Science //

A compass to the brain

Adam Chalmers takes a trip down memory lane.

The brain is as powerful as it is mysterious. While in the last few centuries we’ve decoded many of its secrets and charted its inner workings, one mystery still eludes us. How does the brain store memories? How do we remember and forget? New research from America might just answer this question. Travis Craddock, Jack Tuszynski, and Stuart Hameroff, three researchers from University of Alberta, Alberta, and Arizona respectively, have discovered a mechanism by which the brain encodes memories in individual neurons.

The brain is made up of trillions of neurons – basic building blocks of brain tissue that let you think, feel, and imagine. Individually, each neuron is simple, but they can be linked together by branch-like bits called synapses to display complex behaviour. Like a complicated computer made out of millions of simple transistors, brains get their complexity through networking simple bits together.

This, combined with strong evidence, suggested that memories are formed by synaptic connections. When different neurons trigger at the same time – in response to, say, your tongue tasting food – the synapses connecting them strengthen, and memories are stored – supposedly. But while synapse membranes change constantly in response to new stimuli, memory is relatively stable. As the paper abstract said, “Paradoxically components of synaptic membranes are relatively short-lived and frequently re-cycled while memories can last a lifetime.” This led Craddock, Tuszynski and Hameroff to look for memory-storage in a more stable aspect of the brain. While neural connections change constantly, the neurons themselves remain relatively stable. “This suggests synaptic information is encoded at a deeper, finer-grained scale of molecular information within neurons,” reads the paper.

The researchers identified little cylinders on the surface of neurons, called microtubules. Microtubules contain a hexagonal lattice of kinase proteins, which can be found either holding calcium ions, or holding nothing at all. Like a memory cell in a computer or USB, they have only two states – on (holding an ion) or off (not holding an ion). The resemblance to modern computer storage was a hint to the scientists, who found the behaviour of these microtubules matched the pre-existing models of memory formation. In short – they’d found where the brain stores memory. And it uses a similar system to computers.

This is a huge step forward for neuroscience and medicine. As senior author Hameroff said to Newswise: “Many neuroscience papers conclude by claiming their findings may help understand how the brain works, and treat Alzheimer’s, brain injury and various neurological and psychiatric disorders. This study may actually do that. We may have a glimpse of the brain’s biomolecular code for memory.”

Adam Chalmers is on Twitter: @adam_chal