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Tracking Neural Modulation Depth by Dual Sequential Monte Carlo Estimation on Point Processes for Brain Machine Interfaces

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Yiwen Wang, Xiwei She, Yuxi Liao, Hongbao Li, Qiaosheng Zhang, Shaomin Zhang, Xiaoxiang Zheng and Jose Principe. Zhejiang University and University of Florida

Tracking Neural Modulation Depth

Classic Brain Machine Interface (BMI) approaches decode neural signals from the brain responsible for achieving specific motor movements, which subsequently command prosthetic devices. Brain activities adaptively change during the control of the neuro-prosthesis in BMIs, where the alteration of the preferred direction and the modulation of the gain depth are observed.  The static neural tuning models have been limited by fixed codes, resulting in a decay of decoding performance over the course of the movement and subsequent instability in motor performance. To achieve stable performance, we propose a dual sequential Monte Carlo adaptive point process method, which models and decodes the gradually changing modulation depth of individual neuron over the course of a movement. We use multi-channel neural spike trains from the primary motor cortex of a monkey trained to perform a target pursuit task using a joystick. Our results show that our computational approach successfully tracks the neural modulation depth over time with better goodness-of-fit than classic static neural tuning models, resulting in smaller errors between the true kinematics and the estimations in both simulated and real data. Our novel decoding approach suggests that the brain may employ such strategies to achieve stable motor output, i.e. plastic neural tuning is a feature of neural systems. BMI users may benefit from this adaptive algorithm to achieve more complex and controlled movement outcomes.

Keywords: neuroplasticity, tracking modulation depth, sequential Monte Carlo estimation, point process, brain machine interfaces

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