Development of an invasive brain-machine interface with a monkey model

Abstract

Brain-machine interfaces (BMIs) translate neural activities of the brain into specific instructions that can be carried out by external devices. BMIs have the potential to restore or augment motor functions of paralyzed patients suffering from spinal cord damage. The neural activities have been used to predict the 2D or 3D movement trajectory of monkey's arm or hand in many studies. However, there are few studies on decoding the wrist movement from neural activities in center-out paradigm. The present study developed an invasive BMI system with a monkey model using a 10×10-microelectrode array in the primary motor cortex. The monkey was trained to perform a two-dimensional forelimb wrist movement paradigm where neural activities and movement signals were simultaneous recorded. Results showed that neuronal firing rates highly correlated with forelimb wrist movement; > 70% (105/149) neurons exhibited specific firing changes during movement and > 36% (54/149) neurons were used to discriminate directional pairs. The neuronal firing rates were also used to predict the wrist moving directions and continuous trajectories of the forelimb wrist. The four directions could be classified with 96% accuracy using a support vector machine, and the correlation coefficients of trajectory prediction using a general regression neural network were above 0.8 for both horizontal and vertical directions. Results showed that this BMI system could predict monkey wrist movements in high accuracy through the use of neuronal firing information.

Electronic structure and properties of RbTiOPO4:Ta crystals

“…This enhancement could be due to the larger atomic radius of Ta 5+ (0.640Å) compared to Ti 4+ (0.605Å). The substitution of Ta 5+ for Ti 4+ in RTP increases the degree of distortion of the TiO 6 octahedron, 35 which enhances SHG intensity in RTP:Ta crystals. Ta doping RTP crystals for improvement of SHG efficiency makes them better for laser and nonlinear optical applications.…”

Neural Decoding Using a Parallel Sequential Monte Carlo Method on Point Processes with Ensemble Effect

“…Details about the surgical procedure could be found in [34, 35]. After the surgical procedure, a 128 Cerebus Data Acquisition system (Blackrock Microsystems, USA) was used to record the neuronal action potentials during the experiment.…”

High-fidelity compression of extracellular recordings from motor cortex

“…For clearer demonstration, this algorithm considers compression applied on one channel, compression between different channels are independent according to the third character exploited in section II. After dividing the signal into blocks, we firstly calculate the Quantization Table (QT ) for a sample(line [3][4][5][6][7][8], where F (i) is the DCT coefficients of X (i) and low (i) is the indices of Low Amplitude Components Lc. Then each block sample is compressed with the Dual-Phase Encoding(Line 9-18).…”

“…The dataset of our experiments comes from two male rhesus monkeys (Macaca mulatta) by the BMI system at Zhejiang University Qiushi Academy [6]. In this system, each monkey was trained to perform a four-direction centered-out task by turning a joystick according to some prompt.…”