Non-invasive transmission of sensorimotor information in humans using an EEG/focused ultrasound brain-to-brain interface

Abstract

We present non-invasive means that detect unilateral hand motor brain activity from one individual and subsequently stimulate the somatosensory area of another individual, thus, enabling the remote hemispheric link between each brain hemisphere in humans. Healthy participants were paired as a sender and a receiver. A sender performed a motor imagery task of either right or left hand, and associated changes in the electroencephalogram (EEG) mu rhythm (8–10 Hz) originating from either hemisphere were programmed to move a computer cursor to a target that appeared in either left or right of the computer screen. When the cursor reaches its target, the outcome was transmitted to another computer over the internet, and actuated the focused ultrasound (FUS) devices that selectively and non-invasively stimulated either the right or left hand somatosensory area of the receiver. Small FUS transducers effectively allowed for the independent administration of stimulatory ultrasonic waves to somatosensory areas. The stimulation elicited unilateral tactile sensation of the hand from the receiver, thus establishing the hemispheric brain-to-brain interface (BBI). Although there was a degree of variability in task accuracy, six pairs of volunteers performed the BBI task in high accuracy, transferring approximately eight commands per minute. Linkage between the hemispheric brain activities among individuals suggests the possibility for expansion of the information bandwidth in the context of BBI.

Real Time and Delayed Effects of Subcortical Low Intensity Focused Ultrasound

“…multi-unit ultrasound arrays). While animal studies, even in large brained (and thick-skulled) animals 8 , suggest the general accuracy of linear targeting and human LIFU studies to date 10,[58][59][60] have often elected to forgo per-subject modeling of attenuation and refraction through skull, a fuller, more subject-specific, investigation of possible skull-refractory effects in naturalistic experimental settings in human subjects remains desirable going forward.…”

Transcranial focused ultrasound stimulation of motor cortical areas in freely-moving awake rats

“…The majority of these studies, conducted on anesthetized animals, showed a degree of variability in response to the stimulation, depending on the types and depths of anesthesia [ 24 , 28 , 31 , 37 , 40 ]. To examine the behavioral responses to FUS, without the confounding effects from anesthesia, experimentations in an awake setting are desired, and several recent studies on non-human primates and human subjects started to demonstrate the feasibility of tFUS in brain stimulation without the use of anesthesia [ 18 , 20 – 23 , 25 , 41 , 42 ].…”

Focused ultrasound brain stimulation to anesthetized rats induces long‐term changes in somatosensory evoked potentials

“…The technique has also been applied to modulate the function of deep brain areas, for example, the hippocampus or the thalamus in rodents . Its utility has been extended to provide means for brain stimulation in the context of brain‐to‐brain interface …”

“…[11][12][13][14] Its utility has been extended to provide means for brain stimulation in the context of brain-to-brain interface. 15,16 The presence of durable changes on neural excitability induced by a brain stimulation modality, assimilating the effects such as long-term potentiation (LTP) or long-term depression (LTD), is considered one of the main features that may ultimately lead to neuroplasticity. For example, TMS applied for extended duration has shown LTD-like effects, 17 mediated by changes in activity of the N-methyl-D-aspartate (NMDA) glutamate receptor.…”