While MRI became a standard workhorse in neurology/neurosurgery within a few years of installation of the first MRI unit, fMRI, in spite of being a powerful imaging tool, remains primarily a research tool, even though the first fMRI study was published 25 years ago. Scientifically, fMRI has made a major impact, judging by the number of PubMed citations and publications in high-impact journals. In cognitive neuroscience, fMRI is the most commonly used imaging technique in published peer-reviewed articles. fMRI is used clinically for preoperative brain mapping in neurosurgery to delineate the proximity of the lesion (tumor) to eloquent areas of the brain, with the aim of achieving adequate tumor resection with minimal functional damage to the brain. fMRI connectivity and activation maps have identified altered activation patterns and resting-state networks in psychiatric disorders like schizophrenia, bipolar disorder, autism, and Alzheimer’s disease, but fMRI is still not a standard diagnostic procedure in psychiatry. Diffusion imaging technique is being used for triaging stroke patients who are likely to respond to stroke therapy (embolectomy and/or clot lysis). Meanwhile, major collaborative fMRI studies are in progress in many institutions to collect normative data on connectivity, activation response, and behavioral response as well as correlation among them. Studies focused on specific neuropsychiatric disorders also have been initiated by the National Institutes of Health. All this is a reflection of the huge potential application of fMRI in clinical practice envisioned by the scientific community.
Semantic unification modulates N400 and BOLD signal change in the brain: A simultaneous EEG-fMRI study