A study says brain circuits can change roles: Here’s how you can remember a shopping list, directions and prices at the same time

You walk into a supermarket without checking your shopping list. Milk and bread are easy to remember. Then an employee tells you where to find the flour. Later, you compare the prices of two packets. Nothing about the trip feels remarkable. Yet your brain keeps moving between different kinds of information. Remembering a product is different from holding a direction in mind.

A study from MIT offers a clue to how such flexibility might work. Researchers found that some brain circuits in mice could be reused to hold different kinds of information.

What MIT discovered about flexible brain circuits

The study appeared in Nature Neuroscience on August 17, 2026. Lead author Yuma Osako worked with senior researchers Mriganka Sur and Timothy Buschman.


The team trained mice to compare two sounds. The animals had to remember the first tone, then judge whether the second matched it. Later, they had to hold their planned response in mind. Researchers recorded activity from thousands of neurons.


In the prefrontal cortex, a brain region involved in planning, they identified a group that changed roles. Earlier, it held information about a sound. Later, it held an action plan.

Parietal cortex neurons showed a different pattern. The memory-related neurons there appeared to hold the tone rather than switch to remembering the action.

Working memory keeps useful information within reach

Return to the supermarket aisle. You remember the flour's location long enough to walk towards it. At the shelf, you hold one price in mind while checking another. Psychologists call the temporary holding and use of information “working memory”.

Think of a small classroom whiteboard. A teacher writes something needed for the current question. Once the class moves on, the board can hold something else.

The MIT finding suggests a similar principle at the level of neural activity. Some circuits could carry out a memory operation with different contents at different stages.

Psychologists Alan Baddeley and Graham Hitch proposed a working memory model in 1974. Their account distinguishes between ways of handling different information.

The “phonological loop” helps hold speech-based information. Silently repeating “milk and bread” illustrates the idea. The “visuospatial sketchpad” handles visual and spatial information. Picturing the flour shelf offers an everyday example.

A control system called the “central executive” helps manage attention. The model describes mental functions; it does not assign each function to one fixed group of neurons.

Why reusable brain circuits resemble building blocks

Buschman connects the findings to “compositionality”. The term means using simpler components to build a more complicated activity.

Imagine a box of building blocks. The same pieces can become a house or a bridge. Their usefulness comes from how they fit together.

A grocery trip also combines smaller mental operations. Holding information briefly is useful when remembering a direction. The same general operation matters when keeping a price in mind.


According to MIT's report, reusable circuits could help the brain manage varied tasks without creating a separate circuit for every new demand.Reuse refers to a computation changing contents. It does not mean every part of the brain does every job.

Flexible memory still has limits

At the checkout, someone asks what you are making for dinner. You answer, then suddenly forget the price you were comparing. A flexible system can still have limited space.

Psychologist Nelson Cowan's research describes a central working memory capacity of roughly three to five meaningful items in young adults. Performance varies with the task and the person. The number is not a strict daily allowance. Remembering a familiar combination differs from holding several unrelated details.

The MIT experiment did not test people remembering shopping lists alongside prices. Grocery shopping is an illustration of the broader question. The actual evidence came from mice performing a controlled task. Remembering different things during one outing also differs from processing them all simultaneously.

What the study means for everyday memory

You reach the checkout with your groceries. Along the way, the information you needed kept changing. The study offers evidence that neural resources can change roles as a task unfolds. Understanding that reuse may help explain cognitive flexibility. An ordinary shopping trip now looks a little less ordinary. Your brain's flexibility lies partly in what familiar circuits can do next.

FAQs

Were humans tested in the experiment?

No. Researchers studied mice and used artificial neural network models.

Does circuit reuse mean unlimited multitasking?

No. The study demonstrated reuse during a task, rather than unlimited simultaneous processing.