Non-Invasive Brain-to-Brain Interface (BBI): Establishing Functional Links between Two Brains

Abstract

Transcranial focused ultrasound (FUS) is capable of modulating the neural activity of specific brain regions, with a potential role as a non-invasive computer-to-brain interface (CBI). In conjunction with the use of brain-to-computer interface (BCI) techniques that translate brain function to generate computer commands, we investigated the feasibility of using the FUS-based CBI to non-invasively establish a functional link between the brains of different species (i.e. human and Sprague-Dawley rat), thus creating a brain-to-brain interface (BBI). The implementation was aimed to non-invasively translate the human volunteer’s intention to stimulate a rat’s brain motor area that is responsible for the tail movement. The volunteer initiated the intention by looking at a strobe light flicker on a computer display, and the degree of synchronization in the electroencephalographic steady-state-visual-evoked-potentials (SSVEP) with respect to the strobe frequency was analyzed using a computer. Increased signal amplitude in the SSVEP, indicating the volunteer’s intention, triggered the delivery of a burst-mode FUS (350 kHz ultrasound frequency, tone burst duration of 0.5 ms, pulse repetition frequency of 1 kHz, given for 300 msec duration) to excite the motor area of an anesthetized rat transcranially. The successful excitation subsequently elicited the tail movement, which was detected by a motion sensor. The interface was achieved at 94.0±3.0% accuracy, with a time delay of 1.59±1.07 sec from the thought-initiation to the creation of the tail movement. Our results demonstrate the feasibility of a computer-mediated BBI that links central neural functions between two biological entities, which may confer unexplored opportunities in the study of neuroscience with potential implications for therapeutic applications.

A multi-voxel pattern analysis of neural representation of vibrotactile location

“…Yoo et al also reported a functional link between the brains of different species (i.e. human and rat) developed non-invasively using transcranial focused ultrasound [4].…”

“…Recently many researchers have attempted to create a functional interface between the two brains, often called a brain-to-brain interface (BTBI) [3,4]. For instance, Pais-Vieria et al have established a link between the brains of two rodents and showed that behaviorally meaningful sensorimotor information from one could affect behavior of another in real time even when those animals were separated far apart [3].…”

Human-to-human closed-loop control based on brain-to-brain interface and muscle-to-muscle interface

“…In this study M1 neural ensemble was used as a motor information elicitation source in the encoder rat and invasive intercortical microstimulation (ICMS) as corresponding command inducer in the decoder rat’s brain 3 . BBI was also used to successfully establish artificial information transfer pathway from a human to a rat using electroencephalography (EEG) and transcranial focused ultrasound (FUS) to control a simple motion of the rat’s tail using BBI 4 . In a later study, the first direct brain-to-brain interface between two humans was established, which investigated the feasibility of decoding a command from a sender’s brain by EEG and forcing a receiver to follow the command using transcranial magnetic stimulation (TMS) 1 .…”

Conscious Brain-to-Brain Communication in Humans Using Non-Invasive Technologies

“…Over the last 15 years, technologies for non-invasive transmission of information from brains to computers have developed considerably, and today brain-computer interfaces embody a well-established, innovative field of study with many potential applications [12][13][14][15][16]. Recent work has demonstrated fully non-invasive human to rat B2B communication by combining motor imagery driven EEG in humans on the BCI side with ultrasound brain stimulation on the CBI-rat side [17]. However, the realization of non-invasive CBI in humans remains elusive, and adequate methodologies to provide computer-mediated non-invasive brain conscious interventions are lacking.…”