Damage to the parts of the brain that process visual information can lead to a variety of visual agnosias, depending on which area is damaged. Some people with agnosia have difficulty recognizing familiar faces or objects, others cannot distinguish color, and still others may not perceive movement. A related phenomenon is neglect, which results in inattention to one side of the body (and visual field), so that objects on that side are not noticed. There are many interesting case histories of such individuals, and studying both the site of damage and the particular loss of function can tell us a great deal about how the brain allows us to "see" the world. Such disorders also illustrate the principle that visual perception is somewhat modular, meaning that particular aspects of objects are processed by different brain areas.
To prepare for this Discussion:
Review the information on vision in Chapter 10, particularly the discussion on disorders of visual perception.
Select one of the disorders covered in the book (object agnosia, prosopagnosia, color agnosia, movement agnosia, or neglect) to research in more detail. Locate a research report or other scientific article about this disorder in the Walden Library.
For the disorder you selected, think about the symptoms and problems commonly experienced by people with the disorder and the impact of the disorder on areas of life including work, relationships, and leisure time. Also note the areas of the brain responsible for the disorder and specific behaviors the disorder affects.
With these thoughts in mind:
A summary of the symptoms of the disorder you chose. Include the brain area(s) responsible for the disorder, and common problems that people with such damage have. Explain what everyday life would be like for an individual with the disorder, including its impact on occupation, relationships, and leisure time. Be sure to include how the disorder might affect the person's behaviors and experiences in these settings.
Resources to use:
Readings
Course Text: Garrett, B. (2015). Brain and Behavior: An Introduction to Biological Psychology, (4th ed.). Los Angeles: Sage.
Chapter 9, " Hearing and Language" (pp. 263-284 only)
Chapter
11, " The Body Senses and Movement" (pp. 339-352 only)
Presbycusis
http://www.nidcd.nih.gov/health/hearing/presbycusis.asp
This site, by the National Institutes of Health, contains information about a common cause of hearing loss in adults.
This sequence demonstrates how the basilar membrane responds to sounds of different frequencies (place analysis).
Sound Localization (Brain and Behavior, Figure 9.18)
http://www.sagepub.com/garrettbb2study/animations/9.18.htm
This sequence shows how neural connections to coincidence detector cells in the olivary nucleus allow sound localization.
Visual Projections to the Cortex (Brain and Behavior, Figure 10.4)
http://www.sagepub.com/garrettbb2study/animations/10.4.htm
This sequence traces the route by which the eyes send information to the brain.
Visual Detection of Edges (Brain and Behavior, Figure 10.20)
http://www.sagepub.com/garrettbb2study/animations/10.20.htm
This sequence demonstrates how on-center/off-surround retinal ganglion cells respond to edges and how these responses affect simple cells in the primary visual cortex.