The general linear model (GLM) provides the inferential step after image preprocessing. It relates the measured functional MRI signal at each voxel to task, stimulus, or condition information, producing estimates of voxel-wise responses and statistical maps. This lets investigators move from processed signals to evidence about brain regions associated with an experimental design.
Motion correction, spatial normalization, and smoothing affect how functional MRI data can be interpreted across images and participants. Motion correction addresses movement-related differences, normalization places data into a common spatial framework, and smoothing prepares neighboring voxel signals for analysis. Together, these operations establish a consistent input for later statistical modeling.
SPM and FSL are best viewed as complementary frameworks rather than identical labels for one analysis. Their tools can support the shared workflow of preprocessing, model-based estimation, and statistical mapping, while allowing researchers to organize analyses around different software resources. This complementarity matters when designing reproducible neuroscience workflows that need consistent processing and interpretable outputs.
A typical workflow starts with functional MRI data and applies motion correction, spatial normalization, and smoothing in sequence. The processed signals then enter a general linear model, which estimates responses at individual voxels. Statistical maps provide the resulting analysis output, allowing researchers to examine task- or stimulus-associated regions, compare participants, or relate findings to behavior.
To compare activity across participants, researchers use the statistical maps and voxel-wise estimates generated after modeling. The common spatial framework created during normalization supports comparisons of corresponding brain locations, while the modeled results allow investigators to examine differences associated with tasks, stimuli, or clinical conditions. These comparisons can also be related to behavioral measures.
Applications extend from cognitive neuroscience and brain mapping to investigations of neurological and psychiatric disorders. A study may use task- or stimulus-related estimates to identify associated brain regions, or examine activity in relation to a clinical condition. Linking imaging findings with behavior adds another interpretive dimension, connecting spatial brain patterns with measurable outcomes.