Scientists from the Massachusetts Institute of Technology have managed to rewire the brains of young ferrets so that nerves from the retina are redirected to grow into the auditory thalamus. The study was designed to determine whether activity in a sensory pathway has a specific, instructive role in the development of cortical networks. Modules of neurons sharing a common property are a basic organizational feature of the mammalian sensory cortex. Previously, it had been believed that the visual cortex relied heavily on an intrinsic scaffold of neuronal connections, which are little influenced by activity. The primary visual cortex (V1) is characterized by orientation modules, which are groups of cells that share a preferred stimulus orientation and are organized into a highly ordered orientation map. Results from this study and others demonstrate that much of what characterizes the functional organization of the visual cortex can also be established within the primary auditory cortex (A1) by delivering retinal inputs to A1 through the auditory thalamus. Furthermore, behavioural studies on these 'rewired' ferrets demonstrate that the animals show behavioural responses to visual stimuli that are presented only to the neurons feeding into the rewired cortex; essentially, the animals are seeing with their auditory cortex.
Source
- Sharma et al. 2000. Nature. 404:871-76.
