Study shows our brain is active during familiar, repetitive tasks

Anew research suggests that our brains are never at rest, even when we are not learning anything about the world around us. The research was earlier conducted on mice.

Our brains are often likened to computers, with learned skills and memories stored in the activity patterns of billions of nerve cells. However, the new research shows that memories of specific events and experiences may never settle down. Instead, the activity patterns that store information can continually change, even when we are not learning anything new.

Why does this not cause the brain to forget what it has learned? The University of

Cambridge, Harvard Medical School and Stanford University study reveals how the brain can reliably access stored information despite drastic changes in the brain signals that represent it.

The research, led by Dr Timothy O’Leary from the Cambridge’s Department of Engineering, shows that different parts of our brain may need to relearn and keep track of information in other parts of the brain as it moves around. The study provides some of the first evidence that constant changes in neural activity are compatible with long-term memories of learned skills.

The researchers came to this conclusion through modelling and analysis of data taken from an experiment in which mice were trained to associate a visual cue at the start of a 4.5-metre-long virtual reality maze with turning left or right at a T-junction, before navigating to a reward.

The results of the 2017 study showed that single nerve cells in the brain continually changed the information they encoded about this learned task, even though the behaviour of the mice remained stable over time. The experimental data consisted of activity patterns from hundreds of nerve cells recorded simultaneously in a part of the brain that controls and plans movement, recorded at a resolution that is not yet possible in humans.

Nerve cells connect to hundreds or even thousands of their neighbours and extract information by weighting and pooling it.