Millions of 'Silent Synapses' Could Be The Key to Lifelong Learning

Newborns need to store a lot of new information fast. The hardware that allows this rapid information storage to occur early in life is thought to be silent sphinxes.

As the animals got older, these potential neurological intersections were thought to disappear. The vanishing act might not be as extreme as first thought.

The team didn't set out to look at these connections in a specific way. They were working on the locations of nerve cell extensions.

They got more than they thought they'd get. They captured images of the dendrites, but also many tiny, thread-like protrusions from them.

Mark Harnett, the senior author on the paper, said that the first thing they saw was that there were animals.

Usually hidden in the glare of fluorescent light, the researchers used a special technique to study the proteome.

The new process uses a gel to help lock delicate cellular structures into place and allow researchers to better study them as tissues are manipulated.

Two male and two female adult mice were injected with viruses to help light up the relevant tissues. Their primary visual cortex was removed and divided into smaller slices before being mounted between glass slides.

The researchers were able to take high-resolution images of the fluorescing dendrites because of this.

For the first time, the researchers were able to see that adult mice's brains had a lot of the same stuff as adult humans.

Many of the structures were only expected to have one of the two neurotransmitters needed to function. They were effectively'silent' junctions without the second.

The researchers wanted to know if silent sphinx could be activated.

A small electrical current was produced by releasing the neurotransmitter glutamate at the tips of the filopodia threads.

Within minutes, this procedure silenced the synapses and stimulated the formation of a connection with the neighboring nerve fibers.

The current frees the receptors and allows the filopodia to receive a message.

The team found that it was easy to change the activity of the dendritic spines on a mature neuron.

The researchers are trying to find out if silent synapses exist in the brains of adults.

The paper is the first proof that this is how it works in a brain.

It's possible to have a memory system that is both flexible and robust. You need flexibility to get new information, but you also need stability to keep important information.

The paper was published in a journal.