Dec 9, 2010 09:58 GMT  ·  By

Yale scientists identified a molecule that wires brain cells and also establishes the way we learn things, and concluded this is an important step towards new ways of improving memory and maybe correcting neurological diseases.

They focused on an adhesion molecule that holds synaptic junctions together, called SynCAM 1, and discovered that when it was active in mice, more synaptic connections formed, while mice without the molecule had a much lower rate of synapse production.

Thomas Biederer, associate professor of molecular biophysics and biochemistry and senior author of the study explained that “synapses are dynamic structures.”

When we learn, new synapses form, but the strength of synaptic connections can change during the learning process, depending on the amount of stimuli received, which scientists call 'plasticity'.

The Yale team worked with a group of German researchers led by Valentin Stein, and discovered that SynCAM 1 also controls an important form of synaptic plasticity.

Against all odds, Biedered and colleagues found that mice who had a very high quantity of SynCAM 1 were unable to learn, and mice who did not have SynCAM 1 at all, learned better, even if they had fewer synapses.

The conclusion from all this is that an excess of the adhesion molecules can cause damage, thus supporting the theory according to which having too many connections is not always better; for proper learning and memory, a balance of synaptic activity is most important.

“It appears that SynCAM 1 ties synapses together; some of this molecule is needed to promote contact but too much glues down the synapse and inhibits its function.

“It may act a bit like a sculptor who helps give synapses their shape,” Biederer added.

Synapses are the connections between brain cells over which nerve pulses pass, and they are what regulate learning, memory and the way we think.

When the structure and function of the synapses are suffering from anomalies, autism and mental retardation have been observed, while in the aging brains of people suffering from Alzheimer's, the synapses are lost.

There are still not enough things known about the mechanisms that organize the synapses within the living brain, but the SynCAM 1 molecule looks like a very important piece of the puzzle.

“We hypothesized that this molecule might promote new synapses in the developing brain, but were surprised that it also impacts the maintenance and function of these structures,” said Biederer.

“We can now define how this molecule supports the brain's ability to wire itself.”

The researcher added that this molecule is almost the same in mice and man, so it is very possible that its roles in the human brain are the same.

The finding is reported in the December 9 issue of the journal Neuron.