Exploring the Impact of Quadri-Pulse Stimulation (QPS) on Brain Microstructure and Functional Connectivity
Recent advancements in neurostimulation techniques have opened new avenues for understanding and modulating the human brain's structural and functional properties. A particularly intriguing approach is Quadri-Pulse Stimulation (QPS), a non-invasive method that delivers brief bursts of electrical pulses to specific brain regions. Researchers have been exploring how QPS can influence the brain's microstructural properties and functional connectivity, with the potential to revolutionise our understanding of neural plasticity and brain stimulation therapies. A recent study, by Kimura et al. (2024), offers valuable insights into how QPS, particularly using the DuoMAG MP Quad system, has contributed to these findings.
THE ROLE OF QUADRI-PULSE STIMULATION (QPS) IN BRAIN RESEARCH
QPS has garnered attention for its ability to induce lasting changes in brain activity, making it a powerful tool for studying neural plasticity. In this study, researchers aimed to determine whether microstructural properties of the brain could undergo immediate alterations following two different QPS protocols: QPS5 and QPS50. Additionally, they investigated whether these changes were associated with modifications in the brain's functional connectivity (FC). To achieve these objectives, the researchers employed a rigorous experimental design. Over three days, participants underwent a series of brain imaging sessions, including task-based functional MRI (fMRI), resting-state fMRI (rsfMRI), and diffusion MRI (dMRI). These sessions were conducted before and after administering QPS5 or QPS50, allowing the researchers to capture any immediate changes in brain microstructure and FC.
THE DUOMAG MP QUAD
A key component of this research was the DuoMAG MP Quad system, which played an instrumental role in delivering QPS with precision. This system, equipped with a 70-mm air-cooled butterfly coil (DuoMAG 70BF Air Cooled Coil), allowed the researchers to target the left primary motor cortex (M1) with remarkable accuracy. The coil's air-cooling feature was essential in maintaining a stable temperature during the 30-minute stimulation sessions, ensuring consistent and reliable results. The DuoMAG MP Quad's ability to deliver QPS at specific intervals (5 ms for QPS5 and 50 ms for QPS50) was crucial for the study's design. This precision enabled the researchers to compare the effects of different pulse intervals on the brain's microstructure and FC. The Brainsight system also provided real-time feedback on coil positioning, ensuring that the stimulation was applied consistently across sessions. This level of control was vital in minimising variability and enhancing the reliability of the findings.
Findings
The study's results revealed intriguing insights into how QPS affects the brain. After QPS5, there was a significant decrease in mean diffusivity (MD) values within the left cerebellum, suggesting microstructural alterations in this region. However, these changes were not observed with QPS50, indicating that the different pulse intervals may have distinct effects on brain microstructure. In terms of functional connectivity, QPS5 led to a significant decrease in FC between the left and right M1, as well as between the left M1 and the primary somatosensory cortex. Interestingly, these changes were not observed following QPS50, highlighting the potential for QPS5 to modulate connectivity more effectively.
The findings from this study underscore the potential of QPS, particularly when delivered through advanced systems like the DuoMAG MP Quad, to modulate brain structure and function. The ability to induce immediate changes in brain microstructure and FC opens up exciting possibilities for using QPS as a therapeutic tool in neurological and psychiatric disorders.
Dr Ikko Kimura, co-author of the article, hosted a webinar with the Brainbox Initiative delving into the details of the study. Watch now to learn more details from one of the scientists directly involved with the discussed research.
