…and this is a 
Complexin...not so inconsequential anymore
Category: Neurobiology
Posted on: September 20, 2007 5:10 PM, by Lua Yar
Researchers at MIT's Picower Institute for Learning and Memory may have found the key to controlling how the brain is wired while studying the bursts of activity that occur after communication between neurons.
First, I will give an overview of neural communication. Neural cells communicate with each other at a synapse, which is the point of contact between the cells at which signals are transmitted. The action potential stimulates the input cell (presynaptic) to release neurotransmitters. These neurotransmitters travel across the synaptic cleft and bind to neurotransmitter receptors on the receiving (postsynaptic) cell. However, the action of the neurotransmitter needs to be controlled so that the cell is not continually activated.
That is where this new research, conducted by Sarah Huntwork and J Troy Littleton, comes in. These scientists have identified a molecule, called complexin, which acts as a gatekeeper to help control the release of neurotransmitters. As it turns out, a few cells will continue to release neurotransmitters even after the major electrical stimulus has passed. They call these events "minis", which are regulated by complexin. However, they have discovered that in the absence of complexin, these minis can occur without regulation, and when they do, it can lead to rewiring of the brain and synaptic growth.
So what does this mean in terms of neurological diseases? The activity of complexin can be controlled, and if properly regulated, may allow synaptic growth to be stimulated and rewiring of the brain to occur.
Comments
Posted by: Amenhotep | September 20, 2007 5:39 PM
Lua, did you forget you posted that; do you need a complexin supplement? ;-)
Just kidding - this is fascinating stuff; thanks for posting. The whole area of cellular differentiation in the CNS and the factors leading to rewiring (and the ceasing thereof) are of major importance if we are to understand degenerative brain disease and abnormalities of brain development (including learning disabilities). It's already a hugely complex field, but at least in the case of Fragile X syndrome, there are glimmerings that treatments may become available - a thought that was felt to be ridiculous just a few short *weeks* ago. Also, we need to know more about these pesky stem cells, which is an argument for *more* research, not less, of course.
Posted by: Tatarize | September 20, 2007 5:40 PM
So useful neurons build more neurons. Where I have heard of this before? It vaguely reminds me of something.
Posted by: Jon D. Moulton | September 20, 2007 5:42 PM
A complexin Morpholino would lead to an interesting experiment. Can you do memory/behavior studies with zebrafish?
Posted by: Blake Stacey | September 20, 2007 5:46 PM
Tatarize:
Neural Darwinism, perhaps?
I learned a new unit today from reading that Nature Neuroscience article: a "mini" is what you get when a single vesicle of neurotransmitter dumps into a synapse!
Posted by: Tatarize | September 20, 2007 6:05 PM
Mental Note: Make sarcasm more pronounced. Thanks for the link though. So tempted to buy that book.
Posted by: minimalist | September 20, 2007 7:19 PM
Oh man, I shamefully stopped reading Littleton's work when I stopped working on synaptotagmins. need to check this out, stat.
Thanks for the heads up, PZ.
Posted by: SEF | September 20, 2007 7:53 PM
Erm: "Posted ... by Lua Yar"
Posted by: melior | September 20, 2007 8:00 PM
More fascinating details this week in Science Daily about what's happening on the other side of the cleft too.
Posted by: Bechamel | September 20, 2007 8:09 PM
Wow. I didn't even notice until I got to the comments that it wasn't PZ doing the writing. I'm impressed. (Lua, have you been noticing any growths resembling tentacles lately?)
This is fascinating stuff to this here semi-educated layman.
Posted by: Bee | September 20, 2007 8:58 PM
This is fascinating material. Post more!
Posted by: Ichthyic | September 20, 2007 9:19 PM
so...
shall we call this evidence of Irreducible Complexin?
(sorry, but somebody had to).
Posted by: John Scanlon, FCD | September 20, 2007 10:51 PM
Tatarize, the sarcasm came through loud and clear on the second attempt - but perhaps only because I did rush out and buy it when it came out (or in 1997, to be precise). Not that I regret it - it was my first year of full-time paid employment after being a student for decades, so the odd bit of wastage is only to be expected.
Posted by: Caledonian | September 20, 2007 11:09 PM
Uncontrolled neural rewiring is probably not a good idea. If it were, we likely wouldn't have developed a physiological pathway to limit it in the first place.
Posted by: Chaz | September 20, 2007 11:24 PM
I actually learned about somethine like this today in class!
In other news, "synapse" backwards is "espanys"
Posted by: Glen | September 21, 2007 12:39 AM
Good post. More please Lua.
Posted by: Torbjörn Larsson, OM | September 21, 2007 4:46 AM
So there is a certain tension between normal functioning of neurons and synaptic growth. Not exactly what I would call "nice" :-P, but understandable and interesting.
I'm sorry, but actually I found a more fascinating item on development today, the press release describing results on how nuclear membrane forms during mitosis. I have a vague memory of the disassembling-assembling hypothesis and the machinery it required to evenly divide and reform the nuclear membrane.
But what actually happens makes more sense, a natural folding and binding of ER tubules around the chromatin. Perhaps PZ can get some evo-devo mileage out of that, or at least find some analogy to embryonic tissue layers.
Posted by: Mike Fox | September 21, 2007 9:48 AM
That's some really great writing. I was seriously pulled in. I was hoping there would be more after the fold. With pictures. I don't mean you didn't "do enough", though. I'm telling you that what you have is really good and I want more. :-)
Posted by: No One of Consequence | September 21, 2007 1:13 PM
What I understand of this sounds very cool, but I must admit it's a little over my head. A pretty picture might help and a little bit of "in layman's terms".
Anyway, great post (and still nothing to rip you on).