Your brain treats GPS with images as rewards

Scientists have found that your brain maintains a dedicated neural map that tracks the location of reward experiences with GPS-like precision, updated almost immediately when snacks move to new locations.

Stanford researchers used advanced brain imaging to find on mice navigating virtual reality environments that specific neurons create detailed maps that mark where good things happen—the graphics still last within minutes even when the animals stay away from the reward and change in the reward location.

The discovery reveals how our brains balance two competitive needs: maintaining a stable map of the environment while quickly adapting to the changes we find valuable resources. This subtle neural balancing behavior may have the key to understanding dementia and addiction.

“Where we transfer the rewards, the reward map will be adapted almost immediately,” said Lisa Giocomo, a professor of neurobiology at Stanford University. “I didn’t expect the change to be so fast.”

Two maps, one brain

The team found something compelling in the mouse hippocampus, which is crucial for memory and navigation. Instead of using a single map system, the brain maintains two different neural networks: one tracks spatial locations and the other specifically draws reward locations.

Think of it as having both Google Map and personal restaurant apps running in your mind. Google Maps provides you with street layouts and landmarks that keep you constant. Your restaurant app tracks your favorite coffee shop and updates immediately when your beloved cafe moves or closes.

To study this phenomenon, the researchers created a clever setup. The rats ran on the wheels with three large monitors showing the virtual corridors – “People shot for mice wearing miniature virtual reality goggles, but in reality, it’s more like the situation in the IMAX theater,” explained Marielena Sosa, a postdoctoral scientist who performed the work.

Neural switch

When scientists moved virtual sugar water to a new location, they watched changes in real-time brain activity. The responses of the two neuronal populations are different. A group keeps the virtual environment itself stable map – isolation walls, landmarks and spatial relationships remain constant.

However, when the reward moves, a separate group of neurons switches the activity mode almost immediately. These “reward-related” neurons not only track spots close to snacks. They create sequences of the entire environment, from one reward location to the next, sometimes with the human scope equal to many urban neighborhoods.

It is not emphasized in the initial report that these reward maps are actually through experience rather than fading in. As the mice get better on the task, more neurons join the reward tracking network. The brain actually invests more processing power to map valuable experiences because animals learn where to find food.

The main findings of the study include:

• The reward map continues to exist at a distance equivalent to a city block
• Neurological changes usually pass multiple tests before behavioral changes
• As learning improves, the brain allocates more neurons to reward tracking
• A single neuron can switch between space and reward mapped characters
• Both maps run at the same time without interruption

When the map error occurs

This finding has profound implications for understanding the human condition. Studies have shown that in patients with dementia, these two mapping systems may be disconnected. Some people may remember sitting on their kitchen table but forgetting whether they were there to drink coffee, which is a breakdown between spatial awareness and reward memory.

“For example, people who use drugs for the first time at a concert may always trigger drugs. In addiction, the link between location and reward memory becomes pathologically strong.

It turns out that the timing of neural changes is particularly interesting. Reward map updates are often preceded by behavioral changes, suggesting that these brain circuits will not only respond to the animal’s work, but also help drive future decisions. “The switches on the nerve layer are also obvious before switching on the behavioral level,” Sosa notes.

Flexibility within the structure

Perhaps the most surprising thing is the flexibility of the brain in assigning mapping responsibilities. Neurons are not permanently locked into space or reward characters. Instead, cells can switch functions, and spatial neurons sometimes join the reward network when the situation changes.

This discovery challenges the notion that different brain functions require specialized circuits. Instead, this shows that our brains use flexible networks that can quickly reassign priorities based on survival and success.

Understanding these neural links between spatial information and rewards may ultimately lead to therapy that weakens problematic associations in addiction or enhances useful memory in treatment of dementia.

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