How connections in the brain must change to form memories could help to develop artificial cognitive computers

November 7, 2012
A schematic diagram depicting the recall of a sequence of memory items when the network containing the pool of memory items is triggered by a stimulus. Credit: 2012 A*STAR Institute for Infocomm Research

Exactly how memories are stored and accessed in the brain is unclear. Neuroscientists, however, do know that a primitive structure buried in the center of the brain, called the hippocampus, is a pivotal region of memory formation. Here, changes in the strengths of connections between neurons, which are called synapses, are the basis for memory formation. Networks of neurons linking up in the hippocampus are likely to encode specific memories.

Since direct tests cannot be performed in the brain, for this process of is difficult to obtain but mathematical and computational models can provide insight. To this end, Eng Yeow Cheu and co-workers at the A*STAR Institute for Infocomm Research, Singapore, have developed a model that sheds light on the exact synaptic conditions required in memory formation.

Their work builds on a previously proposed model of auto-associative memory, a process whereby a memory is retrieved or completed after partial activation of its constituent neural network. The earlier model proposed that neural networks encoding short-term memories are activated at specific points during oscillations of . Changes in the strengths of synapses, and therefore the abilities of neurons in the network to activate each other, lead to an auto-associative long-term memory.

Cheu and his team then adapted a mathematical model that describes the activity of a single neuron to incorporate specific characteristics of cells in the hippocampus, including their inhibitory activity. This allowed them to model neural networks in the that encode short-term memories. They showed that for successful formation of auto-associative memories, the strength of synapses needs to be within a certain range: if become too strong, the associated neurons are activated at the wrong time and networks become muddled, destroying the memories. If they are not strong enough, however, activation of some neurons in the network is not enough to activate the rest, and memory retrieval fails.

As well as providing insight into how memories may be stored and retrieved in the brain, Cheu thinks this work also has practical applications. "This study has significant implications in the construction of artificial cognitive computers in the future," he says. "It helps with developing artificial cognitive memory, in which memory sequences can be retrieved by the presentation of a partial query."  According to Cheu, one can compare it to a single image being used to retrieve a sequence of images from a video clip.

Explore further: Neuroscientists isolate molecular 'when' and 'where' of memory formation

More information: Cheu, E. Y., Yu, J., Tan, C. H. & Tang, H. Synaptic conditions for auto-associative memory storage and pattern completion in Jensen et al.'s model of hippocampal area CA3. Journal of Computational Neuroscience advance online publication, 30 May 2012 (doi: 10.1007/s10827-012-0394-8). http://link.springer.com/article/10.1007%2Fs10827-012-0394-8

Related Stories

Neuroscientists isolate molecular 'when' and 'where' of memory formation

October 15, 2012
Neuroscientists from New York University and the University of California, Irvine have isolated the "when" and "where" of molecular activity that occurs in the formation of short-, intermediate-, and long-term memories. Their ...

Neuroscientists identify a master controller of memory

December 22, 2011
When you experience a new event, your brain encodes a memory of it by altering the connections between neurons. This requires turning on many genes in those neurons. Now, MIT neuroscientists have identified what may be a ...

Scientists discover brain structures associated with learning

May 2, 2011
(Medical Xpress) -- Scientists at the Friedrich Miescher Institute for Biomedical Research (FMI, part of the Novartis Research Foundation) have discovered neuronal connections which are formed in the brain when learning occurs, ...

Recommended for you

Cognitive cross-training enhances learning, study finds

July 25, 2017
Just as athletes cross-train to improve physical skills, those wanting to enhance cognitive skills can benefit from multiple ways of exercising the brain, according to a comprehensive new study from University of Illinois ...

Brain disease seen in most football players in large report

July 25, 2017
Research on 202 former football players found evidence of a brain disease linked to repeated head blows in nearly all of them, from athletes in the National Football League, college and even high school.

Zebrafish study reveals clues to healing spinal cord injuries

July 25, 2017
Fresh insights into how zebrafish repair their nerve connections could hold clues to new therapies for people with spinal cord injuries.

Lutein may counter cognitive aging, study finds

July 25, 2017
Spinach and kale are favorites of those looking to stay physically fit, but they also could keep consumers cognitively fit, according to a new study from University of Illinois researchers.

Brain stimulation may improve cognitive performance in people with schizophrenia

July 24, 2017
Brain stimulation could be used to treat cognitive deficits frequently associated with schizophrenia, according to a new study from King's College London.

New map may lead to drug development for complex brain disorders, researcher says

July 24, 2017
Just as parents are not the root of all their children's problems, a single gene mutation can't be blamed for complex brain disorders like autism, according to a Keck School of Medicine of USC neuroscientist.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.