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Our Genetic Inheritance Neural Bases of Behavior Nervous System Organization A Tour Through the Brain © 2014 John Wiley & Sons, Inc. All rights reserved.

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Presentation on theme: "Our Genetic Inheritance Neural Bases of Behavior Nervous System Organization A Tour Through the Brain © 2014 John Wiley & Sons, Inc. All rights reserved."— Presentation transcript:

1 Our Genetic Inheritance Neural Bases of Behavior Nervous System Organization A Tour Through the Brain © 2014 John Wiley & Sons, Inc. All rights reserved. Chapter two Neuroscience and Biological Foundations

2 realworldpsychology © 2014 John Wiley & Sons, Inc. All rights reserved. Things You’ll Learn in Chapter 2 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q5Q5 Can our genes influence whom we vote for in presidential elections? Why can spending the first few months of life in an orphanage lead to long-term problems in cognitive functioning? How can a chemical in the brain lead rats to binge-eat M&Ms? How can stem cell injections lead to restored vision and improved recovery from strokes? Why are former NFL athletes at increased risk of depression, dementia, and suicide?

3 OUR GENETIC INHERITANCE © 2014 John Wiley & Sons, Inc. All rights reserved.

4 The study of how heredity and environment affect us Evolutionary psychology = the application of principles of evolution to explain behavior and mental processes Genes control the transmission of traits Modern research shows most human characteristics are polygenic (controlled by multiple genes, not merely one dominant or two recessive genes) Behavior Genetics © 2014 John Wiley & Sons, Inc. All rights reserved. Most serious genetic disorders are not transmitted by dominant genes. Why?

5 realworldpsychology Most people understand that genes affect our health, such as potential for heart disease, diabetes, and cancer Genes also affect our personality traits, behavioral habits, sexual orientation, and psychological disorders Genes can even influence which political party we side with, and our views on death penalty, unemployment, and abortion (Hatemi & McDermott, 2012) © 2014 John Wiley & Sons, Inc. All rights reserved. Can our genes influence whom we vote for in presidential elections? Q1Q1

6 Environmental factors – both physical and psychological – also influence our characteristics Malnourished children may not reach their full potential genetic height or maximum intelligence Gene-Environment Interaction © 2014 John Wiley & Sons, Inc. All rights reserved.

7 Identical twins share all their genes, fraternal twins share about half of their genes (just like non-twin siblings) Twins raised together by birth parents share the same environment Identical twins should be more alike than fraternal twins (such as in intelligence) Research on adoptive children can trace characteristics to birth parents vs. adoptive parents Research shows many psychological traits (and disorders) run in biological families Genes vs. Environment © 2014 John Wiley & Sons, Inc. All rights reserved. How can psychologists separate genetic causes from environmental causes?

8 Heritability = the percentage of variation in a population attributable to heredity – If no genetic influence, heritability would be 0% – If no environmental influence, heritability would be 100% Heritability does NOT apply to INDIVIDUALS Heritability does not trump environment Heritability © 2014 John Wiley & Sons, Inc. All rights reserved.

9 Many behaviors emerged and still exist because they helped our ancestors survive Natural selection = particular genetic trait gives an organism a reproductive advantage “Reproduction of the fittest,” not “survival of the fittest” Evolutionary Psychology © 2014 John Wiley & Sons, Inc. All rights reserved.

10 NEURAL BASES OF BEHAVIOR © 2014 John Wiley & Sons, Inc. All rights reserved.

11 Building blocks of brain and nervous system: Neurons = responsible for receiving, processing, and transmitting electrochemical information Glial cells = provide structure, nutrition and other support to neurons The Basics © 2014 John Wiley & Sons, Inc. All rights reserved.

12 Dendrites = branching fibers that receive impulses from other neurons and send them to the cell body Cell body = AKA soma, contains cell nucleus Axon = long, tube-like structure that sends impulses away from cell body to other neurons (or to muscles, glands) Parts of a Neuron © 2014 John Wiley & Sons, Inc. All rights reserved.

13 Action Potential © 2014 John Wiley & Sons, Inc. All rights reserved.

14 Sequence of depolarization and repolarization moves the action potential from the cell body to the axon terminal buttons like the “wave” Action Potential © 2014 John Wiley & Sons, Inc. All rights reserved.

15 Electricity moves 36 million meters/second Nerve impulses move 10 meters/second Nerve impulses move 10x faster through axons with myelin sheath Speed of Thought Social isolation during early weeks/months of life (as for babies in orphanage) prevents proper growth of myelin, leading to long-term cognitive impairment © 2014 John Wiley & Sons, Inc. All rights reserved. Why can spending the first few months of life in an orphanage lead to long-term problems in cognitive functioning? Q2Q2

16 Communication WITHIN neuron is electrical, but communication BETWEEN neurons is chemical Sending neuron gets close to receiving neuron at synaptic gap, where neurotransmitters (chemicals) cross the gap to deliver the message Communication Between © 2014 John Wiley & Sons, Inc. All rights reserved.

17 How Neurotransmitters Work Reuptake © 2014 John Wiley & Sons, Inc. All rights reserved.

18 Lock and Key © 2014 John Wiley & Sons, Inc. All rights reserved.

19 Common Neurotransmitters © 2014 John Wiley & Sons, Inc. All rights reserved.

20 Common neurotransmitter elevate mood, reduce pain Opium-based drugs mimic the body’s natural endorphins Endorphins Endorphins affect memory, learning, appetite, and sexual activity. Rats injected with endorphins ate 5% of their body weight in M&Ms! © 2014 John Wiley & Sons, Inc. All rights reserved. How can a chemical in the brain lead rats to binge-eat M&Ms? Q3Q3

21 Endocrine system = network of glands located throughout the body that secretes hormones into the bloodstream Neurons send messages to certain receptors; hormone messages are carried by the blood to any cell that will listen Regulates and maintains long-term body processes, such as growth, sexual characteristics, digestion, and elimination Controls response to emergencies: adrenal glands release cortisol, epinephrine, and norepinephrine Hormones & the Endocrine System © 2014 John Wiley & Sons, Inc. All rights reserved.

22 NERVOUS SYSTEM ORGANIZATION © 2014 John Wiley & Sons, Inc. All rights reserved.

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24 CNS is powerful, but fragile Neuroplasticity = brain can reorganize its functional structure due to usage and experience Central Nervous System (CNS) Neurogenesis = lost cells can be replaced by neural stem cells (rare immature cells that can migrate and grow into any type of cell). No cell transplant for spinal cord injuries in humans, but animal research shows stem cell treatment leads to improvement in paralyzed limbs © 2014 John Wiley & Sons, Inc. All rights reserved. How can stem cell injections lead to restored vision and improved recovery from strokes? Q4Q4

25 Relays AND initiates vital information to other parts of the body Reflexes = automatic behavior in response to stimuli Allows immediate action without delay of routing through brain Spinal Cord What is the evolutionary benefit of the reflex arc? © 2014 John Wiley & Sons, Inc. All rights reserved.

26 Newborn Reflexes © 2014 John Wiley & Sons, Inc. All rights reserved. Rooting reflex – Lightly stroke the cheek and watch how the infant automatically (reflexively) turns toward the stimulation and attempts to suck Grasping Reflex – Place your finger or an object in the infant’s palm and note the automatic grasp Babinski Reflex – Lightly stroke the sole of the foot, and the big toe will move toward the top, while the other toes fan out. A B C

27 The part of the nervous system outside the brain and spinal cord Carries information to and from the CNS Links brain and spinal cord to body’s sense receptors, muscles and glands – Somatic nervous system (SNS): carries sensory information to the brain and instructions back to skeletal muscles – Autonomic nervous system (ANS): responsible for involuntary tasks like heart rate, digestion, and breathing Peripheral Nervous System (PNS) © 2014 John Wiley & Sons, Inc. All rights reserved.

28 Sympathetic division: mobilizes energy to respond to stressor (fight or flight) Parasympathetic division: calms body to conserve energy, returns body to normal functioning after stress Autonomic Nervous System © 2014 John Wiley & Sons, Inc. All rights reserved.

29 A TOUR THROUGH THE BRAIN © 2014 John Wiley & Sons, Inc. All rights reserved.

30 Biological Tools for Research

31 © 2014 John Wiley & Sons, Inc. All rights reserved. Biological Tools for Research (cont.)

32 Forebrain © 2014 John Wiley & Sons, Inc. All rights reserved. Limbic System – The interconnected group of forebrain structures involved with emotions, drives, and memory, as well as major physiological functions Cerebral Cortex– The thin surface layer that regulates most complex behavior (i.e. sensations, motor control).

33 Limbic System © 2014 John Wiley & Sons, Inc. All rights reserved. Hippocampus– Seahorse shaped part of the limbic system involved in forming and retrieving memories Amygdala– Part of the limbic system that controls emotions, like aggression and fear.

34 realworldpsychology Cerebral cortex = surface layer of the brain Responsible for most complex behaviors and higher mental processes Damage to cerebral cortex linked to substance abuse, dementia, and suicide Trauma is particularly common in contact sports, like football, ice hockey, boxing, and soccer © 2014 John Wiley & Sons, Inc. All rights reserved. Why are former NFL athletes at increased risk of depression, dementia, and suicide? Q5Q5

35 Lobes © 2014 John Wiley & Sons, Inc. All rights reserved.

36 realworldpsychology In 1848, 25-year-old railroad worker Phineas Gage had a metal rod accidentally blown through the front of his face, destroying much of his brain’s frontal lobe Experienced drastic personality changes; became impatient and lacked concern for coworkers He eventually obtained a job driving a stagecoach, which required high motor, cognitive, and interpersonal skills What does modern research about neuroplasticity tell us about Gage’s possible recovery? © 2014 John Wiley & Sons, Inc. All rights reserved.

37 Each hemisphere controls the opposite site of the body Corpus callosum = thick band of nerves, connects the two hemispheres Although each side of the brain might have a specialty (like Broca’s area for speech in the left hemisphere), when specific regions of the brain are injured or destroyed their functions can be assumed by neighboring region – or even opposite hemisphere Two Brains in One? © 2014 John Wiley & Sons, Inc. All rights reserved.

38 realworldpsychology Popular myth says left brain is analytical and right brain manages creativity Research shows both hemispheres work together in an integrated manner, like teammates playing soccer; each area might have specialties, but everyone knows what the other is doing and can help when needed © 2014 John Wiley & Sons, Inc. All rights reserved.

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