Our Memory Capacity Is Greater Than We Knew

Our Memory Capacity Is Greater Than We Knew


Scientists have discovered ten times more memory capacity in the human brain.

Wish you had more storage space in your brain? Good news: you do! In fact, scientists have discovered 10 times more memory capacity. I wish I could tell you it’s a boost from all the walnuts and salmon you’ve been eating, but this capacity has been there all along—it’s just that new research has revealed it.

“Our new measurements of the brain’s memory capacity increase conservative estimates by a factor of 10 to at least a petabyte, in the same ballpark as the World Wide Web,” writes Terry Sejnowski, a professor at the Salk Institute in La Jolla, California, and co-senior author of the research, which was published in eLife. “This is a real bombshell in the field of neuroscience.”

It helps to first understand how our memories and thoughts occur: They’re a pattern of both electrical and chemical activity within the brain. A key part of the process is when branches of neurons, which are like electrical wires, interact with each other at junctions called synapses. The output “wire” (called an axon) from one neuron connects to the “input” wire (called a dendrite) of a second neuron. The electrical signal zooms across the junction, the synapse, as chemicals called neurotransmitters let the receiving neuron know what to do with the signal—where to send it next. Each neuron can have thousands of these synapses, connecting with thousands of other neurons.

What the researchers figured out, using microscopy and computer algorithms, is that the size of the synapses ranged much more widely than was previously believed. Synapses used to be categorized as small, medium, and large—like sweaters. “Our data suggests there are 10 times more discrete sizes of synapses than previously thought,” wrote Tom Bartol, a Salk staff scientist. “In computer terms, 26 sizes of synapses correspond to about 4.7 ‘bits’ of information. Previously, it was thought that the brain was capable of just one to two bits for short and long memory storage in the hippocampus.”

Furthermore, the synapses constantly adjust themselves. Every two to 20 minutes, a synapse can go up or down a size according to what signals it is receiving.

“The implications of what we found are far-reaching,” wrote Sejnowski. “Hidden under the apparent chaos and messiness of the brain is an underlying precision to the size and shapes of synapses that was hidden from us.”

So next time you can’t find your keys or blank on someone’s name, be gentle on yourself. Think of all the amazing other things your brain IS doing and is getting right: the powers of electricity and chemicals that are being harnessed to created speech, recognize objects, and learn sophisticated new ideas. Our brains are truly energy-efficient, flexible little miracles.

Kathryn Drury Wagner is a writer and editor based in Los Angeles. Her latest book is Hawaii’s Strangest, Ickiest, Wildest Book Ever!

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