Our 3-dimensional world is a challenge to our eyes and brains. In order to complete various tasks, such as reaching for a glass of water or watching a ball, we need to see in 3D and be able to interpret this data. But how do we manage it? A new study from the University of York have revealed that there are two separate ‘pathways’ for seeing 3D motion in the human brain.
Most mammals have two eyes for a reason. Each eye’s vision is combined in a stereoscopic reality, which become a 3D map in our brain. Vision from each eye is just slightly different by a certain degree and this difference is what allows us to understand whether something is closer or further away. However, it’s not that simple – up until today scientists couldn’t understand the pathways that are needed to analyze these inputs. And now it turns out that there are two distinct pathways that we use to have a 3D vision.
Scientists say that instead of one signal used to interpret 3D reality, there are two – one slow and one fast. Researchers used brain imaging technology to see that these two 3D motion signals are separated out into two distinct pathways in the brain. This allowed realizing that the two signals are interpreted as such and allow us to complete different task with moving or stationary objects. This is quite interesting, but not entirely surprising. People with lazy eye syndrome typically struggle with 3D vision, but do fine in tests with fast moving objects. Now we know why – because fast and slow signals are processed using two different pathways.
In fact, this research may move scientists closer to curing the condition. Dr Julie Harris, one of the researchers in the study, said: “Knowing more about our visual system, and particularly how motion, depth and colour could all be connected in the brain, could help in a number of research areas into what happens when these pathways go wrong, resulting in visual disturbances that impact negatively on people’s quality of life”.
Motion, depth and colour are three main pillars of our vision-processing system. Now scientists think that there could be a connection in the brain between these three visual properties. In particular, there are reasons to believe that colour might be more important in this type of visual processing than previously believed. But more researching is going to be needed to confirm this hypothesis.
This study is a good example of how little we know about the human body. Eyesight is one of the most important senses for us, but we still don’t fully understand the mechanism behind it. Hopefully studies like this will lead to solutions to sight-related conditions.
Source: University of York