**5. Compensatory plasticity in the remaining sensory cortices**

The crossmodal plasticity concept has been extended by studies demonstrating that the loss of one sense induces substantial alteration in remaining sensory cortical areas leading to experience-dependent refinement of neuronal responses. The so-called compensatory plasticity is conceived as underlying higher than normal perceptual abilities. However, it is notable that the available experimental evidence of compensatory plasticity is scarce compared to that documenting crossmodal plasticity. Nonetheless, changes involving processing of visual signals have been described following somatosensory and auditory deprivation. In adult mice, partial somatosensory deprivation (bilateral removal of macro-whiskers) lasting 12 days induced a massive increase of V1 responses elicited by weak visual stimuli, which was accompanied by a marked improvement of spatial frequency and contrast tuning (40%) of V1 neurons, as revealed by intrinsic signal imaging [105]. It is noteworthy that visual acuity and contrast sensitivity determined in behavioral tasks in individual animals improved by 40% and 60%, respectively, i.e., similarly to what was observed in V1. In addition, auditory deprivation in adult mice induces salient changes in visually evoked responses in V1, with improvement of spatial frequency and contrast tuning [106]. Conversely, visual deprivation (one week of dark exposure) in adult mice leads to improved frequency selectivity as well as increased frequency tuning and intensity discrimination performance of A1 neurons [107]. Collectively, these studies show that compensatory plasticity can develop after short-term deprivation in adult sensory cortices and highlight the fact that deprivation of one sense rapidly refines sensory processing in remaining cortical areas, while improving sensory guided behavior.
