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Updated: Aug 8, 2026
Unilateral Pyramidotomy of the Corticospinal Tract in Rats for Assessment of Neuroplasticity-inducing Therapies
Published on: December 15, 2014
Motor deficits are produced by removing some cortical transplants grafted into injured sensorimotor cortex of
R Sandor1, M F Gonzalez, M Moseley
1Department of Neurology, University of California, San Francisco.
Abstract:
Fetal frontal cortex was transplanted into cavities formed in the right motor cortex of neonatal rats. As adults, the animals were trained to press two levers in rapid succession with their left forelimb to receive food rewards. Once they had reached an optimal level of performance, the effect of removing their transplants was assessed. Surgical removal of transplants significantly impaired the performance of 2 of 4 subjects. Placing a cross-strain skin graft to induce the immunological rejection of the transplants produced a behavioral deficit in 1 of 2 subjects with complete transplant removal. Skin grafts produced no behavioral effects in four subjects that had surviving transplants. Since the motor deficits produced by transplant removal resembled those observed following the removal of normal motor cortex, we propose that these three transplants functioned within the host brain. Histology showed that the procedures used to remove cortical grafts did not injure any host brains. Therefore, host brain damage is unlikely to account for the behavioral deterioration that followed transplant removals.
Insights
Fetal frontal cortex transplants integrated into rat motor cortex and supported motor function. Transplant removal impaired performance, indicating successful neural integration and function in the host brain.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Neurotransplantation
Background:
- Fetal cortical transplants offer potential for brain repair.
- Understanding functional integration of transplanted tissue is crucial.
Purpose of the Study:
- To assess the functional integration of fetal frontal cortex transplants in the neonatal rat motor cortex.
- To determine if transplanted tissue supports learned motor behaviors.
Main Methods:
- Fetal frontal cortex was transplanted into neonatal rat motor cortex.
- Adult rats were trained on a sequential lever-pressing task.
- Transplant removal assessed behavioral impact.
- Immunological rejection was induced via skin grafts.
Main Results:
- Surgical removal of transplants impaired performance in 2 out of 4 subjects.
- Immunological rejection led to behavioral deficits in 1 out of 2 subjects with complete removal.
- Histology confirmed no host brain damage from removal procedures.
Conclusions:
- Transplanted fetal frontal cortex can functionally integrate and support learned motor behaviors in the host brain.
- Behavioral deficits after removal suggest the transplants were actively contributing to motor control.
- The study provides evidence for the functional efficacy of cortical transplants in a neonatal brain injury model.
