COGSCI 111 Jan25Lecture - Amended Readings for today's...

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1 Techniques for Studying the Thinking/Feeling Brain January 25, 2008 Amended Readings for today’s lecture Chapter 4 Pages 54-59 on fMRI Chapter 5 Pages 79-84 on dissociations and lesions Outline 1-25-08 • Techniques: noninvasive and invasive.- • Functional magnetic imaging (fMRI) – How it works – Advantages and disadvantages • Cognitive impairments from brain lesions: what we learn from “bent and broken” brains. – Associations – Dissociations and double dissociations
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2 Your Brain on Politics • Marco Iacoboni, Joshua Freedman, Jonas Kaplan, at the Semel Institute for Neuroscience, UCLA • Subjects given a list of questions about their political preferences, then: • fMRI scans taken for 1 hour • While in the scanner, Ss viewed still pix of candidates, then video excerpts from speeches, then the stills again. Ss were asked to rate the candidates on a 0-10 scale (very unfavorable to very favorable) both before and after the scan. • The same subjects will be tested again, before the election.
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3 A big machine fMRI requires strong electromagnetic field Thinking --activates neurons Active neurons-- burn oxygen Oxygen -- red blood cells (hemoglobin ) Brain gets 20% of body’s circulatory blood output Brain: highly vascularized organ Wherever there are neurons there are capillaries nearby FUNCTIONAL MAGNETIC RESONANCE IMAGING (fMRI) • Active neurons need more oxygen than less active ones • Oxygenated blood has different magnetic properties than deoxygenated blood • Detectors sense localized blood oxy/deoxy changes • The signal is based on subtraction oxy minus deoxy fMRI: Spatial and Temporal Resolution--an analogy • A football game on TV--you know your friend is in the stands and you see an audience shot in his/her seating section. – Conventional TV or HDTV? • You want to take pictures of the action on the field and you have 2 cameras, one with a frame rate of 2/sec or 10/sec. – Which camera?
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4 Clicker Q: Which is more important? A = spatial resolution B= temporal resolution 1. The ventromedial Temporal Cortex is involved in recognizing faces. 2. Face recognition is easier when the faces are of the same race as the test subject. 3. Reading 19th C. poetry engages both the temporal and frontal cortices. 4. It is easier to multiply two numbers using Arabic numerals than using Roman numerasls. 5. Cocaine addicted patients do more poorly than marijuana users on imagery tests for spatial rotation. Advantages of fMRI : 3. Localizes task-related brain activity. 4. Pretty good spatial resolution
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This note was uploaded on 02/25/2008 for the course COGST 1110 taught by Professor Adkinsregan,e&ho during the Spring '08 term at Cornell University (Engineering School).

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COGSCI 111 Jan25Lecture - Amended Readings for today's...

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