AP Psychology Unit 2:

1. AP Psychology Unit 2: The Biological Bases of Behavior (Chapters 2 and 4)

2. An Early History of Biopsychology • Plato: the mind is located in the brain • Franz Gall and Phrenology • Early 1800s • Read bumps on skull to understand traits Touch my sexy head lumps. Go on….touch them!

3. Biopsychology Today • Everything we do is ultimately controlled by our body and brain • Body/brain composed of cells • Brain cells called neurons communicate electrically and chemically • Different parts of the brain have specific functions • Our brains create meaningful experiences from sensory information • Brain structure and function is influenced by experience

4. Neurons: Defining and Types • A NEURON is a nerve cell. • There are three basic types of neurons (diagram): • Sensory Neurons: Afferent neurons that detect stimuli from sense organs and relay this information TO the brain and/or spinal cord. • Motor Neurons: Efferent neurons that receive signals from the brain and/or spinal cord and relay this information to glands and muscles. • Interneurons: neurons in the brain and spinal cord that coodinate activity between sensory and motor neurons. • Three Types of Neurons in action! • Glial Cells: provide nutrients to neurons, insulate neurons, and remove debris when neurons die.

5. Neuroanatomy (diagram)

6. The Neural Impulse (diagram) • Intraneural transmission: within on neuron • This is an ELECTRICAL process • Occurs as a result of the exchange of charged particles called ions

7. Neural Impulse: Resting Potential • When more negative ions are inside the neuron than outside • Neuron is not transmitting information • Similar to a compressed spring • The neuron is POLARIZED – meaning it has a charge (-) • System WANTS to reach equilibrium and balance charges, but selectively permeable membrane is closed when in this state known as resting potential

8. Neural Impulse: Action Potential • Sudden, massive change in charge in the neuron • Neuron reaches the threshold of excitation when neighboring neurons’ excitatory signals outnumber inhibitory signals • Ions flow across cell membrane down axon (domino effect) facilitated by myelin sheath • Na+ in, K+ out • Neuron fires and DEPOLARIZES – no charge

9. Neural Impulse: All-or-None Law • A neuron either fires or it does not • When it does fire, it will always produce an impulse of the same strength • Intensity of a stimulus is coded by the frequency of action potentials or the number of neurons that fire

10. Neural Impulse: Refractory • Absolute refractory period • Period immediately after an action potential when another action potential cannot occur • Relative refractory period • Period following absolute refractory period when a neuron will only respond to a stronger than normal impulse • During the refractory period, the neuron is trying to get back to resting potential by pumping out K+ ions!

11. So…? • Impulse has traveled down the length of the axon • Signal end up at terminal buttons, very end points of the axon terminals • Then what? • Signal must get to other neurons, but how?

12. The Synapse (diagram) • The synapse • Composed of the terminal button of one neuron, the synaptic space, and the dendrites or cell body of the receiving neuron • Synaptic space (synaptic cleft) • Tiny gap between neurons • Messages must travel across the space to get from one neuron to the next

13. Transmission Between Neurons Presynaptic Neuron • Interneural: between neurons • a CHEMICAL process • Synaptic vesicles • Sacs in terminal button that release chemicals into synaptic space • Neurotransmitters • Chemicals released by synaptic vesicles • Receptor sites • Location on receptor neuron for specific neurotransmitter • Lock and key • Reuptake • “Recycling” neurotransmitters Postsynaptic Neuron

14. Putting it together…

15. Neurotransmitters and Behavior (diagram) • Neurotransmitters regulate many aspects of behavior • An imbalance of neurotransmitters may cause maladaptive behavior • Neurotransmitters may be inhibitory, excitatory or both

16. Drugs and Neurotransmitters • Drugs’ impact on the body has helped scientists discover neurotransmitters, neuropeptides (e.g. amino acids such as endorphins) and neuromodulators that can increase or decrease the activity of certain neurotransmitters • How do drugs work? • Agonists mimic or prevent reuptake (1, 3) • Antagonists block neurotransmission (2)

17. Botulism Blocks release of ACh at the neuromuscular junction, causing paralysis “Botox” is botulism toxin used to prevent facial muscles from making wrinkles Curare – found in vines in S. America; used as poison Can stun or kill prey quickly Blocks ACh receptors causing paralysis Antipsychotic medications Block dopamine receptors Reduces schizophrenic hallucinations Caffeine Increases the release of excitatory neurotransmitters by blocking the inhibitory neurotransmitter adenosine Cocaine Prevents reuptake of dopamine Leads to heightened arousal of entire nervous system Psychopharmacology

18. The Nervous System (diagram)

19. The Autonomic Nervous System (diagram) • Fight-or-flight response • Sympathetic: Arouses • Parasympathetic: Calms

20. Central Nervous System Central Nervous System (CNS) Brain Spinal Cord • Brain • Enables all functioning • Billions of neurons and their connections • These neurons work together in neural networks to facilitate efficient output. • As we learn, these networks strengthen • Spinal Cord • Connects brain to PNS • Handles reflexes I rule.

21. The Endocrine System (diagram) Tell me about it! I hate being naked in front of all these students… • Helps coordinate and integrate complex psychological reactions • Endocrine glands secrete hormones into the bloodstream • Hormones serve to organize the nervous system and body • Hormones also activate behavior, such as sexual behavior, hunger and aggression

22. Thyroid gland Secretes hormones (primarily thyroxin) that control metabolism Hypothyroidism and Hyperthyroidism Pineal gland Sleep-wake cycle Secretes melatonin Pancreas Regulates blood-sugar levels Secretes insulin Diabetes? Pituitary gland Referred to as the “master gland” regulates many other glands Adrenal glands Reaction to stress Secretes adrenaline (epinephrine) Gonads Ovaries and testes secrete estrogens and androgens Dunno. Got diabeeetus? Endocrine Glands (diagram) diabeetusfetus

23. The Brain • Without our brains, we would really be nothing! • “The mind is what the brain does”

24. Studying the Brain • Studying the brain through lesions or damaged areas • “Ta” and Phineas Gage • Experiments in rats – hypothalamus lesions • Monitoring Electrical Activity: the EEG • Electroencephalograms provide information about cortical activity • Record electrical activity of neurons on surface of brain (neural firing) • A functional technique

25. Studying the Brain: Structural Neuroimaging Techniques • CT Scan (Computerized tomography) • Computer-assisted x-ray of brain • Used to create overall images of brain • MRI (Magnetic Resonance Imaging) • Produces detailed pictures of soft tissue in brain • Can focus on specific regions when CT cannot produce clear images CT scan (top) and MRI (bottom) showing a tumor.

26. Studying the Brain: Functional Neuroimaging Techniques • PET (positron emission tomography) • Image created by the rate at which radioactive glucose is metabolized • Which areas of the brain are active during a particular activity • fMRI (functional MRI) • Combines structural and functional techniques • Multiple images of brain created during a particular task • Records changes in blood flow to indicate regions of greater activity

27. Primitive Brain Structures • Brainstem • Oldest part of brain • Contains medulla, controlling heartbeat, blood pressure and breathing • Also contains pons, which helps regulate sensory information and facial expressions • Contains Reticular Formation (RF) for alertness/arousal, sleep/wakefulness • Thalamus • Pair of egg-shaped structures on top of brainstem • Routes all incoming sensory information except for smell to appropriate areas of brain • Cerebellum • “little brain” at read of brainstem • Controls coordination, balance, and muscle tone These parts of the brain are our “autopilot” so other regions can deal with higher-level “human” functions

28. The Limbic System • Located in between the primitive parts of the brain and the cerebral hemispheres • Hippocampus processes new memories (case of H.M.) • Amygdala controls emotions such as aggression and fear – in animals, the “attack” response (rat study) • Hypothalamus regulates hunger, thirst, body temperature and sex drive – also controls pituitary gland • Rat study – self-stimulation of “pleasure centers” • Human implications? Mild pleasure, addiction tendencies? • Primarily, the limbic system processes drives, smell and various emotional responses

29. The Cortex • Part of the cerebrum, the two large hemispheres comprising 85% of brain weight • Wrinkled outer layer • Why so convoluted? • Higher level functions • Designation of cortical space and “higher level” animals? • Most highly evolved part of the human brain

30. Cortex Breakdown… • Each hemisphere is divided into 4 lobes • Frontal lobe • Temporal lobe • Parietal lobe • Occipital lobe • The lobes are separated by deep convolutions known as fissures

31. Occipital Lobes Visual cortex Damage? Temporal Lobes Auditory cortex Auditory hallucinations? Parietal Lobes Primary sensoryorsomatosensory cortex Allocation of space? Frontal Lobes Most evolved Motor cortex, which allows us to move Allocation of space? Homunculous! Cortex Breakdown…

32. Motor and Sensory Cortex Revealed!

33. The Cortex: Association Areas • We only use 10% of our brains? • Undifferentiated cortex • Association areas

34. Phineas Gage: A Case Study in Frontal Lobe Association Area Damage • In 1848, railroad foreman Phineas Gage – accident! • No longer “himself” • Emotions, the frontal cortex, and the unchecked limbic system The skull of Phineas and rogue tamping iron, displayed proudly at Harvard University’s medical school! For real!

35. Neuroplasticity Shafted again. • Brain’s to change and reorganize as a result of experience • Mark Rosenzweig’s (1922-2009) Rat Studies (1950s-60s) • Implications for humans? Hey guys! Check out our phat crib! Party!

36. Neuroplasticity in Rats

38. Neurogenesis? • Recent evidence has suggested that human brains may be able to generate new brain cells, known as Neurogenesis • Stem cell research?

39. The Two Hemispheres • Two halves are NOT identical • Most have a dominant hemisphere – usually the left, which controls the right side of the body • Both sides serve important functions, revealed by studying split-brain patients

40. Split-Brain • Epilepsy, seizures and the corpus callosum • Reduction in epileptic seizures • Different abilities in each hemisphere • The story of “Vicki” • Michael Gazzaniga

41. Some Hemispheric Strengths • Left Hemisphere • Language in most people: The cases of Ta of Charles Landry • Logic • Right side of body • Right Hemisphere • Perception • Sense of self • Inferences

42. Hemispheric Dominance: Handedness • 90% of humans are right-handed • The 10% of left-handers show less predictable patterns of hemispheric dominance • Causes? • Genetics? • Fetal testosterone levels? • Learned? • Handedness and sexual orientation? • A closer look: a curse or an advantage?

43. Behavior Genetics:What’s the Point? • Behavior Genetics seeks to understand the relative influence of our heredity and our experiences • Nature vs. Nurture? It’s both – but how much of each?

44. Behavior Genetics:Genetics Review • Heredity examines the transmission of trait from one generation to next • Chromosomes • Pairs of thread like bodies that contain genes • Average human cell has 23 pairs • Sex cells? • Deoxyribonucleic acid (DNA) • Organic molecule arranged in a double-helix • Contains the “code of life” • Genes • Basic units of inheritance • Segment of DNA • Genome • “map” for an organism’s genetic complete make-up • Human Genome Project

45. Behavioral Genetics:Studying Nature vs. Nurture • Animal Studies • Strain Studies • Selection Studies • Human Studies • Identical Twins • Fraternal Twins • Separated Twins • Adoption Studies • Family studies

46. Behavioral Genetics:Temperament and Heritability • Temperament refers to emotional reactivity and seems to be set very early in life • Thomas and Chess (easy, difficult, slow-to-warm-up) • Kagan’s “shy child” • Indicates this aspect of behavior is genetically manipulated • Environment can enhance or diminish this genetic predisposition

47. Behavior Genetics: Heritability • Heritability: the extent to which differences among organisms are caused by genes • Does NOT refer to which percentage of a trait is determined by genetics in a given individual! • The more similar and controlled the environment of the organisms is, the more we can attribute differences to genes, and the higher the heritability!

48. So…Nature vs. Nurture…? • Genes and environment interact like “two hands clapping…” • Environment can trigger genetic “switches” • Our genes can provoke us to seek particular environments • e.g. Eating Disorders • Genetic predisposition (some are more susceptible than others) • Cultural regulation (Western culture) • Molecular Genetics • Studies how particular genes influence behavior • e.g. Is there a gene that determines obesity? Sexual orientation? • Promise and peril of molecular genetics? • Genetic engineering • Eugenics

49. Evolutionary Psychology • Whereas behavior geneticists seek to explain our behavioral differences in terms of our genes, evolutionary psychologists focus on our similarities, as dictated by natural selection. • Richard Dawkins The Selfish Gene (1976) • Varied organisms in a population compete to survive • Certain biological and behavioral variations facilitate survival • Surviving organisms may reproduce and pass on their genes • This leads to overall changing characteristics in a population

50. Evolutionary Psychology:Natural Selection, Adaptation and Evolutionary Success • Selection – providing a reproductive advantage, either naturally or artificially (e.g. tame foxes), based on a trait/set of traits • These traits will endure over time • Population will change as a result • Variation can result from mutations (errors in genetic replication right after conception) • Some of these “errors” provide an advantage and are selected for, and therefore persist • The errors are adaptive – increasing our fitness, or our chances to survive (and to reproduce) • Humans have so many shared characteristics – How? • Differences that were not “fit” were not passed on • Those that increased survival were, as these organisms lived and reproduced