Primacy of Vision | Oct 6, 2019

In 1991 Felleman and Essan published a study called “Distributed Hierarchical Processing in the Primate Cerebral Cortex” which established scientifically the centrality of the visual system in primates.

The retina is an outgrowth of the brain. It contains 150 million light-sensitive rod and cone cells. It’s damn sensitive, and incredibly important. Neurons devoted to visual processing in the brain are in the hundreds of millions. They take up about 30% of the cortex.  Touch takes up just 8%, and hearing 3%. The visual system has “extensive connections with cortical areas outside the visual system proper, including the somatosensory cortex, as well as neocortical, transitional, and archicortical regions in the temporal and frontal lobes.” But we all kinda know vision rules already. Our language reflects how central to our way of thinking, feeling and being in the world vision is.  Do you “see” what I mean?

There are so many factors in our ability to see.  In my work I analyze eye movement as part of integrated neuromotor functioning and so I focus primarily on how the 6 extraocular muscles coordinate with the rest of the body’s motor control system. For example the inability to look straight up or straight down can affect the functioning of the entire posterior and anterior kinetic chains.  Muscular function is a slave to the body’s ability to feel safe. Since vision is SO important to our ability to stay safe in the world and meet our basic needs, AND such a large part of our brain’s functioning, it’s supremacy is powerful. So, if you can’t look down, you probably shouldn’t bend down, and your motor cortex will keep you from doing so.

What I’ve found is that it’s not just people with a history of concussion that have eye movement issues. A variety of types of trauma and chronic stress can cause problems. I’ve been continuing my study of ocular motor assessment recently, but I’m just at the BEGINNING of my journey.

Thus I’m very excited to have the opportunity to connect with a real expert, Optometrist Dr. Patrick Quaid of Vue3 Vision Therapy Center in Guelph, and talk about his approach to vision therapy at the end of this week.