1. Neuroscience and Behavior Chapter 2 1

2. I. Phrenology: Different brain areas accounted for specific character and personality traits (Franz Joseph Gall

3. 3 II. Neural Communication A. The body’s information system is built from billions of interconnected cells called neurons.

4. 4 Neural Communication Note the similarities in the above brain regions, which are all engaged in information processing. B. Neurobiologists and other investigators understand that humans and animals operate similarly when processing information.

5. 5 III. Neuron A. A nerve cell, or a neuron, consists of many different parts.

6. 6 B. Parts of a Neuron 1. Cell Body: Life support center of the neuron. 2. Dendrites: Branching extensions at the cell body. Receive messages from other neurons. 3. Axon: Long single extension of a neuron, covered with myelin [MY-uh-lin] sheath to insulate and speed up messages through neurons. 4. Terminal Branches of axon: Branched endings of an axon that transmit messages to other neurons.

7. 7 C. Action Potential 1. A neural impulse. A brief electrical charge that travels down an axon and is generated by the movement of positively charged atoms in and out of channels in the axon’s membrane.

8. 8 D. Excitatory & Inhibitory 1.Excitatory occurs when positive ions enter the neuron, making it more prone to firing an action potential. 2. Inhibitory occurs when negative ions enter the neuron, making it less prone to firing an action potential.

9. 9 E. Threshold 1.Threshold: The level of stimulation required to trigger a neural impulse.

10. 10 F. Refractory Period & Pumps 1. Refractory Period: After a neuron fires an action potential it pauses for a short period to recharge itself to fire again. 2. Sodium-Potassium Pumps: Sodium- potassium pumps pump positive ions out from the inside of the neuron, making them ready for another action potential.

11. 11 G. Action Potential Properties 1. All-or-None Response: When the depolarizing current exceeds the threshold, a neuron will fire. If the depolarizing current fails to exceed the threshold, a neuron will not fire. 2. Intensity of an action potential remains the same throughout the length of the axon.

12. 12 H. Synapse 1. Synapse [SIN-aps] a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. This tiny gap is called the synaptic gap or cleft.

13. 13 IV. Neurotransmitters A.PARAPHRASE! B.Neurotransmitters (chemicals) released from the sending neuron travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing it to generate an action potential.

14. 14 B. Reuptake 1.PARAPHRASE! 2.Neurotransmitters in the synapse are reabsorbed into the sending neurons through the process of reuptake. This process applies the brakes on neurotransmitter action.

15. 15 How Neurotransmitters Influence Us? Serotonin pathways are involved with mood regulation. From Mapping the Mind, Rita Carter, © 1989 University of California Press

16. 16 Dopamine Pathways Dopamine pathways are involved with diseases such as schizophrenia and Parkinson’s disease. From Mapping the Mind, Rita Carter, © 1989 University of California Press

17. 17 Neurotransmitters

18. 18 V. Lock & Key Mechanism A. Neurotransmitters bind to the receptors of the receiving neuron in a key-lock mechanism.

19. 19 B. Agonists

20. 20 C. Antagonists

21. 21 Figure 2.6 Agonists and antagonists Myers: Psychology, Eighth Edition Copyright © 2007 by Worth Publishers

22. 22 VI. Nervous System Central Nervous System (CNS) Peripheral Nervous System (PNS)

23. 23 A. The Nervous System 1. Nervous System: Consists of all the nerve cells. It is the body’s speedy, electrochemical communication system. 2. Central Nervous System (CNS): the brain and spinal cord. 3. Peripheral Nervous System (PNS): the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

24. 24 The Nervous System

25. 25 B. Peripheral Nervous System 1. Somatic Nervous System: The division of the peripheral nervous system that controls the body’s skeletal muscles. 2. Autonomic Nervous System: Part of the PNS that controls the glands and other muscles.

26. 26 C. Autonomic Nervous System (ANS) 1. Sympathetic Nervous System: Division of the ANS that arouses the body, mobilizing its energy in stressful situations. 2. Parasympathetic Nervous System: Division of the ANS that calms the body, conserving its energy.

27. 27 Autonomic Nervous System (ANS) Sympathetic NS “Arouses” (fight-or-flight) Parasympathetic NS “Calms” (rest and digest)

28. 28 D. Central Nervous System 1.Sensory neurons send information from the body’s tissue to the brain 2.Motor neurons are used by the central nervous to communicate instructions 3.Interneurons communicate between sensory neurons and motor neurons

29. 29 Central Nervous System E. The Spinal Cord and Reflexes 1. Simple spinal reflex pathways cause ‘knee-jerk’ responses Simple Reflex

30. 30 VII. The Endocrine System A. The Endocrine System is the body’s “slow” chemical communication system. B. Communication is carried out by hormones synthesized by a set of glands.

31. 31 C. Hormones 1. Hormones are chemicals synthesized by the endocrine glands that are secreted in the bloodstream. Hormones affect the brain and many other tissues of the body. For example, epinephrine (adrenaline) increases heart rate, blood pressure, blood sugar and feelings of excitement during emergency situations.

32. 32 D. Pituitary Gland 1. Is called the “master gland.” The anterior pituitary lobe releases hormones that regulate other glands. The posterior lobe regulates water and salt balance.

33. 33 VIII. The Brain Techniques to Study the Brain A. A brain lesion experimentally destroys brain tissue to study animal behaviors after such destruction. Hubel (1990)

34. 34 B. Clinical Observation Clinical observations have shed light on a number of brain disorders. Alterations in brain morphology due to neurological and psychiatric diseases are now being catalogued. Tom Landers/ Boston Globe

35. 35 C. Electroencephalogram (EEG) An amplified recording of the electrical waves sweeping across the brain’s surface, measured by electrodes placed on the scalp. AJ Photo/ Photo Researchers, Inc.

36. 36 D. PET Scan PET (positron emission tomography) Scan is a visual display of brain activity that detects a radioactive form of glucose while the brain performs a given task. Courtesy of National Brookhaven National Laboratories

37. 37 E. MRI Scan MRI (magnetic resonance imaging) uses magnetic fields and radio waves to produce computer- generated images that distinguish among different types of brain tissue. Top images show ventricular enlargement in a schizophrenic patient. Bottom image shows brain regions when a participants lies. Both photos from Daniel Weinberger, M.D., CBDB, NIMH James Salzano/ Salzano PhotoLucy Reading/ Lucy Illustrations

38. 38 IX. Older Brain Structures A.The Brainstem is the oldest part of the brain, beginning where the spinal cord swells and enters the skull. B.It is responsible for automatic survival functions.

39. 39 C. Brain Stem 1. The Medulla [muh- DUL-uh] is the base of the brainstem that controls heartbeat and breathing. 2. Reticular Formation is a nerve network in the brainstem that plays an important role in controlling arousal.

40. 40 C. Brain Stem 3. Paraphrase! The Thalamus [THAL- uh-muss] is the brain’s sensory switchboard, located on top of the brainstem. It directs messages to the sensory areas in the cortex and transmits replies to the cerebellum and medulla.

41. 41 1. The “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance. D. Cerebellum

42. 42 1. The Limbic System is a doughnut-shaped system of neural structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and drives for food and sex. 2. It includes the hippocampus, amygdala, and hypothalamus. E. The Limbic System

43. 43 F. Amygdala 1. The Amygdala [ah-MIG- dah-la] consists of two almond-shaped neural clusters linked to the emotions of fear and anger.

44. 44 G. Hypothalamus 1. The Hypothalamus lies below (hypo) the thalamus. It directs several maintenance activities like eating, drinking, body temperature, and control of emotions. It helps govern the endocrine system via the pituitary gland.

45. H. Hippocampus 1. Responsible for the logging in of new memories 45

46. 46 Rats cross an electrified grid for self-stimulation when electrodes are placed in the reward (hypothalamus) center (top picture). When the limbic system is manipulated, a rat will navigate fields or climb up a tree (bottom picture). I. Reward Center Sanjiv Talwar, SUNY Downstate

47. 47 J. The Cerebral Cortex 1.The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. 2.It is the body’s ultimate control and information processing center.

48. 48 K. Structure of the Cortex 1.Each brain hemisphere is divided into four lobes that are separated by prominent fissures. 2.These lobes are the frontal lobe (forehead), parietal lobe (top to rear head), occipital lobe (back head) and temporal lobe (side of head).

49. 49 L. Functions of the Cortex 1.The Motor Cortex is the area at the rear of the frontal lobes that control voluntary movements. 2. The Sensory Cortex (parietal cortex) receives information from skin surface and sense organs.

50. 50

51. 51 1. More intelligent animals have increased “uncommitted” or association areas of the cortex. M. Association Areas

52. N. The Brain’s Plasticity 1. The brain is sculpted by our genes but also by our experiences. 2. Plasticity refers to the brain’s ability to modify itself after some type of injury or illness. 52

53. 53 X. Our Divided Brain A. Our brain is divided into two hemispheres. The left hemisphere processes reading, writing, speaking, mathematics, and comprehension skills. In the 1960s, it was termed as the dominant brain.

54. 54 B. Splitting the Brain 1. A procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them. Corpus Callosum Martin M. Rother Courtesy of Terence Williams, University of Iowa

55. 55 C. Split Brain Patients 1. With the corpus callosum severed, objects (apple) presented in the right visual field can be named. Objects (pencil) in the left visual field cannot.

56. 56 D. Divided Consciousness

57. 57 Try This! Try drawing one shape with your left hand and one with your right hand, simultaneously. BBC

58. 58 E. Non-Split Brains 1. People with intact brains also show left-right hemispheric differences in mental abilities. A number of brain scan studies show normal individuals engage their right brain when completing a perceptual task and their left brain when carrying out a linguistic task.

59. 59 X. Brain Organization & Handedness A.Is handedness inherited? Yes. Archival and historic studies, as well as modern medical studies, show that the right hand is preferred. This suggests genes and/or prenatal factors influence handedness.

60. 60 B. Is it Alright to be Left Handed? Being left handed is difficult in a right-handed world.

61. 61 B. Is it Alright to be Left Handed? The percentage of left-handed individuals decreases sharply in samples of older people (Coren, 1993).