Functional magnetic resonance imaging (fMRI) and the 2-deoxyglucose (2-DG) method are both used to study brain function, but they differ in several key aspects:

1. Principle of Measurement:

   • fMRI measures changes in blood oxygenation and flow in the brain associated with neural activity, using the blood oxygenation level-dependent (BOLD) contrast. This method is non-invasive and can provide real-time data on brain activity across different regions as reported in the article from the National Center for Biotechnology Information (NCBI).
   • The 2-DG method, on the other hand, involves injecting a glucose analog (2-DG) into the bloodstream. The brain's metabolically active areas take up more 2-DG, which can later be detected and mapped post-mortem or in animal studies. This method provides a more direct measure of neural metabolism but is invasive and cannot be used in living humans except under specific conditions such as in animal models.

2. Temporal and Spatial Resolution:

   • fMRI offers relatively high temporal resolution, capable of capturing brain activity changes within seconds and with a spatial resolution that can be as fine as a few millimeters, as detailed in the ScienceDirect article.
   • The 2-DG method provides high spatial resolution but is limited in its temporal resolution since it requires a period of uptake followed by sacrifice or scanning at a later time point.

3. Invasiveness:

   • fMRI is non-invasive and can be used repeatedly in the same subject, which is a significant advantage in human studies.
   • The 2-DG method is invasive and typically used in animal studies or in post-mortem human brain studies.

4. Applications:

   • fMRI is widely used in cognitive neuroscience to study a variety of brain functions and disorders, as mentioned in the ResearchGate publication.
   • The 2-DG method is more limited in its application but can provide valuable insights into brain metabolism, particularly in animal models of human diseases.

In summary, while both methods aim to understand brain function, fMRI offers a non-invasive, real-time approach suitable for human studies, whereas the 2-DG method provides a direct metabolic measure but is limited by its invasive nature and lower temporal resolution. Here are some images illustrating both methods:

• An fMRI image:
• A 2-DG autoradiograph: