RT Journal Article SR Electronic T1 Platform for Closed Loop Neuromodulation Based on Dual Mode Biosignals JF bioRxiv FD Cold Spring Harbor Laboratory SP 163329 DO 10.1101/163329 A1 Khalid B. Mirza A1 Nishanth Kulasekeram A1 Simon Cork A1 Stephen Bloom A1 Konstantin Nikolic A1 Christofer Toumazou YR 2017 UL http://biorxiv.org/content/early/2017/07/18/163329.abstract AB Closed loop neuromodulation, where the stimulation is controlled autonomously based on physiological events, has been more effective than open loop techniques. In the few existing closed loop implementations which have a feedback, indirect non-neurophysiological biomarkers have been typically used (e.g. heart rate, stomach distension). Although these biomarkers enable automatic initiation of neural stimulation, they do not enable intelligent control of stimulation dosage. In this paper, we present a novel closed loop neuromodulation platform based on a dual signal mode that is detecting electrical and chemical signatures of neural activity. We demonstrated it on a case of vagus nerve stimulation (VNS). Vagal chemical (pH) signal is detected and used for initiatisng VNS and vagal compound action potential (CAP) signals are used to determine the stimulation dosage and pattern. Although we used the paradigm of appetite control and neurometabolic therapies, the platform developed here can be utilised for prototyping closed loop neuromodulation systems before adapting the final System-on-Chip (SoC) design.