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Yingyue Xu, Nan Xia, Michelle Lim, Xiaodong Tan, Minh Ha Tran, Erin Boulger, Fei Peng, Hunter Young, Christoph Rau, Alexander Rack, Claus-Peter Richter
An emerging method in the field of neural stimulation is the use of photons to activate neurons. The possible advantage of optical stimulation over electrical is attributable to its spatially selective activation of small neuron populations, which is promising in generating superior spatial resolution in neural interfaces. Two principal methods are explored for cochlear prostheses: direct stimulation of nerves with infrared light and optogenetics. This paper discusses basic requirements for developing a light delivery system (LDS) for the cochlea and provides examples for building such devices...
October 2018: Neurophotonics
Borja Blanco, Monika Molnar, César Caballero-Gaudes
Near-infrared spectroscopy (NIRS) offers the potential to characterize resting-state functional connectivity (RSFC) in populations that are not easily assessed otherwise, such as young infants. In addition to the advantages of NIRS, one should also consider that the RS-NIRS signal requires specific data preprocessing and analysis. In particular, the RS-NIRS signal shows a colored frequency spectrum, which can be observed as temporal autocorrelation, thereby introducing spurious correlations. To address this issue, prewhitening of the RS-NIRS signal has been recently proposed as a necessary step to remove the signal temporal autocorrelation and therefore reduce false-discovery rates...
October 2018: Neurophotonics
Stephanie Sutoko, Yukifumi Monden, Tsukasa Funane, Tatsuya Tokuda, Takusige Katura, Hiroki Sato, Masako Nagashima, Masashi Kiguchi, Atsushi Maki, Takanori Yamagata, Ippeita Dan
Functional near-infrared spectroscopy (fNIRS) signals are prone to problems caused by motion artifacts and physiological noises. These noises unfortunately reduce the fNIRS sensitivity in detecting the evoked brain activation while increasing the risk of statistical error. In fNIRS measurements, the repetitive resting-stimulus cycle (so-called block-design analysis) is commonly adapted to increase the sample number. However, these blocks are often affected by noises. Therefore, we developed an adaptive algorithm to identify, reject, and select the noise-free and/or least noisy blocks in accordance with the preset acceptance rate...
October 2018: Neurophotonics
Sabrina Brigadoi, Domenico Salvagnin, Matteo Fischetti, Robert J Cooper
The position of each source and detector "optode" on the scalp, and their relative separations, determines the sensitivity of each functional near-infrared spectroscopy (fNIRS) channel to the underlying cortex. As a result, selecting appropriate scalp locations for the available sources and detectors is critical to every fNIRS experiment. At present, it is standard practice for the user to undertake this task manually; to select what they believe are the best locations on the scalp to place their optodes so as to sample a given cortical region-of-interest (ROI)...
July 2018: Neurophotonics
Takahiro Ikeda, Masahiro Hirai, Takeshi Sakurada, Yukifumi Monden, Tatsuya Tokuda, Masako Nagashima, Hideo Shimoizumi, Ippeita Dan, Takanori Yamagata
Autism spectrum disorder (ASD) is characterized by impairment in social communication and the presence of restricted and repetitive behaviors and interests. Executive function impairment is reportedly partially responsible for these symptoms. Executive function includes planning, flexibility, and inhibitory control. Although planning and flexibility in ASD have been consistently reported as atypical, the atypicality of inhibitory control remains controversial. As most previous studies have used nonsocial stimuli to investigate inhibitory control in ASD, the effects of socially relevant information on the inhibitory control system in individuals with ASD remain unclear...
July 2018: Neurophotonics
Peng Wan, Jingtan Zhu, Jianyi Xu, Yusha Li, Tingting Yu, Dan Zhu
Recently, a variety of tissue optical clearing techniques have been developed to reduce light scattering for imaging deeper and three-dimensional reconstruction of tissue structures. Combined with optical imaging techniques and diverse labeling methods, these clearing methods have significantly promoted the development of neuroscience. Each of them has its own characteristics with certain advantages and disadvantages. Though there are some comparison results, the clearing methods covered are limited and the evaluation indices lack uniformity, which made it difficult to select a best-fit protocol from numerous methods for clearing in practical applications...
July 2018: Neurophotonics
Karla M Bergonzi, Tracy M Burns-Yocum, Jonathan R Bumstead, Elise M Buckley, Patrick C Mannion, Christopher H Tracy, Eli Mennerick, Silvina L Ferradal, Hamid Dehghani, Adam T Eggebrecht, Joseph P Culver
Though optical imaging of human brain function is gaining momentum, widespread adoption is restricted in part by a tradeoff among cap wearability, field of view, and resolution. To increase coverage while maintaining functional magnetic resonance imaging (fMRI)-comparable image quality, optical systems require more fibers. However, these modifications drastically reduce the wearability of the imaging cap. The primary obstacle to optimizing wearability is cap weight, which is largely determined by fiber diameter...
July 2018: Neurophotonics
Damon T DePaoli, Nicolas Lapointe, Younes Messaddeq, Martin Parent, Daniel C Côté
Coherent Raman fiber probes have not yet found their way into the clinic despite their immense potential for label-free sensing and imaging. This is mainly due to the traditional bulky laser systems required to create the high peak power laser pulses needed for coherent Raman, as well as the complications that arise from the propagation of this type of energy through silica. Specifically, a coherent anti-Stokes Raman scattering (CARS) probe that could select its integration volume at high resolution, away from the tip of the fiber, is particularly interesting in the case of electrode implantation neurosurgeries, wherein it is possible to place optical fibers on-board the chronic electrode and provide optical guidance during its implantation, through the semi-transparent tip...
July 2018: Neurophotonics
Lin Li, Olajide Babawale, Amarnath Yennu, Cynthia Trowbridge, Ryan Hulla, Robert J Gatchel, Hanli Liu
A good understanding of age-dependent changes and modifications in brain networks is crucial for fully exploring the effects of aging on the human brain. Few reports have been found in studies of functional brain networks using functional near-infrared spectroscopy (fNIRS). Moreover, little is known about the feasibility of using fNIRS to assess age-related changes in brain connectomes. This study applied whole brain fNIRS measurement, combined with graph theory analysis, to assess the age-dependent changes in resting-state brain networks...
July 2018: Neurophotonics
Colin T Sullender, Andrew E Mark, Taylor A Clark, Tatiana V Esipova, Sergei A Vinogradov, Theresa A Jones, Andrew K Dunn
We present a dual-modality imaging system combining laser speckle contrast imaging and oxygen-dependent quenching of phosphorescence to simultaneously map cortical blood flow and oxygen tension ( <mml:math xmlns:mml=""> <mml:mrow> <mml:msub> <mml:mi>pO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> ) in mice. Phosphorescence signal localization is achieved through the use of a digital micromirror device (DMD) that allows for selective excitation of arbitrary regions of interest...
July 2018: Neurophotonics
Antonia Lichtenegger, Martina Muck, Pablo Eugui, Danielle J Harper, Marco Augustin, Konrad Leskovar, Christoph K Hitzenberger, Adelheid Woehrer, Bernhard Baumann
We implemented a wide field-of-view visible-light optical coherence microscope (OCM) for investigating ex-vivo brain tissue of patients diagnosed with Alzheimer's disease (AD) and of a mouse model of AD. A submicrometer axial resolution in tissue was achieved using a broad visible light spectrum. The use of various objective lenses enabled reaching micrometer transversal resolution and the acquisition of images of microscopic brain features, such as cell structures, vessels, and white matter tracts. Amyloid-beta plaques in the range of 10 to <mml:math xmlns:mml="http://www...
July 2018: Neurophotonics
Stephen H Fairclough, Christopher Burns, Ute Kreplin
Previous research has demonstrated changes in neurovascular activation of the prefrontal cortex to increased working memory load. The primary purpose of the current paper was to investigate overload of working memory capacity using functional near-infrared spectroscopy (fNIRS) within the framework of motivational intensity theory. A secondary goal was to explore the influence of the correlation-based signal improvement (CBSI) as a method for correcting the influence of systemic variables. In study one, 30 participants (15 female, mean age = 21...
July 2018: Neurophotonics
Hada Fong-Ha Ieong, Zhen Yuan
Many patients with substance use disorders (SUDs) live in a stressful environment, and comorbidity is not uncommon. Understanding the neural mechanisms underlying heroin and nicotine dependences and their relationships to social cognition could facilitate behavioral therapy efficacy. We aimed to provide a translational approach that leads to identifying potential biomarkers for opioid use disorder (OUD) susceptibility during recovery. We examined the clinical characters and the relationships between theory of mind (ToM) and executive functions in three groups: heroin plus nicotine-dependent (HND) patients who had remained heroin abstinent ( <mml:math xmlns:mml="http://www...
April 2018: Neurophotonics
Xiaohong Lin, Victoria Lai Cheng Lei, Defeng Li, Zhen Yuan
This study examined the neural mechanism underlying two translation strategies associated with Chinese to English simultaneous interpreting (SI) targeting the left prefrontal cortex (PFC), which is generally involved in the control of interference and conflict resolution and has been identified as the brain area that plays a pivotal role in SI. Brain activation associated with the two strategies including "pairing" and "transphrasing" were compared with that from "nontranslation," which keeps the source language item unchanged in the target language production and is considered as a tactic that does not require complex cognitive operation associated with bilingual processing effort...
April 2018: Neurophotonics
Sant Saran, Neha Gupta, Sukhdev Roy
A detailed theoretical analysis of low-power, fast optogenetic control of firing of Chronos-expressing neurons has been presented. A three-state model for the Chronos photocycle has been formulated and incorporated in a fast-spiking interneuron circuit model. The effect of excitation wavelength, pulse irradiance, pulse width, and pulse frequency has been studied in detail and compared with ChR2. Theoretical simulations are in excellent agreement with recently reported experimental results and bring out additional interesting features...
April 2018: Neurophotonics
Lourdes M Delgado Reyes, Kevin Bohache, Sobanawartiny Wijeakumar, John P Spencer
Motion artifacts are often a significant component of the measured signal in functional near-infrared spectroscopy (fNIRS) experiments. A variety of methods have been proposed to address this issue, including principal components analysis (PCA), correlation-based signal improvement (CBSI), wavelet filtering, and spline interpolation. The efficacy of these techniques has been compared using simulated data; however, our understanding of how these techniques fare when dealing with task-based cognitive data is limited...
April 2018: Neurophotonics
Lina Qiu, Huiyi Cheng, Alessandro Torricelli, Jun Li
Time-domain diffuse correlation spectroscopy (TD-DCS) has been recently proposed to improve detection of deep blood flow dynamics in a biological tissue, such as human brain. To obtain a high sensitive measurement, several experimental parameters such as the source-detector (SD) distance, gate opening time, and width need to be considered and optimized. We use a simulation approach to optimize these parameters based on Monte Carlo computations using a realistic human head model. Two cortical regions are investigated including the frontal and temporal lobes...
April 2018: Neurophotonics
Kathryn Simone, Tamás Füzesi, David Rosenegger, Jaideep Bains, Kartikeya Murari
Fiber photometry uses genetically encoded optical reporters to link specific cellular activity in stereotaxically targeted brain structures to specific behaviors. There are still a number of barriers that have hindered the widespread adoption of this approach. This includes cost, but also the high-levels of light required to excite the fluorophore, limiting commercial systems to the investigation of short-term transients in neuronal activity to avoid damage of tissue by light. Here, we present a cost-effective optoelectronic system for in vivo fiber photometry that achieves high-sensitivity to changes in fluorescence intensity, enabling detection of optical transients of a popular calcium reporter with excitation powers as low as 100 nW...
April 2018: Neurophotonics
Edgar Bermudez-Contreras, Sergey Chekhov, Jianjun Sun, Jennifer Tarnowsky, Bruce L McNaughton, Majid H Mohajerani
Simultaneous recording of optical and electrophysiological signals from multiple cortical areas may provide crucial information to expand our understanding of cortical function. However, the insertion of multiple electrodes into the brain may compromise optical imaging by both restricting the field of view and interfering with the approaches used to stabilize the specimen. Existing methods that combine electrophysiological recording and optical imaging in vivo implement either multiple surface electrodes, silicon probes, or a single electrode for deeper recordings...
April 2018: Neurophotonics
Tal Aharoni, Shy Shoham
Holographic speckle is a major impediment to computer-generated holographic (CGH) projections in applications ranging from display, optical tweezers, and machining to optogenetic neural control. We present an iterative phase retrieval algorithm that allows the projection of amplitude-controlled speckle-free one-dimensional patterns with a high degree of pattern uniformity. The algorithm, termed the weighted Gerchberg-Saxton with phase-control (GSW-PC), is shown to have the ability to simultaneously control both the phase and amplitude of projected patterns with high diffraction efficiencies...
April 2018: Neurophotonics
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