Brainwaves being manipulated by analog circuits.

Brainwave Boost: Can Real-Time Feedback Fine-Tune Your Mind?

Soraya Malik in Health & Wellness December 2025 • 4 min read.

"New research explores how analog feedback can alter alpha-frequency brain oscillations, potentially unlocking new treatments for neuropsychiatric disorders."

Our brains are constantly humming with electrical activity, creating rhythmic patterns known as brainwaves or local field potentials (LFPs). These oscillations are thought to play a critical role in coordinating neural activity and communication between different brain regions. Understanding and controlling these patterns could open new doors for treating a range of neurological and psychiatric conditions.

However, reliably altering LFP oscillations has been a significant challenge. Existing techniques, like transcranial alternating current stimulation (tACS) and deep brain stimulation (DBS), have limitations in their precision and effectiveness. Often, the brain responds by changing activity in different frequency bands than the one being targeted.

Now, a new study offers a promising approach: a closed-loop analog circuit that enhances brain oscillations by feeding them back into the cortex in real-time. This method, tested on rhesus macaques, demonstrates the potential for precisely altering brain activity and could pave the way for innovative therapies.

Decoding the Analog Feedback System

Brainwaves being manipulated by analog circuits.

The researchers focused on alpha oscillations (8-15 Hz), which are associated with top-down cortical processing and have been implicated in various cognitive functions. The key to their system is an analog circuit designed to extract and invert the sign of these neural oscillations using an active inverting band-pass filter. This filter targets a slightly wider band than alpha, at 8-16 Hz, to minimize phase distortion.

Here's a breakdown of how the system works:

Neural Signals Recorded: Brain activity is picked up by chronically implanted electrode arrays.
Analog Filtering: The recorded signals are processed through the analog filter, which isolates the alpha frequency band and inverts the signal.
Real-Time Feedback: The filtered signal is then fed back into the cortex through phase-locked transcranial electrical stimulation (tACS).
Closed-Loop Control: This creates a continuous feedback loop where the stimulation is adjusted in real-time based on the brain's ongoing activity.

The team tested the system in a rhesus macaque, comparing closed-loop stimulation to open-loop stimulation (where the stimulation was not directly tied to the brain's activity). The results were striking: closed-loop stimulation increased alpha oscillatory power for up to a second after stimulation offset, while open-loop stimulation decreased alpha power. Importantly, these effects were frequency-specific, with no changes observed in neighboring beta frequencies or in brain regions not participating in the feedback loop.

The Future of Brainwave Modulation

This study offers preliminary but compelling evidence that analog closed-loop stimulation can effectively alter brain oscillations. While the research is still in its early stages, it holds significant implications for both basic neuroscience research and the treatment of neuropsychiatric diseases.

The researchers acknowledge several challenges that need to be addressed in future work, including carefully managing phase delays in the processing chain and measuring both local and remote stimulation effects. They also emphasize the need for rapidly tunable variable components to match a given patient's peak alpha frequency for optimal results.

As technology advances, real-time digital neural signal processing may become fast enough for effective phase-locked stimulation. This type of rapid feedback stimulation holds promise as a valuable tool for cognitive neuroscience and neuropsychiatric treatment, potentially leading to more personalized and effective interventions for a wide range of brain disorders.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1371/journal.pone.0207781, Alternate LINK

Title: Altering Alpha-Frequency Brain Oscillations With Rapid Analog Feedback-Driven Neurostimulation

Subject: Multidisciplinary

Journal: PLOS ONE

Publisher: Public Library of Science (PLoS)

Authors: Alik S. Widge, Matthew Boggess, Alexander P. Rockhill, Andrew Mullen, Shivani Sheopory, Roman Loonis, Daniel K. Freeman, Earl K. Miller

Published: 2018-12-05

Everything You Need To Know

What are brainwaves, and why are they significant?

Brainwaves, also known as local field potentials (LFPs), are rhythmic patterns of electrical activity in the brain. They are fundamental to neural communication and coordination between different brain regions. Different brainwave frequencies are associated with various cognitive functions. Understanding and manipulating these brainwave patterns may provide new avenues for treating neurological and psychiatric conditions. Alpha oscillations are particularly important and have been associated with top-down cortical processing.

How does the analog feedback system work?

The study uses a closed-loop analog circuit to influence brain activity. The system has the following steps: First, neural signals are recorded using chronically implanted electrode arrays. Second, these signals are processed through an analog filter which isolates the alpha frequency band and inverts the signal. Third, the filtered signal is fed back into the cortex through phase-locked transcranial electrical stimulation (tACS). Lastly, this creates a continuous feedback loop where the stimulation is adjusted in real-time based on the brain's ongoing activity. The feedback loop allows for precise, real-time adjustment of the stimulation based on the current brain activity.

Why did the researchers focus on Alpha oscillations, and what are their implications?

The researchers focused on Alpha oscillations, which have a frequency range of 8-15 Hz. Alpha oscillations are associated with top-down cortical processing. These oscillations have been linked to various cognitive functions. The specific targeting of alpha frequencies is important because it allows for a more targeted approach to influencing brain activity and understanding its impact on specific cognitive processes. Because of the frequency specificity, this method of stimulation did not impact neighboring beta frequencies, showing that the method is precise.

What is the difference between closed-loop and open-loop stimulation, and why does it matter?

Open-loop stimulation does not take into account the current state of the brain. In contrast, closed-loop stimulation uses a feedback system that adjusts stimulation in real-time, based on the ongoing brain activity. This feedback loop allows for precise control over brainwave modulation, providing an effective way to influence brain activity. The study on rhesus macaques found that closed-loop stimulation increased alpha oscillatory power, whereas open-loop stimulation decreased it. This shows that closed-loop is more effective.

What are the potential future impacts of this brainwave modulation study?

The use of analog closed-loop stimulation has significant implications for neuroscience research and the treatment of neuropsychiatric diseases. It offers a new method for precisely altering brain activity, which could lead to innovative therapies for neurological and psychiatric conditions. The study's success in manipulating brainwaves in rhesus macaques could pave the way for new treatments. Specifically, the ability to modulate Alpha oscillations opens up possibilities for treating conditions related to cognitive function. Further research is needed, but this preliminary study demonstrates the potential of this approach to improve brain health.