Transcranial ultrasound neuromodulation induces neuronal correlation change in the rat somatosensory cortex

Abstract

Transcranial focused ultrasound (tFUS) is a neuromodulation technique which has been the focus of increasing interest for noninvasive brain stimulation with high spatial specificity. Its ability to excite and inhibit neural circuits as well as to modulate perception and behavior has been demonstrated, however, we currently lack understanding of how tFUS modulates the ways neurons interact with each other. This understanding would help elucidate tFUS’s mechanism of systemic neuromodulation and allow future development of therapies for neurological disorders. In this study, we investigate how tFUS modulates neural interaction and response to peripheral electrical limb stimulation through intracranial multi-electrode recordings in the rat somatosensory cortex. We deliver ultrasound in a pulsed pattern to induce frequency dependent plasticity in a manner similar to that found following electrical stimulation. We show that neural firing in response to peripheral electrical stimulation is increased after ultrasound stimulation at all frequencies, showing tFUS induced changes in excitability of individual neurons in vivo. We demonstrate tFUS sonication repetition frequency dependent pairwise correlation changes between neurons, with both increases and decreases observed at different frequencies. These results extend previous research showing tFUS to be capable of inducing synaptic depression and demonstrate its ability to modulate network dynamics as a whole.

Transcranial Magneto-Acoustic Stimulation Protects Synaptic Rehabilitation from Amyloid-Beta Plaques via Regulation of Microglial Functions

“…Recent research has indicated that TUS monotherapy can enhance synaptic rehabilitation at 250-720 I SPTA (mW/cm 2 ) [33][34][35][36]; the I SPTA used was 5 to 14 times higher than the 53 mW/cm 2 we utilized. Additionally, the combination of ultrasound with microbubbles to invasively open the blood-brain barrier also enhances synaptic rehabilitation [37][38][39].…”

Transcranial focused ultrasound activates feedforward and feedback cortico-thalamo-cortical pathways by selectively activating excitatory neurons

“…Previous studies have shown that different types of neurons from Layer 5 and Layer 6 are more strongly connected to the thalamus, especially POm. And previous study showed that tFUS has different effects on neurons in different layers of cortex [55]. Further studies are warranted, specifically recording from broader layers and using neuronal subtype labelling methods (such as optogenetic technique) to investigate the specifics of these responses.…”

Ultrasound pulse repetition frequency preferentially activates different neuron populations independent of cell type

“…While thin ring transducers have been applied in mouse imaging studies 34,50 , their focusing ability is even more limited than standard focused ultrasound transducers. Similarly, collimators have been used to further limit the sonication area [51][52][53] (Fig. 2e) but are too bulky for optical imaging compatibility.…”