http://medicalxpress.com/ en-us Medical Xpress internet news portal provides the latest news on Health and Medicine. (Medical Xpress)—One way to increase our understanding of bilateral brains, like our own, is to inspect their paired sensory systems. In our visual system, the optic nerves normally combine at a place called the optic chiasm. Here half the fibers from each eye cross over to the opposite hemisphere. When this natural partition fails to develop normally, the system compensates in different ways. In people with albinism, for example, almost all of the fibers fully cross at the chiasm. As a result, images are combined in the brain in such a way that full depth of vision is limited. Their eyes also may move slightly independent of each other, or dart back and forth in a condition known as nystagmus. When the opposite situation occurs, that in which the optic nerves do not cross at all during their development, it is called congenital achiasma. An individual with this rare condition was recently studied with different forms MRI. The results, reported in the journal Neuropsychologia, show that achiasma can occur as an isolated defect, lacking any structural abnormalities in other pathways that cross the midline. The study also demonstrated that the part of the cortex that first receives the visual input, the primary visual cortex, does not rely on information from the opposite side to perform its immediate functions. http://medicalxpress.com/news/2013-04-congenitally-absent-optic-chiasm-visual.html Neuroscience Mon, 15 Apr 2013 17:10:02 EST news285262412 In experiments on rats outfitted with tiny goggles, scientists say they have learned that the brain's initial vision processing center not only relays visual stimuli, but also can "learn" time intervals and create specifically timed expectations of future rewards. The research, by a team at the Johns Hopkins University School of Medicine and the Massachusetts Institute of Technology, sheds new light on learning and memory-making, the investigators say, and could help explain why people with Alzheimer's disease have trouble remembering recent events. http://medicalxpress.com/news/2013-01-pavlov-rats-rodents-link-rewards.html Neuroscience Wed, 23 Jan 2013 12:00:08 EST news278160769 New research led by Shigeru Tanaka of the University of Electro-Communications and visiting scientist at the RIKEN Brain Science Institute has shown that the responses of cells in the visual cortex can be 're-tuned' by experience. http://medicalxpress.com/news/2012-12-re-tuning-responses-visual-cortex.html Neuroscience Fri, 21 Dec 2012 09:00:37 EST news275302830 (Medical Xpress)—The fascinating but deeply weird illusion of the scintillating grid, where the grid appears to sparkle, has been shown to be more sparkly when you view it with both eyes rather than one eye. http://medicalxpress.com/news/2012-12-paper-illusion-scintillating-grid.html Psychology & Psychiatry Wed, 19 Dec 2012 07:13:39 EST news275123602 Dramatic expansion of the human cerebral cortex, over the course of evolution, accommodated new areas for specialized cognitive function, including language. Understanding the genetic mechanisms underlying these changes, however, remains a challenge to neuroscientists. http://medicalxpress.com/news/2012-11-gene-reveals-molecular-mechanisms-underlying.html Neuroscience Fri, 09 Nov 2012 08:10:01 EST news271669483 (Medical Xpress)—What consciousness is, and why and how it exists, are some of the oldest questions in philosophy. They are also central to one of the fastest-growing areas of neuroscience. http://medicalxpress.com/news/2012-09-human-consciousness.html Psychology & Psychiatry Mon, 17 Sep 2012 09:26:27 EST news267092780 (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. http://medicalxpress.com/news/2012-04-spatially-structured-retinal-early-cortical.html Neuroscience Thu, 26 Apr 2012 10:11:46 EST news254653856 (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. http://medicalxpress.com/news/2012-04-eyes.html Neuroscience Tue, 24 Apr 2012 06:31:08 EST news254467843 (Medical Xpress) -- Researchers from the University of Groningen Medical Centre in the Netherlands have found that for women at least, watching pornographic videos tends to quiet the part of the brain most heavily involved in looking at and processing things in the immediate environment, suggesting that the brain finds arousal more important during that time than is processing what is actually being seen. The team has published a paper in The Journal of Sexual Medicine describing their findings. http://medicalxpress.com/news/2012-04-visual-cortex-women-quiets-viewing.html Neuroscience Fri, 20 Apr 2012 08:00:01 EST news254125250 (Medical Xpress) -- It's a chilling thought--losing the sense of sight because of severe injury or damage to the brain's visual cortex. But, is it possible to train a damaged or injured brain to "see" again after such a catastrophic injury? Yes, according to Tony Ro, a neuroscientist at the City College of New York, who is artificially recreating a condition called blindsight in his lab. http://medicalxpress.com/news/2012-04-visual-cortex.html Neuroscience Tue, 03 Apr 2012 08:25:54 EST news252660339 In everyday life, attention and awareness appear tightly interwoven. Attending to the scissors on the right side of your desk, you become aware of their attributes, for example the red handles. Vice versa, the red handles could attract your attention to the scissors. However, a number of behavioural observations have recently led scientists to postulate that attention and awareness are fundamentally different processes and not necessarily connected. http://medicalxpress.com/news/2011-11-attention-awareness-uncoupled-brain-imaging.html Neuroscience Thu, 10 Nov 2011 14:00:05 EST news240154664