A Boost of Motivation? Enhance Your Astrocytes to Reach Your Goals

Imagine a futuristic world where the brain’s potential is no longer a mystery or a limit. Mental abilities could be switched on and off like light switches. Preparing to run a marathon in the world’s most dazzling city would not require months of training. Just one pill, a precise dose, could activate the brain circuits you need. You take it, and something shifts inside: you start training without hesitation, as if determination had always been there.

For such a possibility to become real, we would need to understand exactly how the cells and molecules inside our brains work. But so far, attention has focused mostly on neurons, leaving out a key player in the story of the brain: glial cells. Among them, astrocytes, cells that surround, protect, and nourish neurons—have long been seen as mere supporting actors, passive onlookers in the complex drama of animal behavior.

We now know that astrocytes communicate through calcium (Ca²⁺) signals. These are triggered by synaptic activity between neurons, but the way each astrocyte responds, how far and how intensely calcium spreads, depends on the astrocyte’s own internal properties. Astonishingly, a single astrocyte can regulate up to 100,000 synapses, those critical contact points where neurons communicate. This raises a fascinating question: could astrocytes coordinate with each other—like neurons do—to influence brain activity?

In Spain, a team of researchers set out to explore this idea. Could astrocytes couple functionally, just like neurons? To investigate, they trained mice to activate their brain’s reward system, a circuit linked to motivation and goal-seeking. This system centers around the nucleus accumbens, a pea-sized structure that lights up when we feel pleasure or success.

Using a clever technique, the researchers injected genes into the nucleus accumbens that were specially designed to target astrocytes. This allowed them to control when astrocytes were turned on or off with great precision. In the experiment, mice received a sugary reward in their drinking water whenever they approached spouts marked with an LED light.

Dr. Irene Serra from the Cajal Institute in Madrid observed something remarkable: as the mice learned that the LED light meant a reward, specific groups of astrocytes became active. Even more intriguing, as learning progressed, more astrocytes joined the active group. In other words, the astrocytes did not just respond passively—they appeared to organize themselves, as if they too were learning alongside the neurons.

When the researchers artificially activated those same astrocyte groups, the mice showed a stronger preference for approaching the LED-lit spouts—but only while the light was on. This suggests that the astrocytes active during learning were key to linking the light with the reward. Even when the reward was removed, mice continued to approach the light, showing increased motivation, even in the absence of a payoff.

This finding opens up an exciting possibility: perhaps this is the key to that futuristic pill—a way to boost motivation by activating specific brain circuits, helping us push through the challenges of training for that marathon.

During the reward process, certain astrocytes became active in two areas of the nucleus accumbens: those linked to pleasure and those involved in associative learning. A classic example of associative learning is the use of mnemonics—like remembering that living things are mostly made of Carbon, Hydrogen, Oxygen, and Nitrogen by grouping the initials into “CHON.” The word, even outside a chemistry context, helps the information stick. In a similar way, astrocytes help create pleasurable sensations and reinforce the neuronal connections formed by repeated or meaningful stimuli.

This study focused on astrocytes in the nucleus accumbens, but the brain’s reward system also involves other regions like the prefrontal cortex, basal ganglia, and limbic system. Astrocyte activity is also tightly connected to neuromodulators like glutamate. So, creating that motivational pill would still require a great deal of research to fully understand how astrocytes shape brain function.

Ultimately, these scientists revealed something extraordinary: astrocytes are not passive in the brain’s reward-related behaviors. Instead, they actively participate in the neural circuits that influence motivation, and perhaps even in the decisions we make to pursue our goals—or to give up on them.

Glossary

Astrocytes

Star-shaped glial cells that provide structural support to neurons and regulate the chemical environment around them. Once considered passive, they are now known to play active roles in brain signaling.

Nucleus accumbens

A small brain region near the intersection of a line from your forehead to the center of your head and a line drawn from your ear upward. This structure is central to the brain's reward system and is responsible for feelings of pleasure and motivation. Its name comes from Latin, meaning “nucleus that lies next to the septum.”

Neuromodulators

Chemical messengers in the brain that influence how neurons respond to signals. Unlike classic neurotransmitters, which send direct messages between cells, neuromodulators “tune” the conversation—like turning up the volume or changing the tone. Examples include dopamine, serotonin, norepinephrine, and acetylcholine. They affect mood, motivation, sleep, learning, and attention.

Prefrontal cortex

Located right behind the forehead, this highly evolved brain area is responsible for planning, decision-making, impulse control, and predicting consequences. It acts like a conductor, coordinating thoughts and behaviors.

Basal ganglia

A group of deep brain structures involved in movement, habit formation, and automatic decision-making. Despite their name, they are not related to the immune system’s “ganglia.” They work closely with the prefrontal cortex and rely heavily on dopamine.

Glutamate

The brain’s main excitatory neurotransmitter. It is like a green light that increases the activity of neurons. While essential for learning and memory, too much glutamate can cause damage—a phenomenon known as excitotoxicity, which plays a role in neurodegenerative diseases like Alzheimer’s and ALS.

Calcium signals (Ca²⁺)

Brief changes in calcium ion levels inside brain cells that act like molecular switches. These pulses trigger events such as neurotransmitter release, synaptic plasticity (learning), and gene expression. Think of calcium as the backstage crew raising the curtain at just the right moment in the brain’s performance.

Reward System

The brain’s reward system is a network of structures and neural connections specialized in processing pleasurable stimuli, motivating adaptive behaviors, and consolidating learning related to survival. Its core function revolves around the release of dopamine, a key neurotransmitter that acts as a “reward signal” to reinforce beneficial behaviors.

Sources

Serra, I., Martín-Monteagudo, C., Sánchez Romero, J. et al. Astrocyte ensembles manipulated with AstroLight tune cue-motivated behavior. Nat Neurosci 28, 616–626 (2025). https://doi.org/10.1038/s41593-025-01870-0

Lines Justin, Baraibar Andres, Nanclares Carmen, Martín Eduardo D., Aguilar Juan, Kofuji Paulo, Navarrete Marta, Araque Alfonso (2023) A spatial threshold for astrocyte calcium surge eLife 12:RP90046 https://doi.org/10.7554/eLife.90046.1

Xu Y, Lin Y, Yu M, Zhou K. The nucleus accumbens in reward and aversion processing: insights and implications. Front Behav Neurosci. 2024;18:1420028. Published 2024 Aug 9. doi:10.3389/fnbeh.2024.1420028

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Biography

Laura Méndez is a doctoral student in Neurotoxicology at CINVESTAV, focused on the chemical and biological processes of the brain. She is passionate about knowledge and an active reader of fiction and philosophy. Through her research, she seeks to understand neurochemical mechanisms and explore the connections between science, culture, and thought.