Myers’ PSYCHOLOGY (7th Ed)

1. Myers’ PSYCHOLOGY (7th Ed) Chapter 2 Neuroscience, Genetics and Behavior James A. McCubbin, PhD Clemson University Worth Publishers

2. Understanding the Brain….D—Ohhhhh!!!

4. Neural Communication • Biological Psychology • branch of psych concerned w/ links between biology & behavior • some biological psychologists AKA: • behavioral neuroscientists • neuropsychologists • behavior geneticists • physiological psychologists…..or • biopsychologists • Neuron • a nerve cell • It’s the basic building block of the nervous system

5. Parts of a Neuron: • Dendrite: bushy, branching extensions of a neuron that receive messages & conduct impulses toward the cell body • Axon: extension of a neuron, ending in branching terminal fibers, -messages are sent thru it to other neurons or to muscles or glands • Myelin [MY-uh-lin] Sheath: a layer of fatty cells segmentally encasing the fibers of many neurons • enables vastly greater transmission speed of neutral impulses… deterioration can = multiple sclerosis • Another “demyelinating” disease: Guillain-Barre Syndrome: Action potentials in peripheral NS --faulty immune reaction attacks the myelin

6. Neural Communication

8. Neural Communication • Synapse [SIN-aps] • Where the end of 1 neuron (axon terminus) & dendrite of next neuron join up… • tiny gap at this junction is called the synaptic gap or cleft • EACH neuron can make up to 10,000 connections!!! • Neurotransmitters • chemical messengers that cross the synaptic gaps between neurons • when released by the sending neuron, N-T’s travel across the synapse & bind to receptor sites on the receiving neuron, & this influences whether it will generate a neural impulse

9. Cell A: Sending neuron Cell B: Receiving neuron

10. Neural networks or connections Inset shows vesicles + receptor sites + neurotransmitters being released from axon of sending to dendrite of receiving..

11. Neural Communication • Action Potential: • a neural impulse; a brief electrical charge that travels down an axon • generated by the mov’t of positively charged atoms in and out of channels in the axon’s membrane   • Threshold • the level of stimulation required to trigger a neural impulse

12. Neuron’s (elec.) impulse = action potential: [“I sing the body electric!” (WW) ] Signals from other neurons can be excitatory (accelerator) orinhibitory (brakes) “party animal vs. party pooper”: fires if animals win! Reaction = is “All-or-nothing”: Like a gun: It fires …or doesn’t Strength of stimulus does NOT = stronger a impulse It IS just more neurons firing EX: Light touch … or big hug?

13. Synapse = 1/millionth of inch wide! N-T’s jump this & carry impulse across thru chem. Process (What does “N-T” stand for???) Chemical process: is “selectively permeable” • i.e., blocks out sodium ions when “resting”… • When hits threshold, charge comes … • GATES open & let in sodium (Na) • This carries charge down to terminal buttons… • Then neurotransmitters (N-T’s) take over

14. (+) & (-) ions: • Fluid inside = (-) ions • Fluid outside = (+) ions When it’s like this it is a resting potential (ain’t fired up yet!) • Gates open …..(+)Na ions get in = firing as reaches threshold…when +Na inside = more than -Na inside • Refractory (resting) period: As each section of axon fires & carries the impulse, it then “rests” (refractory) & it pumps the Na back out… Analogy: like a camera battery..get green light…take pic… get red light… camera has to “rest & recharge • It’s then able to fire again

15. Cell body end of axon Direction of neural impulse: toward axon terminals Neural Communication

16. Neural Communication

17. Neural connections in a neural network: What they really look like…

18. Neural Pathways: • Neurotransmitters: Each N-T has specific routes thru brain… …& these = “pathways” • Functions: see table 2.1, p. 62 EX: Endorphins (“morphine w/in”): released to deal w/ pain….w/ psych. stress….& also w/ strenuous exercise (Endor. can also affect moods)

19. Dopamine Pathways Pathways: Route each N-T takes… Route thru brain is different for each N-T Serotonin Pathways

20. The Dopamine Pathway hits a LOT of areas that deal with pleasure, emotion, etc. Dopamine is plays a large role in many drug addictions

21. Neural Communication…p. 62  KNOW THESE!!!

22. Some major N-T’s: • Acetylcholine [ah-seat-el-KO-leen] = ACh • Some of its functions: triggers muscle contractions… motor activ. • muscle action + invol. mov’t (heart, etc.) • joints • possible memory & arousal (Alzheimer’s) • NOTE: many poisons block or mimic Ach • Endorphins [en-DOR-fins] • “morphine within” • natural, opiate-like N – T’s more  • linked to pain control & to pleasure • Ease pain sensation, help mood: happiness, feel good (“sense of well-being”), etc… • Stress…pain….strenuous exercise

23. Dopamine: involved in volun. mov’t • Also atten. & basic learning • “reward centers” (pleasure) • too little: Parkinson’s too much: Schizophrenia Serotonin: affects mood; also pain control… • control of eating, sleep, & arousal • May affect dreaming • too much = mania too little, depress. Norepinephrine: alertness, wakefulness…& mood GABA: Sleep eating disorders Glutamate: a major excitatory N-T • Involved in memory • Too much: over-stimulates brain & = migraines (MSG in Chinese food?)

24. SSRI’s (selective serotonin reuptake inhibitors) Stops re-absorption of serotonin back into vesicles, allowing more to be processed used to fight depression

25. Agonists & Antagonists:  Agonist: similar enough to mimic NT It excites & gets receptors going more than usual… EX: morphine does this to endorphin receptor sites Antagonist: it inhibits N-T’s Similar enough to take NT’s place, but not cause needed action in receptor EX: ACh & poison curare: blocks reception of NT Muscles(which?) don’t work…& we’re paralyzed …& die 2 ways: Antagonists can inhibit (hold back) NT's release OR… can be enough like the NT that it occupies the site & blocks (EX: curare) its effect, but can't mimic it, so does NOT stimulate the receptor  Note: DVD: Brain, Univ. w/in: Evolution

26. Neurotransmitter molecule Receiving cell membrane Agonist mimics neurotransmitter Receptor site on receiving neuron Antagonist blocks neurotransmitter N-T “Lock & key” system

28. Other Neurotransmitters & drugs that block or mimic them… (What are those called? Block? Mimic?) Note “alcohol!!”

29. Blood/Brain barrier & N-T’s • Lets brain block out unwanted chem. in blood…So some can't sneak thru… EX: Dr’s can't just inject dopamine for Parkinson's (has a shortage of dopamine) b/c blood-brain barrier blocks it… But another substance, L-dopa, canget in… THEN once it’s in, it converts to dopamine, so helps those w/ Parkinsons

30. Facts RE: Dopamine & Parkinson’s: Dopamine is found only in the brain -produced in mid-brain & is chiefly involved in movement & the “reward system” (pleasure) When production slows (like in Parkinson’s), a person has tremors & shuffling movement b/c of loss of dopamine's ability to regulate large movts. Usually also a loss of weight & less interest in sex as there's less dopamine for the pleasure pathways There are dopamine agonists that could treat Parkinson's symptoms, but the problem is getting past the blood-brain barrier. -L-dopa will cross the barrier, but for some reason the brain slowly stops converting L-dopa into dopamine.

31. The Nervous System(s) • Nervous System • body’s speedy, electrochemical communication system • NS = all the nerve cells of the peripheral & central nervous systems • Central Nervous System (CNS) • brain & spinal cord • Peripheral Nervous System (PNS) • the sensory (afferent) & motor (efferent) neurons that connect the central nervous system (CNS) to the rest of the body

32. Nervous system Peripheral Central (brain and spinal cord) Autonomic (controls self-regulated action of internal organs and glands) Somatic: (controls voluntary movements of skeletal muscles) Sympathetic (arousing) Parasympathetic (calming) Wants homeostasis The Nervous System

33. The Nervous System • Nerves • neural “electrical cables” made of neurons …carries info • are part of the peripheralnervous system • connect the central nervous system with muscles, glands, and sense organs EX: optic nerve for vision, auditory for hearing *Are 3 kinds of neurons in nervous system…

34. The Nervous System 3 types of Neurons: 1) Sensory Neurons (aka afferent):sends info from body's tissues & sensory organs into the brain & Sp. cord for processing -carry incoming info from sense receptors to the CNS 2) Interneurons: in sensory neuron’s processing, these are used by CNS to allow internal commmun.betwn. motor & sensory neurons • CNS neurons that internally communicate & intervene between the sensory inputs & motor outputs 3) Motor Neurons (aka efferent):CNS uses these to send instructions back out to the body's tissues • carry outgoing information from the CNStomuscles & glands

35. Nervous System: = CNS (brain + sp.cord) + PNS PNS 2 main parts... • Somatic Nervous System:voluntary things… • the division of the peripheral nervous system that controls the body’s skeletal muscles • Autonomic NS: involuntary • the part of the peripheralnervous system that controls the glands and the muscles of the internal organs (such as the heart)…. ANS is divided into 2 sections…. • Sympathetic NS • division of the autonomic nervous system that arouses the body, mobilizing (Spends) its energy in stressful situations • Parasympathetic NS (p. 66--functions) • division of the autonomic nervous system that calms the body, conserving (Preserves) its energy

36. The Nervous System: Sympathetic nervous system gets you going for physical exertion & exercise OR for emergencies

37. The Nervous System:The Para-Sympathetic Nervous Systemcalms you downand brings you back to homeostasis(what is that?)

38. Neurons in the brain connect with one another to form networks Inputs Outputs The brain learns by modifying certain connections in response to feedback The Nervous System • Neural Networks • interconnected neural cells • with experience (learning), networks can learn, as feedback strengthens or inhibits connections that produce certain results • computer simulations of neural networks show analogous learning

39. Brain Sensory neuron (incoming information) Interneuron Motor neuron (outgoing information) Muscle Spinal cord Skin receptors The Nervous System: The spinal cord: Reflex:simple neural paths to the sp-cord: often = 1 sensory neuron + 1 motor neuron "talking thru" a interneuron • simple, automatic, inborn response to a sensory stimulus EX: "knee-jerk" …headless warm body could do this! EX2: pain reflex…flame to fingers = auto reflex…in fact, jerks away b4 info actually hits brain

40. But if sp-cord severed at top, you'd not feel pain--or pleasure…Would do the knee-jerk, but just wouldn't feel the tap So…Males could get erection & females could auto-lubricate if stimulated…but can’t feel the pleasurable feelings of sex-stim. Neural networks: May put ?’s into the answers Read (on p. 68) & explain this process: a) How is your brain like a computer? b) How do they use Kobe Bryant’s b-ball skills as EX: for this? c) How does Fig. 2.9 show this? Explain this figure d) But how is our brain beyond this simplistic figure?

41. The Brain • Lesion: tissue destruction • a brain lesion is a naturally or experimentally caused destruction of brain tissue

42. How do the brain & the mind differ? Read p. 69 & we will discuss… B4 PET, electron microscope, etc., How did ppl study the brain? Dead ppl: could look at & dissect…but is the mind there? Brain vs. mind: the old philosp. ? Alive: could use lesions…wounds, damage, disease, etc, & have for 5000 yrs. (EX?) -Only in last 200 yrs began to do it scientifically (E---?) -areas of damage changed behaviors certain ways NOW: can use elec., chem., or magnetic signals to stimulate brain to see effects In animals, can inflict lesions to see effects EX: in hypothalamus: 1 area = starving self to death…another = drastically overeating New ways to study the brain: EEG’s, CT’s, PET’s, MRI’s: 

43. Electroencephalogram(EEG) : brain gives off signals that can be picked up various ways…thru EEG's: see brain elec. activity on graph • an amplified recording of the waves of electrical activity that sweep across the brain’s surface • these waves are measured by electrodes placed on the scalp

44. 2 EEG views

45. How we study The Brain today: CT (computed tomography—”CAT”) Scan: series of x-ray photographs taken from different angles & combined by computer into a composite Representation of a slice thru the body; x-ray photos that show damage PET (positron emission tomography) Scan: More dramatic: Shows use of ionized glucose… Neurons consume glucose as they are being used, so inject radioactive glucose & watch it being used as person does stuff …“while the brain performs a given task” (EX: p. 83, bottom)

46. PET SCANS 5 Activities  Parkinson’s/ Norm. 

47. MRI (magnetic resonance imaging): Uses magnetic fields to show soft tissues--like very detailed photo (compared to CT) fMRI's (functional MRI's) • Special MRI that works by monitoring blood flow • Can photogr. activity, like a more detailed PET scan • Shows when things happen, how areas change, & how areas work together

48. MRI Scans:Noting  ventriclesBelow:Pituitary

49. These techniques = what the microscope did for biology & telescope for astronomy • New discoveries are constantly coming in *Look at bottom of p. 71 for new samples of info Parts of The Brain: • Lower brain: Ratio of body wt. to brain wt. ? -capabilities give better view: -primitive vertebrates (EX:shark): breathe, rest, feed…but lower mammals (EX: rats) = more emotion & memory… --even more advanced…humans…have foresight--ability to plan & think ahead

50. The Lower Brain: • Brainstem: the oldest part & central core of the brain, beginning where the spinal cord swells as it enters the skull…looks like “walking stick” • responsible for automatic survival functions • Medulla [muh-DUL-uh] • base of the brainstem where sp-cord enters brain • controls heartbeat and breathing • can cut this from the higher brain & can still breathe & live