A team of researchers from the Salk Institute together with other international scientists have discovered that the capacity of our memory is much greater than the estimates that had been made previously when testing the size of our neural connections and unveiling a real “bomb in the field. of neuroscience ”.
“ We have discovered the key to unlocking the design principle of the way that neurons in the hippocampus function with low energy , but with high power of efficiency. Our new measures of the memory capacity of the brain increase by a factor of 10 with respect to the conservative estimates ”, explains Terry Sejnowski, co-author of the study.
And it is that our memories and thoughts are the result of the patterns of electrical and chemical activity within our brain. Thus, a fundamental part of this activity occurs when the connections of neurons interact at certain junctions, which we know as synapses ; and each neuron can have thousands of these synapses with thousands of other neurons.
Reconstructing each dendrite, axon, synapse … of a rat hippocampal volume the size of a single blood cell, experts were a bit puzzled by the complexity and diversity between synapses. However, the 3D reconstruction of this tissue from the brain’s memory center revealed something unusual . In some cases, a single axon from one neuron formed two synapses upon reaching a single dendrite from a second neuron, meaning that the first neuron appeared to be sending a duplicate message to the first.
To delve into this astonishing duplication of the hippocampus, they used the advanced microscopy and computational algorithms they had developed to image rat brains and reconstruct the area of brain tissue with connectivity, shapes, volumes, and surface area down to a nanomolecular level. The synapses were almost identical. Since the memory capacity of neurons depends on the size of the synapse, the difference found of + 8% turned out to be a key number to measure the potential amount of information that could be stored in the synaptic connections.
“Our data suggest that there are 10 times more discrete synapse connections than previously thought,” says Tom Bartol, a co-author of the study.
“ The work resulting from this collaboration has opened a new chapter in the search for learning and memory mechanisms. The implications of what we find are far-reaching. Hidden under the apparent chaos and disorder of the brain there is an underlying precision to the size and shapes of the synapses that you hide from us ”, clarifies Sejnowski.
The study has been published in the eLife journal.
