Background Information
Meditation is known to affect emotional regulation and mental health, but we still lack a clear picture of how it changes the brain—especially in deep regions like the amygdala and hippocampus. Previous studies using
EEG
An electroencephalogram (EEG) is a recording of brain activity. During this painless test, small sensors are attached to the scalp to pick up the electrical signals produced by the brain.
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and
fMRI
An fMRI (functional Magnetic Resonance Imaging) measures changes in blood flow related to neural activity in the brain, offering insights into brain function and activity patterns.
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have shown altered brain activity during meditation, but these techniques can’t directly access the limbic system. This study takes advantage of a rare opportunity: patients with implanted neurostimulation devices in their amygdala and hippocampus for epilepsy treatment. These implants allow researchers to directly measure the brain’s electrical activity during meditation with high spatial and temporal resolution.
Loving-kindness meditation (LKM), the focus of this study, is a practice that involves cultivating warm, benevolent feelings toward oneself and others (one of the
Brahmavihārās
Brahma Vihara meditation, also known as the Four Immeasurables, involves cultivating four qualities: loving-kindness (metta), compassion (karuna), empathetic joy (mudita), and equanimity (upekkha). It aims to develop a state of unconditional love, compassion towards suffering, joy in the happiness of others, and a balanced mind in all situations.
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). Previous research has shown it can increase positive emotions and reduce stress, but this is one of the first attempts to look at its effects inside the brain itself, in real time, and in novice meditators. These findings complement earlier research by Lutz et al. (2004), who observed pronounced gamma synchrony in experienced meditators during loving-kindness meditation, suggesting that meditation experience may intensify these neurological effects.
What They Did
Eight participants with implanted brain electrodes took part in a short loving-kindness meditation session. After five minutes of listening to guided instruction (serving as a baseline), they meditated for ten minutes while continuing to be recorded. Participants rated their depth of meditation afterward, reporting fairly high levels of engagement.
The researchers examined several types of brain signals in the amygdala and hippocampus:
- Rhythmic Oscillations: These are periodic, wave-like bursts of electrical activity at specific frequencies. The team looked at the strength (power) and duration of two kinds of waves—
beta
Beta brain waves are a type of brainwave pattern that oscillate between approximately 12 to 30 Hz. Beta waves are typically associated with active thinking, focus, alertness, and engagement with the external world. They are prominent during conscious, goal-directed activity and are linked to cognitive tasks such as problem-solving, decision-making, and sustained attention.
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View in glossary (13–30 Hz) and gamma Gamma brain waves are a type of brainwave pattern that oscillate at approximately 25 to 100 Hz. Gamma waves are associated with states of heightened perception, problem-solving, and consciousness. Gamma waves play a crucial role in cognitive functioning, including memory, and information processing, and are thought to integrate thoughts and information from different parts of the brain.
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View in glossary (30–55 Hz). Beta waves are associated with attention and control, while gamma waves are linked to emotional integration and memory processing. - Background Activity: In addition to rhythmic bursts, the brain also generates continuous background activity that reflects general levels of excitability and arousal. The researchers checked whether meditation changed this baseline activity but found no evidence that it did.
- Presence of Oscillations: The team also checked whether meditation increased the number of channels showing detectable rhythmic activity, which would suggest a broad recruitment of brain networks.
The findings were then compared to participants’ self-reported meditation depth to assess how these brain changes might relate to real-world experience.
One Big Result
A single session of loving-kindness meditation was enough to increase high-frequency gamma activity in the emotional centers of the brain—even in first-time meditators.
This gamma increase occurred in both the amygdala and hippocampus, and most participants showed this effect individually. These fast brain rhythms are thought to reflect intense, focused neural processing, and are often associated with positive affect and memory recall—both central to LKM practice.
“These findings provide anatomically localized and neurophysiologically detailed evidence for the role of these regions in meditation and suggest an association with their known roles in memory and emotional regulation processes.”
Miscellaneous Interesting Takeaways
Emotional and Attentional Shifts
While gamma activity increased, beta wave duration decreased during meditation. Beta waves are often associated with outward-directed attention and environmental monitoring. Their reduction suggests a shift away from scanning the external world, and toward a more internal, emotionally focused mental state.
“Decreased β oscillations with LKM may also represent a shift from negative emotional states, in turn for more positively salient γ oscillations at the network level.”
No Broadening of Activity
The meditation didn’t activate more brain regions—it changed how already active areas were behaving. There was no increase in the number of electrodes showing rhythmic activity, but in those already engaged, the nature of the activity changed: longer gamma bursts, shorter beta bursts, and stronger gamma power.
Deep Access to the Emotional Brain
This study is one of the first to show that even a brief meditative state can modulate the amygdala and hippocampus directly. These structures are heavily involved in mood and memory, and are often dysregulated in depression and anxiety.
Final Reflection
This work opens a window into the brain’s emotional circuitry during meditation and suggests that even beginners can meaningfully reshape neural activity with just a few minutes of focused practice.
Loving-kindness meditation can immediately shift the emotional brain toward patterns associated with calm, connection, and positive affect. While this study focused on loving-kindness meditation, Hagerty et al. (2013) found distinct patterns of brain activation during jhana meditation, highlighting how different meditation techniques may recruit different neural networks.
Citation
Maher, C., Tortolero, L., Jun, S., Cummins, D. D., Saad, A., Young, J., Nunez Martinez, L., Schulman, Z., Marcuse, L., Waters, A., Mayberg, H. S., Davidson, R. J., Panov, F., & Saez, I. (2025). Intracranial substrates of meditation-induced neuromodulation in the amygdala and hippocampus. Proceedings of the National Academy of Sciences, 122(6). 10.1073/pnas.2409423122