anhinga_anhinga (anhinga_anhinga) wrote,

Listening to the talks at a conference somewhat resembles reading an LJ friends page :-)

More neuroconference, and an aircraft carrier too.

The third day of the conference is better. A great starting talk by Mark Bear from MIT, "How monocular deprivation shifts ocular dominance in visual cortex". They switched from cats (traditional in these experiments) to mice, and this had numerous positive consequences in terms of experimental possibilities. Among other things they demonstrated that if the retina is chemically turned off (instead of just stiching the eyelid together) the depression of neuronal response in the cortex does not occur. So the depression in this case is not caused by "the lack of use", as it is customary to believe, but by the retinal noise from the eye which is shut. The retina of the closed eye still works, and the noise coming from it convinces the downstream cells, that the input is incompetent and the corresponding synapses should be depressed. The lack of input does not cause depression.

His group did a lot of other cool things in the course of these experiments, with synaptic placticity and "secondary placticity" (changes in the ability to learn, which is related to the ratio of NR2A and NR2B subunits of the NMDA receptors). I still have to learn how to write these details well in the LJ format, somehow it does not feel comfortable.

Another punchline of the conference is that superficially similar phenomena might have very different mechanism and function. Mark remarked that there are multiple mechanisms of LTD (long-term synaptic depression). During the first day Nancy Kopell showed that the brain waves of the same frequency might have half a dozen of different generating mechanisms and, correspondingly, different cognitive functions.

Also David Sheinberg (Brown U.) presented a nice collection of experiments in the talk "From seeing to knowing: The role of inferotemporal cortex in vision", and he actually convinced me that visual object recognition really happens in the inferotemporal (IT) cortex.

And... what was that... we do have a visiting aircraft carrier this weekend, USS John F. Kennedy. There will probably be crowds, however (and the Boston Globe site also wants free registration now, which can be defeated by the usual means)...
Tags: neuroscience, retrospective 1

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