A piece of the mouse hippocampus illustrates the place cells have been genetically engineered to fluoresce when lively utilizing GCaMP, a genetically encoded calcium indicator generally used to picture mind exercise. Credit score: Giocomo Lab
Think about you are strolling to work when the unspeakable happens: Your favourite espresso store—the place you cease day by day—is closed. You groggily navigate to a newly opened espresso store a pair blocks away, which, you are happy to find, really makes fairly a very good morning brew. Quickly, you end up trying ahead to stopping on the new location as a substitute of the outdated one.
That swap most likely alters extra than simply your morning routine. Every time you go to that new espresso store, the expertise probably strengthens a neural map marking the positions of rewarding experiences—a map that may information you again to these experiences even from miles away.
Whereas the existence of a reward map is acquainted from earlier work, Wu Tsai Neuro researchers working with mice have been shocked to search out that the map persists even when mice transfer many meters away from a deal with, and that it updates nearly instantly when the placement of the deal with modifications.
The work has been revealed in Nature Neuroscience.
“No matter where we moved the reward, the reward map adapted almost immediately,” mentioned Lisa Giocomo, a professor of neurobiology at Stanford Drugs and certainly one of Wu Tsai Neuro’s deputy administrators. “I wasn’t expecting the change to be so quick.”
The outcomes might make clear quite a lot of human situations, together with dementia and habit, in addition to illuminating an essential side of how animals survive within the wild.
To check how rewarding experiences are encoded within the brains of mice, Giocomo and her colleagues first changed a little bit of a mouse’s cranium with a clear window. That allowed the researchers to make use of a delicate method known as two-photon microscopy to look at neural exercise in actual time in a area of the mind known as the hippocampus.
The mice needed to keep beneath a stationary microscope for the method to work, so as a substitute of permitting the animals to seek for rewards in actual life, the researchers used a digital actuality surroundings.
“People picture mice wearing miniature virtual reality goggles, but actually it’s more like an IMAX Theater situation,” mentioned Marielena Sosa, a postdoctoral scientist who carried out the work together with former Giocomo Lab graduate pupil Mark Plitt, a member of Wu Tsai Neuro’s Thoughts, Mind, Computation and Know-how program.
The mice ran on wheels whereas surrounded by three massive screens that performed a video of a hallway that superior as they ran, sort of like a first-person (first-rodent?) online game. The researchers programmed the equipment in order that it allotted a drop of sugar water to the mouse when it approached a specific location within the digital surroundings. The group then moved the digital location of the sugar water and watched as neural exercise within the mind tailored.
As they anticipated, one inhabitants of neurons within the hippocampus maintained a secure map of the surroundings. Much less anticipated was the remark {that a} separate inhabitants of neurons turned on and off fluidly because the reward’s location modified, including a layer of adaptability that allow the mouse simply modify when the placement of the meals modified—an essential tactic within the wild.
The neurons that make up the 2 maps are additionally not fully distinct. Slightly, the neurons that make up the spatial map can generally swap to being concerned within the reward map and vice versa. Nonetheless, the full variety of neurons within the spatial map remained comparatively fixed, whereas the variety of neurons making up the reward map elevated because the mouse revisited the reward.
Anatomical distributions of reward-relative and track-relative cells. Credit score: Nature Neuroscience (2025). DOI: 10.1038/s41593-025-01985-4
Ultimately, the reward map might hold monitor of an animal’s place relative to the sugar water from meters away. On a human scale, that could possibly be equal to many metropolis blocks.
When the researchers modified the place of the deal with, “the switch at the neural level was obvious even before the switch at the behavioral level,” Sosa mentioned. That would imply that the neural reward map shapes a mouse’s future habits as a lot as its previous habits shapes the map.
There’s proof that people additionally retailer places they intend to return to in a separate set of neurons than these used to map their basic environment. Understanding the connections between these two maps might bear relevance to dementia and habit issues, the researchers imagine.
Folks with dementia are likely to neglect the sequences through which occasions occurred, which could possibly be defined, not less than partially, by a lack of the power to visualise the place they have been after they accomplished sure duties.
For instance, somebody with dementia might not bear in mind whether or not they drank their morning espresso within the kitchen or introduced it with them within the automotive, whereas a wholesome individual would distinctly bear in mind sitting at their kitchen desk with a cup in hand. That distinction could possibly be defined by an uncoupling between the reward map and the spatial map in folks with dementia.
Within the case of habit, recollections of rewarding experiences, like utilizing medicine, are sometimes tightly tied to spatial places.
“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 mentioned.
That could possibly be as a result of the hyperlink between the reward map and the spatial map created by the highly effective drug is unhealthily robust.
Understanding the neural hyperlinks between spatial info and rewards might in the end result in therapies that weaken these hyperlinks and assist folks overcome cravings introduced on by particular places. Conversely, therapies that strengthen the hyperlinks might assist folks residing with dementia.
The analysis group has extra questions, certainly one of which is how reward maps information animals as they discover their pure environments. “If you’re a mouse, how do you decide if you want to explore the possibility of finding food in new locations or return to a place where you’ve found food before?” Giocomo asks.
Finding out such questions might additionally reveal how people resolve when to hunt out novel experiences and when to return to the consolation of outdated habits.
The researchers additionally ponder whether fulfilling experiences in addition to meals are mapped utilizing the sort of neural construction. For instance, are the places of social interactions marked on reward maps? Mice and people are each extremely social animals, however will we use the identical kind of psychological maps to search out our buddies as we use to search out meals?
Giocomo thinks her lab has the instruments to search out out. “The technology is finally at the stage where we can start to tackle some of these more complex behaviors,” she mentioned.
Extra info:
Marielena Sosa et al, A versatile hippocampal inhabitants code for expertise relative to reward, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-01985-4
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Neural maps used to find rewards could also be disrupted in dementia and heightened in habit (2025, June 11)
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