Scientists are one step closer to understanding how vision works by creating a mathematical model. This model is the first of its kind that comes closer to explaining the complicated visual system. Mathematician Lai-Sang Young partnered with fellow mathematician Logan Chariker and neuroscientist Robert Shapley to produce several scholarly papers over the past few years. They have created a model which challenges the previous understandings of the visual system.
What’s so different about this study is that they have finally been able to combine scientific studies of vision with a model that clearly delineates how the visual cortex functions. Until now, the visual cortex has been shrouded in mystery and no one has been able to explain the structures of the visual cortex.
In our vision, light enters the visual field of the retina, which is connected to the visual cortex. There are only around 10 nerve cells which connect the visual cortex and the retina together and represent the only way that outside visual input travels into the brain. These nerve cells can only send a pulse as a message to the visual cortex that there has been a change in light or darkness, but that’s all it does.
The visual cortex then goes to work with its many layers of neurons (up to 4,000 neurons in each layer) to fill in the gaps. It doesn’t sound like these few mechanisms and pathways could account for the whole visual system, does it? Lai-Sang Young says that due to the scarce information the eyes receive from the outside world, “…a lot of the things you think you see you’re actually making up.”
There are hundreds of neurons connected to each individual neuron in the visual cortex and it forms a feedback loop. Until the work of Young, Chariker, and Shapley, the visual cortex was only understood as a “feed forward” rather than a “feedback” loop. Feedback loops are inherently more complicated and mysterious because the information comes back and changes the organism and continues to return and change the organism, like a butterfly effect. This is the challenge of creating a model that functions true to the process of a biological structure.
- Hartnett, Kevin. “A Mathematical Model Unlocks the Secrets of Vision.” Quanta Magazine, 21 Aug. 2019, https://www.quantamagazine.org/a-mathematical-model-unlocks-the-secrets-of-vision-20190821/.