J Reconstr Microsurg 2008; 24(8): 551-557
DOI: 10.1055/s-0028-1088231
© Thieme Medical Publishers

Cortical Brain Mapping of Peripheral Nerves Using Functional Magnetic Resonance Imaging in a Rodent Model

Younghoon R. Cho1 , Seth R. Jones1 , Christopher P. Pawela2 , Rupeng Li2 , Dennis S. Kao1 , Marie L. Schulte3 , Matthew L. Runquist2 , Ji-Geng Yan1 , Anthony G. Hudetz3 , Safwan S. Jaradeh4 , James S. Hyde2 , Hani S. Matloub1
  • 1Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin
  • 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin
  • 3Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
  • 4Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
Further Information

Publication History

Publication Date:
15 October 2008 (online)


The regions of the body have cortical and subcortical representation in proportion to their degree of innervation. The rat forepaw has been studied extensively in recent years using functional magnetic resonance imaging (fMRI), typically by stimulation using electrodes directly inserted into the skin of the forepaw. Here we stimulate the nerve directly using surgically implanted electrodes. A major distinction is that stimulation of the skin of the forepaw is mostly sensory, whereas direct nerve stimulation reveals not only the sensory system but also deep brain structures associated with motor activity. In this article, we seek to define both the motor and sensory cortical and subcortical representations associated with the four major nerves of the rodent upper extremity. We electrically stimulated each nerve (median, ulnar, radial, and musculocutaneous) during fMRI acquisition using a 9.4-T Bruker scanner (Bruker BioSpin, Billerica, MA). A current level of 0.5 to 1.0 mA and a frequency of 5 Hz were used while keeping the duration constant. A distinct pattern of cortical activation was found for each nerve that can be correlated with known sensorimotor afferent and efferent pathways to the rat forepaw. This direct nerve stimulation rat model can provide insight into peripheral nerve injury.


James S Hyde, Ph.D. 

Department of Biophysics, Medical College of Wisconsin

8701 Watertown Plank Road, Milwaukee, Wisconsin 53226

Email: [email protected]