Brains, Bodies, and Behavior

1. Brains, Bodies, and Behavior

2. Brains, Bodies, and Behavior • The Neuron Is the Building Block of the Nervous System • Our Brains Control Our Thinking, Feeling, and Behavior • Psychologists Study the Brain Using Many Different Methods • Putting It All Together: The Nervous System and the Endocrine System

3. The Neuron Is the Building Block of the Nervous System

4. The Neuron Is the Building Block of the Nervous System • Learning Objectives • Describe the structure and functions of the neuron • Draw a diagram of the pathways of communication within and between neurons. • List three of the major neurotransmitters and describe their functions.

5. The Neuron Is the Building Block of the Nervous System

6. The Neuron Is the Building Block of the Nervous System • Specialized parts of an axon • myelin sheath – layer of fatty tissue surrounding the axon • insulates the axon • speeds the transmission of the electrical signal • terminalbutton – branching toward the end of an axon

7. Image of a motor neuron, with dendrite, axon and cell body labeled and described

8. Neurons Communicate Using Electricity and Chemicals • Communication is electrical, taking the form of a charge called an action potential • Communication is chemical, via neurotransmitters which travel across the gap between two neurons Within a Neuron Between Neurons

9. Neurons Communicate Using Electricity and Chemicals

10. Neurons Communicate Using Electricity and Chemicals • The myelin sheath wraps around the axon, but also leaves small gaps called the Nodes of Ranvier. • The action potential jumps from node to node as it travels down the axon

11. Neurotransmitters: The Body’s Chemical Messengers

12. Neurotransmitters: The Body’s Chemical Messengers

13. When the nerve impulse reaches the terminal button, it triggers the release of neuro-transmitters into the synapse. • The neuro-transmitters fit into receptors on the receiving dendrites in the manner of a lock and key

14. Neurotransmitters: The Body’s Chemical Messengers

15. Drug that mimics or enhances the influence of a given neurotransmitter • e.g., cocaine is a dopamine agonist • Drug that blocks or inhibits the activity of a given neurotransmitter • e.g., curare is an acetylcholine antagonist Agonist Antagonist

16. Neurotransmitters: The Body’s Chemical Messengers

17. Neurotransmitters: The Body’s Chemical Messengers

18. The Neuron Is the Building Block of the Nervous System • Key Takeaways • The Central Nervous System (CNS) is the collection of neurons that make up the brain and the spinal cord. • The Peripheral Nervous System (PNS) is the collection of neurons that link the CNS to our skin, muscles, and glands. • Neurons are specialized cells, found in the nervous system, which transmit information. Neurons contain a dendrite, a soma, and an axon.

19. The Neuron Is the Building Block of the Nervous System • Key Takeaways, continued • Some axons are covered with a fatty substance known as the myelin sheath which surrounds the axon acting as an insulator, allowing faster transmission of the electrical signal • The dendrite is a treelike extension that receives information from other neurons and transmits electrical stimulation to the soma.  • The axon is an elongated fiber that transfers information from the soma to the terminal buttons.

20. The Neuron Is the Building Block of the Nervous System • Key Takeaways, continued • Neurotransmitters relay information chemically from the terminal buttons and across the synapses to the receiving dendrites using a type of lock and key system. • The many different neurotransmitters work together to influence cognition, memory, and behavior. • Agonists are drugs that mimic the actions of neurotransmitters, whereas antagonists are drugs that block the action of neurotransmitters.

21. Our Brains Control Our Thinking, Feeling, and Behavior

22. Our Brains Control Our Thinking, Feeling, and Behavior Learning Objectives: • Describe the structures and function of the “old brain,” and its influence on behavior. • Explain the structure of the cerebral cortex (its hemispheres and lobes) and the function of each area of the cortex. • Define the concepts of brain plasticity, neurogenesis, and brain lateralization.

23. Our Brains Control Our Thinking, Feeling, and Behavior • The “Old Brain” • Includes the brain structures nearest the spinal cord • Regulates basic survival functions, such as breathing, moving, resting, and feeding • Contributes to experiences of emotion

24. In addition to the old brain, humans have a large and highly developed outer brain layer known as the cerebral cortex. • The cortexprovides humans with excellent memory, outstanding cognitive skills, and the ability to experience complex emotions.

25. The Old Brain: Wired For Survival

26. The Old Brain: Wired For Survival

27. The Old Brain: Wired For Survival

28. The Old Brain: Wired For Survival

29. The Old Brain: Wired For Survival

30. The Cerebral Cortex Creates Consciousness and Thinking • cerebral cortex – the outer, bark-like layer of the human brain that allows us to use language, acquire complex skills, create tools, and live in social groups • contralateral control – the left side of the cortex responds to and controls the right side of the body, and vice versa

31. The brain is divided into two hemispheres -- left and right. • Each hemisphere has four lobes -- temporal, frontal, occipital and parietal.

32. The Cerebral Cortex Creates Consciousness and Thinking

33. The Cerebral Cortex Creates Consciousness and Thinking • In addition to its motor and sensory areas, the cortex contains association areas. • In the association areas, sensory and motor information is combined and related to our stored knowledge.

34. The Brain is Flexible: Neuroplasticity • neuroplasticity – the brain’s ability to change its structure and function in response to experience or damage • neurogenesis – the forming of new neurons

35. The Left and Right Hemispheres • Brain Lateralization • The left and right hemispheres are specialized to perform different functions. • The corpus callosum is a band of fibers connecting the two hemispheres. • Sperry’s research on split brain patients contributed to our understanding of brain lateralization.

36. The Left and Right Hemispheres Corpus Callosum connects left and right hemispheres Right Hemisphere -- perceptual skills -- recognizing objects and faces -- recognizing patterns and melodies -- drawing pictures Left Hemisphere -- language -- mathematics -- judging time and rhythm --sequencing complex movements

37. Our Brains Control Our Thinking, Feeling, and Behavior • Key Takeaways • The old brain, including the brainstem, medulla, pons, reticular formation, thalamus, cerebellum, amygdala, hypothalamus and hippocampus regulates basic survival functions such as breathing, moving, resting, feeding, emotions and memory. • The cerebral cortex, made up of billions of neurons and glial cells, is divided into the right and left hemispheres and into four lobes. • The frontal lobes are primarily responsible for thinking, planning, memory and judgment. The parietal lobes are primarily responsible for bodily sensations and touch. The temporal lobes are primarily responsible for hearing and language. The occipital lobes are primarily responsible for vision. Other areas of the cortex act as association areas, responsible for integrating information.

38. Our Brains Control Our Thinking, Feeling, and Behavior • Key Takeaways, continued • The brain changes as a function of experience and potential damage in a process known as plasticity. The brain can generate new neurons through neurogenesis. • The motor cortex controls voluntary movements. Body parts requiring the most control and dexterity take up the most space on the motor cortex. • The sensory cortex receives and processes bodily sensations. Body parts that are the most sensitive occupy the greatest amount of space on the sensory cortex. • The left cerebral hemisphere is primarily responsible for language and speech in most people, whereas the right hemisphere specializes in spatial and perceptual skills, visualization, and the ability to recognize patterns, faces, and melodies.

39. Our Brains Control Our Thinking, Feeling, and Behavior • Key Takeaways, continued • The severing of the corpus callosum, which connects the two hemispheres, creates a “split brain patient,” with the effect of creating two separate minds operating in one person. • Studies with split-brain patients as research participants have been used to study brain lateralization. • Neuroplasticity allows the brain to adapt and change as a function of experience or damage.

40. Psychologists Study the Brain Using Many Different Methods

41. Psychologists Study the Brain Using Many Different Methods • Learning Objective: • Compare and contrast the techniques that scientists use to view and understand brain structures and functions.

42. Psychologists Study the Brain Using Many Different Methods • Cadaver Approach • The most direct approach to understanding the structure of the brain

43. Lesions Provide a Picture of What is Missing • Lesions • In living humans, lesions are areas of brain damage resulting from accidents, strokes, gunshots, or other injuries. • Lesions may also be created intentionally in animals. • Lesions allow scientists to observe the loss of function that results.

44. Lesions Provide a Picture of What is Missing • Areas in the frontal lobes of Phineas Gage were damaged when a metal rod was blasted through it. • Gage’s personality, emotions, and moral reasoning were influenced. • The accident helped scientists understand the role of the frontal lobes in these processes.

45. Recording Electrical Activity in the Brain • In animals, detectors can be placed in the brain to study the electrical activity caused by the firing of specific neurons. • In living humans, the electrical activity of the brain’s neurons can be studied using scalp electrodes – this is electroencephalography, or EEG.

46. Recording Electrical Activity in the Brain • Useful in understanding brain abnormalities such as epilepsy • Participants can move around during recordings • Allows changes to brain activity to be tracked very quickly • Does not provide a clear picture of the brain’s structure Advantages of EEG Disadvantage of EEG

47. Peeking Inside the Brain: Neuroimaging • Functional Magnetic Resonance Imaging (fMRI) • a type of brain scan that uses a magnetic field to create images of the activity in each brain area • detects the blood flow in each brain region • currently the most common method of learning about brain structure

48. Peeking Inside the Brain: Neuroimaging

49. Peeking Inside the Brain: Neuroimaging • Transcranial Magnetic Stimulation (TMS) • procedure in which magnetic pulses are applied to a living person’s brain to temporarily and safely deactivate a small brain area • allows cause-and-effect conclusions about the influence of brain structures on thought and behavior

50. Psychologists Study the Brain Using Many Different Methods • Key Takeaways • Studying the brains of cadavers can lead to discoveries about brain structure, but are limited due to the fact that the brain is no longer active. • Lesion studies are informative about the effects of different brain regions. • Electrophysiological recording may be used in animals to directly measure brain activity.