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Get this article [1]Chelazzi L, Miller EK, Duncan J, Desimone R. A neural basis for visual search in inferior temporal cortex. Nature 1993; 363: 345-347.

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Presentation on theme: "Get this article [1]Chelazzi L, Miller EK, Duncan J, Desimone R. A neural basis for visual search in inferior temporal cortex. Nature 1993; 363: 345-347."— Presentation transcript:

1 Get this article [1]Chelazzi L, Miller EK, Duncan J, Desimone R. A neural basis for visual search in inferior temporal cortex. Nature 1993; 363: 345-347.

2 Project Anatomy of a grant: 1.Background - puts your question into a framework in which its scientific importance is highlighted 2.Theory - state in one sentence what your theory is 3.Specific Predictions - describe one or more situations/findings/facts that must be true if your theory is true (test your theory) for your project you need only one specific prediction 4.Experimental approach - describe the experiment(s) to test your prediction and provide methodological details this criteria will be emphasized in your project

3 Project Anatomy of a grant: 1.Background - puts your question into a framework in which its scientific importance is highlighted 2.Theory - state in one sentence what your theory is 3.Specific Predictions - describe one or more situations/findings/facts that must be true if your theory is true (test your theory) for your project you need only one specific prediction 4.Experimental approach - describe the experiment(s) to test your prediction and provide methodological details this criteria will be emphasized in your project

4 Project Anatomy of a grant: 1.Background - puts your question into a framework in which its scientific importance is highlighted 2.Theory - state in one sentence what your theory is 3.Specific Predictions - describe one or more situations/findings/facts that must be true if your theory is true (test your theory) for your project you need only one specific prediction 4.Experimental approach - describe the experiment(s) to test your prediction and provide methodological details this criteria will be emphasized in your project

5 Project Anatomy of a grant: 1.Background - puts your question into a framework in which its scientific importance is highlighted 2.Theory - state in one sentence what your theory is 3.Specific Predictions - describe one or more situations/findings/facts that must be true if your theory is true (test your theory) for your project you need only one specific prediction 4.Experimental approach - describe the experiment(s) to test your prediction and provide methodological details this criteria will be emphasized in your project

6 Project Anatomy of a grant: 1.Background - puts your question into a framework in which its scientific importance is highlighted 2.Theory - state in one sentence what your theory is 3.Specific Predictions - describe one or more situations/findings/facts that must be true if your theory is true (test your theory) for your project you need only one specific prediction 4.Experimental approach - describe the experiment(s) to test your prediction and provide methodological details this criteria will be emphasized in your project

7 Project Anatomy of a grant: 5.Timeline - what milestones and when? 6.Budget - how much do you need to do this project? 7.Training of “HQP” (Highly-Qualified Personnel) It is unnecessary to include these in your project for this class

8 Project Example: Background: Geography has played a prominent role in constraining the advancement of human societies throughout history. Societies with sophisticated understanding of the kinds of geographic features in their locality have successfully leveraged this knowledge to advance their economies. Although historically overshadowed by classical spherical-earth theories, recent advancements in geographic theory have hinted at intriguing “alternative geometries” to describe the shape of our Earth.

9 Project Example: Theory: This proposal is to test the theory that the Earth is flat

10 Project Example: Prediction: If the Flat Earth theory is true, objects that travel away from any point in a constant direction must eventually fall off the Earth, never to be seen again.

11 Project Example: Experiment: To test this prediction, an expedition comprised of graduate students in a boat will depart from Vancouver Island and sail directly west. The graduate students will submit hourly progress reports by carrier pigeon. Discontinuation of these reports can be taken as strong evidence that the graduate students have fallen off the edge of the Earth, never to be heard from again.

12 The Role of “Extrastriate” Areas Different visual cortex regions contain cells with different tuning properties represent different features in the visual field V5/MT is selectively responsive to motion V4 is selectively responsive to color

13 The Role of “Extrastriate” Areas V4 and V5 are doubly-dissociated in lesion literature:

14 The Role of “Extrastriate” Areas V4 and V5 are doubly-dissociated in lesion literature: –achromatopsia (color blindness): there are many forms of color blindness cortical achromatopsia arises from lesions in the area of V4 singly dissociable from motion perception deficit - patients with V4 lesions have other visual problems, but motion perception is substantially spared

15 The Role of “Extrastriate” Areas V4 and V5 are doubly-dissociated in lesion literature: –akinetopsia (motion blindness): bilateral lesions to area V5 (extremely rare) severe impairment in judging direction and velocity of motion - especially with fast-moving stimuli visual world appeared to progress in still frames similar effects occur when M-cell layers in LGN are lesioned in monkeys

16 Dual Pathways V4 and V5 are key parts of two larger functional pathways: –Dorsal or “Where” pathway –Ventral or “What” pathway –Ungerleider and Mishkin (1982) Magno and Parvo dichotomy arose at the retina and gives rise to two distinct cortical pathways

17 Dual Pathways Why “What” and “Where”? –monkey lesion experiments –human lesions –differences in tuning properties of cells –neuroimaging

18 Dual Pathways Pohl (1973) Early dissociations of Temporal and Parietal functions Landmark task: –Monkeys trained to find reward in well near a landmark –once they get the task the contingency is switched –#errors until relearning indicates ability to use the spatial relationship information to perform task

19 Dual Pathways Pohl (1973) Early dissociations of Temporal and Parietal functions Landmark task: –Dissociates Parietal and Temporal lobes –Parietal lesions impair relearning of landmark task

20 Dual Pathways Pohl (1973) Early dissociations of Temporal and Parietal functions Object task: –Reward location is indicated by one of two objects –contingency is switched –# errors to relearn indicates ability to use object distinction to perform task

21 Dual Pathways Pohl (1973) Early dissociations of Temporal and Parietal functions Object task: –Adding this task doubly dissociates Parietal and Temporal lesions –Temporal lesions impair object task

22 Dual Pathways Cells within Dorsal and Ventral pathways have dramatically different response properties Beyond just V4 and V5 distinctions

23 Dual Pathways Cells in Parietal lobe have little preference for the size of stimuli

24 Dual Pathways Cells in Temporal Lobe are sharply tuned to the form of an object


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