Chapter 3 Biological Foundations of Behavior © 2011 The McGraw-Hill Companies, Inc.

Chapter Preview Nervous System Neurons Brain Endocrine System Damage, Plasticity, and Repair Genetics and Behavior Biological Foundations and Health and Wellness © 2011 The McGraw-Hill Companies, Inc.

Nervous System Neuroscience…study of the body’s electrochemical communication circuitry Characteristics of the nervous system complexity integration adaptability (plasticity) electrochemical transmission © 2011 The McGraw-Hill Companies, Inc.

Nervous System: Pathways Afferent Nerves carry information  spinal cord and brain Efferent Nerves carry information  muscles © 2011 The McGraw-Hill Companies, Inc.

Nervous System: Divisions Central Nervous System (CNS) brain and spinal cord Peripheral Nervous System (PNS) somatic nervous system – sensory nerves muscular activity autonomic nervous system – internal organs sympathetic nervous system – arouses parasympathetic nervous system – calms © 2011 The McGraw-Hill Companies, Inc.

Nervous System: Divisions © 2011 The McGraw-Hill Companies, Inc.

Nervous System - Cells Neurons Glial Cells information processing about 100 billion in brain mirror neurons (in primates) Glial Cells provide support and nutrition © 2011 The McGraw-Hill Companies, Inc.

Neurons: Structure cell body dendrites axon myelin sheath © 2011 The McGraw-Hill Companies, Inc.

Neurons: Structure © 2011 The McGraw-Hill Companies, Inc.

Neural Impulse Axons Resting Potential ions/ion channel negatively/positively charged semipermeable membrane polarization Resting Potential stable charge of an inactive neuron © 2011 The McGraw-Hill Companies, Inc.

Neural Impulse Action Potential depolarization (ion channel opens) repolarization ion exchange sweeps along length of axon all-or-none principle once initiated, cannot be stopped © 2011 The McGraw-Hill Companies, Inc. 11

Synapses and Neurotransmitters Synapse/Synaptic Gap space between sending axon’s terminal buttons and the receiving dendrite or cell body Synaptic Transmission electrical impulse is converted into a chemical signal axon vesicle releases neurotransmitter into gap dendrite receptor site detects neurotransmitter © 2011 The McGraw-Hill Companies, Inc.

Synapses and Neurotransmitters © 2011 The McGraw-Hill Companies, Inc.

Neurotransmitters Neurotransmitters carry information across the synaptic gap to next neuron. Acetylcholine muscle actions, learning, memory black widow venom ↑ Ach levels botox (botulin) ↓ Ach levels Alzheimer’s disease: ↓ Ach levels GABA anxiety: ↓ GABA levels © 2011 The McGraw-Hill Companies, Inc.

Neurotransmitters Glutamate Norepinephrine excitatory learning & memory involved in many psychological disorders Norepinephrine stress and mania: ↑ norepinephrine levels depression: ↓ norepinephrine levels regulates sleep states in conjunction with ACh © 2011 The McGraw-Hill Companies, Inc.

Neurotransmitters Dopamine voluntary movement reward anticipation stimulant drugs: activate dopamine receptors Parkinson’s disease: ↓ dopamine levels schizophrenia: ↑ dopamine levels © 2011 The McGraw-Hill Companies, Inc.

Neurotransmitters Serotonin Endorphins regulation of sleep, mood, attention, learning depression: ↓ serotonin levels prozac: ↑ serotonin levels Endorphins natural opiates mediate feelings of pleasure and pain © 2011 The McGraw-Hill Companies, Inc.

Neurotransmitters Oxytocin both a hormone and a neurotransmitter related to onset of lactation in new mothers related to attachment/emotional bonds Note: Drugs can interfere with neurotransmitters mimics or enhances NT effects blocks effects of NT © 2011 The McGraw-Hill Companies, Inc.

Neural Networks interconnected pathways of nerve cells integrate sensory input and motor output take years to develop a given piece of information embedded in multiple connections between neurons © 2011 The McGraw-Hill Companies, Inc.

Studying the Brain Brain Lesioning Electrical Recording naturally occurring or induced Electrical Recording electroencephalograph (EEG) single-unit recording © 2011 The McGraw-Hill Companies, Inc.

Brain Imaging X-Ray CT Scan PET MRI fMRI TMS © 2011 The McGraw-Hill Companies, Inc.

Brain: Structure and Function © 2011 The McGraw-Hill Companies, Inc. 22

Hindbrain Brainstem Cerebellum medulla – control breathing, regulate reflexes pons – sleep & arousal Cerebellum motor coordination © 2011 The McGraw-Hill Companies, Inc.

Brain: Structure and Function © 2011 The McGraw-Hill Companies, Inc. 24

Midbrain Substantia Nigra Reticular Formation Parkinson disease stereotyped behavior patterns like walking © 2011 The McGraw-Hill Companies, Inc.

Brain: Structure and Function © 2011 The McGraw-Hill Companies, Inc.

Forebrain Limbic System Thalamus memory and emotion amygdala - discrimination of objects needed for survival - emotional awareness and expression hippocampus - formation and recall of memories Thalamus relay station for much sensory information © 2011 The McGraw-Hill Companies, Inc.

Forebrain (cont’d) Basal Ganglia Hypothalamus coordination of voluntary movements Hypothalamus eating, drinking, sexual behaviors regulate body’s internal state emotion, stress, reward © 2011 The McGraw-Hill Companies, Inc.

Brain: Structure and Function © 2011 The McGraw-Hill Companies, Inc. 29

Cerebral Cortex Neocortex: outermost layer Four Lobes: occipital (vision) temporal (hearing, language processing, memory) frontal (intelligence, personality, voluntary muscles) parietal (spatial location, attention, motor control) © 2011 The McGraw-Hill Companies, Inc.

Cerebral Cortex © 2011 The McGraw-Hill Companies, Inc.

Somatosensory, Motor, and Association Cortex Somatosensoy Cortex (in parietal lobe) body sensations Motor Cortex (in frontal lobe) voluntary movements Point-to-Point Mapping Association Cortex (75% of cortex) not sensory or motor, but associations between © 2011 The McGraw-Hill Companies, Inc.

Split-Brain Research W.J., the Split Brain Patient Corpus Callosum Large bundle of axons that connects the two hemispheres of the brain W.J., the Split Brain Patient x X © 2011 The McGraw-Hill Companies, Inc.

Hemispheres of the Cortex Hemispheric Specialization of Function left hemisphere verbal processing, speech, grammar Broca’s Area Wernicke’s Area right hemisphere spatial perception, visual recognition, emotion © 2011 The McGraw-Hill Companies, Inc.

Endocrine System set of glands that regulate the body by secreting hormones into the bloodstream hormones = chemical messages relatively slow communication system interconnected with the nervous system pituitary, thyroid, parathyroid, adrenal glands, pancreas, ovaries, testes © 2011 The McGraw-Hill Companies, Inc.

Brain Damage and Plasticity Recovery from brain damage depends on age of the individual extent of the damage Repairing the damaged brain collateral sprouting substitution of function neurogenesis brain tissue grafts © 2011 The McGraw-Hill Companies, Inc.

Genetics and Behavior chromosomes, genes, and DNA dominant-recessive genes principle Besides the brain, many other aspects of ourselves affect our psychological functioning. We have trillions of cells. The nucleus of each cell contains 46 chromosomes 23 pairs of chromosomes with one of each pair coming from each parent. Chromosomes contain deoxyribonucleic acid, or DNA. DNA is the molecule that carries a person’s genetic information. Genes are the segments of chromosomes that are composed of DNA. Genes carry the heredity information of the individual. According to the dominant-recessive genes principle, if one of the genes of a pair is dominant over the other, the dominant gene resides over the recessive one. For example, if a person inherits the blue-eyed gene from his or her mother and the brown-eyed gene from the father and the blue-eyed gene is dominant, the person will have blue eyes. Other characteristics do not come from one specific gene. Polygenic inheritance describes how multiple genes influence other aspects of self like behavior, personality, intelligence, etc. © 2011 The McGraw-Hill Companies, Inc. 37

Genetics and Behavior molecular genetics selective breeding behavior genetics and adoption studies Gregor Mendel first started the research on genetics in the mid-nineteenth century when he studied heredity in pea plants by cross breeding them and seeing what the plant offspring looked like. He realized that some genes are more likely to show up in offspring. These are the dominant genes. Modern researchers use Mendel’s techniques to study genetics today. Molecular genetics involves the manipulation of genes. The term genome refers to the instructions for making an organism. Selective breeding occurs when organisms are chosen for reproduction based on how much of a particular trait they display. Research has been done with rats by breeding those good at running mazes and those not so good to see whether the offspring were good. Behavior genetics is the study of the degree and nature of heredity’s influence on behavior. In twin studies, behavior genetics studies the extent to which individuals are shaped by their heredity and the influence of the environment on them. The behavioral similarity of identical twins is compared to the behavioral similarity of fraternal twins. Identical twins are found to be consistently more similar so it seems likely that genes play a role in behavioral expression. Even in studies of twins reared apart they have found similarities which gives further evidence to show the role of genes in behavior. © 2011 The McGraw-Hill Companies, Inc. 38

Genes and the Environment Genotype – genetic heritage + the effects of experience = Phenotype – observable characteristics environment alters how genetic traits develop both physical & psychological characteristics genetic expression © 2011 The McGraw-Hill Companies, Inc.