Seminar 4 Major Assignment

Jennifer Riccobono

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How Does Blindess Affect the Developing Structure of the brain?

The brain may be affected largely if a person is born blind or becomes blind at some point within their lives. Research has shown that the brain makes different connections between neurons depending upon if a person has sight or not. These connections are may be changed over time as the brain becomes accustomed to the loss of sight.These connections are influenced by anatomy, environment, experience and heredity.

A Person Who Has Sight

In the typical individual sight is intact and the eyes and brain work together to help a person perceive and interpret the world around them. Many things happen so that a person is able to see the world around them. These include the amount of light that is taken into the eye, the placement of the structures within the eye, rods, cones and the placement and function of the neurons within the brain (Breedlove & Watson, 2013, pg. 292). In a person with typical vision light enters the eye through the retina and whatever is in the line of sight is then projected upon a small space called the fovea (Breedlove & Watson, 2013, pg. 292). Many different signals are then sent to the brain. The information is carried to the visual cortex by the use of the optic nerve (Breedlove & Watson, 2013, pg. 300). The person’s brain then determines what the person thinks they see. A video of normal sight and brain function may be seen at: https://www.youtube.com/watch?v=wbVdlIc5DPE

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A Person Experiencing Blindness

In a person who experiences blindness the steps that allow vision in a person are not the same. Blindness may be caused by an array of things. The most common reasons are due to trauma, disease or being born blind (Charlie Rose, 2009).Researchers have found that blind individuals are able to perceive their world around them despite not being able to rely on their sense of sight. This is due to their brain’s neuroplasticity (MindHacks, 2007). The brain in a person who is blind is able to make different neuron connections within the brain which in turn seems to heighten their senses of smell, hearing, taste and touch so that they may adapt to the world around them (University of California, 2009). Some people who have been blind for many years may undergo surgery so that they may regain some of their vision. When this is possible and successful they have found that an individual’s brain must retrain itself, make new neural connections and learn how perceive the world through the sense of vision due to the person lacking neuron connections that have had this type of practice for years (Rose, 2009). Dr. Brian Wandell has worked hands-on with a patient who has undergone this treatment. His speech about his patient who had to retrain his brain to compensate for his new vision may be found at: https://www.youtube.com/watch?v=VVgfC_FV2hI

Structural Brain Differences in Sight vs Blindness

There are some differences associated with brain development in people who experience full sight and blindness. Researchers contribute some of these differences to the brains neuroplasticity. They have found that the visual centers of the brain are smaller in people who are blind than they are in people who are able to see (University of California, 2009). They also found in people who experience blindness that the places in the brain that interpret the rest of the five sense are larger and more developed (University of California, 2009). This helps to support the heightened senses theory in people who experience blindness.

In another study, researchers have found another difference between individuals with normal sight versus people who experience blindness. They have found that the myelin sheath is missing around the nerves in the corpus callosum when a person is born blind or has become blind at a very young age (University of California, 2009). The myelin sheath is completely intact and aids with visual processing in this area in a healthy person who does not have any other ailments and is able to see.

References

Breedlove, S.M., & Watson, N.V. (2013). Biological psychology: An introduction to behavioral, cognitive, and clinical neuroscience (7th ed.). Sunderland, MA: Sinauer Associates, Inc.


Diopsys. (2009). Educational video on the vision system – Diopsys. YouTube. Retrieved fromhttps://www.youtube.com/watch?v=wbVdlIc5DPE


MindHacks. (2007). The unique construction of the blind brain. MindHacks. Retrieved from http://mindhacks.com/2007/04/12/the-unique-construction-of-the-blind-brain/


Rose, Charlie. (2009). Charlie Rose: The perceiving brain –sight and visual perception – with scientists Tony Movshon, Nancy Kanwisher, Ted Adelson, and Pawan Sinha. MIT Video. Retrieved from http://video.mit.edu/watch/charlie-rose-the-perceiving-brain-sight-and-visual-perception-with-scientists-tony-movshon-na-4815/


ScienceDaily. (2009). Blindness causes structural brain changes, implying brain can reorganize itself to adapt. ScienceDaily. Retrieved from http://www.sciencedaily.com/releases/2009/11/091118143259.htm


Wandell, B. (2009). Understanding blindness and the brain. Stanford University. Retrieved from https://www.youtube.com/watch?v=VVgfC_FV2hI