Maryam Khorrami Shamsaddin MD, Abstract Co-Author: Nothing to Disclose

Scott Hunter Faro MD, Presenter: Nothing to Disclose

Asha Seshadri BS, Abstract Co-Author: Nothing to Disclose

Shweta Moonat BS, Abstract Co-Author: Nothing to Disclose

Jeffrey Lidicker MS, Abstract Co-Author: Nothing to Disclose

Feroze Babu Mohamed PhD, Abstract Co-Author: Nothing to Disclose

The purpose of this study was to evaluate the accuracy of sensory and motor areas of activation by two of the most widely used fMRI motor tasks: a simple hand squeeze versus a more complex finger-to-thumb (FTT) opposition.

Twelve normal volunteers were recruited. 26 axial images using T1, T2 and FLAIR imaging were acquired using an 8-channel head coil. fMRI images were acquired with EPI sequence. The fMRI parameters: matrix=64*64; FoV=22cm; ST=4mm; TR=3s; & TE=50 ms. The subjects were presented with 6 blocks of activation and rest conditions. During each block (30 sec), 10 volumes of EPI images were acquired. All the subjects performed a sequential movement of FTT and hand squeeze using both hands. Imaging was performed at 1.5T. The data was then analyzed using SPM to generate SPM{t} maps, and further region of interest analysis was performed using WFU pick-atlas and Marsbar software's.

Statistical analysis of the volume of activation generated by FTT and squeeze tasks reveal different volumes of brain activity. The total volume of motor plus sensory for ipsilateral and contralateral areas for the FTT was statistically larger than the squeeze (p = 0.009). This effect is only due to the volume of the sensory areas, which was statistically larger for FTT (p = 0.004). The motor area volume was not significantly different between each task. The Lateralization Index scores showed that squeeze produced significantly higher values than the FTT (p = 0.02 and p = 0.003).

The results show that the finger-to-thumb task produced overall greater sensory-motor strip activation compared to the hand squeeze task, and was primarily due to a larger area of activation in the post-central sensory cortex. There was less lateralization, and therefore a greater degree of bilateral sensory-motor activation, in the finger-to-thumb task, which acts as a control, make it more advantageous in clinical fMRI. This task is preferred to hand squeeze if a subject can competently perform this task.

Finger-to-thumb fMRI task produced overall greater sensory-motor strip activation compared to the hand squeeze task and will be the task of choice for presurgical motor cortex mapping

Khorrami Shamsaddin, M, Faro, S, Seshadri, A, Moonat, S, Lidicker, J, Mohamed, F, Optimization of Motor Function fMRI Tasks for Neurosurgical Applications.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4436112.html