Neural Prostheses



A. Active Carbon-nanotube Microelectrode Arrays

Introduction :Carbon-nanotubes (CNTs) with intriguing electrochemical properties have been an attractive material for neuro-electronic interfaces. While all other researchers focused on coating CNTs on electrodes to interface neurons extracellularly, we have demonstrated the feasibility of probing neural activity intracellularly with CNTs (Fig.1). Intracellular recording measures the potential of intracellular fluid of neurons directly, allowing sophisticated neuron activity like post-synaptic potentials to be probed with single-neuron resolution. By extending this research finding, we have been developing customized CNT microelectrode arrays (CMEA) with integrated circuitry for long-term neural recording and stimulation.

 

Characteristics : This research relies on close collaboration with neuroscientists, mechanical engineers, and material scientists. After modelling the interface of CNT microelectrodes, integrated circuits able to record and stimulate neurons through the CNT interface are designed and tested.

Pre-requisites:Knowledge in electronics, VLSI design, basic neuroscience, and basic electrochemistry

Professional skills obtained:Knowledge in neuro-electrophysiology, Methodology in modeling and designing bio-electronic interfaces, Design of mixed-mode integrated circuit for neural recording and stimulation.

Fig.1 :(a)The CNT probes for experimenting with crayfish (b)An action potential(top) and a postsynaptic potential(bottom) recorded by CNT probes intracellularly (c)The impedance of CNT probe decrease (red curve) after current stress. (d)The flexible CMEA integrated with recording and stimulating circuits on-a-chip (e)The neural activity of crayfish and (f) the electrocorticogram of a rat recorded by the flexible CMEA.

 

B. Implantable, Wireless Microsystems for Studying the Mechanism of Deep Brain Stimulation

Introduction :The Pakinson's Disease (PD) is one of the most common diseases for the elderly, andis attributed to the degeneration of neurons in the brain. The main PD symptom in the early stage is irregular movement, which degrades the quality of life of PD patients seriously. Although the deep-brain stimulation (DBS) has been found helpful for suppressing the irregular motor symptoms, the mechanism underlying the DBS remains not well known. Understanding the mechanism is important for developing more effective treatments on the PD. Basing on our rich experience in designing customized brain-machine interface, this project looks to develop an implantable microsystem with wireless power and data transmission for studying the mechanism of DBS on rat models. By recording PD-related brain regions before and after the application of DBS, the dynamics of the PD-related brain regions will be modelled. The model will underpin the development of novel and more efficient DBS treatment for PD or other neural disorders.

 

Characteristics : This research relies on close collaboration with neuroscientists, mechanical engineers, material scientists, and medical doctors. After modelling the interface of microelectrodes, a microchip including neural recording and stimulation, ADC, digital core, and wireless power/data modules is designed and verified with rat models. The signal acquired from biological experiments will

Pre-requisites:Knowledge in electronics, VLSI design, basic neuroscience, and basic electrochemistry, signal processing.

Professional skills obtained:Knowledge in neuro-electrophysiology and neural diseases, Modeling and designing bio-electronic interfaces, Design of mixed-mode integrated circuits, signal processing, algorithms for feature extraction and data classification, models of nonlinear, dynamic systems, experience in biological experiments.

Fig.2 : The microsystem for studying the mechanism of DBS on rat models

 

                                    (a)

                    (b)

Fig.3 :(a) The architecture and (b) the layout of the implantable, wireless microsystem