Combined functional MRI and tractography to demonstrate the connectivity of the human primary motor cortex in vivo.
In this study, we combined advanced MR techniques to explore primary motor cortex (M1) connectivity in the human brain. We matched functional and anatomical information using motor functional MRI (fMRI) and white matter tractography inferred from diffusion tensor imaging (DTI). We performed coregistered DTI and motor task fMRI in 8 right-handed healthy subjects and in 1 right-handed patient presenting with a left precentral tumour. We used the fast-marching tractography (FMT) algorithm to define 3D connectivity maps within the whole brain, from seed points selected in the white matter adjacent to the location of the maximum of fMRI activation. Connectivity maps were then anatomically normalised and analysed using statistical parametric mapping software (SPM99) allowing group comparisons (left versus right hemisphere in control subjects and patient versus control subjects). The results demonstrated, in all control subjects, strong connections from M1 to the pyramidal tracts, premotor areas, parietal cortices, thalamus, and cerebellum. M1 connectivity was asymmetric, being more extensive in the dominant hemisphere. The patient had differences in M1 connectivity from the control group. Thus, fMRI-correlated DTI-FMT is a promising tool to study the structural basis of functional networks in the human brain in vivo.
Guye
Maxime
M
The National Society of Epilepsy MRI Unit, Department of Clinical and Experimental Epilepsy, University College London, London, UK.
Parker
Geoffrey J M
GJ
Symms
Mark
M
Boulby
Philip
P
Wheeler-Kingshott
Claudia A M
CA
Salek-Haddadi
Afraim
A
Barker
Gareth J
GJ
Duncan
John S
JS
D000328:Adult; D000465:Algorithms; D001931:Brain Mapping / Q000379:methods; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D002531:Cerebellum / Q000473:pathology / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D004292:Dominance, Cerebral / Q000502:physiology; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology*; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D016571:Neural Networks, Computer; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology; D011712:Pyramidal Tracts / Q000473:pathology / Q000503:physiopathology; D012016:Reference Values; D013788:Thalamus / Q000473:pathology / Q000503:physiopathology