Psych 324: Week 1
Psych 324: Week 1 Psych 324
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This 6 page Class Notes was uploaded by Allie S on Monday August 31, 2015. The Class Notes belongs to Psych 324 at Clemson University taught by Dr. Claudio Cantalupo in Fall 2015. Since its upload, it has received 104 views. For similar materials see Brain and Behavior Psychology in Psychlogy at Clemson University.
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Date Created: 08/31/15
Physiological Psychology Week 1 I Physiological Psychology Biopsychology Branch of psych that studies the relationship between behavior and the body brain a Not Neuroscience i Neuroscience multidisciplinary study of the nervous system II Origins of Physiological Psychology a MindBrain Problem i What is the nature of the mind and the brain ii What is the relationship between the mind and the brain b Two philosophical Views i Dualism Mind and brain belong to two different worlds 1 The mind controls the brain by interacting with it ii Monism mind and brain belong to the same world physical world Materialism 1 The mind is the product of physical processes in the brain c Rene Descartes 17th century philosopher i Dualist mind non physical but body physical 1 Body of every organism human too is a machine a Therefore you can discover how the machine is built and how it works actions are mechanical 2 In humans the mind interacts with the body at a single point in the m a Pineal gland the seat of the soul physical explanation of soul ii He put emphasis on the physical explanation of behavior III Model proposed mechanism for how something works a Descartes Hydraulic Model i Nerves are hollow tubes where a uid animal spirit ows ii Pineal gland pumps the uid through brain and nerves iii Mind soul tilts the Pineal gland to direct uid to specific nerves specific muscles in ate move iv Important because it can be tested b Galvani 1700 s and his frogs nerves are like wires conducting electricity c Helmholtz 1800 s how come nerves conduction speed is only 90ftsec IV Nature amp Nurture Heredity amp Environment Innate amp Learned a Basic philosophical question driving psychology along with mindbody problem i How much of Brain and Behavior is due to Heredity ii How much of Brain and Behavior is due to Environment iii How do heredity and environment interact Physiological Psychology b Must understand basic genetics to study brain and behavior V Genetics a Gene unit of heredity i Found in chromosomes inside nucleus of each cell b Humans have 46 chromosomes in 23 pairs c Chromosome is composed of DNA Adenine Thymine Guanine cytosine VI Genes and their Effects a Dominant produces its effects regardless of Which gene it is paired With b Recessive produces its effects only When paired With the same recessive gene on the other chromosome Heterozygous 2 traits Homozygous two of same traits Characteristics determined by a single pair of genes eye color Characteristics determined by several gene pairs height i Polygenic VII Structure and Function of the Nervous System a Microscopic Level i Neuron Specialized cells that receive information and send it to other cells carry info Within the brain and throughout the rest of the body Transfer cells 1 About 100 billion neurons in the brain 2 Types a Motor Neuron receives information from other neurons carries information to muscle or glands W999 b Sensory Neurons receives a particular type of sensory information and carries information to other neurons c Interneuron connect one neuron to another in a particular part of the CNS ii Glial cells cells that provide structural and functional support for neurons 1 Oligodendrocytes build myelin around axons in CNS brain and spinal cord interneurons 2 Schwan cells build myelin around axons in the PNS periphery sensory neurons motor neurons receptors andor muscles b Neural Membrane critical for the neuron s ability to carry information i Phospholipid fat derivatives molecules 1 Head is hydrophilic like water tail is hydrophobic afraid ii Protein molecules 1 Channels 2 Pumps active burns energy creates gradients EC amp GC unlike channel iii Polarization difference in electrical charge voltage between the inside and outside of the cell Physiological Psychology 1 Resting Potential difference in electrical charge between the inside and outside of the membrane of a neuron at rest 70mv a Due to unequal distribution of ions on the two sides of the membrane i Atoms or molecules that are positive or neg charged ii Anion and Cation iv Membrane is Selectively permeable some chemicals can pass through it more freely than others 1 Protein molecules embedded in the membrane a Na channels closed at rest K channels slightly open at rest b NaK Pump repeatedly moves 3 Na out of the neuron and 2 K inside the neuron at Lst 2 Three reasons negative negative charge inside NAK pump K channel trickles 3 K ions attracted inside by Electrical Gradient outside by Concentration Gradient for K the two gradients are almost in balance 4 Na ions attracted inside by both Electrical Gradient and Concentration Gradient Na would rush inside if Na channels were open 5 Na and K channels are voltage activated their permeability depends on the voltage potential across the membrane v Graded Potential and Action Potential Slides vi Rate law intensity of a stimulus is encoded by the rate of action potentials 1 Not on Action Potential Slide c Spontaneous Activity firing of a neuron in absence of environmental stimulation September 4 2014 I Resting potential a K ions attracted inside by the electrical gradient means a difference in charge and outside by he concentration gradient i So the electrical gradient is going inside the cell ii The electrical gradient would keep the K ions in the cell iii The concentration gradient does the opposite iv The concentration gradient is slightly stronger than the electrical gradient b So what would happen to sodium if open up the channels i The Na would go in for electrical AND the Na would go in for the concentration gradient ii Na goes inwards for both gradients both draw Na in iii What would happen if something made the Na channels open Na would move inside and this would change the charge of the neuron and this is how a charge is transmitted Physiological Psychology c So what causes the Na channels to open and close i Na and K channels are voltage activated their permeability depends on the voltage across the membrane ii When this is 70mV the channels are closed iii But if something causes the resting potential to change then all of a sudden the Na channels would open this is the electrochemical signal 11 Changes in the membrane potential a No polarization at 0 while resting membrane potential is 70 mV b On the y axis is the membrane potential and the x axis is the time c So nothing changes if the neuron stays at rest d This little changes in a membrane potential that has been caused is called hyperpolarization dips below 70mV more negative than rest e So what would see if it makes it more positive i We call this depolarization or a decrease in polarization anytime the membrane potential goes towards 0 that is depolarization ii For depolarization there is a limit on the size of the stimulus and the size of the response in other words there is a value called the threshold of excitation iii So as long as depolarization stays below threshold nothing changes iv As soon as it reaches threshold the neurons fires V This is called the action potential abrupt depolarization and slight reversal of the usual polarization of the membrane Vi Always look at where the 0 is Vii Allows the neuron to send signals over long distances 111 Action Potentials a Occurs only in axons not in dendrites or soma b It s strength is independent of the intensity of the stimulus allornone law c It does not decay as it travels down an axon nondecremental i Spontaneous Activity Neurons are always firing even when no stimuli is present ii The more the stimulus happens the more the neurons fire but the intensity doesn t change iii All or None Law 1 ex light it doesn t matter how hard you hit the light switch the brightness of the light isn t going to get brighter 2 Ex a smell stronger than other isn t going to change the intensity of the neuron just how fast it fires IV Propagation of an action potential a Propagation of an action potential slide b Axon hillock first part of the axon that you can see an action potential Is like a dent on axon near cell body and dendrites c Part of axon node naked d Explained Graph Physiological Psychology i Describes the uphill section of the graphs First section would be the axon hillock where the action starts Reaches excitation and the sodium channels opens up ii Shows the downfall part of graphs iii Starts it over ips back and forth as it goes Triggered as a brand new one all the time as it travels down the axon The section of the axon were nothing is happening is in the relative refractory period iv Peak gt resting point is absolute refractory period V Resting point gt on is relative refractory period V Myelination and Conduction Speed of Action potentials a Myelin produced by glial cells Oligodendrocytes and Schwann b Slide i Conduction speed in axon 1msec 120msec ii Two strategies for increasing conduction speed 1 Developing larger axons motor neuron of squid 2 Myelination by glial cells iii Saltatory conduction faster and cheaper c Myelin sheath is not continuous there are tiny spaces between them called Nodes of Ranvier d Hillock is naked node where picture has Na marked e What happens i Na channels open gt action potential ii Depolarization spreads within the axon very rapidly iii The action potential is triggered at the next node and the next and the next iv Essentially jumping very fast from one node to the next saltatory conduction means jumping v Saltatory Conduction faster 15 times and cheaper than in unmyelinated axons 1 Less energy used up by cell speeds up the process of the action potential going through VI Communication between Neurons a Synapse connection between two neurons b Presynaptic neuron sends information input neuron also contains the presynaptic terminal c Postsynaptic neuron receives information output neuron also contains VII Chemical Synapses graph a Vesicles membrane around neurotransmitter and makes into round ball b Exocytosis Greek exmovement from inside to outside cytocell There is calcium Ca2 in synaptic cleft The ca2 channels will open and ca2 will move in to presynaptic terminal causes the neurotransmitter to leak down c Neurotransmitters reach channels sodium potassium chloride which match up with shape of each other The part the neurotransmitter matches with is receptor sites Lock and key transmitter match VIII Test a b c Physiological Psychology Inside of receiving neuron membrane potential 70mv As more sodium comes in the EPSP happens and the potential goes toward the threshold of excitation EPSP reaches partial depolarization because it could reach action potential but it doesn t always i Makes an action potential more likely to occur in the post synaptic neuron 1 Higher rate of firing Potassium leaves the neuron and returns to the synaptic cleft and the potential reaches below 70 i lower rate of firing EPSPs and IPSPs both graded potentials Action potentials not considered either EPSP or IPSP Postsynaptic Integration i A typical neuron receives EPSPs and IPSPs from 1000 other neurons ii EPSPs and IPSPs are combined at the axon hillock in 2 ways 1 Temporal Summation combines PSPs arriving a short time apart 2 Spatial Summation combines PSPs arriving at the same time from different locations on dendrites and soma What happens to the neurotransmitter left in the synaptic cleft i Molecules are reabsorbed by the terminal and repackaged into vesicles reuptake 1 In come cases they are first broken down into simpler components ii Absorbed by glial cells 1 two
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