Biopsychology Course Outline - PSYC 222

Welcome to Biopsychology PSYC 222 Expectations Attendance is mandatory Tracked on MyCourses 9 absences (twice a week classes) or 11 absences (three times a week classes) will result in an ”F” Use of laptops is mandatory...

Welcome to Biopsychology PSYC 222 Expectations Attendance is mandatory Tracked on MyCourses 9 absences (twice a week classes) or 11 absences (three times a week classes) will result in an ”F” Use of laptops is mandatory Classwork, assessments and exams will be done on a device. Keep cellphones on silent and out of sight (except for when used for activities) Drinks allowed; foot not allowed Expectations Use of artificial intelligence Any AI tool may be used as a tool. Do not plagiarize. Submissions must be your own words. Plagiarism will be reported to the university and result in disciplinary action. Course requirements Lecture material Presentations, videos and activities available on MyCourses. Resources Cengage Textbook - mandatory Laptop - mandatory Platforms MyCourses: lecture material, course information, attendance, grades Cengage: textbook, homework assignments, activities Assessments Homework Assignments 5 activities; 30 min Worth 10% of your course grade Accessible through Cengage In-class Assignments 5 pair/group assignments Worth 10% of your course grade Original submission assignments Quizzes and Exams 5 quizzes (top 4); worth 20% 1 midterm; worth 30% 1 final exam; worth 30%  Detail of assessments ASSESSMENT TYPE QUANTITY VALUE WEIGHT DETAILS Homework Assignment 5 2 10 Completion grade Quizzes 4 5 20 Score grade 5 offered; lowest dropped In-class Assignments 5 2 10 Completion grade Midterm 1 30 30 Score grade Final 1 30 30 Score grade Total 100 Course structure Study Guides Introduction All psychology is biological. Cultural, social, and cognitive influences, genetics, evolution, hormones, body physiology, and brain mechanisms. Biological psychology is the study of the evolutionary and developmental mechanisms of behavior and experience. Biological Explanations of Behavior Biological explanations of behavior fall into four categories: Physiological: relates a behavior to the activity of the brain and other organs. Ontogenetic: describes how something develops Evolutionary: reconstructs the evolutionary history of a structure or behavior Functional: describes why a structure or behavior evolved as it did Neuroethics (1 of 3) Several ethical disputes resist agreement. Among those issues are abortion and the use of animals in research. Why do biological psychologists study nonhumans? Many of the mechanisms of behavior are similar across species, and sometimes they are easier to study in a nonhuman species. We are interested in animals for their own sake. What we learn about animals sheds light on human evolution. Legal or ethical restrictions prevent certain kinds of research on humans. Neuroethics (2 of 3) The legal standard emphasizes “the three Rs”: Reduction of animal numbers (using fewer animals) Replacement (using computer models or other substitutes for animals when possible) Refinement (modifying the procedures to reduce pain and discomfort). Neuroethics (3 of 3) Research with humans raises different types of ethical concerns. Sometimes a patient undergoing surgery is invited to participate in a study. A successful procedure may have negative effects. Most research has been done in North America or Europe, and most studies of humans have used relatively prosperous people, mostly people of European ancestry, not a representative sample of all humanity. Santiago Ramón y Cajal, a Pioneer of Neuroscience In the late 1800s, the Spanish investigator Santiago Ramón y Cajal (1852–1934) was the first to demonstrate that the individual cells comprising the nervous system remained separate. Golgi stains could help identify each, unique, individual neural cell. Golgi believed the nervous system was one, long connected system. Cajal used Golgi stain methods to identify separate cells. Check your knowledge Central nervous system Interneuron Repolarization Peripheral nervous system Dendrite Hyperpolarization Somatic Axon Refractory period Autonomic Axon terminal Sympathetic Myelin sheath Parasympathetic Resting potential Motor neuron Action potential Sensory neuron Depolarization The Structures of an Animal Cell (1 of 2) Like other cells in the body, neurons contain the following structures: Membrane Nucleus Mitochondria Ribosomes Endoplasmic reticulum The Structures of an Animal Cell (2 of 2) Membrane: separates the inside of the cell from the outside environment Nucleus: contains the chromosomes Mitochondrion: performs metabolic activities and provides energy that the cells requires Ribosomes: sites at which the cell synthesizes new protein molecules Endoplasmic reticulum: network of thin tubes that transports newly synthesized proteins to their location Neurons (1 of 4) Compared to other cells, the most distinctive feature of neurons is their highly variable shape. Neurons (2 of 4) Motor neuron Has its soma in the spinal cord Receives excitation from other neurons Conducts impulses along its axon to a muscle or gland Interneuron Connects motor and sensory neurons Sensory neuron Is specialized at one end to be highly sensitive to a particular type of stimulation (touch, light, sound, etc.) Neurons (3 of 4) An afferent axon brings information into a structure. An efferent axon carries information away from a structure. Glial cells Astrocytes pass chemicals back and forth between neurons and blood Microglia remove waste material, viruses, and fungi from the brain as well as dead, dying, or damaged neurons Oligodendrocytes (in the brain and spinal cord) and Schwann cells (in the periphery of the body) build the myelin sheath that surrounds and insulates certain vertebrate axons Radial glia guide the migration of neurons and the growth of their axons and dendrites during embryonic development The Blood–Brain Barrier A mechanism that surrounds the brain and blocks most chemicals from entering The immune system destroys damaged or infected cells throughout the body. Because neurons in the brain generally do not regenerate, it is vitally important for the blood–brain barrier to block incoming viruses, bacteria, or other harmful material from entering. Active transport is used to pump necessary chemicals, glucose, hormones, amino acids etc. into the brain Nourishment of Vertebrate Neurons Vertebrate neurons depend almost entirely on glucose. A sugar that is one of the few nutrients that can pass through the blood–brain barrier Allows visualization via PET scans Neurons need a steady supply of oxygen. Twenty percent of all oxygen consumed by the body is used by the brain. Allows visualization via MRI scans Action potential The Resting Potential of the Neuron Messages in a neuron develop from disturbances of the resting potential. At rest, the membrane maintains an electrical gradient known as polarization. A difference in the electrical charge inside and outside of the cell The inside of the membrane is slightly negative with respect to the outside (approximately −70 millivolts). The resting potential of a neuron refers to the state of the neuron prior to the sending of a nerve impulse. Forces Acting on Sodium and Potassium Ions The membrane is selectively permeable, allowing some chemicals to pass more freely than others. Sodium, potassium, calcium, and chloride pass through channels in the membrane. When the membrane is at rest: Sodium channels are closed (for exit but can enter the cell passively down the concentration gradient). Potassium channels are partially closed allowing the slow passage of potassium. Ion Channels The sodium–potassium pump is a protein complex. Continually pumps three sodium ions out of the cells while drawing two potassium ions into the cell Helps to maintain the electrical gradient Uses active transport (requires ATP) The electrical gradient and the concentration gradient—the difference in distributions of ions—work to pull sodium ions into the cell. The Action Potential The resting potential remains stable until the neuron is stimulated. Threshold All-or-none law Depolarization Repolarization Depolarize Repolarize Hyperpolarization Absolute refractory period Relative refractory period Threshold Resting potential Hyperpolarize The Action Potential The Molecular Basis of the Action Potential The chemical events behind the action potential make sense if you remember three principles: At the start, sodium ions are mostly outside the neuron, and potassium ions are mostly inside (due to the active transport via the sodium-potassium pump). Depolarizing the membrane opens the sodium and potassium channels (voltage-gated channels), drawing these positive ions into the cell. At the peak of the action potential, the sodium channels close (become inactive). Propagation of the Action Potential In a motor neuron, the action potential begins at the axon hillock (a swelling where the axon exits the soma). Propagation of the action potential: the transmission of the action potential down the axon The action potential does not directly travel down the axon. After an action potential, a neuron has a refractory period during which time the neuron resists the production of another action potential. The absolute refractory period The relative refractory period Propagation of an action potential The Myelin Sheath and Saltatory Conduction The myelin sheath of axons are interrupted by short unmyelinated sections called nodes of Ranvier. Myelin is an insulating material composed of fats and proteins. At each node of Ranvier, the action potential is regenerated by a chain of positively charged ions pushed along by the previous segment. The “jumping” of the action potential from node to node Provides rapid conduction of impulses