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BIO303: Neurobiology

Unit 4: Neural Plasticity and Repair   Plasticity is the process by which neurons change and connect as a result of new experiences. It is most evident in infancy and childhood, where the growing brain will rapidly learn new skills and acquire knowledge. The adult brain, although less able to adapt, is able to form new memories throughout its lifetime thanks to plasticity. Neural repair reshapes connections, though this process is much more varied. Researchers continue to deepen their appreciation for the importance of plasticity in adults as they seek clues as to how the brain and spinal cord recover from injury. This unit will study plasticity in growing and injured neurons and discuss the leading theories explaining how neurons adapt.

Unit 4 Time Advisory
This unit will take you 7.5 hours to complete.

☐    Subunit 4.1: 1 hour

☐    Subunit 4.2: 1 hour

☐    Subunit 4.3: 2.5 hours

☐    Subunit 4.4: 1.5 hours

☐    Subunit 4.5: 1.5 hours

Unit4 Learning Outcomes
Upon successful completion of this unit, the student will be able to:    
        - explain how the developing braintranslates early experiences intopermanently altered wiring; - explain how Long-Term Potentiation (LTP) functions in the formation and/or retrieval of some forms of memory; - compare and contrast the cellular death mechanisms of apoptosis and necrosis; - list potential consequences of neuronal cell death on normal functioning; - list the positive and negative results of excitotoxicity; - compare and contrast the responses to injury in the peripheral and central nervous systems; and - explain the recent advances in neuronal cell replacement therapy.

4.1 Critical Periods   4.1.1 Language Development   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 24: The Development of Language: A Critical Period in Humans” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 24: The Development of Language: A Critical Period in Humans” (HTML)
 
Instructions: Read the webpage linked above.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.1.2 Visual System Development   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 24: Critical Periods of Visual System Development” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 24: Critical Periods of Visual System Development” (HTML)
 
Instructions: Read the entire webpage.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.
 

4.2 Hebb’s Postulate   4.2.1 Long-term Potentiation   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 25: Long-term Synaptic Potentiation” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 25: Long-term Synaptic Potentiation” (HTML)
 
Instructions: Read the entire webpage linked above.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.2.2 Cooperation and Competition   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 24: Mechanism by Which Neuronal Activity Affects the Development of Neural Circuits” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 24: Mechanism by Which Neuronal Activity Affects the Development of Neural Circuits” (HTML)
 
Instructions: Read the entire webpage.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.3 Neuronal Death in Injury   4.3.1 Apoptosis and Necrosis   - Reading: Reading: The University of Texas’s Neuroscience Online: Dr. Pramod Dash’s “Ch 12: Neurotransmitter and Cell Death” Link: The University of Texas’s Neuroscience Online: Dr. Pramod Dash’s “Ch 12: Neurotransmitter and Cell Death” (HTML and Adobe Flash)
 
Instructions: Read the sections titled “Proteolytic Mechanisms of Cell Death” and “Secondary Injury.” Apoptosis is cell suicide, where as necrosis is unintentional cell death. Necrosis activates major inflammatory pathways and results in a host of other problems that apoptosis does not incur. Be sure to understand how and why one occurs and not the other.
 
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4.3.2 Anterograde Degeneration   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 1: The Organization of the Nervous System – Recovery from Neural Injury” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 2nd Edition: “Ch 1: The Organization of the Nervous System – Recovery from Neural Injury” (HTML)
 
Instructions: Read the entire webpage, click on the embedded hyperlinks, and explore all figures. This reading also covers section 4.4.1 and 4.5.2.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: The Saylor Foundation’s “Wallerian Degeneration” Link: The Saylor Foundation’s “Wallerian Degeneration (PDF)
     
    Instructions: Download the reading linked above. Make sure to pay close attention to the figure provided.

4.3.3 Retrograde Degeneration   - Reading: The Saylor Foundation’s “Retrograde Degeneration” Link: The Saylor Foundation’s “Retrograde Degeneration (PDF)
 
Instructions: Download the reading linked above. Make sure to pay close attention to the figure provided

4.3.4 Transneuronal Degeneration   - Reading: The University of Texas’s Neuroscience Online: Dr. Andrew Bean’s “Ch 9: “Synapse Formation, Survival, and Elimination” Link: The University of Texas’s Neuroscience Online: Dr. Andrew Bean’s “Ch 9: Synapse Formation, Survival, and Elimination” (HTML and Adobe Flash)
 
Instructions: Read the section titled “Neurons of the CNS Have Very Limited Capacity to Regenerate.”
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.3.5 Excitotoxicity   - Reading: Psychiatrist.com: Dr. Stephen M. Stahl’s “Excitotoxicity and Neuroprotection” Link: Psychiatrist.com: Dr. Stephen M. Stahl’s “Excitotoxicity and Neuroprotection” (HTML)
 
Instructions: Read the entire webpage.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.4 Brain Repair   4.4.1 CNS Damage Repair   Note: This topic is covered in the reading under subunit 4.3.2.

4.4.2 Stem Cell Replacement   - Reading: NCBI Bookshelf: NeuroRX: Olle Lindvall and Anders Bjorklund’s (guest editors) Cell Replacement Therapy – “Helping the Brain to Repair Itself” Link: NCBI Bookshelf: NeuroRX: Olle Lindvall and Anders Bjorklund’s (guest editors) Cell Replacement Therapy – “Helping the Brain to Repair Itself” (HTML)
 
Instructions: Read the entire webpage for an overview of cell replacement therapy in relation to the human brain.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.5 PNS Repair   4.5.1 Peripheral Nerve Regeneration   - Reading: The University of Texas’s Neuroscience Online: Professor Andrew Bean’s “Ch 9: Synapse Formation, Survival, and Elimination” Link: The University of Texas’s Neuroscience Online: Professor Andrew Bean’s “Ch 9: Synapse Formation, Survival, and Elimination” (HTML and Adobe Flash)
 
Instructions: Read the section titled “Neurons in the Peripheral Nervous System Can Regenerate Their Axons.”
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.5.2 Regeneration of Peripheral Synapses   - Reading: The University of Texas’s Neuroscience Online: Professor Andrew Bean’s “Ch 9: “Synapse Formation, Survival, and Elimination” Link: The University of Texas’s Neuroscience Online: Professor Andrew Bean’s “Ch 9: Synapse Formation, Survival, and Elimination” (HTML and Adobe Flash)
 
Instructions: Read the section on “Neuronal Regeneration.” This also covers section 4.5.3.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.5.3 Schwann Cells and Macrophage Repair   Note: This topic is covered by the reading under subunit 4.5.2.

  • Assessment: The Saylor Foundation’s “Unit 4 Assessment” Link: The Saylor Foundation's “Unit 4 Assessment (PDF)

    Instructions: Complete this quiz after working through Unit 3. The questions are either multiple choice, matching, or labeling diagrams. Your answers can be checked against The Saylor Foundation's “Unit 4 Assessment Answer Key” (PDF). This assessment will take roughly 30 minutes to complete.