Stemming from our intellectual interests on how physical forces influence neuronal signalling and brain function, we began developing noninvasive methods for mapping and modulating brain activity patterns using low-intensity, low-frequency ultrasound (LILFU). Ultrasound is a mechanical pressure wave that can be safely and nonivasively focused to millimeter scale regions of the intact human brain. Ultrasound can be used to visualize neural activity through photoacoustic tomography or similar spectroscopic approaches or even more readily by conventional Doppler blood flow imaging. In these cases, the neural signals reported by ultrasound are hemodynamic and closely related to the same ones reported by fMRI BOLD imaging. However, ultrasound technology is far more portable and far less expensive comapred to MR, CT, PET or other known human brain imaging techniques. Thus we have anticpated that ultrasound for brain mapping efforts can provide the largest and most diverse data sets since it can (and is already) more broadly deployed than any of the aforementioned brain imaging technologies.
Other advantages of ultrasound are that it can be focused through the skull to any discrete region of the brain with millimeter accuracy. Ultrasound has a technology architecture already in place, which is readily capable of providing real-time data reporting structural and functional activity maps of the human brain. Further, ultrasound has been long known capable of modulate the activity of cells by acting through thermal and/or nonthermal mechanisms of action. Through our studies on the nonthermal (mechanical) actions of ultrasound on brain circuits we discovered ultrasonic neuromodulation (UNMOD) methods for nonivasively stimulating brain cirucits with ultrasound. Now we are leading efforts to translate our technology through multi-national, multi-institutional, and multi-organization efforts on functional brain mapping and noninvasive neuromodulation.
All cells including neurons are constantly subjected to a mechanical forces arising from lipid-protein interactions, the cytoskeleton, adhesion molecules, and others. The brain is viscoelastic and the subcellular components of neurons including ion channels are mechanically sensitive. Many brain diseases are associated with changes in the rigidity and stiffness of neurons and brain circuits. Neuronal activity and plasticity are affected by mechanical forces. How? This is one of the main questions we are addressing
To understand how to improve brain function, we study neuronal circuits underlying cognitive behaviors in humans. In these studies we use a variety of approaches, such as EEG and fMRI to monitor brain activity during decision making, problem solving, and learning while biasing activity in these circuits using noninvasive neuromodulation.