The Brain Mechanism Behind Multitasking

Summary: Reactivating a learned memory is key to our ability to multitask, researchers report.

Source: AFTAU.

The brief reactivation of a learned memory can block interference from competing tasks, Tel Aviv University researchers say.

Although “multitasking” is a popular buzzword, research shows that only 2% of the population actually multitasks efficiently. Most of us just shift back and forth between different tasks, a process that requires our brains to refocus time and time again — and reduces overall productivity by a whopping 40%.

New Tel Aviv University research identifies a brain mechanism that enables more efficient multitasking. The key to this is “reactivating the learned memory,” a process that allows a person to more efficiently learn or engage in two tasks in close conjunction.

“The mechanism may have far-reaching implications for the improvement of learning and memory functions in daily life,” said Dr. Nitzan Censor of TAU’s School of Psychological Sciences and Sagol School of Neuroscience. “It also has clinical implications. It may support rehabilitation efforts following brain traumas that impact the motor and memory functions of patients, for example.”

The research, conducted by TAU student Jasmine Herszage, was published in Current Biology.

Training the brain

“When we learn a new task, we have great difficulty performing it and learning something else at the same time. For example, performing a motor task A (such as performing a task with one hand) can reduce performance in a second task B (such as performing a task with the other hand) conducted in close conjunction to it. This is due to interference between the two tasks, which compete for the same brain resources,” said Dr. Censor. “Our research demonstrates that the brief reactivation of a single learned memory, in appropriate conditions, enables the long-term prevention of, or immunity to, future interference in the performance of another task performed in close conjunction.”

The researchers first taught student volunteers to perform a sequence of motor finger movements with one hand, by learning to tap onto a keypad a specific string of digits appearing on a computer screen as quickly and accurately as possible. After acquiring this learned motor memory, the memory was reactivated on a different day, during which the participants were required to briefly engage with the task — this time with an addition of brief exposure to the same motor task performed with their other hand. By utilizing the memory reactivation paradigm, the subjects were able to perform the two tasks without interference.

By uniquely pairing the brief reactivation of the original memory with the exposure to a new memory, long-term immunity to future interference was created, demonstrating a prevention of interference even a month after the exposures.

Image shows a cartoon of a person multitasking.

By uniquely pairing the brief reactivation of the original memory with the exposure to a new memory, long-term immunity to future interference was created, demonstrating a prevention of interference even a month after the exposures. NeuroscienceNews.com image is for illustrative purposes only.

“The second task is a model of a competing memory, as the same sequence is performed using the novel, untrained hand,” said Dr. Censor. “Existing research from studies on rodents showed that a reactivation of the memory of fear opened up a window of several hours in which the brain was susceptible to modifications — in which to modify memory.

“In other words, when a learned memory is reactivated by a brief cue or reminder, a unique time-window opens up. This presents an opportunity to interact with the memory and update it — degrade, stabilize or strengthen its underlying brain neural representations,” Dr. Censor said. “We utilized this knowledge to discover a mechanism that enabled long-term stabilization, and prevention of task interference in humans.

The researchers are eager to understand more about this intriguing brain mechanism. “Is it the result of hardwired circuitry in the brain, which allows different learning episodes to be integrated? And how is this circuitry represented in the brain? By functional connections between distinct brain regions? It is also essential to determine test whether the identified mechanism is relevant for other types of tasks and memories, not only motor tasks,” Dr. Censor concluded.

About this neuroscience research article

Source: George Hunka – AFTAU
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Memory Reactivation Enables Long-Term Prevention of Interference” by Jasmine Herszage and Nitzan Censor in Current Biology. Published online April 13 2017 doi:10.1016/j.cub.2017.04.025

Cite This NeuroscienceNews.com Article
AFTAU “Human Voices Are Unique But We’re Not That Good at Recognizing Them.” NeuroscienceNews. NeuroscienceNews, 21 June 2017.
<http://neurosciencenews.com/multitasking-brain-mechanism-6949/>.
AFTAU (2017, June 21). Human Voices Are Unique But We’re Not That Good at Recognizing Them. NeuroscienceNew. Retrieved June 21, 2017 from http://neurosciencenews.com/multitasking-brain-mechanism-6949/
AFTAU “Human Voices Are Unique But We’re Not That Good at Recognizing Them.” http://neurosciencenews.com/multitasking-brain-mechanism-6949/ (accessed June 21, 2017).

Abstract

Memory Reactivation Enables Long-Term Prevention of Interference

Highlights
•Exposing the brain to different memories induces interference, reducing performance
•Memory reactivation prevented long-term interference even following a month
•Preventing interference specifically depended on the reactivation-induced time window

Summary
The ability of the human brain to successively learn or perform two competing tasks constitutes a major challenge in daily function. Indeed, exposing the brain to two different competing memories within a short temporal offset can induce interference, resulting in deteriorated performance in at least one of the learned memories. Although previous studies have investigated online interference and its effects on performance, whether the human brain can enable long-term prevention of future interference is unknown. To address this question, we utilized the memory reactivation-reconsolidation framework stemming from studies at the synaptic level, according to which reactivation of a memory enables its update. In a set of experiments, using the motor sequence learning task we report that a unique pairing of reactivating the original memory (right hand) in synchrony with novel memory trials (left hand) prevented future interference between the two memories. Strikingly, these effects were long-term and observed a month following reactivation. Further experiments showed that preventing future interference was not due to practice per se, but rather specifically depended on a limited time window induced by reactivation of the original memory. These results suggest a mechanism according to which memory reactivation enables long-term prevention of interference, possibly by creating an updated memory trace integrating original and novel memories during the reconsolidation time window. The opportunity to induce a long-term preventive effect on memories may enable the utilization of strategies optimizing normal human learning, as well as recovery following neurological insults.

“Memory Reactivation Enables Long-Term Prevention of Interference” by Jasmine Herszage and Nitzan Censor in Current Biology. Published online April 13 2017 doi:10.1016/j.cub.2017.04.025

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