Australian researchers have overturned the long-held view that there is only one route for information to travel from the eye to the brain, with the discovery of a second "pathway" boosting hopes for future treatments to prevent blindness.
"It is a very novel idea," said Associate Professor James Bourne from Monash University's Australian Regenerative Medicine Institute. "It's a great leap forward in understanding how the brain is wired."
The findings, outlined on Tuesday in the journal Current Biology, in effect redraw the map of the human brain as we know it and provide a greater insight into the brain's capacity to rewire itself after injury.
It was thought that one route from the eye to the brain was responsible for conscious vision and if this were damaged, sight was lost.
However, the results show that the brain is able to redirect the messages containing visual information, ensuring they bypass the damaged section.
The second pathway is in an area of the brain called the pulvinar, which is part of the thalamus, a kind of "sorting office" for sensory information obtained by vision, touch and hearing.
It has been widely accepted that by birth, development of the thalamus is complete and changes to the brain after birth are confined to the cortex.
However, the research, led by Monash University, shows that if the primary pathway is injured in the first year of life, the brain can modify its structure and continue to function normally.
Professor Bourne said that given its complexity, the pulvinar was an area of the brain that had been ignored for years, though there were likely other pathways yet to be discovered.
Vision is the most complex sense. More than 50 per cent of the large outer layer of the brain, known as the cortex, is devoted to it.
People with conditions such as autism or schizophrenia, which feature sensitivity to light or hallucinations, may also benefit from the new brain findings.
"This gives a bit of a clue and an insight into how those things might be happening if the primary pathway looks normal," Professor Bourne said. "Understanding this route of information is really important, and this is really the first study looking at it."