How 'mental time travel' functions?

A team of neuroscientists from Vanderbilt University in the US have decoded "mental time travel" - recollection of memories regarding the time and place of an original experience in so much detail that it is like travelling through time.

The team shed new light on how the brain processes these elaborate memories by analysing the brain activity of individuals performing a simple memory recollection task.

They found that they can use the activity patterns in a specific region of the brain to substantially improve their ability to predict the order in which the participants recall information that they have recently studied.

"It is extremely important that we understand what different brain regions are doing as we search through our memories," said assistant professor of psychology, Sean Polyn who is heading the study.

Diseases like Alzheimer's and epilepsy are devastating to memory and this information can help us develop treatments to preserve patients' memories, and identify adverse effects that new psychotropic drugs may have on people's memory," he said.

Scientists have known for some time that a portion of the brain called the medial temporal lobe (MTL) plays a central role in memory because injuries to the MTL causes amnesia and other memory-related problems.

However, they have not been able to answer the question as to how does the brain control the fidelity of an individual memory?

Polyn and his team developed a model that accounts for the structures in the MTL support memory retrieval.

They have found that the anterior region of the MTL signals that a memory is being retrieved but does not indicate how detailed it is.

However, when the posterior region of the MTL becomes active, it indicates that the person is experiencing a "time travel" memory accompanied by considerable detail.

The researchers tested their model in an experiment with 20 participants (seven male and 13 female) between ages 18 and 35.

They found that when a strong memory is formed, it may include information about the sights, sounds, smells, emotions and other information that was present at the time of the experience.

All of this information becomes temporally linked and time-travel memory allows a person to bring it back to the mind.

The memory model is an example of a new generation of brain simulations that are attempting to link the brain activity with specific cognitive functions, the authors concluded in a paper published in the Journal of Neuroscience.