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  • 1
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    Online Resource
    The development of ultra–high field MRI guidance technology for neuronavigation
    Journal of Neurosurgery Publishing Group (JNSPG) ; 2022
    In:  Journal of Neurosurgery Vol. 137, No. 5 ( 2022-11-01), p. 1265-1277
    Details
    In: Journal of Neurosurgery, Journal of Neurosurgery Publishing Group (JNSPG), Vol. 137, No. 5 ( 2022-11-01), p. 1265-1277
    Abstract: Magnetic resonance imaging at 7T offers improved image spatial and contrast resolution for visualization of small brain nuclei targeted in neuromodulation. However, greater image geometric distortion and a lack of compatible instrumentation preclude implementation. In this report, the authors detail the development of a stereotactic image localizer and accompanying imaging sequences designed to mitigate geometric distortion, enabling accurate image registration and surgical planning of basal ganglia nuclei. METHODS Magnetization-prepared rapid acquisition with gradient echo (MPRAGE), fast gray matter acquisition T1 inversion recovery (FGATIR), T2-weighted, and T2*-weighted sequences were optimized for 7T in 9 human subjects to visualize basal ganglia nuclei, minimize image distortion, and maximize target contrast-to-noise and signal-to-noise ratios. Extracranial spatial distortions were mapped to develop a skull-contoured image localizer embedded with spherical silicone fiducials for improved MR image registration and target guidance. Surgical plan accuracy testing was initially performed in a custom-developed MRI phantom (n = 5 phantom studies) and finally in a human trial. RESULTS MPRAGE and T2*-weighted sequences had the best measures among global measures of image quality (3.8/4, p 〈 0.0001; and 3.7/4, p = 0.0002, respectively). Among basal ganglia nuclei, FGATIR outperformed MPRAGE for globus pallidus externus (GPe) visualization (2.67/4 vs 1.78/4, p = 0.008), and FGATIR, T2-weighted imaging, and T2*-weighted imaging outperformed MPRAGE for substantia nigra visualization (1.44/4 vs 2.56/4, p = 0.04; vs 2.56/4, p = 0.04; vs 2.67/4, p = 0.003). Extracranial distortion was lower in the head’s midregion compared with the base and apex ( 1.17–1.33 mm; MPRAGE and FGATIR, p 〈 0.0001; T2-weighted imaging, p 〉 0.05; and T2*-weighted imaging, p = 0.013). Fiducial placement on the localizer in low distortion areas improved image registration (fiducial registration error, 0.79–1.19 mm; p 〈 0.0001) and targeting accuracy (target registration error, 0.60–1.09 mm; p = 0.04). Custom surgical software and the refined image localizer enabled successful surgical planning in a human trial (fiducial registration error = 1.0 mm). CONCLUSIONS A skull-contoured image localizer that accounts for image distortion is necessary to enable high-accuracy 7T imaging–guided targeting for surgical neuromodulation. These results may enable improved clinical efficacy for the treatment of neurological disease.
    Type of Medium: Online Resource
    ISSN: 0022-3085 , 1933-0693
    URL: Article
    DOI: 10.3171/2021.11.JNS211078
    RVK:
    XA 10000
    RVK:
    XA 55270
    Language: Unknown
    Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
    Publication Date: 2022
    detail.hit.zdb_id: 2026156-1
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  • 2
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    Video_1.MP4
    Frontiers Media SA ; 2022
    In:  Frontiers in Neuroscience Vol. 16 ( 2022-9-23)
    Details
    In: Frontiers in Neuroscience, Frontiers Media SA, Vol. 16 ( 2022-9-23)
    Abstract: Tonic extracellular neurotransmitter concentrations are important modulators of central network homeostasis. Disruptions in these tonic levels are thought to play a role in neurologic and psychiatric disease. Therefore, ways to improve their quantification are actively being investigated. Previously published voltammetric software packages have implemented FSCV, which is not capable of measuring tonic concentrations of neurotransmitters in vivo . In this paper, custom software was developed for near-real-time tracking (scans every 10 s) of neurotransmitters’ tonic concentrations with high sensitivity and spatiotemporal resolution both in vitro and in vivo using cyclic voltammetry combined with dynamic background subtraction (M-CSWV and FSCAV). This software was designed with flexibility, speed, and user-friendliness in mind. This software enables near-real-time measurement by reducing data analysis time through an optimized modeling algorithm, and efficient memory handling makes long-term measurement possible. The software permits customization of the cyclic voltammetric waveform shape, enabling experiments to detect a specific analyte of interest. Finally, flexibility considerations allow the user to alter the fitting parameters, filtering characteristics, and size and shape of the analyte kernel, based on data obtained live during the experiment to obtain accurate measurements as experimental conditions change. Herein, the design and advantages of this near-real-time voltammetric software are described, and its use is demonstrated in in vivo experiments.
    Type of Medium: Online Resource
    ISSN: 1662-453X
    URL: Article
    URL: Article
    DOI: 10.3389/fnins.2022.899436
    DOI: 10.3389/fnins.2022.899436.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2411902-7
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  • 3
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    Online Resource
    Cocaine increases stimulation-evoked serotonin efflux in the nucleus accumbens
    American Physiological Society ; 2022
    In:  Journal of Neurophysiology Vol. 127, No. 3 ( 2022-03-01), p. 714-724
    Details
    In: Journal of Neurophysiology, American Physiological Society, Vol. 127, No. 3 ( 2022-03-01), p. 714-724
    Abstract: Although dopamine is the most implicated neurotransmitter in the mediation of the pathophysiology of addiction, animal studies show serotonin also plays a vital role. Cocaine is one of the most common illicit drugs globally, but the role of serotonin in its mechanism of action is insufficiently characterized. Consequently, we investigated the acute effects of the psychomotor stimulant cocaine on electrical stimulation-evoked serotonin (phasic) release in the nucleus accumbens core (NAcc) of urethane-anesthetized (1.5 g/kg ip) male Sprague–Dawley rats using N-shaped fast-scan cyclic voltammetry (N-FSCV). A single carbon fiber microelectrode was first implanted in the NAcc. Stimulation was applied to the medial forebrain bundle using 60 Hz, 2 ms, 0.2 mA, 2-s biphasic pulses before and after cocaine (2 mg/kg iv) was administered. Stimulation-evoked serotonin release significantly increased 5 min after cocaine injection compared with baseline (153 ± 21 nM vs. 257 ± 12 nM; P = 0.0042; n = 5) but was unaffected by saline injection (1 mL/kg iv; n = 5). N-FSCV’s selective measurement of serotonin release in vivo was confirmed pharmacologically via administration of the selective serotonin reuptake inhibitor escitalopram (10 mg/kg ip) that effectively increased the signal in a separate group of rats ( n = 5). Selectivity to serotonin was further confirmed in vitro in which dopamine was minimally detected by N-FSCV with a serotonin to dopamine response ratio of 1:0.04 (200 nM of serotonin:1 µM dopamine ratio; P = 0.0048; n = 5 electrodes). This study demonstrates a noteworthy influence of cocaine on serotonin dynamics, and confirms that N-FSCV can effectively and selectively measure phasic serotonin release in the NAcc. NEW & NOTEWORTHY Serotonin plays a vital role in drug addiction. Here, using N-shaped fast-scan cyclic voltammetry, we demonstrated the effect of cocaine on the phasic release of serotonin at the nucleus accumbens core. To the best of our knowledge, this has not previously been elucidated. Our results not only reinforce the role of serotonin in the mechanism of action of cocaine but also help to fill a gap in our knowledge and provide a baseline for future studies in cocaine addiction.
    Type of Medium: Online Resource
    ISSN: 0022-3077 , 1522-1598
    URL: Article
    DOI: 10.1152/jn.00420.2021
    RVK:
    XA 10000 ; XA 552555
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2022
    detail.hit.zdb_id: 80161-6
    detail.hit.zdb_id: 1467889-5
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  • 4
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    Online Resource
    Evaluation of electrochemical methods for tonic dopamine detection in vivo
    Elsevier BV ; 2020
    In:  TrAC Trends in Analytical Chemistry Vol. 132 ( 2020-11), p. 116049-
    Details
    In: TrAC Trends in Analytical Chemistry, Elsevier BV, Vol. 132 ( 2020-11), p. 116049-
    Type of Medium: Online Resource
    ISSN: 0165-9936
    URL: Article
    DOI: 10.1016/j.trac.2020.116049
    RVK:
    VG 2000
    RVK:
    VA 7720
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
    detail.hit.zdb_id: 2014041-1
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  • 5
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    A compact stereotactic system for image-guided surgical intervention
    IOP Publishing ; 2020
    In:  Journal of Neural Engineering Vol. 17, No. 6 ( 2020-12-01), p. 066014-
    Details
    In: Journal of Neural Engineering, IOP Publishing, Vol. 17, No. 6 ( 2020-12-01), p. 066014-
    Abstract: Objective . Stereotactic technology enables fine navigation to small structures in the human body. While current stereotactic systems facilitate accurate targeting, they are mechanically cumbersome and limited in scope. Here, we hypothesized that a stereotactic system could be developed with a reduced footprint while maintaining broad targeting capabilities in order to improve versatility in frame placement location and surgical workflow. Approach . We designed a stereotactic system around the center-of-arc principle, with mechanical properties that would enable a compact design and ample targeting and trajectory maneuverability. To examine the opportunity for a low-cost rapidly-deployable system we developed two fabrication variants, one using three dimensional (3D)-printing and the other using conventional machining. Mechanical and image-guided accuracies were tested in phantom studies using magnetic resonance imaging (MRI) and computed tomography. Using human cadaver head specimens, we assessed the system’s surgical workflow and its ability to reliably and accurately implant electrodes in deep brain stimulation (DBS) surgery. Main results . We developed a small 7.7 × 5.4 cm 2 device platform that rigidly mounts to curvilinear bone and supports the attachment of surgical instrumentation. Attachment of two surgical instruments, an imaging localizer and a compact targeting device, demonstrated successful MRI-guided intervention in phantom studies with a vector error of 1.79 ± 0.41 mm. Evaluation of the 3D-printed system for DBS surgery confirmed ease of device platform attachment and instrument functionality, as well as demonstrated a surgical targeting accuracy of 1.83 ± 0.15 mm. In addition, we found the surgical time to be 78.3 ± 5.4 min for bilateral electrode implantation. Significance . We developed a light and compact stereotactic system whose accuracy is on par with those used clinically. This technology is suitable for clinical translation and its flexibility in positioning will seamlessly expand the capabilities for stereotaxy to treat a wide range of conditions, both within neurosurgery and beyond.
    Type of Medium: Online Resource
    ISSN: 1741-2560 , 1741-2552
    URL: Article
    DOI: 10.1088/1741-2552/abc743
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 2135187-9
    SSG: 12
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  • 6
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    The development of an implantable deep brain stimulation device with simultaneous chronic electrophysiological recording and stimulation in humans
    Elsevier BV ; 2021
    In:  Biosensors and Bioelectronics Vol. 176 ( 2021-03), p. 112888-
    Details
    In: Biosensors and Bioelectronics, Elsevier BV, Vol. 176 ( 2021-03), p. 112888-
    Type of Medium: Online Resource
    ISSN: 0956-5663
    URL: Article
    DOI: 10.1016/j.bios.2020.112888
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 1496379-6
    SSG: 12
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  • 7
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    Advances in neurochemical measurements: A review of biomarkers and devices for the development of closed-loop deep brain stimulation systems
    Walter de Gruyter GmbH ; 2020
    In:  Reviews in Analytical Chemistry Vol. 39, No. 1 ( 2020-12-31), p. 188-199
    Details
    In: Reviews in Analytical Chemistry, Walter de Gruyter GmbH, Vol. 39, No. 1 ( 2020-12-31), p. 188-199
    Abstract: Neurochemical recording techniques have expanded our understanding of the pathophysiology of neurological disorders, as well as the mechanisms of action of treatment modalities like deep brain stimulation (DBS). DBS is used to treat diseases such as Parkinson’s disease, Tourette syndrome, and obsessive-compulsive disorder, among others. Although DBS is effective at alleviating symptoms related to these diseases and improving the quality of life of these patients, the mechanism of action of DBS is currently not fully understood. A leading hypothesis is that DBS modulates the electrical field potential by modifying neuronal firing frequencies to non-pathological rates thus providing therapeutic relief. To address this gap in knowledge, recent advances in electrochemical sensing techniques have given insight into the importance of neurotransmitters, such as dopamine, serotonin, glutamate, and adenosine, in disease pathophysiology. These studies have also highlighted their potential use in tandem with electrophysiology to serve as biomarkers in disease diagnosis and progression monitoring, as well as characterize response to treatment. Here, we provide an overview of disease-relevant neurotransmitters and their roles and implications as biomarkers, as well as innovations to the biosensors used to record these biomarkers. Furthermore, we discuss currently available neurochemical and electrophysiological recording devices, and discuss their viability to be implemented into the development of a closed-loop DBS system.
    Type of Medium: Online Resource
    ISSN: 2191-0189 , 0793-0135
    URL: Article
    DOI: 10.1515/revac-2020-0117
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2020
    detail.hit.zdb_id: 2602435-4
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  • 8
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    Online Resource
    Tonic Serotonin Measurements In Vivo Using NShaped Multiple Cyclic Square Wave Voltammetry
    American Chemical Society (ACS) ; 2021
    In:  Analytical Chemistry Vol. 93, No. 51 ( 2021-12-28), p. 16987-16994
    Details
    In: Analytical Chemistry, American Chemical Society (ACS), Vol. 93, No. 51 ( 2021-12-28), p. 16987-16994
    Type of Medium: Online Resource
    ISSN: 0003-2700 , 1520-6882
    URL: Article
    URL: Article
    URL: Article
    DOI: 10.1021/acs.analchem.1c02131
    DOI: 10.1021/acs.analchem.1c02131.s001
    DOI: 10.1021/acs.analchem.1c02131.s002
    Language: English
    Publisher: American Chemical Society (ACS)
    Publication Date: 2021
    detail.hit.zdb_id: 1483443-1
    detail.hit.zdb_id: 1508-8
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  • 9
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    Clinical applications of neurochemical and electrophysiological measurements for closed-loop neurostimulation
    Journal of Neurosurgery Publishing Group (JNSPG) ; 2020
    In:  Neurosurgical Focus Vol. 49, No. 1 ( 2020-07), p. E6-
    Details
    In: Neurosurgical Focus, Journal of Neurosurgery Publishing Group (JNSPG), Vol. 49, No. 1 ( 2020-07), p. E6-
    Abstract: The development of closed-loop deep brain stimulation (DBS) systems represents a significant opportunity for innovation in the clinical application of neurostimulation therapies. Despite the highly dynamic nature of neurological diseases, open-loop DBS applications are incapable of modifying parameters in real time to react to fluctuations in disease states. Thus, current practice for the designation of stimulation parameters, such as duration, amplitude, and pulse frequency, is an algorithmic process. Ideal stimulation parameters are highly individualized and must reflect both the specific disease presentation and the unique pathophysiology presented by the individual. Stimulation parameters currently require a lengthy trial-and-error process to achieve the maximal therapeutic effect and can only be modified during clinical visits. The major impediment to the development of automated, adaptive closed-loop systems involves the selection of highly specific disease-related biomarkers to provide feedback for the stimulation platform. This review explores the disease relevance of neurochemical and electrophysiological biomarkers for the development of closed-loop neurostimulation technologies. Electrophysiological biomarkers, such as local field potentials, have been used to monitor disease states. Real-time measurement of neurochemical substances may be similarly useful for disease characterization. Thus, the introduction of measurable neurochemical analytes has significantly expanded biomarker options for feedback-sensitive neuromodulation systems. The potential use of biomarker monitoring to advance neurostimulation approaches for treatment of Parkinson’s disease, essential tremor, epilepsy, Tourette syndrome, obsessive-compulsive disorder, chronic pain, and depression is examined. Further, challenges and advances in the development of closed-loop neurostimulation technology are reviewed, as well as opportunities for next-generation closed-loop platforms.
    Type of Medium: Online Resource
    ISSN: 1092-0684
    URL: Article
    DOI: 10.3171/2020.4.FOCUS20167
    Language: Unknown
    Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
    Publication Date: 2020
    detail.hit.zdb_id: 2026589-X
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  • 10
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    Video1.MP4
    Frontiers Media SA ; 2021
    In:  Frontiers in Pharmacology Vol. 12 ( 2021-7-6)
    Details
    In: Frontiers in Pharmacology, Frontiers Media SA, Vol. 12 ( 2021-7-6)
    Abstract: For over 40 years, in vivo microdialysis techniques have been at the forefront in measuring the effects of illicit substances on brain tonic extracellular levels of dopamine that underlie many aspects of drug addiction. However, the size of microdialysis probes and sampling rate may limit this technique’s ability to provide an accurate assessment of drug effects in microneural environments. A novel electrochemical method known as multiple-cyclic square wave voltammetry (M-CSWV), was recently developed to measure second-to-second changes in tonic dopamine levels at microelectrodes, providing spatiotemporal resolution superior to microdialysis. Here, we utilized M-CSWV and fast-scan cyclic voltammetry (FSCV) to measure changes in tonic or phasic dopamine release in the nucleus accumbens core (NAcc) after acute cocaine administration. Carbon-fiber microelectrodes (CFM) and stimulating electrodes were implanted into the NAcc and medial forebrain bundle (MFB) of urethane anesthetized (1.5 g/kg i.p.) Sprague-Dawley rats, respectively. Using FSCV, depths of each electrode were optimized by determining maximal MFB electrical stimulation-evoked phasic dopamine release. Changes in phasic responses were measured after a single dose of intravenous saline or cocaine hydrochloride (3 mg/kg; n = 4). In a separate group, changes in tonic dopamine levels were measured using M-CSWV after intravenous saline and after cocaine hydrochloride (3 mg/kg; n = 5). Both the phasic and tonic dopamine responses in the NAcc were augmented by the injection of cocaine compared to saline control. The phasic and tonic levels changed by approximately x2.4 and x1.9, respectively. These increases were largely consistent with previous studies using FSCV and microdialysis. However, the minimal disruption/disturbance of neuronal tissue by the CFM may explain why the baseline tonic dopamine values (134 ± 32 nM) measured by M-CSWV were found to be 10-fold higher when compared to conventional microdialysis. In this study, we demonstrated phasic dopamine dynamics in the NAcc with acute cocaine administration. M-CSWV was able to record rapid changes in tonic levels of dopamine, which cannot be achieved with other current voltammetric techniques. Taken together, M-CSWV has the potential to provide an unprecedented level of physiologic insight into dopamine signaling, both in vitro and in vivo , which will significantly enhance our understanding of neurochemical mechanisms underlying psychiatric conditions.
    Type of Medium: Online Resource
    ISSN: 1663-9812
    URL: Article
    URL: Article
    DOI: 10.3389/fphar.2021.705254
    DOI: 10.3389/fphar.2021.705254.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2587355-6
    SSG: 15,3
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