Dataset for: Decoding Motor Plans Using a Closed-Loop Ultrasonic Brain-Machine Interface

Description

This dataset accompanies "Decoding Motor Plans Using a Closed-Loop Ultrasonic Brain-Machine Interface". It includes the 2 Hz real-time data (.mat files), metadata about each session (`project_record.json`), and description of the contents of each .mat file (`DescriptionOfVariables.pdf`).

Abstract of "Decoding Motor Plans Using a Closed-Loop Ultrasonic Brain-Machine Interface"

Brain-machine interfaces (BMIs) enable people living with chronic paralysis to control computers, robots, and more with nothing but thought. Existing BMIs have tradeoffs across invasiveness, performance, spatial coverage, and spatiotemporal resolution. Functional ultrasound (fUS) neuroimaging is an emerging technology that balances these attributes and may complement existing BMI recording technologies. In this study, we use fUS to demonstrate a successful implementation of a closed-loop ultrasonic BMI. We streamed fUS data from the posterior parietal cortex of two rhesus macaque monkeys while they performed eye and hand movements. After training, the monkeys controlled up to eight movement directions using the BMI. We also developed a method for pretraining the BMI using data from previous sessions. This enabled immediate control on subsequent days, even those that occurred months apart, without requiring extensive recalibration. These findings establish feasibility of ultrasonic BMIs, paving the way for a new class of less invasive (epidural) interfaces that generalize across extended time periods and promise to restore function to people with neurological impairments.

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Methods

In brief, we used a programmable high-framerate ultrasound scanner (Vantage 256; Verasonics, Kirkland, WA) to drive the ultrasound transducer and collect pulse echo radiofrequency data. We used a custom-built computer running NeuroScan Live (ART INSERM U1273 & Iconeus, Paris, France) attached to the 256-channel Verasonics Vantage ultrasound scanner. This software implemented a custom plane-wave imaging sequence optimized to deliver Power Doppler images in real-time at 2 Hz with minimal latency between ultrasound pulses and Power Doppler image formation. The sequence used a pulse-repetition frequency of 5500 Hz and transmitted plane waves at 11 tilted angles equally spaced from -6° to 6°. These tilted plane waves were compounded at 500 Hz. Power Doppler images were formed from 200 compounded B-mode images (400 ms). To form the Power Doppler images, the software used an ultrafast Power Doppler sequence with an SVD clutter filter that discarded the first 30% of components. The resulting Power Doppler images were transferred to a MATLAB instance in real-time and used for the fUS-BMI. Each fUS image and associated timing information were saved for post hoc analyses. During each fUS-BMI session, we placed the ultrasound transducer (128-element miniaturized linear array probe, 15.6 MHz center frequency, 0.1 mm pitch, Vermon, France) on the dura with ultrasound gel as a coupling agent. We consistently positioned the ultrasound transducer across recording sessions using a slotted chamber plug. The imaging field of view was 12.8 mm (width) by 13-20 mm (height) and allowed the simultaneous imaging of multiple cortical regions, including lateral intraparietal area (LIP), medial intraparietal area (MIP), ventral intraparietal area (VIP), Area 7, and Area 5.

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