At early cortical processing stages, sensory modalities are mapped across topographically organized neuronal networks. It was long believed that connectivity within such early feature maps is fixed after critical periods in development. In contrast, we show that V1 (primary visual cortex) map layout can still be reorganized in a specific manner through modulation of cortical excitability. We apply voltage-sensitive dye optical imaging (VSDI) to capture modifications of cortical maps during either postlesional reorganisation or non-invasive interventions with controlled visual and transcranial magnetic stimulation (TMS) protocols. The underlying mechanisms have practical implications for perceptual learning and rehabilitation in traumatic or neurodegenerative impairment of the brain.