 This cross-activation may arise due to a failure of the normal developmental process of pruning, which is one of the key mechanisms of synaptic plasticity, in which connections between brain regions are partially eliminated with development.Similarly, lexical → gustatory synesthesia may be due to increased connectivity between adject regions of the insula in the depths of the lateral sulcus involved in taste processing that lie adjacent to temporal lobe regions involved in auditory processing.Similarly, taste → touch synesthesia may arise from connections between gustatory regions and regions of the somatosensory system involved in processing touch.