Alternative ‘visual pathway’ may be significant to overcoming blindness

The paper (Warner et al., 2015 published in Current Biology) details the discovery by Assoc Prof James Bourne’s group of a second ‘pathway’ that can shunt visual, auditory, and touch sensory information via the pulvinar, a component of the thalamus that has extensive interconnectivity with much of the occipital (visual) cortex (area V1).After studying similar visual cortex lesions (V1 lesions) in very young and adult marmoset monkeys, the authors were able to show that the pulvinar was responsible for preserving vision in young animals, the retina-pulvinar-mid-tporal part of the visual cortex (MT) pathway rained ‘unpruned’ following V1 lesions in the young, the retina-pulvinar-MT offered an alternative pathway for visual information, and retinal input to the lateral geniculate nucleus (LGN) degenerates after V1 lesions in the young.The MT area receives input from the retinorecipient layers of the LGN as well as from the medial subdivision of the inferior pulvinar. Both can contribute, potentially, to the preservation of vision and the authors concluded that sustained visual input through the pulvinar to the MT in early life has the capacity to produce improved visual outcomes following early V1 damage.

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