Finish: Overview of the History of Cog Psych then Review of Physiological Methods in Cog Psych

1. Finish: Overview of the History of Cog PsychthenReview of Physiological Methods in Cog Psych Psychology 355: Cognitive PsychologyInstructor: John Miyamoto04/03/2014: Lecture 01-4 This Powerpoint presentation may contain macros that were used to create the slides. The macros aren’t needed to view the slides. If necessary, you can disable the macros without any change to the presentation.

2. Outline • How did cognitive psychology become a major focus within psychology? Overview of Physiological Methods in Cognitive Psychology • Single cell recordings of neural activity • Event-related potentials (ERP) • Positron emission tomography (PET) • Functional magnetic resonance imaging (fMRI) • Example of fMRI applied to localization of perceptual function # Psych 355, Miyamoto, Spr '14

3. Overview of the History of Cognitive Psychology • Precursors to cognitive psychology • Aristotle, Plato – epistemology, theory of ideas and their relation to human action • Experimental psychology begins in 19th century Germany • FranciscusDonders (response time analysis, method of subtraction) • Hermann von Helmholtz (perception, unconscious inference) • Hermann Ebbinghaus (experimental study of memory) • Wilhelm Wundt (analytic introspection, analysis of conscious experience) • Behaviorist hiatus in America: roughly 1920 – 1960 • During the behaviorist period (1920-1960), cognitive psychology continued to be studied in Europe. • Revival of cognitive psychology in America (1950 – 1970) • 1970 – present: Cognitive psychology plays a major role in psychology pretty much everywhere in the world Behaviorism Lost Its Grip on American Psychology Psych 355, Miyamoto, Spr '14

4. Behaviorism lost its grip on American psychology during the 1960's. Why did this happen? • Problematic results • Learning without responding:Rats that are temporarily paralyzed with atropine can learn the layout ofa maze from being wheeled around the maze. • Learning without reinforcement:Rats that explore a maze with no reinforcements show learning of the mazewhen they are later rewarded for running the maze. Revival of Cognitive Psychology – Information Processing Psych 355, Miyamoto, Spr '14

5. Behaviorism lost its grip on American psychology during the 1960's. Why did this happen? • Problematic results • Behaviorism couldn’t explain what scientists wanted to understand, e.g., language, perception, attention, reasoning. (Lashley, Chomsky, Miller-Galanter-Pribram). • Alternative approaches came along that looked more promising. • Structural models, e.g., transformational grammar, genetic epistemology. • Computer models, e.g., the General Problem Solver of Newell and Simon. • Change of focus to experimentation on human information processing. • Is it unscientific to postulate unobserved psychological processes in a psychological theory? • Behaviorist framework was inadequate for ALL of psychology. Revival of Cognitive Psychology – Information Processing Psych 355, Miyamoto, Spr '14

6. Cognitive Psychology Since 1960 • Experimental cognitive psychology – Emphasizes the behavioral approach • Perception & Attention, Memory, Language, Reasoning & problem solving, Cognitive development • Computer modeling of cognitive processes – Usually a mixture of the behavioral and computational approach • Physiological Approach • Single-cell recordings • PET, fMRI, ERP • Study effects of drugs Behavioral Approach:All dependent measures in a study are observed behavior. Physiological Approach:All dependent measures in a study are measures of physiological states or physiological responses. Hybrid Approach (Cognitive Neuroscience): The study attempts to explain behavioral responses, physiological responses, and may include computational modeling of behavior. END Psych 355, Miyamoto, Spr '14

7. Outline – Physiological Methods in Cognitive Neuroscience • Single cell recordings of neural activity • Event-related potentials (ERP) • Positron emission tomography (PET) • Functional magnetic resonance imaging (fMRI) • Example of fMRI applied to localization of perceptual function Brief Introduction to Neural Information Processing Psych 355, Miyamoto, Spr '14

8. Brief Introduction to Neural Information Processing • Structure of a neuron (nerve cell) • How neurons transmit information Diagram of Nerve Cell & Info Transmission Psych 355, Miyamoto, Spr '14

9. The Parts of a Neuron (Nerve Cell) Next Slide • Cell body or soma – main body of the neuron. • Dendrites –brushy projections that receive stimulation from other cells. • Axon – long projection that carries stimulation to other cells. • Terminal buttons (a.k.a. axon terminals or synaptic terminals) – End of axon where a neurochemical signal is passed to other nerve cells. Same Slide without the Red Ovals Psych 355, Miyamoto, Spr '14

10. The Parts of a Neuron (Nerve Cell) • Cell body or soma – main body of the neuron. • Dendrites –brushy projections that receive stimulation from other cells. • Axon – long projection that carries stimulation to other cells. • Terminal buttons (a.k.a. axon terminals or synaptic terminals) – End of axon where a neurochemical signal is passed to other nerve cells. Enlargement of Synapse Psych 355, Miyamoto, Spr '14

11. The Synapse – Point of Contact Between Two Nerve Cells • Neurotransmitters (chemicals) are transferred from one neuron to the next at a synapse. • At any synapse, the transmission is in only one direction. • One neuron is the sending neuron. • The other neuron is the receiving neuron. • Neurons can either excite or inhibit the neural actions of other neurons. Image downloaded from Wikipedia (1/9/07):http://en.wikipedia.org/wiki/Synapse Nice pictures of a synapse are available at: http://www.rnceus.com/meth/Introneurotrans.htmland http://www.educarer.com/brain.htm . Action Potentials are All-of-None Psych 355, Miyamoto, Spr '14

12. Action Potentials: Electrochemical waves that pass down the axon of a neuron. • Action potentials are all-or-nothing. • The rate of action potentials matters. The resting rate is not zero. • The size is the same for all action potentials. Diagram Shows the Time of Occurrence of an Action Potential (Spike) Time  Summary re Neural Signals Psych 355, Miyamoto, Spr '14

13. Summary re Neural Signals • Information is carried by the firing rate of a neuron, not the size of an action potential (all are of equal size). • Inputs to a neuron can increase (excite) or decrease (inhibit)the firing rate of the neuron. • The signal is transmitted from one neuron to the nextby means of neurotransmitter chemicals that are passed from one neuron to another at the synapse. Single Cell Recordings Psych 355, Miyamoto, Spr '14

14. Single Cell Recordings • The firing rate of individual neurons is measured by means of single cell recordings. • Today it is possible to record simultaneously from a number of of individual cells. Strengths and Weaknesses of Single Cell Recordings Psych 355, Miyamoto, Spr '14

15. Strengths and Weaknesses of Single Cell Recording Methods Strengths • Excellent spatial information – the scientist has a very good idea where the recording is located in the brain. • Excellent temporal information – the scientist knows when the neuron fires to a high level of precision. Drawbacks • Practically difficult to record from more than a small number of cells at a given time, e.g., 15 to 20 cells simultaneously. • The method is very invasive. Event-Related Potentials (ERP’s) Psych 355, Miyamoto, Spr '14

16. Event-Related Potentials (ERP’s) • Measures electrical potentials on the scalp while processing a stimulus. Strengths and Weaknesses of ERP’s Psych 355, Miyamoto, Spr '14

17. Event-Related Potentials (ERP’s) • Strengths and weaknesses of ERP’s as research tool. • Poor spatial resolution. • Excellent temporal resolution. • Relatively non-invasive. • Sketchy understanding of the brain processes that are producing the EEG signal. Positron Emission Tomography (PET) Psych 355, Miyamoto, Spr '14

18. Positron Emission Tomography (PET) • Measures blood flow via radioactive tracers • Utilizes the subtraction technique(Test state) – (Control State) = Activity Strengths: • Quick results • Different compounds can show blood flow, oxygen, glucose metabolism Weaknesses: • Limited to short observations due to rapid decayof tracer • Injecting radioactive traces into the blood is invasive. Picture of an MRI Machine Psych 355, Miyamoto, Spr '14

19. fMRI Uses a Big Magnet This images is used with permission of the author, J. J. B. Allen at the University of Arizona. Graphic Showing BOLD Contrast Psych 355, Miyamoto, Spr '14

20. Measuring Activation – A Subtraction Measure ControlCondition TestCondition Brain Activity = Oxygen Concentration in Test Condition MINUS Oxygen Concentration in Control Condition OxygenatedBlood DeoxygenatedBlood Details of fMRI Measurement Psych 355, Miyamoto, Spr '14

21. How Does fMRI Measure Brain Activity ControlCondition TestCondition Local neuronal activity  Increased local metabolic rate  Increased blood flow  Increased oxygenated hemoglobin  Uptake of O2 less than supply  Decreased concentrations of deoxyhemoglobin  Increased local fMRI T2* signal (electromagnetic signal) • BOLD response – Blood Oxygenated Level-Dependent response (the response is dependent on the level of oxygenated blood) • A.k.a. hemodynamic response (response observed in the blood over time) Strengths and Weaknesses of fMRI Psych 355, Miyamoto, Spr '14

22. Strengths and Weaknesses of fMRI Measures of Brain Activity • Excellent spatial resolution • Magnetic changes can be measured at a resolution of 1 - 3mm³. • Temporal resolution is poor. • In the 1990’s the temporal resolution was about 4 seconds. • Today the temporal resolution is about 2 seconds. • MRI machines impose physical limitations on the subjects. Localization of Function Psych 355, Miyamoto, Spr '14