Browsing by Author "Kim, Robin"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Fiber Optics
    (Rice University, 5/4/2017) Vadasz, Daniel A.; Henderson, Carl J.; Chapagain, Ayush; Kim, Robin; Department of Electrical and Computer Engineering
  • Thumbnail Image
    Item
    Longitudinal behavioral detectability and selective neural activation evoked by low current intracortical microsimulation using ultra-flexible electrodes
    (2022-12-02) Kim, Robin; Luan, Lan
    Studies on human patients have allowed better understanding of the conscious sensations associated with ICMS (intracortical microstimulation) in hopes of restoring sensory functions. An effective clinical neuro- prosthetic should manipulate neural activity at a high spatial resolution, minimize charge injection, and demonstrate chronic stability. In this thesis, we propose that the Stimulating NanoElectronic Threads (StimNETs) possess these attributes by examining and providing experiment evidence for the following three research goals: (1) Using two-photon (2P) calcium imaging of awake animals, we visualized and verified selective neuronal activation patterns under low-current ICMS. (2) To evaluate the behavioral effects of ICMS, we designed a go/no-go detection threshold task and observed thresholds as little as 0.25 nC/phase. (3) To show that stim-NETs are chronically stable, we present longitudinal data with the longest behavioral performing animal 10 months post-implantation. These results show that tissue-integrated ultraflexible electrodes provide high-resolution, efficacy, and stability in neuromodulation.
  • Thumbnail Image
    Item
    Low-threshold, high-resolution, chronically stable intracortical microstimulation by ultraflexible electrodes
    (Cell Press, 2023) Lycke, Roy; Kim, Robin; Zolotavin, Pavlo; Montes, Jon; Sun, Yingchu; Koszeghy, Aron; Altun, Esra; Noble, Brian; Yin, Rongkang; He, Fei; Totah, Nelson; Xie, Chong; Luan, Lan; Bioengineering; Electrical and Computer Engineering; Rice Neuroengineering Initiative
    Intracortical microstimulation (ICMS) enables applications ranging from neuroprosthetics to causal circuit manipulations. However, the resolution, efficacy, and chronic stability of neuromodulation are often compromised by adverse tissue responses to the indwelling electrodes. Here we engineer ultraflexible stim-nanoelectronic threads (StimNETs) and demonstrate low activation threshold, high resolution, and chronically stable ICMS in awake, behaving mouse models. In vivo two-photon imaging reveals that StimNETs remain seamlessly integrated with the nervous tissue throughout chronic stimulation periods and elicit stable, focal neuronal activation at low currents of 2 μA. Importantly, StimNETs evoke longitudinally stable behavioral responses for over 8 months at a markedly low charge injection of 0.25 nC/phase. Quantified histological analyses show that chronic ICMS by StimNETs induces no neuronal degeneration or glial scarring. These results suggest that tissue-integrated electrodes provide a path for robust, long-lasting, spatially selective neuromodulation at low currents, which lessens risk of tissue damage or exacerbation of off-target side effects.