Article Abstract:
The experimental results of some recent research may solve the discussion on the cause of orientation selectivity of lateral geniculate cells in the primary visual cortex. Research by Ferster, Chung and Wheat conclude that orientation selectivity occurs due to direct excitatory convergence of inputs from the geniculate cells. Experiments by Torsten Wiesel and David Hubel, using visual stimulation and single-cell recording, show that the primary visual cortex analyzes visual scene by the light-dark contour. The theories by Blakemore and Tobin, Chapman, Zahs and Stryker, and Ferster are discussed.
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Article Abstract:
Degradation of ornithine decarboxylase (ODC), dependent on adenosine triphosphate (ATP) and antizymes, is prevented by immunodepletion of cell extract proteasomes. The protease which catalyzes the degradation of ODC is identified. The 26S proteasome degrades ODC even in the absence of ubiquitin, suggesting that this proteasome, though regarded as specific for ubiquitin-conjugated proteins, may also be involved in ubiquitin-independent proteolysis.
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Article Abstract:
Research involving monkeys showed that the anterior inferotemporal cortex (IT), the part of the brain that is the last stage in the processing of visual information, is made up of columns. Each column houses cells whose shape enables them to recognize similarly shaped objects. Although other portions of the visual cortex had been shown to be columnar in organization, this is the first evidence that this is also the IT's structure.
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