The Language of the Brain: What Are Brain Waves?

Brain waves are rhythmic electrical currents generated when the electrical activity of neurons synchronizes as they communicate with each other. When a neuron is stimulated, it generates an action potential, which is transmitted to other neurons through synapses. During this process, neurotransmitters are released, causing changes in the membrane potential of surrounding neurons. These electrical fluctuations form specific patterns and cycles, which can be considered the brain’s fundamental mode of communication—essentially, the "language of the brain."

Although the electrical activity of individual neurons is difficult to detect directly, the synchronized activity of many neurons appears as brain waves. Brain waves are categorized by frequency into delta, theta, alpha, beta, and gamma waves, each reflecting different brain states. For example, delta waves are associated with deep sleep, alpha waves are prominent in a relaxed state, and gamma waves are linked to intense focus and creative thinking. Analyzing brain waves plays a crucial role in studying learning, memory, and cognition.

Brain Waves That Drive Memory and Learning: Theta-Gamma Coupling

Among brain waves, theta-gamma coupling (TGC) is particularly noteworthy in learning and memory processes. This unique phenomenon occurs when gamma waves emerge within the cycle of theta waves, helping to coordinate neural signaling and systematically process information. The stronger the theta-gamma coupling, the more efficiently memories are formed and learning occurs.

Conversely, in conditions like Alzheimer’s disease or alcoholism, where memory formation is impaired, this coupling weakens. This suggests that theta-gamma coupling is not merely an electrical signal but a crucial marker of cognitive ability. Scientists have explored ways to artificially induce and enhance this coupling by modulating neural plasticity.

The Link Between Neural Plasticity, Brain Waves, and Learning

Neural plasticity refers to the brain’s ability to adapt and reorganize itself in response to new experiences and learning. During this process, the strength of synaptic connections can be enhanced (LTP: Long-Term Potentiation) or weakened (LTD: Long-Term Depression), allowing the brain to absorb new information and restructure existing knowledge. This adaptability is the foundation of learning and cognitive flexibility.

Theta-gamma coupling is closely connected to neural plasticity, and enhancing or restoring this coupling can improve learning and memory capabilities. Such research has significant implications not only for treating neurodegenerative diseases like Alzheimer’s but also for enhancing memory and learning abilities in healthy individuals.

New Approaches to Neuromodulation

Neuromodulation refers to techniques that regulate neural activity externally, either through stimulation or pharmacological interventions, to modify brain function. This technology is used to restore balance in neural networks or enhance specific functions. Various neuromodulation methods include electrical stimulation (tDCS, DBS), magnetic fields (TMS), and light-based techniques (optogenetics). However, these methods face limitations in precisely targeting specific brain regions or stimulating deeper brain structures. Additionally, many of these approaches are invasive, making clinical applications challenging.

In contrast, ultrasound technology is emerging as a groundbreaking alternative that overcomes these limitations. Ultrasound can non-invasively reach deep brain structures with high spatial precision, allowing for selective control of specific neuron populations. Moreover, by fine-tuning its intensity, frequency, and patterns, ultrasound can either activate or inhibit neuronal activity.

[Figure 1] Ultrasound Transforming the Brain

In this study, researchers developed a novel ultrasound stimulation technology called TBUS (Theta-Gamma coupled Burst Ultrasound Stimulation), which mimics theta-gamma coupling (TGC). This technique uses ultrasound stimulation that aligns with the brain’s natural rhythms, inducing brain wave activity and modulating neuronal connections by either strengthening or weakening them. Notably, TBUS was proven to be highly effective when combined with existing neural plasticity protocols that induce LTP (Long-Term Potentiation) and LTD (Long-Term Depression), leading to more efficient modifications in brain function.

A variation of TBUS, iTBUS (intermittent TBUS), applies brief, periodic stimulation to activate neuronal activity. This method showed remarkable effects in enhancing learning speed and memory retention. In one experiment, rodents that received iTBUS exhibited a significantly steeper learning curve compared to the control group and demonstrated superior memory retention after learning.

In contrast, cTBUS (continuous TBUS) delivers sustained stimulation aimed at suppressing excessive neuronal excitation. This approach was found to prevent brain fatigue caused by overactivation but also resulted in reduced learning and memory abilities. These differences highlight that TBUS is not merely a method for stimulating neurons—it precisely regulates brain wave rhythms and neural activity.

The Potential to Reshape Brain Structure and Function

Perhaps the most striking finding was that TBUS stimulation induced long-term structural changes in the brain, rather than just temporary effects. Even a short ultrasound stimulus lasting less than three minutes led to persistent modifications in neuronal connectivity and the reorganization of neural circuits.

These results underscore ultrasound stimulation as a powerful tool for modulating neural plasticity. TBUS holds great potential not only for enhancing memory and learning abilities but also as a promising therapeutic approach for neurodegenerative diseases like Alzheimer’s.

A New Paradigm in Brain Disease Treatment

This study presents a revolutionary approach to treating neurological disorders by leveraging brain waves to induce behavioral changes and bidirectionally regulate brain activity. Unlike traditional treatments that primarily rely on medication to alleviate symptoms, TBUS offers a fundamental therapeutic solution by modulating brain waves through ultrasound. This breakthrough technology has the potential to redefine the future of neural disease treatment.