TABLE 1.

An overview of neuroimaging methods used to study neuroplasticity in humans.

Modality	Information obtained	Advantages for neuroplasticity research	Limitations in neuroplasticity research
Structural
Magnetic Resonance Imaging (MRI)	• Morphological characteristics assessed with voxel-based morphometry (VBM; to assess gray volume/density) or indexes of cortical thickness. • Plasticity specific: Information about alteration in the brain’s macroscopic structure, with various plausible underlying biological mechanisms (synaptogenesis, neurogenesis, gliogenesis, angliogenesis).	• Plasticity specific: Information about alteration in the brain’s macroscopic structure, with various plausible underlying biological mechanisms (synaptogenesis, neurogenesis, gliogenesis, angliogenesis). • Does not require performance of the task in the scanner.	• In cross-sectional studies, structural methods may not only detect differences that are specific to learning the skill of interest but also more general group differences (professional musicians who devoted years to musical training may be more persistent that novices, which may be reflected in brain structure). For further limitation of structural neuroimaging techniques in neuroimaging research see Thomas and Baker (2013).
Diffusion-based MRI (Diffusion Tensor Imaging; DTI)	• Information about the white-matter integrity, microstructure, and white matter connections based on the directional asymmetry of water diffusion. Fractional anisotropy (FA) is a global estimate of the linearity of diffusion, while mean diffusivity (MD) quantifies the amount of diffusion in each voxel. Higher FA and lower MD denote higher levels of organization of the white matter structure.	• Quantification of white matter integrity as well as delineation of white matter pathways connecting different regions of the brain associated with expertise or changes during learning. • Does not require performance of the task in the scanner.
	• Plasticity specific: Information about regional reorganization of myelinating tracts, with various plausible underlying biological mechanisms (myelination, synaptogenesis, neurogenesis, gliogenesis).
Functional
Task-related Functional MRI (fMRI)	• Detection of changes in the blood oxygenation level-dependent (BOLD) signal, which is affected by changes in neural activation in a specific brain region and the underlying physiology. • Localization of brain activation associated with performing a cognitive task and/or behavior.	• Detection of changes in brain activation while individuals perform a task of interest (e.g., playing an instrument).	• Task-related methods may not always be suitable for cross-sectional studies (as novices will not be able to perform the task) or for tasks that are impossible to perform in the scanner environment. • In longitudinal research, may detect changes in activation not specific to learning a new skill, but instead changes in perceived task-difficulty or awareness of task sequential structure (for further discussion see Poldrack, 2000).
			• In isolation, task-related activations/deactivations are ambiguous and may reflect compensatory activations, task performance automatization or underlying changes in vascular or metabolic environment.
Task-related Electroencephalogram (EEG) & Evoked Related Potentials (ERP)	• Direct recording of underlying electrical brain activation associated with a cognitive task and/or behavior.		• Requires a carefully selected control condition.
Task-related Magnetoencephalography (MEG)	• Direct recording of brain activation, assessing brain magnetic fields.
Functional Connectivity (FC)	• Functional interactions (neural synchronization) between different brain regions.	• Does not require performance of a task in the scanner. • Possible to compare experts and novices, or track connectivity longitudinally.	• In cross-sectional studies, may not only detect differences that are specific to learning the skill of interest but also more general group differences (for example, professional musicians who devoted years to musical training may be more persistent that novices, which may be reflected in FC).