A brain-machine interface instructed by direct intracortical microstimulation

Abstract

Brain–machine interfaces (BMIs) establish direct communication between the brain and artificial actuators. As such, they hold considerable promise for restoring mobility and communication in patients suffering from severe body paralysis. To achieve this end, future BMIs must also provide a means for delivering sensory signals from the actuators back to the brain. Prosthetic sensation is needed so that neuroprostheses can be better perceived and controlled. Here we show that a direct intracortical input can be added to a BMI to instruct rhesus monkeys in choosing the direction of reaching movements generated by the BMI. Somatosensory instructions were provided to two monkeys operating the BMI using either: (a) vibrotactile stimulation of the monkey's hands or (b) multi-channel intracortical microstimulation (ICMS) delivered to the primary somatosensory cortex (S1) in one monkey and posterior parietal cortex (PP) in the other. Stimulus delivery was contingent on the position of the computer cursor: the monkey placed it in the center of the screen to receive machine–brain recursive input. After 2 weeks of training, the same level of proficiency in utilizing somatosensory information was achieved with ICMS of S1 as with the stimulus delivered to the hand skin. ICMS of PP was not effective. These results indicate that direct, bi-directional communication between the brain and neuroprosthetic devices can be achieved through the combination of chronic multi-electrode recording and microstimulation of S1. We propose that in the future, bidirectional BMIs incorporating ICMS may become an effective paradigm for sensorizing neuroprosthetic devices.

Biological and bionic hands: Natural neural coding and artificial perception

“…Early examples of somatosensory neuroprostheses demonstrated that animals could perform behavioural tasks based on largely arbitrary patterns of ICMS delivered to S1 [17][18][19][20]. These studies applied Romo's finding-that animals could discriminate ICMS that varied in frequency-to establish a proof-of-principle that this approach might be applied to bi-directional brain-machine interfaces-i.e.…”

Optical imaging of cortical networks via intracortical microstimulation

“…Studies that use electrical stimulation to evoke complex motor movements use less, with typical values being 300 Hz, 500 ms, and amplitudes ranging from 10 to 300 A depending on cortical area (Bruce et al 1985;Graziano et al 2002;Thier and Andersen 1998). Finally, awake behaving studies have found current detection thresholds to be around 10 A, or less with training, when intracortical microstimulation is applied to sensory cortices (Medina et al 2012;Murphey and Maunsell 2007;Ni and Maunsell 2010;O'Doherty et al 2009;Salzman et al 1990; for reviews, see Clark et al 2011;Histed et al 2013). For the parameters tested, cortical activation was dependent on both the current amplitude of a single pulse and the number of pulses.…”

Untitled

“…Figure 3 shows the schematics of the first brain-computer-brain interface (BCBI) designed in Nicolelis laboratory by O'Doherty, Lebedev and their colleagues [80]. Microelectrode arrays were implanted into motor and somatosensory cortex of monkeys.…”

“…The sensory part of the loop serves as a feedback tool. It transmits artificial tactile signals into somatosensory cortex through intracortical microstimulation (O'Doherty et al [80]). Integration of brain activity of several subjects using a brain net Each monkey was seated in a separate room and watched a virtual arm on the screen; the task was to touch the object using the virtual arm (A).…”