PSYC 223 BIOLOGICAL PSYCHOLOGY

Transcription

1 PSYC 223 BIOLOGICAL PSYCHOLOGY Session 5 ORGANIZATION OF THE NERVOUS SYSTEM PART II Lecturer: Dr. Adote Anum, Dept. of Psychology Contact Information: aanum@ug.edu.gh College of Education School of Continuing and Distance Education 2014/ /2017

2 Session Overview In this session, we will continue the discussion on Nervous System but the emphasis will shift neurodevelopmental plasticity. The brain has the capacity to change and continues to change throughout life. In children who suffer brain damage, usually, the brain reorganizes so that the functions or behaviors associated with the damaged structure is not lost. This will be the focus of this session. Slide 2

3 Session Outline The key topics to be covered in the session are as follows: What is plasticity of the brain? Levels of plasticity Structural changes in the brain Factors that influence plasticity and reorganization Slide 3

4 Reading List Read Chapter Five of Biological Psychology 9 th Edition by J. W. Kalat; pages Read Chapters Seven and Eight of An Introduction to Brain and Behavior, 4 th Edition. McMillan Learning, by Kolb, B. & Whishaw, I. Q. (2013). Slide 4

5 Topic One WHAT IS BRAIN OR NEUROPLASTICITY? Slide 5

6 Neuroplasticity Neuroplasticity is the ability of the brain to change, for better or for worse, throughout the individual s life span. It involves forming neuronal connections in response to information derived from experiences in the environment, sensory stimulation, and normal development

7 Neuroplasticity Neuroplasticity refers to the moldable structure of the brain and nerves that results from changes in neural pathways and synapses. These changes stem from changes in behavior, environment, neural processes as well as changes from bodily injury. The brain does change throughout life.

8 Topic Two LEVELS OF PLASTICITY Slide 8

9 Levels of Neuroplasticity Cellular changes (result of learning) There is a continued change in the brain from birth till death. This involves new synaptic connections that occur as a result of learning or problem-solving Cortical remapping (response to injury) This usually occurs in response to brain damage. It is however limited to or dependent on several factors some of which are discussed in this session

10 Topic Three STRUCTURAL CHANGES IN THE BRAIN Slide 10

11 Structural Changes in the Brain There are structural changes that occur as part of brain development and these are: Neurogenesis Neuronal migration Neural cell death Synaptic plasticity Synaptogenesis Some of these have been described in the following slides.

12 Neurogenesis Neurogenesis is the creation of new neurons. It largely occurs in the developing brain. Limited neurogenesis occurs in the adult brain. Neuronal migration is a process whereby neurons extend from their place of birth to connect to far reaching areas of the brain. Neural cell death - Neurons die. This can happen from either damage, over-excitation, or disease. Natural programmed cell death including apoptosis also occurs. Apoptosis - the death of cells that occurs as a normal and controlled part of an organism's growth or development.

13 Synaptic Plasticity Synaptic plasticity refers to changes in the strength of connections between synapses. Long-term potentiation (LTP) Long-term depression (LTD) Changes in the number of receptors for specific neurotransmitters Up-regulation Down-regulation

14 Synaptogenesis & Synaptic Pruning The creation and removal of entire groups of synapses. This builds and destroys connections between neurons respectively.

15 Synaptic Pruning Synaptic pruning is a regulatory process that facilitates a change in neural structure by reducing the overall number of neurons and synapses. This makes for efficient information processing. Synapses that are frequently used have strong connections whereas those that are rarely used are eliminated.

16 Topic Four PLASTICITY AND REORGANIZATION Slide 16

17 Functional Reorganization As the brain develops, certain areas of the brain become specialized for specific tasks. If your experience changes dramatically or parts of the brain are damaged, areas previously specialized for a certain function can take on the work of other areas.

18 Exercise Induced Neuroplasticity All forms of exercise appear to produce neuronal changes in the brain; however, different forms of exercise produce changes in different brain regions. More demanding forms of exercise seem to promote change in more diverse areas of the brain.

19 Plasticity and Reorganization Collateral Sprouting Brain regrows/reorganizes after injury Rehabilitation and Retraining Improvements in walking Improvement in cognitive and perceptual handicaps

20 Plasticity and Reorganization Intact Brain structures help in recovery Among stroke victims it has been shown that moving the affected hand activates the motor cortex on both sides. This suggests that the motor cortex on the same side of the injury appears to be involved in recovery and restoration of function.

21 References Read Chapter Five of Biological Psychology 9 th Edition by J. W. Kalat; pages Read Chapters Eight of An Introduction to Brain and Behavior, 4 th Edition. McMillan Learning, by Kolb, B. & Whishaw, I. Q. (2013). Slide 21