Researchers map functional connections between retinal neurons at single-cell resolution

By comparing a clearly defined visual input with the electrical output of the retina, researchers at the Salk Institute for Biological Studies were able to trace for the first time the neuronal circuitry that connects individual photoreceptors with retinal ganglion cells, the neurons that carry visual signals from the eye to the brain.

Their measurements, published in the Oct. 7, 2010, issue of the journal Nature, not only reveal computations in a neural circuit at the elementary resolution of individual neurons but also shed light on the neural code used by the retina to relay color information to the brain.

photoreceptors
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Groups of neurons in the brain rewire by changing images

Neuroscientists studying the mind’s ability to process images have completed the first empirical study to demonstrate, using animal models, how populations of nerve cells in visual cortex adapt to changing images. Their findings could lead to sight-improving therapies for people following trauma or stroke. The study at The University of Texas Health Science Center at Houston appears in the March 13 issue of the journal Nature.

eyeanatomy.jpg

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New MIT tool probes brain circuits

Researchers at the Picower Institute for Learning and Memory at MIT report in the Jan. 24 online edition of Science that they have created a way to see, for the first time, the effect of blocking and unblocking a single neural circuit in a living animal.

This revolutionary method allowed Susumu Tonegawa, Picower Professor of Biology and Neuroscience, and colleagues to see how bypassing a major memory-forming circuit in the brain affected learning and memory in mice.

mouse hippocampus

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Monkeys can perform mental addition

Researchers at Duke University have demonstrated that monkeys have the ability to perform mental addition. In fact, monkeys performed about as well as college students given the same test.

The findings shed light on the shared evolutionary origins of arithmetic ability in humans and non-human animals, according to Assistant Professor Elizabeth Brannon, Ph.D. and Jessica Cantlon, Ph.D., of the Duke Center for Cognitive Neuroscience.

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Cognitive ‘fog’ of normal aging linked to brain system disruption

Comparisons of the brains of young and old people have revealed that normal aging may cause cognitive decline due to deterioration of the connections among large-scale brain systems. The researchers linked the deterioration to a decrease in the integrity of the brain’s “white matter,” the tissue containing nerve cells that carry information. The researchers found that the disruption occurred even in the absence of pathology associated with Alzheimer’s disease (AD).

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Scientists uncover how the brain controls what the eyes see

Vase or face” When presented with the well known optical illusion in which we see either a vase or the faces of two people, what we observe depends on the patterns of neural activity going on in our brains.

“In this example, whether you see faces or vases depends entirely on changes that occur in your brain, since the image always stays exactly the same,” said John Serences, a UC Irvine cognitive neuroscientist.
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Scientists have developed a way to operate machines only by thoughts

Neuroscientists have significantly advanced brain-machine interface (BMI) technology to the point where severely handicapped people who cannot contract even one leg or arm muscle now can independently compose and send e-mails and operate a TV in their homes. They are using only their thoughts to execute these actions.

Thanks to the rapid pace of research on the BMI, one day these and other individuals may be able to feed themselves with a robotic arm and hand that moves according to their mental commands.
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