Methods of treating various medical conditions by neuromodulation of a target site of interhemispheric fibers. Such medical conditions include unilateral motor deficits, movement disorders, psychiatric disorders, speech or cognitive deficits associated with hemispheric lesions, visual deficits associated with hemispheric lesions, hereditary/genetic disorders, congenital malformations, infection disease, degenerative disorder, autoimmune disorders, and metabolic disorders. A method of providing recovery and rehabilitation from states of reduced consciousness by neuromodulating a target site of interhemispheric fibers is also provided.