BIOL178 Lecture 1 Summer24 PDF

BIOLOGY 178 HORMONES AND BEHAVIOR Instructor: April M. Arquilla Ph.D. Candidate in Evolution, Ecology, and Organismal Biology  Announcements Make sure to go to discussion tomorrow! My office hours: Tues/Wed. 11:00am-12:00pm (or by appt.) Except th...

BIOLOGY 178 HORMONES AND BEHAVIOR Instructor: April M. Arquilla Ph.D. Candidate in Evolution, Ecology, and Organismal Biology  Announcements Make sure to go to discussion tomorrow! My office hours: Tues/Wed. 11:00am-12:00pm (or by appt.) Except this week! Only Wed. office hours. 2  Outline of Today’s Lecture 1. Overview of Course & Introductions 2. Introduction to Behavioral Endocrinology 3. Levels of Analysis 4. Key Principles of Behavioral Endocrinology 5. Hormone-Behavior Interactions 6. Techniques in Behavioral Endocrinology 3  A Little Bit About Me… B.A. in Biology from the College of Wooster (Ohio) Past Research Interests: Role of vision in courtship behavior of spotted fruit flies (REU at KU) Potential coral snake mimicry of juvenile Clelia Clelia snakes in Costa Rica Salamander hybridization in Ohio 4 A Little Bit About Me… Research Interests: 7th-year Ph.D. Candidate in EEOB Males provide parental care in with Dr. Wendy Saltzman less than 10 % of mammalian species; the mechanisms underlying paternal care are not well understood. My studies examine the role of auditory communication between pups and parents Behavioral experiments Vocal analysis (pups) and auditory brainstem responses (parents) Neural activation of auditory brain regions in fathers 5 Overview of the Course  General Course Information Lecture slides will be posted under the module for each week (i.e., Week 1) Attendance at discussion is mandatory, including this week. No textbook. 7  General Course Information See syllabus for more information on: Exams: One midterm + final exam Consist of multiple choice, matching, fill-in-the-blank, and short- answer questions You may use 1 standard sheet of paper for notes as a “cheat sheet” but do not rely on it too much or you may run out of time! Online quizzes: Posted each Monday; due each Friday at 11:59 pm Help is available at office hours, but go through the questions on your own beforehand If you have trouble submitting answers on Canvas, email them to me by the deadline. 8  General Course Information See syllabus for more information on: Discussion and Active Learning exercises: Active-learning exercise: work in small groups. Any questions? Contact your TA. Final project: Annotated bibliography; due 7/24 by 11:59pm Follow the instructions carefully! Instructions will be posted today 9  General Course Information Point distribution: Midterm 100 Final 125 Final Project 30 Online quizzes 30 Discussion 70 Total 355 Grade cutoffs will be on a straight (90/80/70/60) scale or lower (easier). 10  Learning Objectives By the end of today’s lecture, you should be able to… 1. Explain what types of questions the field of behavioral endocrinology addresses and describe the first experiment performed in this field. 2. List and define the four major levels of behavioral analysis. 3. Describe the major types of mechanisms by which hormones and behavior can influence one another. 4. Describe the common techniques used and what type of question each one addresses. 5. Explain and give examples of 8 key principles of this field. 11 Introduction to Behavioral Endocrinology  Intro to Behavioral Endocrinology What is it? The study of the interaction between hormones and behavior Interdisciplinary & highly integrative between systems Comparative (most studies are on non-human animals) 13  Intro to Behavioral Endocrinology Why study it? Important for understanding the relationship between hormones, animal behavior, and physiology Important for understanding hormonal function in humans; it impacts every aspect of human health! Relevant to clinical and public-policy issues Ex: Endocrine-disrupting chemicals that leak into the environment often cause issues in wild populations of animals It’s really, really interesting! 14  Behavioral Endocrinology & Human History Castration traditionally served many religious, social, or agricultural functions Eunuchs Italian castrato 15  History of Behavioral Endocrinology Berthold (1848): first formal experiment in behavioral endocrinology Illustrates a classic approach for the field: removal and replacement of the source of a hormone Illustrates a classic focus of the field: examining sex differences in behavior Rooster Capon - male chicken that (testes has been castrated (testes intact) removed) before adulthood 16  History of Behavioral Endocrinology Berthold (1848 cont.) Implanted testes Attached to intestines Developed vascular supply (but not neural connections) Produced sperm 17  History of Behavioral Endocrinology Berthold (1848 cont.) Conclusion: Showed that a blood-borne substance from the testes affected morphology and behavior 18 Levels of Biological Analysis: allow us to consider multiple, complementary explanations for the same behavior  Levels of Analysis A. Ultimate Causation 1. Evolution Evolutionary history “Why” 2. Adaptive Function questions Current utility B. Proximate Causation 1. Ontogenetic Development During individual’s lifetime “How” questions 2. Immediate Causation Physiological, neural, sensory mechanisms 20  Levels of Analysis Example: Why Do Male Zebra Finches Sing? A. Ultimate Causation 1. Evolution All finches sing Finches evolved from a common ancestor that sang 2. Adaptive Function Singing is used in courtship and territorial displays Singing allows males to rear more offspring by attracting females to territory and excluding rival males 21  Levels of Analysis Example: Why Do Male Zebra Finches Sing? B. Proximate Causation 1. Ontogenetic Development Young males learn to sing by hearing adult males sing and then practicing their own song 2. Immediate Causation A series of nuclei in the brain controls singing behavior If testosterone is present, cues from females or rival males activate song-control system in the brain 22  Important Principles of Behavioral Endocrinology  Key Principles of Behavioral Endocrinology 1. Hormones don’t cause behavior - they alter probabilities that behaviors will be expressed under certain conditions. 24  Key Principles of Behavioral Endocrinology 2. Hormones and behavior have bi-directional effects. 25  Key Principles of Behavioral Endocrinology 3. Hormones often exert complementary effects on the brain and the body. Testosterone Oxytocin Antler Aggressive Milk Maternal growth motivation release motivation 26  Key Principles of Behavioral Endocrinology 4. Hormone-behavior interactions are often - but not always - mediated by the central nervous system. 27  Key Principles of Behavioral Endocrinology 5. Linear and non-linear relationships can exist between hormones and behavior. 28  Key Principles of Behavioral Endocrinology 6. Hormone-behavior correlation does not prove causation. 29  Key Principles of Behavioral Endocrinology 7. Both immediate and previous (developmental) exposure to hormones can influence behavior. 8. Hormone-behavior interactions may differ between and within species. 30 Hormone-Behavior Interactions  Criterion for Demonstrating Hormonal Influences on Behavior 1. Remove/block hormone → behavior changes 2. Replace hormone/restore function → behavioral change is reversed 3. Hormone and behavior correlate to some extent. 32  How Can Hormones Affect Behavior? 1. Input systems Sensory systems 2. Integrators Central nervous system 3. Output systems (effectors) Muscles, motor neurons, scent glands, etc. 4. Socially mediated effects Hormones in one individual can cause behavioral, morphological, or physiological changes that affect other animals’ behavior. 33  Example: How Can Testosterone Affect Male Sexual Behavior in Rats? 1. Input (sensory) systems Tactile receptors on penis 2. Integrators (central nervous system) Actions on brain to  libido 3. Output systems (muscles & other effectors) Bulbocavernosus muscle – penile erections 4. Socially mediated effects Male’s testosterone levels can affect females’ sexual behavior toward him. 34  How Can Behavior Affect Hormones? 1. Actions on the central nervous system a) Reflexes Suckling → oxytocin release b) “Psychologically mediated” effects Psychological stress  neural activity in forebrain → cortisol, epinephrine release 2. Metabolic effects Eating →  blood glucose → insulin release 3. Immunologically mediated effects Fighting → wounding → activation of immune system → → →  cortisol release 35  Example: How Can Social Subordination Lead to High Levels of Cortisol? 1. Actions on the brain Psychological stress, defeat, lack of control, lack of predictability 2. Metabolic effects Increased physical activity, altered food intake 3. Immunologically mediated effects Increased wounding 36 What techniques are used in behavioral endocrinology?  Technique #1: Ablation and Replacement What are the effects of a hormone? a) Surgically remove or destroy (ablate) gland - Observe behavioral effects of removal - Similar to what Berthold employed in his capon studies b) Replace hormone - Determine whether replacement reverses the consequences of ablation (Also, “experiments of nature” = naturally occurring deficiencies in hormone secretion or function, such as aging, menopause, etc. can give us helpful correlative informtion) 38  Technique #2: Pharmacological Techniques What are the effects of a hormone? A. Agonists Mimic hormone action Most are receptor agonists – bind to and activate the receptors for a particular hormone B. Antagonists Block hormone action Most are receptor antagonists – bind to and block receptors for a particular hormone 39  Techniques in Behavioral Endocrinology Hormones can be measured in… ―Blood (plasma or serum) ―Urine ―Feces ―Saliva ―Hair ―Tissues Different techniques can be used to measure concentrations of… ―Biologically active hormones ―Immunologically active hormones 40  Technique #3: Bioassays How much biologically active hormone is in a sample? Uses a live animal (in vivo) or animal tissue (in vitro) to determine the biological activity of a hormone or sample Bioassay can be conducted on alternate species from which a hormone has been derived “The Rabbit Test” is a famous example of bioassay involving two different species. This was developed in the late 1920’s and was used to detect human pregnancies until the late 1950’s. Human female urine injected into immature female rabbits Rabbit ovaries developed if hCG (pregnancy hormone) was present. 41  Technique #4: Immunoassays How much immunologically active hormone is in a sample? a) Radioimmunoassay (RIA) Plasma testosterone levels in prairie voles (monogamous, biparental) and meadow Use radioactivity to measure hormone- voles (promiscuous, uniparental) antibody binding b) Enzyme-linked immunosorbent assay (ELISA) -Antibody is labeled with enzyme -Use enzymatic reaction to measure hormone- antibody binding via color change 42  Technique #5: Immunohistochemistry (IHC) Where is a hormone (or receptor) located? Antibody bound to dye is applied to tissue Determines location of antigen (hormone) CRH-containing neurons in prairie vole (A,C) and meadow vole (B,D) brain (Lim et al., 2006) 43  Technique #6: In situ hybridization Is expression of a particular gene occurring in a tissue? cDNA or cRNA is applied to a tissue as a probe for a specific mRNA Hybridization of probe to mRNA is detected by radioactivity or fluorescence Urocortin-1 mRNA in brains of prairie voles (A) and meadow voles (C) (Lim et al., 2006) 44  Technique #7: DNA Microarrays Which genes are expressed in a tissue? Chip contains thousands of specific cDNA probes Expose chip to tissue sample mRNA from tissue sample hybridizes with probes Hybridization is detected by fluorescence from www.gene-chip.com 45  Technique #8: Autoradiography Where are the receptors located? Vasopressin receptors in the ventral Radiolabeled hormone is applied to tissue pallidum of prairie voles (a,e) and meadow voles (b,f) (Lim et al., 2004) 46  Technique #9: Genetic Manipulations What are the long-term effects of a specific gene? a. Knockouts Organisms with specific genes deleted Permanent method of gene silencing b. Knockdowns Expression of vasopressin receptors in Organisms with expression of specific genes reduced ventral pallidum of meadow voles following viral-vector-mediated gene Temporary method of gene silencing transfer (a) or control procedure (b) (Lim et al., 2004) c. Transgenics Organisms with specific genes inserted 47  Technique #10: Brain Lesions What is the function of a brain region? Destroy part of brain and determine the effect on behavior (or some other measure) Can be done surgically, chemically, or electrically Not done on humans (anymore) for obvious reasons… 48  Technique #11: Optogenetics What is the function of a group of neurons? Involves the use of light to activate or deactivate groups of neurons with high temporal and spatial resolution. These neurons are rendered sensitive to light of a specific wavelength by genetically engineered viral vectors carrying genes encoding light-sensitive ion channels, called opsins. 49 End of Lecture 1 50