these field strengths include about 3.5 mm at 1.5 T and 3.4 mm for spin-echo BOLD at 3 T.

Download the dataset (JSON, described by its JSON Schema).

Loading…