Vision and Brains

On Friday 28th February, we were excited to welcome Professor Holly Bridge from the Wellcome Centre for Integrative Neuroimaging to deliver the fourth in the Rumble Museum’s series of Future Season Breakfast Talks.

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Holly started by introducing the students to how the eye works. She explained that someone people are born without eyes because the eyes move forward to the front of the brain and then grow, but if something has prevented them from doing this, then they never grow. In healthy eyes, there are rod and cone cells. There are three different types of cone cells, and these control focus and also the ability to see colour (two of the types of cone cells are on the X chromosome which is why colourblindness is much more common in males than in females). Holly showed some photos of how the world might look to someone with colour blindness. She also pointed out that colour blindness didn’t mean that you couldn’t see colour, but it affected your ability to see certain colours.

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She asked the group to stare at a black dot, which was surrounded by four different circles – red, yellow, blue and green. When she then switched the slide to a blank screen, the group generally found that they could see a moving image of four dots of different colours to the original circles. Holly explained that staring at the same dot had made the cone cells become tired. She also asked the group to focus on a cross and then she put up some words to the side. The group could not really read the words on the side, but she told us that our brains simply ‘make up’ what they expect us to see when they aren’t sure.

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She showed some examples of particular eye diseases where vision was limited to a central area (tunnel vision) and where vision is only able to see around the edges. She also showed us a video of a woman whose brain had been damaged, and who therefore wasn’t able to recognise objects she looked at. She was presented with a watch, and she could identify features about it, but she could not match it up with a watch in her head, until she was able to pick it up, at which point touch allowed her to instantly work it out. Holly explained there was a similar condition where people were unable to recognise faces.

The talk provided a fascinating insight into how the eye and the brain work together and what happens when this goes wrong. We are very grateful to her for all her time and for a really stimulating introduction that helped us all better understand our own perceptions. 

 

 

 

 

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