Neuropsychology & Philosophy: Descartes, Spinoza, & Modern Psychology - Prof. John Salamon, Study notes of Psychology

Download Neuropsychology & Philosophy: Descartes, Spinoza, & Modern Psychology - Prof. John Salamon and more Study notes Psychology in PDF only on Docsity! SECTION I. 1.1 History of Psychology Origins of Psychology - philosophy - medicine/physiology Early German Psychologists: Psychology is.. “Geisteswissenschaft” “Naturewissenschaft” “Social Science” “Natural Science” PSYC 1100 is an Introduction to Psychology as a Natural Science HISTORICAL INFLUENCES: ANCIENT GREEKS & BEYOND - “psyche” is a Greek word; referring to “mind” and “soul” Ancient Greek philosophers discussed topics of interest to psychologists - memory - acquisition of knowledge - importance of temporal contiguity Ancient Greek physicians also made advances in medicine. In the middle ages, Arab physicians preserved many of the ancient Greek writings, developed more advanced medical techniques. EMERGENCE OF MODERN SCIENCES - PHYSICS: discoveries and theories in physics revolutionized how people viewed their physical world - CHEMISTRY: the science of chemistry helped people understand the chemical composition of their surroundings However…. in order to have a science of psychology, people needed to think about living beings, and their behavior, in scientific terms. PHILOSOPHICAL DEVELOPMENTS: DUALISM VS. MONISM DESCARTES - mind/body “dualism” - body operates according to mechanical principles - mind is separate from body, interacts with body through the pineal gland SPINOZA - mind/body “monist” - mind and body are two different aspects of the same phenomenon - established a philosophical basis for much of psychology and neuroscience FURTHER PHILOSOPHICAL DEVELOPMENTS: BRITISH EMPIRICISTS AND ASSOCIATIONISM (e.g. Locke and Hume) - emphasized sensory experience as the basis of knowledge - emphasized that sensory experiences could be associated or lined; suggested “Laws of Association” - one of these was the Law of temporal contiguity DEVELOPMENTS IN PHYSIOLOGY AND MEDICINE - Physiology views organisms as functioning according to physical, chemical and mechanical principles - Harvey; basis of circulation.. heart acts as a pump - Studies of physiology helped to change the way life science was viewed; various functions, including psychological functions, began to be viewed as scientific phenomena PSEUDOSCIENCE and SCIENCE - The pseudoscience of Phrenology assumed that different brain areas had different functions, but erroneously linked bumps on the head to made-up functions. Nevertheless, it did popularize the idea that there was localization of function in the brain. - Scientific Studies of Brain Function… medical scientists came to understand how different parts of the brain performed different functions, including psychological functions such as language, or aspects of behavior - e.g. case of Phineas Gage DEVELOPMENT OF SCIENTIFIC PSYCHOLOGY - sensory physiologists started to study perceptual phenomena in laboratories - Wilhelm Wundt established the first psychology laboratory in 1879 - Wilhelm Wundt and William James wrote influential psychology textbooks - Ivan Pavlov studied the physiology of reflexes, later discovered basic mechanisms of learning (i.e., “conditioning”) 1.2 The Individual Neuron and the Organization of the Nervous System Several organ systems are important for biological basis of psychology - motor, digestive, endocrine - nervous system is particularly important The first few weeks of class will focus upon the relation between nervous system function and psychology. To begin, we will focus upon the individual nerve cell, or “neuron”. Neurons: Neurons are nerve cells, the basic cellular units of the nervous system Parts of the neuron: - soma - dendrite - axon (can be covered with myelin) - terminal Neurons are electrically and chemically active - electrical activity, “action potentials” - chemical signaling, release of chemicals on other neurons THE SYNAPSE The SYNAPSE is the point of functional connection between two neurons. There is a gap called the synaptic cleft, which separates two neurons. Most neurons communicate to each other by releasing chemical signals known as neurotransmitters. Neurotransmitters are released from the terminals of the presynaptic neuron when an action potential reaches the terminal. The neurotransmitter diffuses across the synapse to act on the postsynaptic membrane of the second cell. The postsynaptic cell then transduces this chemical activity into some type of metabolic or electrical change. ORGANIZATION OF NERVOUS SYSTEM Central Nervous System (CNS) - brain - spinal cord Peripheral Nervous System (PNS) - Axons, terminals and cell bodies in the rest of the body, including sensory, motor and autonomic systems AGGREGATIONS OF CELLULAR COMPONENTS Aggregations of cell bodies (somata): Nucleus (CNS) Ganglion (PNS) Sometimes called “gray matter” Bundles of axons: Tract (CNS) Nerve (PNS) Sometimes called “white matter” 1.3 METHODS FOR STUDYING RELATION BETWEEN PSYCHOLOGICAL AND NERVOUS SYSTEM FUNCTIONS LESION METHOD: study effects of tissue damage - clinical - experimental RECORDING METHODS Electrical recording - EEG (electroencephalograph), records fluctuations in electrical activity, useful for sleep and epilepsy research - evoked potential (or ERP), an EEG response evoked by a stimulus - single neuron recording, records action potentials from individual neurons Chemical recording - microdialysis - sampling of cerebrospinal fluid DRUGS - study how drugs, which cause neurochemical changes, affect behavior IMAGING METHODS 1.6 Neurophysiology, Neurochemistry and Drug Action Neurons are… -electrically active - chemically active Neurons transduce information - sensory information - chemical signals from other neurons Neurons also transmit information - neurons are electrically active - electrical impulses are generated in response to stimulation - chemical signals are sent to other neurons ELECTRICAL ACTIVITY OF NEURONS: RESTING MEMBRANE POTENTIAL At rest, inside of nerve cell membrane is about… - 70 mV relative to the outside IMPORTANT IONS FOR ELECTROPHYSIOLOGY OF NEURONS Anions (-) Cations (+) SODIUM- Na+ POTASSIUM- K+ CHLORIDE- Cl- CALCIUM- Ca++ FORCES THAT MOVE IONS 1. Movement along a chemical gradient (from area of high concentration to area of low concentration). i.e. diffusion 2. Movement along an electrical gradient (like charges repel, opposite charges attract). MEMBRANE-BOUND PROTEINS CHANNELS- pores that open or close, allowing ions to pass through RECEPTORS- detect the presence of the neurotransmitters; transmitters bind to their receptors ENZYMES- biological catalysts that promote chemical reactions; they synthesize transmitters and intracellular signals known as “second messengers” TRANSPORT MECHANISMS- pump substances across the membrane; e.g. “sodium pump” or “sodium-potasium pump” RESTING MEMBRANE POTENTIAL WHAT ARE THE CONDITIONS “AT REST” ????? - K+ channels mostly open - Cl- channels mostly open - Na+ channels are MOSTLY CLOSED - Na+ pump (Na+/K+ pump) is spending energy to pump Na+ out of the cell RESTING MEMBRANE POTENTIAL Why is it negative? - Something positive (Na+) is actively pumped out - The positive Na+ ions cannot get back in because Na+ channels are closed - This sets up an electromotive force for sodium; i.e. a ‘sodium-powered battery’ or capacitor How does the neuron become excited? - anything that makes membrane more permeable to Na+ will ‘discharge’ the sodium powered battery - excitation results from increase in Na+ influx into cell - inside of cell moves in positive direction ELECTRICAL ACTIVITY OF NEURONS EPSP- excitatory postsynaptic potential; small, transient movement in the positive direction; ‘depolarization’; can vary in size IPSP- inhibitory postsynaptic potential; small, transient movement in the negative direction; ‘hyperpolarization’; can vary in size ACTION POTENTIAL- very large, rapid change in positive direction, followed by return to baseline; neuron ‘fires’; also known as a ‘spike’; action potential fires when voltage crosses the threshold PROPAGATION OF THESE ELECTRICAL IMPULSES EPSPs and IPSPs are propagated in a graded and decremental fashion. Graded – they vary in size, can be larger or smaller depending upon the size of the inputs Decremental – they are largest at the point (i.e., synapse) of initial stimulation, and decrease in size as they move away from that point EXAMPLE: EPSPs and IPSPs are like ripples on the surface of a pond PROPAGATION OF ACTION POTENTIALS Action Potentials are not graded and not decremental. Action potentials…. - are ALL OR NONE (they either fire, or they don’t) - remain the same size as they travel down the axon EXAMPLES OF MECHANISMS THAT PRODUCE EPSPs AND IPSPs Excitatory neurotransmitter: GLUTAMATE Inhibitory neurotransmitter: GABA CHEMICALLY-GATED CHANNELS - linked to receptors - detection of transmitter by receptor opens channel EPSP: RECEPTORS DETECT GLUTAMATE, RECEPTOR LINKED TO A POSITIVE-ION CHANNEL, Na+ GOES INTO CELL IPSP: RECEPTORS DETECT GABA, RECEPTOR LINKED TO A Cl- CHANNEL, Cl- GOES INTO CELL MECHANISMS UNDERLYING ACTION POTENTIAL - voltage shoots up in positive direction (ascending limb) and then shoots down in negative direction (decending limb) - these effects are mediated by opening of voltage-gated channels - Ascending limb: voltage gated Na+ channels open, Na+ goes in - Descending limb: voltage gated K+ channels open, K+ goes out INFORMATION PROCESSING BY NEURONS Each neuron receives many excitatory and inhibitory inputs. These inputs are integrated (i.e., summed) Over time (temporal summation) And space (spatial summation) If the integrated excitatory input crosses the threshold at any moment, an action potential is triggered. INFORMATION PROCESSING BY NEURONS EPSPs and IPSPs are graded and decremental. Action Potentials are not graded and not decremental. Action potentials…. - are ALL OR NONE (they either fire, or they don’t) - remain the same size as they travel down the axon If they cannot vary in height to convey information, how can action potentials encode for information?????? They convey information by their pattern and frequency. CHEMICAL TRANSMISSION NEUROTRANSMITTER RELEASE IS TRIGGERED BY.. The action potential, when it reaches the terminal, opens Voltage gated calcium channels And calcium flows into the terminal. EXAMPLES OF NEUROTRANSMITTERS GLUTAMATE (GLU) GABA DOPAMINE (DA) SEROTONIN (5-HT) NOREPINEPHRINE (NE) ACETYLCHOLINE (ACH) Important neuromodulator: ADENOSINE STAGES OF CHEMICAL TRANSMISSION SYNTHESIS – transmitter made by enzyme STORAGE – stored in vesicles RELEASE – released from terminals POST-SYNAPTIC ACTION – moves across synapse, acts on receptors INACTIVATION – by enzymes or uptake DRUGS MODIFY THE PROCESS OF CHEMICAL TRANSMISSION IN THE NERVOUS SYSTEM - Alter neurotransmitter synthesis - Block storage of transmitter - Stimulate or reduce release - Stimulate or block receptors - Block the inactivation (enzymatic breakdown or uptake) of transmitter ANTIDEPRESSANT DRUGS Prozac Zoloft -BLOCK THE INACTIVATION OF SEROTONIN (5-HT) - other antidepressants can have actions on other transmitters (NE) ANTIPSYCHOTIC DRUGS Haldol Thorazine Clozapine -BLOCK RECEPTORS FOR THE NEUROTRANSMITTER DOPAMINE (DA) ANTIANXIETY DRUGS Valium Librium Xanax - FACILITATE THE INHIBITORY ACTIONS OF GABA ON A TYPE OF GABA RECEPTOR (GABAa) MAJOR STIMULANT DRUGS Cocaine Methamphetamine Ritalin - BLOCK THE INACTIVATION OF DOPAMINE (DA), or STIMULATE RELEASE OF DA; also act on NE and 5-HT MINOR STIMULANT DRUGS Caffeine Theophylline (components of coffee, tea, “energy” drinks) - BLOCK ADENOSINE RECEPTORS 1.7 Sensory Processes SENSORY RECEPTOR CELLS TRANSDUCE INFORMATION FROM THE ENVIRONMENT TYPES OF INFORMATION TRANSDUCED Chemical (taste, smell) Mechanical (touch, hearing) Electromagnetic (vision) Information about the physical stimulus is… a) encoded in the form of neural activity (frequency and pattern of Action Potentials), and … b) relayed to the brain by specific circuits PSYCHOPHYSICS The field that relates the physical characteristics of stimuli to their psychological characteristics. JND- Just noticeable difference. The minimal amount of physical change in a stimulus can be detected. Absolute Threshold- The minimal intensity of a physical stimulus that can be detected. Stevens Power Law- The relation between physical intensity and psychological intensity is linear on a log-log plot, but different modalities have different slopes. SIGNAL DETECTION THEORY