sample_midterm_3_2005_key

sample_midterm_3_2005_key - YOUR NAME_ Student ID#_ MIDTERM...

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YOUR NAME__________________________ Student ID#_________________ 1 NPB 100 MIDTERM 3 SPRING, 2005 Your signature______________________ Question Score Total 1 15 2 9 3 12 4 5 5 6 6 4 7 18 8 14 9 17 TOTAL 100
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YOUR NAME__________________________ Student ID#_________________ 2 Question 1 (15 points) In class you saw the Hermann Grid illusion shown below on the left . When you looked at the black squares separated by white spaces you saw illusory dark spots at the white intersections. 1a. (5 points) Using center-surround OFF-center receptive fields, illustrate on the figure below on the right how OFF-center receptive fields can cause this illusion. THIS IS THE ILLUSION YOU SAW DRAW YOUR RECEPTIVE FIELDS HERE Points: 3 points for drawing the 2 receptive fields at the right size and location. 2 point for drawing the correct sign (OFF-center) receptive fields. 1b. (10 points) Explain your answer. Both receptive fields have their centers completely in the white (light) region (2 points). Since we are using OFF-center cells, both cells have equal inhibition from their centers (1point). The cell at the intersection has more of its surround in the light (2 points). Therefore it is getting more excitation from the surround region than the other cell (1 point). Since both cells get equal inhibition, and the cell at the intersection gets more excitation, the cell at the intersection will fire more action potentials (2 points). An OFF-center cell firing more action potentials tells the brain that it is darker at the intersection, therefore we see the dark illusory spot (2 points). GO ON TO THE NEXT PAGE!
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YOUR NAME__________________________ Student ID#_________________ 3 Question 2 (9 points) The following diagram shows 3 possible lesions through the visual pathway. Lesion 1 represents a cut all the way through the right optic nerve. Lesion 2 represents a cut all the way through the right optic tract. Lesion 3 represents a cut through the optic chiasm which cuts contralaterally projecting axons from each eye, and does not cut ipsialterally projecting axons from either eye. Left eye Right eye 1 2 3 2a. (3 points) If you lesion the optic nerve only at location 1, and you close your left eye, how will you perceive the world only using your right eye? a) Normal vision through the right eye b) No vision (blind in the right eye) c) Only perceive left visual field through the right eye d) Only perceive right visual field through the right eye 2b. (3 points) If you lesion the optic tract only at location 2, and you close your left eye, how will you perceive the world only using your right eye? e)
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sample_midterm_3_2005_key - YOUR NAME_ Student ID#_ MIDTERM...

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