1. Neurons, Hormones, and the Brain
Chapter 4
Prepared by Michael J. Renner, Ph.D.
These slides ©2002 Prentice Hall Psychology Publishing.

2. Neurons, Hormones, and the Brain
The Nervous System: A Basic Blueprint
Communication in the Nervous System
Mapping the Brain
A Tour Through the Brain
The Two Hemispheres of the Brain
Two Stubborn Issues in Brain Research

3. The Nervous System: A Basic Blueprint
The Central Nervous System
The Peripheral Nervous System

4. Divisions of the Nervous System
Central Nervous System
Brain
Spinal cord
Peripheral Nervous System
Somatic
Autonomic
Figure 4.01 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

5. Nervous System Organization
Figure 4.03 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

6. The Central Nervous System
Central Nervous System: The portion of the nervous system consisting of the brain and spinal cord.
Spinal Cord: A collection of neurons and supportive tissue running from the base of the brain down the center of the back, protected by a column of bones (the spinal column).

7. The Peripheral Nervous System
Somatic Nervous System: The subdivision of the PNS that connects to sensory receptors and to skeletal muscles; sometimes called the skeletal nervous system.
Autonomic Nervous System: The subdivision of the PNS that regulates the internal organs and glands.

8. Sympathetic and Parasympathetic
Figure 4.02 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

9. Communication in the Nervous System
The Structure of the Neuron
How Neurons Communicate
Chemical Messengers in the Nervous System

10. Different Kinds of Neurons
Figure 4.04 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.
Neurons vary in size and shape, depending on their location and function. More than 200 types have been identified in mammals.

11. The Structure of the Neuron
Dendrite: Branches that receive signals and transmit to cell body
Cell Body: Controls cell metabolism and determines firing
Axon: Carries impulses away from cell body
Myelin Sheath: Fatty insulation
Figure 4.05 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

12. How Neurons Communicate
Synapse: Site where a nerve impulse is transmitted from one neuron to another; includes the axon terminal, synaptic cleft, and receptor sites on receiving cell.
Neurotransmitter: Chemical substance that is released by transmitting neuron at the synapse and alters the activity of the receiving neuron.

13. Plasticity in Brain & Behavior
Some rats are housed alone in empty cages
Their littermate twins are group-housed in cages with toys, which are changed frequently
Richer environments led to heavier, thicker brains, more synapses, and better learning
Figure 2.06 from
Morris, C.G., & Maisto, A.A. (1999). Psychology, 10th Edition. Upper Saddle River, NJ: Prentice Hall.
Source:
Rosenzweig, M..R., Bennett, E.L., & Diamond, M.C. (1972). Scientific American.
See also:
Renner, M. J., & Rosenzweig, M.R. (1987). Enriched and Impoverished Environments: Effects on Brain and Behavior. New York: Springer Verlag.

14. Getting Connected
Figure 4.06 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.
Neurons in a newborn’s brain are widely spaced, but form connections quickly.

15. Chemical Messengers in the Nervous System
Neurotransmitters are released into synaptic cleft
Bind to receptor site on receiving neuron
Electrical state of receiving neuron changes, becoming more (or less) likely to fire
Figure 4.07 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

16. Major Neurotransmitters
Acetylcholine (ACh)
Dopamine
Serotonin
Norepinephrine
Gamma amino butryic acid (GABA)

17. Endorphins
Chemical substances in the nervous system that are similar in structure and action to opiates; they are involved in pain reduction, pleasure, and memory, and are known technically as endogenous opioid peptides.

18. Hormones
Hormones: Chemical substances, secreted by organs called glands, that affect the functioning of other organs.
Endocrine Glands: Internal organs that produce hormones and release them into the bloodstream.

19. Mapping the Brain

20. Electroencephalogram (EEG)
Figure 2.8 from:
Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.
Source:

21. Positron Emission Tomography
Active areas have increased blood flow
Radioactive isotopes (small amounts) are placed in the blood
Sensors detect radioactivity
Different tasks show distinct activity patterns
Figure 2.09 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.

22. Magnetic Resonance Imaging
Magnetic fields align certain ions and compounds
When field is removed, these molecules release energy as radio waves
Computer calculates tissue density from radio waves
Provides clear, 3D images
Figure 2.10 from:
Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.

23. A Tour Through the Brain
The Brain Stem
The Cerebellum
The Thalamus
The Hypothalamus and the Pituitary Gland
The Limbic System
The Cerebrum

24. The Human Brain
This view shows the brain as if split in half front-to-back
Inside surface of right half of brain
Eyes on the left, near the word “hypothalamus”
Figure 4.10 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

25. The Brain Stem
Brain Stem: At the top of the spinal cord, consisting of medulla and pons
Medulla: Responsible for some automatic functions, such as breathing and heart rate
Pons: Involved in sleep, waking, and dreaming.
Reticular Activating System: A dense network of neurons found in the core of the brain stem; it arouses the cortex and screens incoming information.

26. The Cerebellum
Cerebellum: Regulates movement and balance, and is involved in learning some simple responses.

27. Thalamus and Hypothalamus
Thalamus: Relays sensory messages to the cerebral cortex.
Hypothalamus: Involved in emotions and drives vital to survival (e.g., fear, hunger, thirst, and reproduction); it regulates the autonomic nervous system.
Pituitary Gland: Small endocrine gland at the base of the brain, which releases many hormones and regulates other endocrine glands.

28. The Limbic System
Limbic System: A group of brain areas involved in emotional reactions and motivated behavior.
Amygdala: Involved in the arousal and regulation of emotion and the initial emotional response to sensory information.
Hippocampus: Involved in the storage of new information in memory.
Figure 4.11 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

29. The Cerebrum Occipital Lobes: Vision Parietal Lobes: body sensation
Temporal Lobes: Hearing, language
Frontal Lobes: Thinking, planning, movement

30. The Two Hemispheres of the Brain
Split Brains: A House Divided
A Question of Dominance

31. Visual Pathways
Each hemisphere receives information about the opposite side of the visual field.
Objects to your left put images on right side of each retina; goes to right side of brain
Half of optic nerve fibers cross at the optic chiasm

32. Split Brains: A House Divided
Hemispheres of brain sometimes separated to treat severe epilepsy
Split brain operation includes the optic chiasm
Optic nerve no longer crosses
Visual information goes only to one hemisphere
Different sides of brain see different information

33. Divided Brain, Divided View
Figure 4.15 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

34. Two Stubborn Issues in Brain Research
Why Do We Dream?
Are There “His” and “Hers” Brains?

35. Why Do We Dream?
Rapid Eye Movement (REM) Sleep: Sleep periods characterized by fast eye movement behind closed eyelids, loss of muscle tone, and dreaming.
Activation-Synthesis Theory: Theory that dreaming results from cortical synthesis and interpretation of neural signals triggered by activity in the lower part of the brain.

36. Are There “His” & “Hers” Brains?
Sex differences in the brain have been studied for many years.
Many findings seem to reflect cultural bias, and change with cultural changes
Reliable differences have been found in activity of certain brain areas during some tasks
Example: MRI of language task, right ♂ ♀