If you’ve ever looked at the abs of a footballer or the neck of a Formula 1 driver and admired their devotion to building and maintaining all that muscle, you might be surprised to know that a similar process is at work deep inside you – and in part, contributed to by that very thought.

That is, the muscle work is ongoing in your brain.

According to new research recently published in the journal Cell, there are some intricate signals being relayed – very similar to those molecular signals that make your arm or leg muscles contract – working in your brain at this very moment.

Whenever you are learning or remembering something, the study suggests, a newly-investigated network of subcellular structures are hard at work; and these structures are similar to those that send signals in our biceps and calves to instruct them to contract when we exercise.

The study was conducted by a team led by Jennifer Lippincott-Schwartz, who explained in a statement that their hypothesis emerged when they realised that membranes inside brain cells were acting interestingly.

In observed samples of Endoplasmic Reticulum (ER) of neuron cells from mammalian brains, the team noticed molecules moving in a curious way:

“The molecules were tracing a repeating, ladder-like pattern along the entire length of the dendrites – the branch-like extensions on brain cells that receive incoming signals.”

This observation led the team to compare the patterns to the only other parts of the body in which similar patterns are known to occur. In muscle cells, the paper explains, a similar ladder-like structure is followed by certain molecules.

And in their investigations, this molecule, known as junctophilin, was also discovered to be a key part of dendrites in the brain – meaning that messages are passed to neurons in cells in the brain following a similar pattern to in muscle cells.

In their further application of this research, the team discovered that this pattern was also key to transmitting calcium signals, which are vital to cell communication, with research scientist Lorena Benedetti explaining in the statement that the patterns followed by molecules across dendrites helps to transmit and amplify signals to the neuron, and then eventually (if required) throughout the body:

“How that information travels over long distances and how the calcium signal gets specifically amplified was not known. We thought that ER could play that role, and that these regularly distributed contact sites are spatially and temporally localized amplifiers: they can receive this calcium signal, locally amplify this calcium signal, and relay this calcium signal over a distance.”

Thanks to their astute observations, the team were able to conclude that calcium enters the dendrite, which causes the ER to release extra calcium. This catalyses a reaction in the cell that stimulates memory-forming proteins, ultimately allowing messages to be passed to the neuron too.

And this, the researchers explain, could be fundamental to not only our deeper understanding of how messages are transmitted through neurons in the brain, but also to helping us to deepen our knowledge of how the brain functions.

That deeper understanding, it is hoped, will help the comprehension and treatment of conditions like Alzheimer’s.

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