The Darwinian plasticity hypothesis for tinnitus and pain.

We present the hypothesis that expression of neural plasticity is a form of adaptation based on natural selection, where cells or cell groups deprived of sensory input actively go and look for information in order to survive. The Darwinian model of brain plasticity can explain the symptomatology induced by deprivation of input which was not well explained by classical plasticity without contradicting pertinent data from the neurophysiological, neuroanatomical, functional neuroimaging, and clinical literature. Applying the concept of Darwinian plasticity to sensory plasticity that causes symptoms and signs of disease might lead to the development of new treatments for deprivation of input induced symptomatology. We will use results from the application of electrical and magnetic stimulation of the auditory and the somatosensory cortices for treatment of tinnitus and for alleviating some forms of pain in support of the Darwinian hypothesis about neural plasticity. We will also review the literature regarding physiological and anatomical, as well as imaging data that support the existence of this hypothetical form of plasticity.