Blindness and the Brain
How blindness can affect the structure of the brain
In what ways can blindness affect the structure of the brain while developing?
There are a few ways that blindness can change the overall construct of one's vision, along with structure of their brain, which include:
- Binocular deprivation-This term applies to people who have not been subjected to light in both eyes in early life, thus, it ultimately changes the neurons in the visual cortex of the brain (Breedlove & Watson, 2013). The visual cortex is located at the most posterior part of the occipital lobe (Breedlove & Watson, 2013).
- Monocular deprivation-This term applies to subjecting only one eye to light, while depriving the other eye (Breedlove & Watson, 2013). If this happens, the eye that is light deprived has significant changes to areas of the brain, such as the thalamus, and the visual cortex (Breedlove & Watson, 2013).
- Visual areas within the brain tend to be smaller than those of people that can see; however, other senses are heightened since these areas tend to grow larger to adapt to a blind person's surroundings (University of California, 2009).
- When one is born blind and their brain is constantly developing, researchers have found that the visual cortex is more enhanced when it comes to spatial tasks, along with tactile information due to the concept of neural plasticity (Georgetown University Medical Center, 2010).
The above picture is a model of the human brain. Notice the major regions that result in vision for people who can see, which are the same areas that learn to adapt in people that are blind. These regions include: the occipital lobe (located on the left), the frontal lobe (located on the right), and the thalamus (located in the middle).
The blind brain verse the seeing brain
There are a few differences when it comes to the brain of a blind person and one that can see. .
- A blind person has less synaptic nerves running to their visual cortex (Breedlove & Watson, 2013). This happens via the Hebbian synapse. The hebbian synpases are considered the target cell that are shown to grow weak if not used (Breedlove & Watson, 2013). The visual cortex has also been shown changing its function to better adapt to processing language over the process of vision (MIT, 2011).
- In a seeing eye person, the visual cortex has a normal amount of neurons, especially in terms of a person's early synaptic development (Breedlove & Watson, 2013).
- The thalamus is a cluster of nuclei that is responsible for all sensory information that the person's is subjected to; thus, a blind person's thalamus, along with other major areas of the brain may be less myelinated in comparison to those that can see (University of California, 2009).
- Research has shown that the frontal lobe of a blind person is significantly larger than that of a person who can see (University of California, 2009). This may explain why people who are blind tend to have a better working memory, than those that are not (University of California, 2009).
Article 1: The "adapting" brain
Here is a link to an article that explores how a blind person's brain re-configures itself, especially pertaining to other senses; such as, smell, touch, and hearing.
Article 2: The "switching functions" brain
Here is a link to an article that explores how the brain of a blind person actually switches functions to be of better assistance.
- Breedlove, S. M., & Watson, N. V. (2013). Biological psychology: An introduction to behavioral, cognitive, and clinical neuroscience. (7th ed). Sunderland, MA: Sinauer Associates.
- Georgetown University Medical Center. (2010, October 10). People blind from birth use visual brain are to improve other senses: Can hear and feel with greater acuity. Retrieved from https://www.sciencedaily.com/releases/2010/10/101006131203.htm
- Massachusetts Institute of Technology. (2011, March 1). Parts of brain can switch functions: In people born blind, brain regions that usually process vision can tackle language. Retrieved from https://www.sciencedaily.com/releases/2011/02/110228163143.htm
- University of California-Los Angeles. (2009, November 19). Blindness causes structural brain changes, implying brain can re-organize itself to adapt. Retrieved from https://www.sciencedaily.com/releases/2009/11/091118143259.htm
- Harvard Medical School. (2015, July 1). Seeing is believing: how brains make sense of the visual world. Retrieved from http://www.psypost.org/2015/07/seeing-is-believing-how-brains-make-sense-of-the-visual-world-35422
- Human brain. (2013, December 2). Retrieved from http://www.keralapscinfo.com/2013/12/human-brain.html
- Bausch & Lomb. (Producer). (2010, August 3). A journey through the human eye; How we see [Video file]. Retrieved from https://www.youtube.com/watch?v=gvozcv8pS3c
- Ted Talk. (Producer). (2014, October 28). Blindness is just another way of seeing [Video file]. Retrieved from https://www.youtube.com/watch?v=B-xI3YxAPW4