New enabling technologies for monitoring and manipulation of chemical and electrical neural activity in the brain can provide a holistic image of neural signal pathways. Such new capabilities would be of great benefit to physicians to better understand neuronal communication for more effective clinical treatments. One such new enabling technology is low-power, multichannel, CMOS microchips that can be interfaced with micromachined recording electrodes to condition, process, and wirelessly transmit electrical action potentials and neurochemical signals from inside the body to the outside world. Wireless operation eliminates the need for a cable link between the subject and the recording equipment, which adversely affects behavior and excludes experimental models involving complex or enriched environments.
This seminar will first present the design, implementation, testing, and performance characterization of wireless integrated recording systems to remotely monitor neurochemical signals and electrical action potentials in the central nervous system. The resulting microchips, fabricated using the AMI 0.5åµm CMOS process, have been interfaced with carbon-fiber microelectrodes, and, for the first time, extracellular levels of dopamine elicited by electrical stimulation in a rat's brain have been successfully recorded wirelessly using fast-scan cyclic voltammetry (FSCV). In addition to applications in basic science research, this work constitutes an important step towards the development of a closed-loop neuroprosthesis with chemical sensing feedback, advancing the neuromodulation approach for treating the Parkinson's disease and other neuropathologies.
The presentation will next focus on the development of an implantable microsystem for activity-dependent intracortical microstimulation to demonstrate a novel approach for orchestrating new long-range connectivity patterns in the cerebral cortex after a traumatic brain injury (TBI). The neurophysiological rationale behind this work as well as our preliminary measurement results from a prototype device fabricated using the TSMC 0.35åµm CMOS process will be presented. This work has the potential to remarkably advance the neuro-rehabilitation field at the level of functional neurons and networks.