Browsing by Author "Rodgers, Richard"

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    Agreement Study Using Gesture Description Analysis
    (IEEE, 2020-10) Madapana, Naveen; Gonzalez, Glebys; Zhang, Lingsong; Rodgers, Richard; Wachs, Juan; Neurological Surgery, School of Medicine
    Choosing adequate gestures for touchless interfaces is a challenging task that has a direct impact on human-computer interaction. Such gestures are commonly determined by the designer, ad-hoc, rule-based or agreement-based methods. Previous approaches to assess agreement grouped the gestures into equivalence classes and ignored the integral properties that are shared between them. In this work, we propose a generalized framework that inherently incorporates the gesture descriptors into the agreement analysis (GDA). In contrast to previous approaches, we represent gestures using binary description vectors and allow them to be partially similar. In this context, we introduce a new metric referred to as Soft Agreement Rate (SAR) to measure the level of agreement and provide a mathematical justification for this metric. Further, we performed computational experiments to study the behavior of SAR and demonstrate that existing agreement metrics are a special case of our approach. Our method was evaluated and tested through a guessability study conducted with a group of neurosurgeons. Nevertheless, our formulation can be applied to any other user-elicitation study. Results show that the level of agreement obtained by SAR is 2.64 times higher than the previous metrics. Finally, we show that our approach complements the existing agreement techniques by generating an artificial lexicon based on the most agreed properties.
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    Magneto-Electric Nanoparticles Cobalt Ferrite (CoFe2O4) -- Barium Titanate (BaTiO3) for Non-Invasive Neural Modulations
    (2020-09) Nguyen, Tyler; White, Fletcher; Blesch, Armin; Jin, Xiaoming; Rodgers, Richard; Khizroev, Sakhrat
    Non-invasive brain stimulation is valuable for studying neural circuits and treating various neurological disorders in human. However, current technologies of noninvasive brain stimulation usually have low spatial and temporal precision and poor brain penetration, which greatly limit their application. A new class of nanoparticles known as magneto-electric nanoparticles (MENs) is highly efficient in coupling an externally applied magnetics wave with generating local electric fields for neuronal activity modulation. Here, a new type of MENs was developed that consisted of CoFe2O4- BaTiO3 and had excellent magneto-electrical coupling properties. Calcium imaging technique was used to demonstrate their efficacy in evoking neuronal activity in organotyic and acute cortical slices that expressed GCaMP6 protein. For in vivo noninvasive delivery of MENs to brain, fluorescently labeled MENs were intravenously injected and attracted to pass through blood brain barrier to a targeted brain region by applying a focal magnet field. Magnetic wave (~450 G at 10 Hz) applied to mouse brain was able to activate cortical network activity, as revealed by in vivo two-photon and mesoscopic imaging of calcium signals at both cellular and global network levels. The effect was further confirmed by the increased number of c-Fos expressing cells after magnetic stimulation. Histological analysis indicated that neither brain delivery of MENs nor the subsequent magnetic stimulation caused any significant increases in the numbers of GFAP and IBA1 positive astrocytes and microglia in the brain. MENs stimulation also show high efficacy in short-term pain relieve when tested with a tibial nerve injury mouse model. The study demonstrates the feasibility of using MENs as a novel efficient and non-invasive technique of brain stimulation, which may have great potential for translation.