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Visual Cortex

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Primary visual cortex (V1, Brodman 17) and extrastriate visual cortical areas (V2, V3, V4, V5, Brodmann 18, 19). There is a visual cortex in each hemisphere of the brain.

The left hemisphere visual cortex receives signals from the right visual field and the right visual cortex from the left visual field.

V1 transmits information to two primary pathways: The mangocellular pathway (dorsal stream) deals with conceptualising the movement of objects and their position in space (green). It goes to the posterior parietal cortex. (visual control). The pavocellular pathway (ventral stream) is concerned with detailed visual information used for the recognition of objects (blue). It goes to the inferior temporal cortex. (visual perception). It is also associated with storage of long-term memory.

Brodmann area 18 is regarded as a secondary sensory area concerned with the elaboration and synthesis of visual information. Area 19 is well-connected with many other cortical regions, and thus is believed to be concerned with integrating visual information with information from the other senses. Most high-order processing of visual information seems to occur outside of the occipital lobe. Projections to area 39 in the parietal lobe are concerned with symbols, including numbers and letters. Projections to area 7 are concerned with movement and stereoscopic vision. Projections to area 20/21 in the temporal lobe are concerned with detail and color. Electrical stimulation of area 21 may produce visual hallucinations.


Two Minute Papers - How Do Neural Networks See The World? A Vision of the Brain. The Laboratory of Neurobiology headed by prof.

A Vision of the Brain

Semir Zeki is offering the book A Vision of the Brain for free download. As the book is out of print and the author is not going to edit a second edition, they are offering it freely worldwide. To get the PDF, you just have to register in their website. Journal home : Nature Neuroscience.

Around half of the boutons in the main thalamorecipient L4 carried orientation-tuned information, and their orientation and direction biases were also dominant in the L4 neuron population, suggesting that these neurons may inherit their selectivity from tuned thalamic inputs. Cortical neurons in all layers exhibited sharper tuning than thalamic boutons and a greater diversity of preferred orientations. – weihler

Wellcome Laboratory of Neurobiology.

I was loving the way he explained the history of neuroscience. Liked especially the development and plasticity sections. – weihler

Individual Universal Map Of Vision In The Human Brain.

Latest research results create a map of vision in the brain based upon an individual's brain structure, even for people who cannot see. The result can, among other things, guide efforts to restore vision using a neural prosthesis that stimulates the surface of the brain. Scientists frequently use a brain imaging technique called functional MRI (fMRI) to measure the seemingly unique activation map of vision on an individual's brain. This fMRI test requires staring at a flashing screen for many minutes while brain activity is measured, which is an impossibility for people blinded by eye disease. The Penn team has solved this problem by finding a common mathematical description across people of the relationship between visual function and brain anatomy. – weihler

How Attention Helps You Remember - New Study Finds Long-Overlooked Cells Help The Brain Respond To Visual Stimuli.

150 years they did not know, what those Astrocytes do. – weihler
Attention increases activity of Nucleus Basalis, which is producing Acetylchlorine. Acetylchlorine activates Astrocytes in Visual Cortex.They boost calcium level, which is indicating activity and is strengthening percepion and information processing. – weihler
A new study from MIT neuroscientists sheds light on a neural circuit that makes us likelier to remember what we're seeing when our brains are in a more attentive state. When the brain is attentive, those cells, called astrocytes, relay messages alerting neurons of the visual cortex that they should respond strongly to whatever visual information they are receiving. Astrocytes are critically important for processing sensory information. The star-shaped cells were first discovered and named 150 years ago, but since then, it's been a mystery what they do. In this study, the researchers focused on what astrocytes do when the brain is stimulated to pay attention to a particular visual stimulus. When someone is paying close attention to something, the nucleus basalis floods the brain with a neurotransmitter called acetylcholine. Some of this acetylcholine targets astrocytes in the visual cortex. They are boosting their calcium level indicating high activity. Strengthening effect. – weihler

Men And Women See Things Differently. Visual problems have a role in dyslexia. ScienceWise - Jan/Feb 2009 Dr Kristen Pammer.

In terms of reading, the pavocellular pathway is vital for recognising letters and words but interestingly enough, it's deficiencies in the mangocellular pathway that seem to be related to reading difficulties. The researchers found that those who did badly on the mangocellular pathway tests before they learned to read, also showed signs of dyslexia once they could read. This finding lends weight to the idea that inherent deficiencies in the visual cortex may be at least a partial cause for dyslexia rather than a consequence of it. "Reading is a particularly interesting area of research because he brain has not evolved to read. It has specialised centres to deal with spoken language but in order to read, it has to recruit areas that have evolved for other purposes and build them into a network." – weihler
Probably "head cinema": Visual cortex, wernicke, boca, amygdala, motor cortex, hippocampus .... Gonna check that again. – weihler
Visual problems have a role in dyslexia