Your Brain Maps Treats Like a GPS for Rewards

Scientists have discovered that your brain maintains a specialized neural map that tracks the locations of rewarding experiences with GPS-like precision, updating almost instantly when treats move to new locations.

Using advanced brain imaging techniques on mice navigating virtual reality environments, researchers at Stanford University found that specific neurons create detailed maps marking where good things happen—maps that persist even when animals travel many meters away from rewards and adapt within minutes when reward locations change.

The discovery reveals how our brains balance two competing needs: maintaining stable maps of our environment while quickly adapting to changes in where we find valuable resources. This delicate neural balancing act may hold keys to understanding both dementia and addiction.

“No matter where we moved the reward, the reward map adapted almost immediately,” said Lisa Giocomo, a professor of neurobiology at Stanford Medicine. “I wasn’t expecting the change to be so quick.”

Two Maps, One Brain

The research team discovered something remarkable in the mouse hippocampus—the brain region crucial for memory and navigation. Rather than using a single map system, the brain simultaneously maintains two distinct neural networks: one that tracks spatial locations and another that specifically charts reward positions.

Think of it like having both Google Maps and a personal restaurant app running in your head. Google Maps gives you street layouts and landmarks that stay constant. Your restaurant app tracks your favorite coffee shops, updating instantly when a beloved café moves or closes.

To study this phenomenon, researchers created an ingenious setup. Mice ran on wheels while surrounded by three large monitors displaying virtual hallways—”People picture mice wearing miniature virtual reality goggles, but actually it’s more like an IMAX Theatre situation,” explained Marielena Sosa, a postdoctoral scientist who performed the work.

The Neural Switch

When scientists moved virtual sugar water to new locations, they watched brain activity change in real time. Two populations of neurons responded differently. One group maintained steady maps of the virtual environment itself—tracking walls, landmarks, and spatial relationships that remained constant.

But a separate group of neurons switched their activity patterns almost immediately when rewards moved. These “reward-relative” neurons didn’t just track spots close to treats. They created sequences spanning the entire environment, from one reward location to the next, sometimes stretching distances equivalent to many city blocks in human terms.

What wasn’t highlighted in initial reports is that these reward maps actually strengthen with experience rather than fade. As mice got better at the task, more neurons joined the reward-tracking network. The brain literally invested more processing power in mapping valuable experiences as animals learned where to find food consistently.

Key findings from the research include:

• Reward maps persist across distances equivalent to city blocks
• Neural changes often precede behavioral changes by several trials
• Brain allocates more neurons to reward tracking as learning improves
• Individual neurons can switch between spatial and reward mapping roles
• Both maps operate simultaneously without interference

When Maps Go Wrong

The discovery carries profound implications for understanding human conditions. In people with dementia, the research suggests, these two mapping systems may become disconnected. Someone might remember sitting at their kitchen table but forget whether they had coffee there—a breakdown between spatial awareness and reward memory.

“Someone who first uses drugs at a concert might always be triggered to seek out drugs when they’re at a concert, for instance. And that can be a big problem because it causes people in recovery to relapse when they encounter those triggering environments,” Giocomo said. In addiction, the link between location and reward memories becomes pathologically strong.

The timing of neural changes proved particularly intriguing. Reward map updates often preceded behavioral changes, suggesting these brain circuits don’t just respond to what animals do—they help drive future decisions. “The switch at the neural level was obvious even before the switch at the behavioral level,” Sosa noted.

Flexibility Within Structure

Perhaps most surprising was the brain’s flexibility in assigning mapping duties. Neurons weren’t permanently locked into spatial or reward roles. Instead, cells could switch functions, with spatial neurons sometimes joining the reward network when circumstances changed.

This finding challenges the idea that different brain functions require dedicated, specialized circuits. Instead, it suggests our brains use flexible networks that can rapidly reassign priorities based on what matters most for survival and success.

Understanding these neural links between spatial information and rewards could ultimately lead to therapies that weaken problematic associations in addiction or strengthen helpful memories in dementia treatment.