Principal Investigator, Extramural Fellow
National Institute of Neurological Disorders and Stroke
National Institutes of Health (NIH)

Recovery from cortical ischemia

For my first postdoctoral fellowship, I received extensive training in investigating the effects of experience-dependent motor recovery after unilateral ischemia. In so doing, I learned how to train animals to criterion in a single-pellet reaching task, perform craniotomies, induce focal unilateral stroke in caudal forelimb area by topically applying a vasoconstrictive peptide to sensorimotor cortex, and assess the amount of cortical territory controlling forelimb movements using intracortical microstimulation mapping (ICMS). ICMS involves in vivo surgeries, in which Layer V motor cortex is stimulated at equidistant points in the transverse plane, and corresponding limb movements are recorded. After behavioral and in vivo mapping data were collected, we performed neurohistology to assess the extent of the cortical infarct. Initial data seemed to indicate that training the good limb after unilateral infarct impedes reaching recovery in the impaired forelimb, and expands the amount of motor cortical territory controlling the good limb (Markham et al., 2007). However, change to a synthetic peptide for lesion induction resulted in a floor effect. Also, data from other animals with differently treated lesions preliminarily suggested that edema may be a contributing factor in cortical recovery. I acquired substantial skills in grant writing, animal anesthesia, and stereotaxic surgeries, among other things. I look forward to using these skills in developmental experiments.

[link to Society for Neuroscience 2007 presentation]