Archive by tag | optogenetics

Too much of a good thing?

Posted by I-han Chou | Categories: ,

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We published another double header yesterday, this time on the role of particular cell types in visual responses. Both studies describe the effect of optogenetically manipulating various interneuron classes in mouse visual cortex. The papers are Lee et al. from Yang Dan‘s lab and Wilson et al. from Mriganka Sur‘s labs. And in fact, both were preceded by Atallah et al. from Massimo Scanziani’s lab, which appeared in Neuron earlier this year. Which means a bonanza of data on the effects of activating parvalbumin-expressing interneurons, and also a bonanza of different conclusions about their exact role – everyone comes to slightly different conclusions.  Read more

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Positive feedback drives network (and manuscript) maturation.

Posted by Noah Gray | Categories: ,

Positive feedback drives network (and manuscript) maturation.

It really is an embarrassment of riches here at Nature these days, what with so many excellent neuroscience-related studies emerging. Just in the last couple of weeks, we’ve had the following studies:  … Read more

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Fear of the Light

Posted by Noah Gray | Categories: ,

Fear of the Light

It is commonly believed that distinct mini-networks of neurons, firing together, may be the means by which memories and other conceptual encoding requirements are handled in the brain. However, it is only recently that we have had the tools available to directly test the sufficiency of such a mechanism. Today, a new study in Nature from the lab of Susumu Tonegawa documents the ability to use light as a means to activate distinct subsets of neurons responsible for the encoding of fear memories.  Read more

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Layer magic and monkey business

Posted by I-han Chou | Categories: ,

Image from Wikipedia

We’ve known for over a century that sensory cortex is arranged in distinct layers, each containing a different make up of neuronal types and projection patterns, but we don’t actually know that much about the actual computations performed in each layer.  Today a paper from Massimo Scanziani’s lab takes a big step towards cracking the function of the bottom layer (layer 6) in mice. Layer 6 neurons project both to upper cortical layers and to the lateral geniculate nucleus in the thalamus, which itself is the primary input to cortex, and so are primed to play a large modulatory role. Using a monumental combination of optogenetics, intracellular recording, and behavioral testing, the paper convincingly makes the case that layer 6 controls the gain of visual responses of upper layer neurons (i.e.  Read more

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