Psychology 201- Mind and Brain
Psychology 201- Mind and Brain PSY 201
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CHEM 142 COLLEEN CRAIG - GENERAL CHEMISTRY
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This 12 page Bundle was uploaded by Emily Richardson on Wednesday February 11, 2015. The Bundle belongs to PSY 201 at University of Oregon taught by Sereno in Fall. Since its upload, it has received 62 views. For similar materials see Psychology in Psychlogy at University of Oregon.
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Date Created: 02/11/15
Psychology 201 Mind and Brain 01142015 Inferential Statistics 0 Compute probability that a set of data ie the difference between means occurred simply by chance variation 0 If this probability is small less than 5 then you can conclude that the differences found are statistically signi cant Problems with Interpreting Results 0 Confounding Variables variables other than the IV are causing the result 0 Random variables eg non intoxicated group is just really uncoordinated Can be avoidedreduced by prescreening larger sample size test the same group under different conditions you re testing match groups in terms of gender age etc 0 Subject expectancy or placebo effect a subject s expectations in uence the results Use a placebo condition in the experiment 0 Experimenter expectancy experimenter unintentionally communicates expected results eg quotmaze brightquot and quotmaze dullquot rats Use quotdoubleblind control condition to control expectancy effects neither subject nor experimenter know condition assignments The Brain Neurons Cell Types Neurons building blocks of behavior a billion to a trillion cells 0 Glia quothelper cellsquot form myelin sheaths around the axon Blood vessels nervous system requires plenty of blood and fuel glucose 0 About 40 of the blood from your heart goes to the brain Neurons Basic units of the nervous system Receive integrate and transmit information Operate through electrical impulses Communicate with other neurons through chemical signals Structure Dendrites receives information Cell body soma keeps cell alive integrates signals Axon transmits signal carries signals out Synapse at the end of axon where axons make contact Terminal buttons nodules at the ends of axons contain synaptic vesicles release chemicals neurotransmitters into the synaptic cleft Neuronal activity can be studied at several levels eg ERP groups of neurons single cells Electrochemical communication is the hallmark of neurons The basic signal in the brain is the action potential Neuronal communication failures lead to impaired thought feelings and actions eg the effects of prescriptionrecreational drugs 0 Behavior is Controlled by Signals in Neuronal Circuits Example re exes built in response patterns executed automatically The quotRe ex Circuit eg the pain withdrawal re ex Central Nervous SystemPeripheral Nervous System Re ex works through sensory neurons interneurons and motor neurons Nerve Cell Communication Membrane Potential charge across membrane protein gates and pumps quotion channelsquot embedded in cell membrane control movement of ions such that lN and OUT Ions are charged molecules Resting Membrane Potential 70 mVlnside more negative relative to the outside SodiumPotassium Pump places more Na outside the axon and more K inside the axon The Sodium Potassium Pump 0 Pumps 3 Na out of the neuron for every 2 K into the neurons Ions will try to move to equalize concentration and charge 0 Open ion gate to sodium the sodium would move in because the neuron is already more negatively charged Electrostatic forcesdiffusion drives Na in electrostatic K in diffusion drives K out o The Action Potential rapid reversal of membrane potential Occurs when the membrane potential reaches 55 mV quotthreshold potentialquot at 55 mV the action potential is triggered Reversal happens when the inside becomes positive then quickly returns to normal 0 Action potential a very brief sudden reversal of the membrane potential 0 If the membrane potential reaches 55 mV the channels open to let Na molecules through Na ions rush in until 50 mV is reached and the channels close 0 When membrane reaches 50 mV channels open to let K through K rushes out of cell until membrane potential back to normal 70 mV Action Potential Propagation Positive inside potential spreads to nearby part of axon causing a depolarization positive change and triggering another Action Potential there AP travels down axon Synaptic Transmission 0 Action potential causes terminal buttons to release transmitter balance Transmitter molecules activate postsynaptic receptors which open ion channels 0 Ion ux results in postsynaptic potential 0 Excitatory or Inhibitory Post Synaptic Potentials EPSPs amp lPSPs Inhibitory neurons go past 70 and excitatory goes above 55 Neural Integration in Postsynaptic Neuron the neuron receiving signals Temporal and spatial summation of PSPs at axon If have many EPSPs occurring over time cell res many action potential Firing Rate of action potential is the message a neuron communicates to the neuron it synapses on Example The ring rate of a cell increases as intensity increases A neurons ring rate is de ned as the number of action potentials occurring per second Neurotransmitters and Effects of Drugs Events ending transmitter in uence 0 Reuptake to presynaptic terminal button 0 Enzymes deactivate neurochemica 0 Autoreceptors signal the axon to stop releasing neurotransmitter Agonist drugs can increase the release of neurotransmitters They can block the reuptake of neurotransmitters They can mimic a particular neurotransmitter binding to postsynaptic receptors and either activating them or increasing the neurotransmitter s effects Antagonist drugs can blockthe release of neurotransmitters They can block the reuptake of neurotransmitters They can mimic a particular neurotransmitter binding to postsynaptic receptors enough to block neurotransmitter binding Example Drug Effects on Behavior Effects of addictive drugs eg cocaine meth alcohol nicotine heroine etc Cause increased activity in quotreward circuitsquot basal ganglia nucleus accumbens and limbic system amygdala and cingulate These regions are normally active during any pleasurable experience Drugs cause a huge increase in release and effects of the neurotra nsmitters dopamine These drugs are dopamine agonists block dopamine reuptake This is associated with increased arousal and euphoria Dopamine in these regions serves functions of motivation and motor control Behavior is guided towards rewarding leading to additional reward Even cues associated with the experience triggers cravings and behaviors to attain that experience again The problem Long term drug use leads to perhaps permanent changes in brain chemistry over time decrease in dopamine production and decrease activation in these circuits and impaired cognitive abilities memory judgment motor control Eventually users need the drug to feel normal Learning in Neural Networks 0 The correlated ring of a pre and postsynaptic cell strengthens the synapse between them so the presynaptic cell becomes more effective it produces more EPSPs in ring the postsynaptic neuron quotCells that re together wire togetherquot 0 This is the basis for long term memories eg associative memory but is also essential for the development of sensory systems Rats in enriched and deprived environments have thicker cortex larger neurons larger and more synapses more neurotransmitters etc 0 The Brain Cerebral Cortex important in perception language memory planning intellectual and artistic function social responsibility emotions conscious thought action etc Gray matter cell bodies dendrites synapses White matter myelinated axons Early theories of functional localization in the brain bumps on the skull surface corresponded to personality traits Proposed by Franz Gall and Joseph Spurzheim around 1790 To support the brain s high metabolic needs a vascular system is needed Modern methods of localization fMRl scans depend on blood ow to give functional images of human brains Can study exclusively human behaviors like studying maps Features of Cortical Organization 0 1 Functional Specialization different parts of cortex serve different functions 0 2 Topographic Organization sensory and motor areas contain a map of the receptor surface or muscles 0 3 Contralateral Connections Right side of cortex is connected to the left side of the body and vice versa 4 Asymmetry of Higher Functions hemispheric specialization 0 Cortical Areas Topographic Organization Cortex sensory and motor cortex in mammals consists of many topographicallyorganized areas Primary sensory areas receive rather direct input from the sensory surface Primary motor area sends axons down to motor neurons in the brainstem and spinal cord Electrical stimulation produced twitches in a single or a few muscles quotAssociationquot areas are areas beyond the primary areas receive inputs from other sensory areas generally not polymodal ie each area represents information from one modality or sensory system Example Primate visual system has 30 areas arranged in a semi hierarchical fashion The function of sensory areas is detecting properties of the world eg representing object shape for recognition or grasping Frontal areas Important for initiating planning controlling and assessing behavior quotExecutive behaviorquot integrating information to make decisions Association cortex includes the regions of cortex beyond the primary areas Example of functional specialization Phineas Gage Receptive eld is the part of space for vision or body surface for somatosensation that a cell responds to Maps are distorted a mount of cortex devoted to each part of the receptor surface or muscles does not correspond to the size of the body part Maps are plastic eg monkey somatosensory maps move around after nger denervation phantom limb phenomenon Contralateral Connections F Examples Damage to right motor cortex inability to move muscles on the left side of the body Right somatosensory cortex damage inability to feel the left side of the body Right side of visual space is represented in the left side of the brain and vice versa Integration The two hemispheres are connected to each other and communicate with each other via a massive bundle of axons called the corpus callosum Asymmetry of Higher Functions Hemispheric Specialization in Humans In most humans the left hemisphere is more important for language functions and the right hemisphere is more important for spatial information 0 Evidence form splitbrain patients corpus caosum is cut to control seizures Each side of the brain is blind to what the other side sees of feels Left hemisphere controls speech 0 Right hemisphere is mute but can see stimulus in left visual eld can feel a stimulus with left hand can understand some language and is better at spatial judgments Color Vision 0 The purpose of color vision is perceptual segregation to separate objects from each other or a background 0 Thought to have evolved to help us detect food in foliage Color Vision De ned The ability to discriminate between different wavelengths of light when no brightness cues are present 0 Color is a psychological construct Physical stimuli may differ in wavelengths they re ect but those wavelengths have no intrinsic hue o A prism can break apart visible light to show the spectrum of colors Physical v Psychological Perceptual Wavelength Hue color Amplitude Brightness Purity Saturation Color and Wavelength Experience of color depends on wavelengths of light that hit the eye 0 See lightcolor o 1 directly from light sources the sun light bulbs TVcomputer screens or o 2 from light bounced off of Le re ected from a surface Color Mixing o Mixing of color is called subtractive color mixing when you mix 2 pigments only those wavelengths absorbed by neither pigment ie re ected by both will be seen 0 The pigments that are re ected by the two mixed colors are what you see 0 Additive color mixing occurs when colored lights v pigments are mixed It is additive because all wavelengths are added to each other Eg lights projected onto a projection screen can use add light together to make white light Two Theories of Color Vision Psychophysical experiments done in the 18005 derived results were used to propose two different competing physiological mechanisms of color vision 0 Both theories con rmed within the past 50 years with physiological experiments Trichromatic Theory v OpponentProcess Theory Trichromatic Theory 0 Three primaries law of color Color matching experiments can select no less than 3 different wavelengths and match the color of any visible wavelength by mixing them in various proportions ie intensities See graph in slideshow Hypothesis Color vision depends on a 3 receptor mechanism each with different spectral sensitivies 0 Light of a particular wavelength stimulates the 3 receptors to different degrees 0 Therefore each wavelength is represented by a unique pattern of activity in the 3 receptors 0 This hypothesis is true there are blue green and red cones in the retina Explanation of Color Matching Experiments 0 Evidence and explanation for trichromatic theory if 2 lights with different wavelength compositions stimulate the receptors in the same ratios they will appear to be the same color though they are physically different 0 To get yellow 50 red 50 green 0 blue wi exactly match yeow OpponentProcess Theory Proposed to explain perceptual phenomena in which the colors redgreen and blueyellow seemed to be paired with each other as oppos es o Opposing afterimages red has a green afterimage bue has a yellow afterimage It is easy to visualize certain colors such as a bluishgreen turquoise or reddishyellow orange but impossible to visualize other colors such as reddishgreen or bluishyellow Hypothesis Color vision is based on 3 mechanisms that respond in opposite ways to light intensities or wavelengths blackwhite red green bueyeow The function of opponent ces Enhances the ability to distinguish between different wavelengths Summary Perception is shapeddetermined by neural processing Color perception is both trichromatic as measured by color matching experiments and opponent opponent effects Both theories are correct because they represent mechanisms at different stages of neural processing Color De ciency Linked to X chromosome 0 See graph in slideshow 0 Perception What is Perception o Perception is the ability to organize recognize and make sense of the world from the sensory input 0 Perceptual processes extract information from the arrangement of individual stimulus elements in space and time Psychophysics 0 De ned the study of relationships between physical stimuli and psychological responses 0 One of the earliest elds of psychology Structuralists in Germany asked questions like how dim a light can be detected Detection 0 Absolute threshold smallest amount of stimulus energy that can be detected faintest detectable stimulus 0 Subthreshold lt threshold ltsuprathreshold Intensity of a stimulus eg light that is sufficient for detection 50 of the time 0 See graph in slideshow Discrimination Difference Threshold 0 Difference Threshold smallest difference in stimulus energy that can be discriminated between two stimuli Gestalt Procedure present standard stimulus always the same intensity and the comparison stimulus different intensities Also known as the justnoticeabledifference The size of the difference which can be detected 50 of the time The justnoticeabledifference is smaller for less intense standard stimuli and larger for more intense standard stimuli Psychology Describes various ways our perceptual system tends to organize or group elements into whole objects Gestalt Psychology was a reaction against the structuralists Emphasized that our visual system actively organizes the world into objects v just registering the brightness levels and color of stimuli quotwhole is different from the sum of its partsquot Phiphenomenon FigureGround Automatic tendency to see some parts of a scene as objects and other parts as background Figure the parts of the scene that stand out from the other parts as sharply delineated distinct shapes The gure is usually the smaller surrounded eld located in front of the ground Contour seems to belong to the gure Ground Usually the larger enclosing eld Extends behind the gure Grouping Principles simple rules by which we perceive shapes and form Proximity tend to see stimulus elements that are near each other as part of the same object or group 3D Form Similarity elements that are similar tend to be grouped together Closure We tend to supply missing elements to closecomplete a familiar gure Good Continuation We see elements in ways that produce continuous lines with minimal change of direction Common MovementFate When elements are moving in the same direction at the same rate we tend to see them as part of a single object Good Form or Simplicity Perceptual system strives for the simplest interpretations Examples of all in sideshow and Depth Perception Role of vision is to register the 3D spatial arrangements of objects and surfaces in the environment The 2D array of light contains cues to 3D depth and distance Going from a 2D retinal image to a 3D representation of the world is not always straightforward sometimes different 3D arrangements in the world can give rise to the same 2D image Thus there may be multiple 3D interpretations of the retinal image Examples in sideshow
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