Application: Neural Communication

Damage to the nervous system typically results in sensory, cognitive, and/or behavioral impairment. The type and extent of impairment depends in part on the location of damage. For example, damage to the occipital lobe would probably result in visual impairment, although the specific type of impairment would depend on where in the occipital lobe the damage occurred. Cells in the damaged area would no longer be able to communicate effectively with one another or with cells in other parts of the nervous system, and this loss of communication would be the basis for the visual impairment.

Fortunately, there are ways in which the nervous system can recover from damage. Natural processes such as compensation and reorganization often facilitate recovery of lost or impaired functions. Furthermore, there are experimental treatments that may promote the growth of neurons in the mature nervous system; these neurons eventually may take the place of cells that were damaged, and thus restore function.

In this Application Assignment, you will apply your knowledge of neural communication, functions of specific brain areas, and mechanisms for recovery from brain damage to a case in which an individual suffered a stroke to his right hemisphere.

To prepare for this assignment:

Review Chapter 2, focusing on how neural communication is likely to be disrupted by the loss of brain cells.

Review Chapter 3 and refer to Figure 3.10, paying attention to how areas of the motor cortex correspond to movement produced in specific parts of the body. Also review the section entitled "Development and Change in the Nervous System," focusing on why brain cells are not usually replaced in the mature brain as well as on ways in which the patient might recover some of his lost functions.

The assignment (1-2 pages):

Read the following case study:

Joseph is a 59-year-old construction worker who recently suffered a stroke. A small blood clot became lodged in one of the vessels serving the right side of his brain and restricted blood flow to a portion of his right precentral gyrus. Many neurons in that area were damaged or destroyed and, as a result, Joseph is partially paralyzed on the left side of his body. He is able to move his left leg and walk, and can also move his left arm, but his left hand and the left side of his face are paralyzed.

Answer the following questions about the case study:

Why were Joseph's left face and hand paralyzed, but not the rest of his arm or his leg?

What is preventing Joseph from moving his left hand? In your answer, include the following:

First, describe normal function of a motor neuron that forms a synapse with a muscle cell. How is the signal that initiates movement transmitted from the neuron to the muscle? Describe this process in detail.

Next, keeping in mind that the motor neuron itself is not damaged, explain how damage or destruction of a neuron that communicates with the motor neuron prevents Joseph from moving his hand.

With time, and perhaps some physical therapy, Joseph may recover some of the movement in his left hand and face. What factors might contribute to this recovery? In your answer, include the following:

Why can't Joseph's brain simply replace those neurons that were damaged and destroyed by the stroke?

How might compensation allow Joseph to regain some of his lost movement?

Describe at least one experimental treatment that might improve movement in Joseph's case, and explain how this treatment would impact Joseph's nervous system.

Support your Application Assignment with specific references to all resources used in its preparation. You are asked to provide a reference list only for those resources not included in the Learning Resources for this course.

Resources to use:

Learning Resources

Please read and view (where applicable) the following Learning Resources before you complete this week's assignments.

Readings

Review Course Preview and read Course Introduction (located on the left navigation bar)

Course Text: Garrett, B. (2015). Brain and Behavior: An Introduction to Biological Psychology, (4th ed.). Los Angeles: Sage.
Chapter 2, "Communication Within the Nervous System" (pp. 23-49)
Chapter 3, "The Organization and Functions of the Nervous System" (pp. 55-88)
Chapter 4, "The Methods and Ethics of Research"

An article from the Walden Library that addresses a topic of your choice. The article must be a research report.

Web Sites

Biopsychology News
http://www.biopsychology.com/news/
This site contains links to online paper and magazine articles related to biological psychology.

Neural Impulse (Brain and Behavior, Figure 2.8)
http://www.sagepub.com/garrettbb2study/animations/2.8.htm
This sequence demonstrates the movement of ions across the neural membrane from resting potential through an action potential.

Transmission at the Synapse (Brain and Behavior, Figure 2.15)
http://www.sagepub.com/garrettbb2study/animations/2.15.htm
This sequence demonstrates the events occurring at the synapse during synaptic transmission.

Spatial and Temporal Summation (Brain and Behavior, Figure 2.18)
http://www.sagepub.com/garrettbb2study/animations/2.18.htm
This sequence shows the processes of temporal and spatial summation.

The Spinal Cord (Brain and Behavior, Figure 3.16)
http://www.sagepub.com/garrettbb2study/animations/3.16.htm
This sequence demonstrates the neural connections involved in a spinal reflex, such as withdrawing the hand from a painful stimulus.