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Development of Orientation and Ocular Dominance Columns in Infant Macaques

Neural Information Processing Systems

Maps of orientation preference and ocular dominance were recorded optically from the cortices of 5 infant macaque monkeys, ranging in age from 3.5 to 14 weeks. In agreement with previous observations, we found that basic features of orientation and ocular dominance maps, as well as correlations between them, are present and robust by 3.5 weeks of age. We did observe changes in the strength of ocular dominance signals, as well as in the spacing of ocular dominance bands,both of which increased steadily between 3.5 and 14 weeks of age. The latter finding suggests that the adult spacing of ocular dominance bands depends on cortical growth in neonatal animals. Since we found no corresponding increase in the spacing of orientation preferences, however, there is a possibility that the orientation preferences of some cells change as the cortical surface expands. Since correlations between the patterns of orientation selectivity and ocular dominance are present at an age, when the visual system is still immature, it seems more likely that their development maybe an innate process and may not require extensive visual experience.


Development of Orientation and Ocular Dominance Columns in Infant Macaques

Neural Information Processing Systems

Maps of orientation preference and ocular dominance were recorded optically from the cortices of 5 infant macaque monkeys, ranging in age from 3.5 to 14 weeks. In agreement with previous observations, we found that basic features of orientation and ocular dominance maps, as well as correlations between them, are present and robust by 3.5 weeks of age. We did observe changes in the strength of ocular dominance signals, as well as in the spacing of ocular dominance bands, both of which increased steadily between 3.5 and 14 weeks of age. The latter finding suggests that the adult spacing of ocular dominance bands depends on cortical growth in neonatal animals. Since we found no corresponding increase in the spacing of orientation preferences, however, there is a possibility that the orientation preferences of some cells change as the cortical surface expands. Since correlations between the patterns of orientation selectivity and ocular dominance are present at an age, when the visual system is still immature, it seems more likely that their development may be an innate process and may not require extensive visual experience.


Topography and Ocular Dominance with Positive Correlations

Neural Information Processing Systems

This is motivated by experimental evidence that these phenomena may be subserved by the same mechanisms. An important aspect of this model is that ocular dominance segregation can occur when input activity is both distributed, and positively correlated between the eyes. This allows investigation of the dependence of the pattern of ocular dominance stripes on the degree of correlation between the eyes: it is found that increasing correlation leads to narrower stripes. Experiments are suggested to test whether such behaviour occurs in the natural system.


Fleetwood Best Placed to End American Dominance of Majors

U.S. News

Tommy Fleetwood was Two rounds of 63 made on different sides of the Atlantic over the past eight months are fuelling the belief that Tommy Fleetwood can end the American dominance of the majors at the British Open.


How the Rest of the World Feels About U.S. Dominance of the Internet

Slate

Then there's the fact that international internet governance debates are dominated by Americans. At U.N. meetings, the U.S. delegation is often bigger than the entire diplomatic staff of the poorest countries it deals with. What American diplomats see as effective advocacy appears to others as bull-headed arrogance and determination to make the world safe for Big Tech's business model. The governments of developing countries are worried their shaky infrastructure can't deal with spam or that the national telecoms company is losing money to YouTube and WhatsApp. But they just get a pat on the head and a lecture about globalization.