A new study shows how our brain makes new memories, without deleting the older ones.
Columbia scientists have developed a new mathematical model that helps to explain how the human brain’s biological complexity allows it to lay down new memories without wiping out old ones, illustrating how the brain maintains the fidelity of memories for years, decades or even a lifetime.
This model could help neuroscientists design more targeted studies of memory, and also spur advances in neuromorphic hardware, powerful computing systems inspired by the human brain.
- Samajwadi Party Crisis Deepens: Here’s How It Will Impact UP Polls
- 24 Maoists Killed In Encounter In Odisha
- Varun Gandhi Under Attack Over Defence Deals: Here’s How
- This Diwali, Let Blind Students Brighten Up your Homes With Candles & Diyas
- CBI Files Supplementary Chargesheet In Sheena Bora Murder Case
- Soha Ali Khan And Vir Das Starrer 31st October Audience Reaction
- Sahara Chief Subrata Roy’s Parole Extended Till November 28
- Simple Tips To Secure Your Debit Card From Fraudsters
- New Zealand & India Team Being Welcomed In Chandigarh
- Mumbai Call Centre Scam: All You Need To Know
- Jammu Kashmir Chief Minister Mehbooba Mufti Appeals To Police: Here’s What She Said
- Shocker From Ahmedabad: Find Out What Happened
- Bigg Boss 10 Day 3 Review: Celebs Fail To Do Well in First Task
- Airtel Offers 10GB Data At Rs 259 For New 4G Smartphone Users
- Aamir Khan Starrer Dangal’s Trailer Launched: First Impressions
“The brain is continually receiving, organizing and storing memories. These processes, which have been studied in countless experiments, are so complex that scientists have been developing mathematical models in order to fully understand them,” said Stefano Fusi, the paper’s senior author. “The model that we have developed finally explains why the biology and chemistry underlying memory are so complex, and how this complexity drives the brain’s ability to remember.”
Memories are widely believed to be stored in synapses, tiny structures on the surface of neurons. These synapses act as conduits, transmitting the information housed inside electrical pulses that normally pass from neuron to neuron. In the earliest memory models, the strength of electrical signals that passed through synapses was compared to a volume knob on a stereo; it dialed up to boost (or down to lower) the connection strength between neurons. This allowed for the formation of memories.
These models worked extremely well, as they accounted for enormous memory capacity. But they also posed an intriguing dilemma.
“The problem with a simple, dial-like model of how synapses function was that it was assumed their strength could be dialed up or down indefinitely,” said Dr Fusi, adding, “But in the real world this can’t happen. Whether it’s the volume knob on a stereo, or any biological system, there has to be a physical limit to how much it could turn.”
When these limits were imposed, the memory capacity of these models collapsed.
So Dr Fusi, in collaboration with fellow Zuckerman Institute investigator Larry Abbot offered an alternative each synapse is more complex than just one dial, and instead should be described as a system with multiple dials.
In 2005, Drs Fusi and Abbott published research explaining this idea. They described how different dials within a synapse could operate in tandem to form new memories while protecting old ones. But even that model, the authors later realized, fell short of what they believed the brain, particularly the human brain, could hold.
“We came to realize that the various synaptic components, or dials, not only functioned at different timescales, but were also likely communicating with each other,” said Marcus Benna, the first author of today’s Nature Neuroscience paper. “Once we added the communication between components to our model, the storage capacity increased by an enormous factor, becoming far more representative of what is achieved inside the living brain.”
See what else is making news.
Dr Benna likened the components of this new model to a system of beakers connected to each other through a series of tubes.
“In a set of interconnected beakers, each filled with different amounts of water, the liquid will tend to flow between them such that the water levels become equalized. In our model, the beakers represent the various components within a synapse,” explained Dr Benna. “Adding liquid to one of the beakers or removing some of it represents the encoding of new memories. Over time, the resulting flow of liquid will diffuse across the other beakers, corresponding to the long-term storage of memories.”
Both the researchers are hopeful that this work can help neuroscientists in the lab, by acting as a theoretical framework to guide future experiments, ultimately leading to a more complete and more detailed characterization of the brain.
“While the synaptic basis of memory is well accepted, in no small part due to the work of Nobel laureate and Zuckerman Institute codirector Dr Eric Kandel, clarifying how synapses support memories over many years without degradation has been extremely difficult,” said Dr Abbott “The work of Drs Benna and Fusi should serve as a guide for researchers exploring the molecular complexity of the synapse.”
The technological implications of this model are also promising. Dr Fusi has long been intrigued by neuromorphic hardware, computers that are designed to imitate a biological brain.
“Today, neuromorphic hardware is limited by memory capacity, which can be catastrophically low when these systems are designed to learn autonomously,” said Dr Fusi “Creating a better model of synaptic memory could help to solve this problem, speeding up the development of electronic devices that are both compact and energy efficient and just as powerful as the human brain.”
This paper titled, “Computational principles of synaptic memory consolidation” is published online in Nature Neuroscience.