Functional Magnetic Resonance Imaging (fMRI)

MRI has revolutionized cognitive neuroscience over the last decades. It has enabled researchers to measure the brain responses of human subjects while they are performing cognitive or sensory tasks. It thus allows for the mapping of a particular function to a given brain structure. fMRI exploits the different magnetic properties of oxygenated and deoxygenated blood. When a subject is placed in a high magnetic field (the MR scanner), task-induced changes in brain metabolism alter the ratio of oxy- and deoxy-hemoglobin locally, causing measurable changes in MR signal intensity. These changes can then be overlayed on a high-resolution structural image of that subject which links brain function with brain structure. MRI is absolutely safe and thus can be repeated many times in the same individual, for example to trace changes in functional organization across development or disease progression. 

We are using fMRI to investigate language processing, such as auditory-visual speech processing and reading in healthy subjects and patients with epilepsy. One of the goals is to use fMRI to inform ECoG electrode placement and its use as a tool for language mapping in pre-surgical patients. We are also looking at cortical reorganization of motor and somato-sensory function in patients with epilepsy and brain lesions.The fMRI scanning is done on a 3T Siemens Allegra scanner in the Center for Brain Imaging at NYU, which comprises a vibrant community of fMRI researchers.

fMRI results to word reading in a single subject:

fmri1

fMRI group results to word reading in 10 subjects:

fmri2

 

Example publications:
Thesen T., McDonald C.R., Carlson C., Doyle W., Cash S., Sherfey J., Felsovalyi O., Girard H., Barr W., Devinsky O., Kuzniecky R., Halgren E. Sequential then interactive processing of letters and words in the left fusiform gyrus. Nature Communications. (2012) Dec 18;3:1284. PMID: 23250414. [Pubmed] [PDF]

McDonald C. R., Thesen T., Carlson C., Blumberg M., Girard H. M., Trongnetrpunya A., Sherfey J. S., Devinksy O., Kuzniecky R., Doyle W. K., Cash S. S., Leonard M. K., Hagler D., J., Dale A. M. & Halgren E. (2010). Multimodal imaging of repetition priming: Multimodal imaging of repetition priming: Using fMRI, MEG, and intracranial EEG to reveal spatiotemporal profiles of word processing. NeuroImage. 2010 Nov 1;53(2):707-17. [Pubmed] [PDF]