(Medical Xpress) — Remarkably, cortical maps show that neurons in the primary visual cortex have specific preferences for the location and orientation of a given visual field stimulus but how these maps develop and what function they play in visual processing remains a mystery. Evidence suggests that the retinotopic map is established by molecular gradients, but little is known about how orientation maps are wired. One hypothesis: at their inception, these orientation maps are seeded by the spatial interference of ON- and OFF-center retinal receptive field mosaics. Recently, scientists in the Departments of Neurobiology and Psychology at the University of California, Los Angeles have shown that this proposed mechanism predicts a link between the layout of orientation preferences around singularities of different signs and the cardinal axes of the retinotopic map, and have confirmed this prediction in the tree shrew primary visual cortex. The researchers say their findings support the idea that spatially structured retinal input may provide a blueprint of sorts for the early development of cortical maps and receptive fields and that the same may hold true for other senses as well.
psychology
How your eyes deceive you
(Medical Xpress) — Researchers at the University of Sydney have thrown new light on the tricks the brain plays as it struggles to make sense of the visual and other sensory signals it constantly receives.
New guidelines: Treatments can help prevent migraine
Research shows that many treatments can help prevent migraine in certain people, yet few people with migraine who are candidates for these preventive treatments actually use them, according to new guidelines issued by the American Academy of Neurology. The guidelines, which were co-developed with the American Headache Society, will be announced at the American Academy of Neurology’s 64th Annual Meeting in New Orleans and published in the April 24, 2012, print issue of Neurology®, the medical journal of the American Academy of Neurology.
Protein prevents DNA damage in the developing brain and might serve as a tumor suppressor
St. Jude Children’s Research Hospital scientists have rewritten the job description of the protein TopBP1 after demonstrating that it guards early brain cells from DNA damage. Such damage might foreshadow later problems, including cancer.
Cocaine decreases activity of a protein necessary for normal functioning of the brain’s reward system
New research from Mount Sinai Medical Center in New York reveals that repeated exposure to cocaine decreases the activity of a protein necessary for normal functioning of the brain’s reward system, thus enhancing the reward for cocaine use, which leads to addiction. Investigators were also able to block the ability of repeated cocaine exposure, to induce addiction. The findings, published online April 22 in the journal Nature Neuroscience, provide the first evidence of how cocaine changes the shape and size of neuron rewards in a mouse model.