Neuroplasticity in vision dysfunction

Adaptation is critical to the survival of any species and is present in many systems within the brain. Rehabilitation can evoke neuroplasticity through adaptive mechanisms. Four subjects with the vision dysfunction of convergence insufficiency where two have mild traumatic brain injury and two were congenital participated in 18 hours of vision training. Clinical, behavioral, functional imaging and diffusion tensor imaging (DTI) are measured before and after therapy. Clinical parameters show improvement. Vergence eye-movements show an increase in peak velocity where independent component analysis revealed an increase in the magnitude of the preprogrammed transient component. Functional imaging using an oculomotor learning task shows increased area and intensity of activation suggesting neuronal recruitment and synchronization. DTI shows an increase in fractional anisotropy and an increase in the number of fibers suggesting changes in structural connectivity. Preliminary data suggest that neuroplasticity from vision training results in a change in behavioral oculomotor neural control through an increased magnitude of the preprogrammed disparity transient component potentially caused in part by neuronal recruitment, synchronization and improved structural connectivity.