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Suematsu N, Vazquez AL, Kozai TDY. Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex. J Neural Eng 2024; 21:026033. [PMID: 38537268 PMCID: PMC11002944 DOI: 10.1088/1741-2552/ad3853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/28/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
Objective. Intracortical microstimulation (ICMS) can be an effective method for restoring sensory perception in contemporary brain-machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site.Approach. Different microstimulation frequencies were investigatedin vivoon Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging.Main results. Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies.Significance. These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by ICMS and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
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Affiliation(s)
- Naofumi Suematsu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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2
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Cullins MJ, Connor NP. Differential impact of unilateral stroke on the bihemispheric motor cortex representation of the jaw and tongue muscles in young and aged rats. Front Neurol 2024; 15:1332916. [PMID: 38572491 PMCID: PMC10987714 DOI: 10.3389/fneur.2024.1332916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 03/04/2024] [Indexed: 04/05/2024] Open
Abstract
Introduction Dysphagia commonly occurs after stroke, yet the mechanisms of post-stroke corticobulbar plasticity are not well understood. While cortical activity associated with swallowing actions is bihemispheric, prior research has suggested that plasticity of the intact cortex may drive recovery of swallowing after unilateral stroke. Age may be an important factor as it is an independent predictor of dysphagia after stroke and neuroplasticity may be reduced with age. Based on previous clinical studies, we hypothesized that cranial muscle activating volumes may be expanded in the intact hemisphere and would contribute to swallowing function. We also hypothesized that older age would be associated with limited map expansion and reduced function. As such, our goal was to determine the impact of stroke and age on corticobulbar plasticity by examining the jaw and tongue muscle activating volumes within the bilateral sensorimotor cortices. Methods Using the middle cerebral artery occlusion rat stroke model, intracortical microstimulation (ICMS) was used to map regions of sensorimotor cortex that activate tongue and jaw muscles in both hemispheres. Young adult (7 months) and aged (30 months) male F344 × BN rats underwent a stroke or sham-control surgery, followed by ICMS mapping 8 weeks later. Videofluoroscopy was used to assess oral-motor functions. Results Increased activating volume of the sensorimotor cortex within the intact hemisphere was found only for jaw muscles, whereas significant stroke-related differences in tongue activating cortical volume were limited to the infarcted hemisphere. These stroke-related differences were correlated with infarct size, such that larger infarcts were associated with increased jaw representation in the intact hemisphere and decreased tongue representation in the infarcted hemisphere. We found that both age and stroke were independently associated with swallowing differences, weight loss, and increased corticomotor thresholds. Laterality of tongue and jaw representations in the sham-control group revealed variability between individuals and between muscles within individuals. Conclusion Our findings suggest the role of the intact and infarcted hemispheres in the recovery of oral motor function may differ between the tongue and jaw muscles, which may have important implications for rehabilitation, especially hemisphere-specific neuromodulatory approaches. This study addressed the natural course of recovery after stroke; future work should expand to focus on rehabilitation.
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Affiliation(s)
- Miranda J. Cullins
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
| | - Nadine P. Connor
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, WI, United States
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3
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Suematsu N, Vazquez AL, Kozai TD. Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573814. [PMID: 38260671 PMCID: PMC10802282 DOI: 10.1101/2024.01.01.573814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Objective . Intracortical microstimulation can be an effective method for restoring sensory perception in contemporary brain-machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site. Approach . Different microstimulation frequencies were investigated in vivo on Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging. Main results . Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies. Significance . These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by intracortical microstimulation and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
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Ortiz-Rios M, Agayby B, Balezeau F, Haag M, Rima S, Cadena-Valencia J, Schmid MC. Optogenetic stimulation of the primary visual cortex drives activity in the visual association cortex. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 4:100087. [PMID: 37397814 PMCID: PMC10313868 DOI: 10.1016/j.crneur.2023.100087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 02/14/2023] [Accepted: 03/22/2023] [Indexed: 07/04/2023] Open
Abstract
Developing optogenetic methods for research in non-human primates (NHP) is important for translational neuroscience and for delineating brain function with unprecedented specificity. Here we assess, in macaque monkeys, the selectivity by which optogenetic stimulation of the primary visual cortex (V1) drives the local laminar and widespread cortical connectivity related to visual perception. Towards this end, we transfected neurons with light-sensitive channelrhodopsin in dorsal V1. fMRI revealed that optogenetic stimulation of V1 using blue light at 40 Hz increased functional activity in the visual association cortex, including areas V2/V3, V4, motion-sensitive area MT and frontal eye fields, although nonspecific heating and eye movement contributions to this effect could not be ruled out. Neurophysiology and immunohistochemistry analyses confirmed optogenetic modulation of spiking activity and opsin expression with the strongest expression in layer 4-B in V1. Stimulating this pathway during a perceptual decision task effectively elicited a phosphene percept in the receptive field of the stimulated neurons in one monkey. Taken together, our findings demonstrate the great potential of optogenetic methods to drive the large-scale cortical circuits of the primate brain with high functional and spatial specificity.
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Affiliation(s)
- Michael Ortiz-Rios
- Biosciences Institute, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
- Functional Imaging Laboratory, Deutsches Primatenzentrum (DPZ), Leibniz-Institut für Primatenforschung, Göttingen, Germany
| | - Beshoy Agayby
- Biosciences Institute, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Fabien Balezeau
- Biosciences Institute, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Marcus Haag
- Biosciences Institute, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
- Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700, Fribourg, Switzerland
| | - Samy Rima
- Biosciences Institute, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
- Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700, Fribourg, Switzerland
| | - Jaime Cadena-Valencia
- Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700, Fribourg, Switzerland
| | - Michael C. Schmid
- Biosciences Institute, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
- Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700, Fribourg, Switzerland
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Bundy DT, Barbay S, Hudson HM, Frost SB, Nudo RJ, Guggenmos DJ. Stimulation-Evoked Effective Connectivity (SEEC): An in-vivo approach for defining mesoscale corticocortical connectivity. J Neurosci Methods 2023; 384:109767. [PMID: 36493978 DOI: 10.1016/j.jneumeth.2022.109767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/07/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Cortical electrical stimulation is a versatile technique for examining the structure and function of cortical regions and for implementing novel therapies. While electrical stimulation has been used to examine the local spread of neural activity, it may also enable longitudinal examination of mesoscale interregional connectivity. NEW METHOD Here, we sought to use intracortical microstimulation (ICMS) in conjunction with recordings of multi-unit action potentials to assess the mesoscale effective connectivity within sensorimotor cortex. Neural recordings were made from multielectrode arrays placed into sensory, motor, and premotor regions during surgical experiments in three squirrel monkeys. During each recording, single-pulse ICMS was repeatably delivered to a single region. Mesoscale effective connectivity was calculated from ICMS-evoked changes in multi-unit firing. RESULTS Multi-unit action potentials were able to be detected on the order of 1 ms after each ICMS pulse. Across sensorimotor regions, short-latency (< 2.5 ms) ICMS-evoked neural activity strongly correlated with known anatomical connections. Additionally, ICMS-evoked responses remained stable across the experimental period, despite small changes in electrode locations and anesthetic state. COMPARISON WITH EXISTING METHODS Previous imaging studies investigating cross-regional responses to stimulation are limited to utilizing indirect hemodynamic responses and thus lack the temporal specificity of ICMS-evoked responses. CONCLUSIONS These results show that monitoring ICMS-evoked neural activity, in a technique we refer to as Stimulation-Evoked Effective Connectivity (SEEC), is a viable way to longitudinally assess effective connectivity, enabling studies comparing the time course of connectivity changes with the time course of changes in behavioral function.
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Affiliation(s)
- David T Bundy
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Scott Barbay
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Heather M Hudson
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Shawn B Frost
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Randolph J Nudo
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA; Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA.
| | - David J Guggenmos
- Departiment of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
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Oz R, Edelman-Klapper H, Nivinsky-Margalit S, Slovin H. Microstimulation in the primary visual cortex: activity patterns and their relation to visual responses and evoked saccades. Cereb Cortex 2022; 33:5192-5209. [PMID: 36300613 DOI: 10.1093/cercor/bhac409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 09/22/2022] [Accepted: 09/22/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
Intracortical microstimulation (ICMS) in the primary visual cortex (V1) can generate the visual perception of a small point of light, termed phosphene, and evoke saccades directed to the receptive field of the stimulated neurons. Although ICMS is widely used, a direct measurement of the spatio-temporal patterns of neural activity evoked by ICMS and their relation to the neural responses evoked by visual stimuli or how they relate to ICMS-evoked saccades are still missing. To investigate this, we combined ICMS with voltage-sensitive dye imaging in V1 of behaving monkeys and measured neural activity at a high spatial (meso-scale) and temporal resolution. We then compared the population response evoked by small visual stimuli to those evoked by microstimulation. Both stimulation types evoked population activity that spread over few millimeters in V1 and propagated to extrastriate areas. However, the population responses evoked by ICMS have shown faster dynamics for the activation transients and the horizontal propagation of activity revealed a wave-like propagation. Finally, neural activity in the ICMS condition was higher for trials with evoked saccades as compared with trials without saccades. Our results uncover the spatio-temporal patterns evoked by ICMS and their relation to visual processing and saccade generation.
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Affiliation(s)
- Roy Oz
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
| | - Hadar Edelman-Klapper
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
| | - Shany Nivinsky-Margalit
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
| | - Hamutal Slovin
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
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7
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Stieger KC, Eles JR, Ludwig KA, Kozai TDY. In vivo microstimulation with cathodic and anodic asymmetric waveforms modulates spatiotemporal calcium dynamics in cortical neuropil and pyramidal neurons of male mice. J Neurosci Res 2020; 98:2072-2095. [PMID: 32592267 DOI: 10.1002/jnr.24676] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022]
Abstract
Electrical stimulation has been critical in the development of an understanding of brain function and disease. Despite its widespread use and obvious clinical potential, the mechanisms governing stimulation in the cortex remain largely unexplored in the context of pulse parameters. Modeling studies have suggested that modulation of stimulation pulse waveform may be able to control the probability of neuronal activation to selectively stimulate either cell bodies or passing fibers depending on the leading polarity. Thus, asymmetric waveforms with equal charge per phase (i.e., increasing the leading phase duration and proportionately decreasing the amplitude) may be able to activate a more spatially localized or distributed population of neurons if the leading phase is cathodic or anodic, respectively. Here, we use two-photon and mesoscale calcium imaging of GCaMP6s expressed in excitatory pyramidal neurons of male mice to investigate the role of pulse polarity and waveform asymmetry on the spatiotemporal properties of direct neuronal activation with 10-Hz electrical stimulation. We demonstrate that increasing cathodic asymmetry effectively reduces neuronal activation and results in a more spatially localized subpopulation of activated neurons without sacrificing the density of activated neurons around the electrode. Conversely, increasing anodic asymmetry increases the spatial spread of activation and highly resembles spatiotemporal calcium activity induced by conventional symmetric cathodic stimulation. These results suggest that stimulation polarity and asymmetry can be used to modulate the spatiotemporal dynamics of neuronal activity thus increasing the effective parameter space of electrical stimulation to restore sensation and study circuit dynamics.
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Affiliation(s)
- Kevin C Stieger
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.,Center for the Neural Basis of Cognition, University of Pittsburgh, Carnegie Mellon University, Pittsburgh, PA, USA
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin Madison, Madison, WI, USA.,Department of Neurological Surgery, University of Wisconsin Madison, Madison, WI, USA.,Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, USA
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.,Center for the Neural Basis of Cognition, University of Pittsburgh, Carnegie Mellon University, Pittsburgh, PA, USA.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
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8
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Friedman RM, Morone KA, Gharbawie OA, Roe AW. Mapping mesoscale cortical connectivity in monkey sensorimotor cortex with optical imaging and microstimulation. J Comp Neurol 2020; 528:3095-3107. [PMID: 32255200 DOI: 10.1002/cne.24918] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 12/24/2022]
Abstract
To map in vivo cortical circuitry at the mesoscale, we applied a novel approach to map interareal functional connectivity. Electrical intracortical microstimulation (ICMS) in conjunction with optical imaging of intrinsic signals (OIS) was used map functional connections in somatosensory cortical areas in anesthetized squirrel monkeys. ICMS produced activations that were focal and that displayed responses which were stimulation intensity dependent. ICMS in supragranular layers of Brodmann Areas 3b, 1, 2, 3a, and M1 evoked interareal activation patterns that were topographically appropriate and appeared consistent with known anatomical connectivity. Specifically, ICMS revealed Area 3b connections with Area 1; Area 1 connections with Areas 2 and 3a; Area 2 connections with Areas 1, 3a, and M1; Area 3a connections with Areas M1, 1, and 2; and M1 connections with Areas 3a, 1, and 2. These somatosensory connectivity patterns were reminiscent of feedforward patterns observed anatomically, although feedback contributions are also likely present. Further consistent with anatomical connectivity, intra-areal and intra-areal patterns of activation were patchy with patch sizes of 200-300 μm. In summary, ICMS with OIS is a novel approach for mapping interareal and intra-areal connections in vivo. Comparisons with feedforward and feedback anatomical connectivity are discussed.
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Affiliation(s)
- Robert M Friedman
- Division of Neuroscience, Oregon National Primate Research Center, OHSU, Beaverton, Oregon
| | - Katherine A Morone
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Omar A Gharbawie
- Department of Neurobiology, Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Anna Wang Roe
- Division of Neuroscience, Oregon National Primate Research Center, OHSU, Beaverton, Oregon.,Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
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9
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Principles of Intrinsic Motor Cortex Connectivity in Primates. J Neurosci 2020; 40:4348-4362. [PMID: 32327531 DOI: 10.1523/jneurosci.0003-20.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/02/2020] [Accepted: 04/06/2020] [Indexed: 11/21/2022] Open
Abstract
The forelimb representation in motor cortex (M1) is an important model system in contemporary neuroscience. Efforts to understand the organization of the M1 forelimb representation in monkeys have focused on inputs and outputs. In contrast, intrinsic M1 connections remain mostly unexplored, which is surprising given that intra-areal connections universally outnumber extrinsic connections. To address this knowledge gap, we first mapped the M1 forelimb representation with intracortical microstimulation (ICMS) in male squirrel monkeys. Next, we determined the connectivity of individual M1 sites with ICMS + intrinsic signal optical imaging (ISOI). Every stimulation site activated a distinctive pattern of patches (∼0.25 to 1.0 mm radius) that we quantified in relation to the motor map. Arm sites activated patches that were mostly in arm zones. Hand sites followed the same principle, but to a lesser extent. The results collectively indicate that preferential connectivity between functionally matched patches is a prominent organizational principle in M1. Connectivity patterns for a given site were conserved across a range of current amplitudes, train durations, pulse frequencies, and microelectrode depths. In addition, we found close correspondence in somatosensory cortex between connectivity that we revealed with ICMS+ISOI and connections known from tracers. ICMS+ISOI is therefore an effective tool for mapping cortical connectivity and is particularly advantageous for sampling large numbers of sites. This feature was instrumental in revealing the spatial specificity of intrinsic M1 connections, which appear to be woven into the somatotopic organization of the forelimb representation. Such a framework invokes the modular organization well-established for sensory cortical areas.SIGNIFICANCE STATEMENT Intrinsic connections are fundamental to the operations of any cortical area. Surprisingly little is known about the organization of intrinsic connections in motor cortex (M1). We addressed this knowledge gap using intracortical microstimulation (ICMS) concurrently with intrinsic signal optical imaging (ISOI). Quantifying the activation patterns from dozens of M1 sites allowed us to uncover a fundamental principle of M1 organization: M1 patches are preferentially connected with functionally matched patches. Relationship between intrinsic connections and neurophysiological map is well-established for sensory cortical areas, but our study is the first to extend this framework to M1. Microstimulation+imaging opened a unique possibility for investigating the connectivity of dozens of tightly spaced M1 sites, which was the linchpin for uncovering organizational principles.
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10
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Eles JR, Kozai TDY. In vivo imaging of calcium and glutamate responses to intracortical microstimulation reveals distinct temporal responses of the neuropil and somatic compartments in layer II/III neurons. Biomaterials 2020; 234:119767. [PMID: 31954232 DOI: 10.1016/j.biomaterials.2020.119767] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/22/2019] [Accepted: 01/05/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Intracortical microelectrode implants can generate a tissue response hallmarked by glial scarring and neuron cell death within 100-150 μm of the biomaterial device. Many have proposed that any performance decline in intracortical microstimulation (ICMS) due to this foreign body tissue response could be offset by increasing the stimulation amplitude. The mechanisms of this approach are unclear, however, as there has not been consensus on how increasing amplitude affects the spatial and temporal recruitment patterns of ICMS. APPROACH We clarify these unknowns using in vivo two-photon imaging of mice transgenically expressing the calcium sensor GCaMP6s in Thy1 neurons or virally expressing the glutamate sensor iGluSnFr in neurons. Calcium and neurotransmitter activity are tracked in the neuronal somas and neuropil during long-train stimulation in Layer II/III of somatosensory cortex. MAIN RESULTS Neural calcium activity and glutamate release are dense and strongest within 20-40 μm around the electrode, falling off with distance from the electrode. Neuronal calcium increases with higher amplitude stimulations. During prolonged stimulation trains, a sub-population of somas fail to maintain calcium activity. Interestingly, neuropil calcium activity is 3-fold less correlated to somatic calcium activity for cells that drop-out during the long stimulation train compared to cells that sustain activity throughout the train. Glutamate release is apparent only within 20 μm of the electrode and is sustained for at least 10s after cessation of the 15 and 20 μA stimulation train, but not lower amplitudes. SIGNIFICANCE These results demonstrate that increasing amplitude can increase the radius and intensity of neural recruitment, but it also alters the temporal response of some neurons. Further, dense glutamate release is highest within the first 20 μm of the electrode site even at high amplitudes, suggesting that there may be spatial limitations to the amplitude parameter space. The glutamate elevation outlasts stimulation, suggesting that high-amplitude stimulation may affect neurotransmitter re-uptake. This ultimately suggests that increasing the amplitude of ICMS device stimulation may fundamentally alter the temporal neural response, which could have implications for using amplitude to improve the ICMS effect or "offset" the effects of glial scarring.
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Affiliation(s)
- James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, Carnegie Mellon University, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
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11
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Baldwin MKL, Cooke DF, Goldring AB, Krubitzer L. Representations of Fine Digit Movements in Posterior and Anterior Parietal Cortex Revealed Using Long-Train Intracortical Microstimulation in Macaque Monkeys. Cereb Cortex 2019; 28:4244-4263. [PMID: 29136133 DOI: 10.1093/cercor/bhx279] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/03/2017] [Indexed: 12/30/2022] Open
Abstract
The current investigation in macaque monkeys utilized long-train intracortical microstimulation to determine the extent of cortex from which movements could be evoked. Not only were movements evoked from motor areas (PMC and M1), but they were also evoked from posterior parietal (5, 7a, 7b) and anterior parietal areas (3b, 1, 2). Large representations of digit movements involving only the index finger (D2) and thumb (D1), were elicited from areas 1, 2, 7b, and M1. Other movements evoked from these regions were similar to ethologically relevant movements that have been described in other primates. These include combined forelimb and mouth movements and full hand grasps. However, many other movements were much more complex and could not be categorized into any of the previously described ethological categories. Movements involving specific digits, which mimic precision grips, are unique to macaques and have not been described in New World or prosimian primates. We propose that these multiple and expanded motor representations of the digits co-evolved with the emergence of the opposable thumb and alterations in grip type in some anthropoid lineages.
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Affiliation(s)
- Mary K L Baldwin
- Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA, USA
| | - Dylan F Cooke
- Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA, USA.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada
| | - Adam B Goldring
- Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA, USA
| | - Leah Krubitzer
- Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA, USA.,Department of Psychology, University of California, Davis, CA, USA
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12
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Sound- and current-driven laminar profiles and their application method mimicking acoustic responses in the mouse auditory cortex in vivo. Brain Res 2019; 1721:146312. [PMID: 31323198 DOI: 10.1016/j.brainres.2019.146312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 06/14/2019] [Accepted: 06/27/2019] [Indexed: 11/24/2022]
Abstract
The local application of electrical currents to the cortex is one of the most commonly used techniques to activate neurons, and this intracortical stimulation (ICS) could potentially lead to new types of neuroprosthetic devices that can be directly applied to the cortex. To identify whether ICS-activated circuits are physiological vs. profoundly artificial, it is necessary to record in vivo the responses of the same neuronal population to both natural sensory stimuli and artificial electric stimuli. However, few studies have extensively reported simultaneous electrophysiological recordings combined with ICS. Here, we evaluated the similarity between sound- and ICS-driven cortical response patterns in different cortical layers. In the mouse auditory cortex, we performed laminar recordings using 16-channel silicon electrodes and ICS using sharp glass-pipette electrodes containing biocytin for layer identification. In different cortical depths, short current pulses were delivered in vivo to mice under urethane anesthesia. For the recorded data, we mainly analyzed properties of local field potentials and current source densities (CSDs). We demonstrated that electrical stimulation evoked different excitation patterns according to the stimulated cortical layer; responses to electric stimuli in layer 4 were most likely to mimic acoustic responses. Next, we proposed a CSD-based stimulation method to artificially synthesize sound-driven responses, using an approximation method associated with a linear combination of CSD patterns electrically stimulated in the different cortical layers. The result indicates that synthesized responses were consistent with the canonical model of sound processing. Using these approaches, we provide a new technique in which natural sound-driven responses can be mimicked by well-designed computational stimulation pattern sequences in a layer-dependent manner. These findings may aid in the future development of an electrical stimulation methodology for a cortical prosthesis.
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Voigt MB, Kral A. Cathodic-leading pulses are more effective than anodic-leading pulses in intracortical microstimulation of the auditory cortex. J Neural Eng 2019; 16:036002. [PMID: 30790776 DOI: 10.1088/1741-2552/ab0944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Intracortical microstimulation (ICMS) is widely used in neuroscientific research. Earlier work from our lab showed the possibility to combine ICMS with neuronal recordings on the same shank of multi-electrode arrays and consequently inside the same cortical column in vivo. The standard stimulus pulse shape for ICMS is a symmetric, biphasic current pulse. Here, we investigated the role of the leading-phase polarity (cathodic- versus anodic-leading) of such single ICMS pulses on the activation of the cortical network. APPROACH Local field potentials (LFPs) and multi-unit responses were recorded in the primary auditory cortex (A1) of adult guinea pigs (n = 15) under ketamine/xylazine anesthesia using linear multi-electrode arrays. Physiological responses of A1 were recorded during acoustic stimulation and ICMS. For the ICMS, the leading-phase polarity, the stimulated electrode and the stimulation current where varied systematically on any one of the 16 electrodes while recording at the same time with the 15 remaining electrodes. MAIN RESULTS Cathodic-leading ICMS consistently led to higher response amplitudes. In superficial cortical layers and for a given current amplitude, cathodic-leading and anodic-leading ICMS showed comparable activation patterns, while in deep layers only cathodic-leading ICMS reliably generated local neuronal activity. ICMS had a significantly smaller dynamic range than acoustic stimulation regardless of leading-phase polarity. SIGNIFICANCE The present study provides in vivo evidence for a differential neuronal activation mechanism of the different leading-phase polarities, with cathodic-leading stimulation being more effective, and suggests that the waveform of the stimulus should be considered systematically for cortical neuroprosthesis development.
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Affiliation(s)
- Mathias Benjamin Voigt
- Department of Experimental Otology, Institute of AudioNeuroTechnology (VIANNA), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany. Cluster of Excellence 'Hearing4all', Hannover, Germany
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Spatio-temporal characteristics of population responses evoked by microstimulation in the barrel cortex. Sci Rep 2018; 8:13913. [PMID: 30224723 PMCID: PMC6141467 DOI: 10.1038/s41598-018-32148-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/03/2018] [Indexed: 11/09/2022] Open
Abstract
Intra-cortical microstimulation (ICMS) is a widely used technique to artificially stimulate cortical tissue. This method revealed functional maps and provided causal links between neuronal activity and cognitive, sensory or motor functions. The effects of ICMS on neural activity depend on stimulation parameters. Past studies investigated the effects of stimulation frequency mainly at the behavioral or motor level. Therefore the direct effect of frequency stimulation on the evoked spatio-temporal patterns of cortical activity is largely unknown. To study this question we used voltage-sensitive dye imaging to measure the population response in the barrel cortex of anesthetized rats evoked by high frequency stimulation (HFS), a lower frequency stimulation (LFS) of the same duration or a single pulse stimulation. We found that single pulse and short trains of ICMS induced cortical activity extending over few mm. HFS evoked a lower population response during the sustained response and showed a smaller activation across time and space compared with LFS. Finally the evoked population response started near the electrode site and spread horizontally at a propagation velocity in accordance with horizontal connections. In summary, HFS was less effective in cortical activation compared to LFS although HFS had 5 fold more energy than LFS.
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Orcioni S, Paffi A, Camera F, Apollonio F, Liberti M. Automatic decoding of input sinusoidal signal in a neuron model: High pass homomorphic filtering. Neurocomputing 2018. [DOI: 10.1016/j.neucom.2018.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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16
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Orcioni S, Paffi A, Camera F, Apollonio F, Liberti M. Automatic decoding of input sinusoidal signal in a neuron model: Improved SNR spectrum by low-pass homomorphic filtering. Neurocomputing 2017. [DOI: 10.1016/j.neucom.2017.06.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Bosking WH, Beauchamp MS, Yoshor D. Electrical Stimulation of Visual Cortex: Relevance for the Development of Visual Cortical Prosthetics. Annu Rev Vis Sci 2017; 3:141-166. [PMID: 28753382 PMCID: PMC6916716 DOI: 10.1146/annurev-vision-111815-114525] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electrical stimulation of the cerebral cortex is a powerful tool for exploring cortical function. Stimulation of early visual cortical areas is easily detected by subjects and produces simple visual percepts known as phosphenes. A device implanted in visual cortex that generates patterns of phosphenes could be used as a substitute for natural vision in blind patients. We review the possibilities and limitations of such a device, termed a visual cortical prosthetic. Currently, we can predict the location and size of phosphenes produced by stimulation of single electrodes. A functional prosthetic, however, must produce spatial temporal patterns of activity that will result in the perception of complex visual objects. Although stimulation of later visual cortical areas alone usually does not lead to a visual percept, it can alter visual perception and the performance of visual behaviors, and training subjects to use signals injected into these areas may be possible.
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Affiliation(s)
- William H Bosking
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030; , ,
| | - Michael S Beauchamp
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030; , ,
| | - Daniel Yoshor
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030; , ,
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Mesoscale Mapping of Mouse Cortex Reveals Frequency-Dependent Cycling between Distinct Macroscale Functional Modules. J Neurosci 2017; 37:7513-7533. [PMID: 28674167 DOI: 10.1523/jneurosci.3560-16.2017] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 06/13/2017] [Accepted: 06/19/2017] [Indexed: 12/17/2022] Open
Abstract
Connectivity mapping based on resting-state activity in mice has revealed functional motifs of correlated activity. However, the rules by which motifs organize into larger functional modules that lead to hemisphere wide spatial-temporal activity sequences is not clear. We explore cortical activity parcellation in head-fixed, quiet awake GCaMP6 mice from both sexes by using mesoscopic calcium imaging. Spectral decomposition of spontaneous cortical activity revealed the presence of two dominant frequency modes (<1 and ∼3 Hz), each of them associated with a unique spatial signature of cortical macro-parcellation not predicted by classical cytoarchitectonic definitions of cortical areas. Based on assessment of 0.1-1 Hz activity, we define two macro-organizing principles: the first being a rotating polymodal-association pinwheel structure around which activity flows sequentially from visual to barrel then to hindlimb somatosensory; the second principle is correlated activity symmetry planes that exist on many levels within a single domain such as intrahemispheric reflections of sensory and motor cortices. In contrast, higher frequency activity >1 Hz yielded two larger clusters of coactivated areas with an enlarged default mode network-like posterior region. We suggest that the apparent constrained structure for intra-areal cortical activity flow could be exploited in future efforts to normalize activity in diseases of the nervous system.SIGNIFICANCE STATEMENT Increasingly, functional connectivity mapping of spontaneous activity is being used to reveal the organization of the brain. However, because the brain operates across multiple space and time domains a more detailed understanding of this organization is necessary. We used in vivo wide-field calcium imaging of the indicator GCaMP6 in head-fixed, awake mice to characterize the organization of spontaneous cortical activity at different spatiotemporal scales. Correlation analysis defines the presence of two to three superclusters of activity that span traditionally defined functional territories and were frequency dependent. This work helps define the rules for how different cortical areas interact in time and space. We provide a framework necessary for future studies that explore functional reorganization of brain circuits in disease models.
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Morone KA, Neimat JS, Roe AW, Friedman RM. Review of functional and clinical relevance of intrinsic signal optical imaging in human brain mapping. NEUROPHOTONICS 2017; 4:031220. [PMID: 28630881 PMCID: PMC5466092 DOI: 10.1117/1.nph.4.3.031220] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/12/2017] [Indexed: 05/30/2023]
Abstract
Intrinsic signal optical imaging (ISOI) within the first decade of its use in humans showed its capacity as a precise functional mapping tool. It is a powerful tool that can be used intraoperatively to help a surgeon to directly identify functional areas of the cerebral cortex. Its use is limited to the intraoperative setting as it requires a craniotomy and durotomy for direct visualization of the brain. It has been applied in humans to study language, somatosensory and visual cortices, cortical hemodynamics, epileptiform activity, and lesion delineation. Despite studies showing clear evidence of its usefulness in clinical care, its clinical use in humans has not grown. Impediments imposed by imaging in a human operating room setting have hindered such work. However, recent studies have been aimed at overcoming obstacles in clinical studies establishing the benefits of its use to patients. This review provides a description of ISOI and its use in human studies with an emphasis on the challenges that have hindered its widespread use and the recent studies that aim to overcome these hurdles. Clinical studies establishing the benefits of its use to patients would serve as the impetus for continued development and use in humans.
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Affiliation(s)
- Katherine A. Morone
- Vanderbilt University Medical Center, Department of Neurology, Nashville, Tennessee, United States
| | - Joseph S. Neimat
- University of Louisville School of Medicine, Department of Neurosurgery, Louisville, Kentucky, United States
| | - Anna W. Roe
- Oregon Health and Science University, Division of Neuroscience, Oregon National Primate Research Center, Beaverton, Oregon, United States
- Zhejiang University, Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, HuaJiaChi Campus, Hangzhou, China
| | - Robert M. Friedman
- Oregon Health and Science University, Division of Neuroscience, Oregon National Primate Research Center, Beaverton, Oregon, United States
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Saturation in Phosphene Size with Increasing Current Levels Delivered to Human Visual Cortex. J Neurosci 2017; 37:7188-7197. [PMID: 28652411 DOI: 10.1523/jneurosci.2896-16.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 11/21/2022] Open
Abstract
Electrically stimulating early visual cortex results in a visual percept known as a phosphene. Although phosphenes can be evoked by a wide range of electrode sizes and current amplitudes, they are invariably described as small. To better understand this observation, we electrically stimulated 93 electrodes implanted in the visual cortex of 13 human subjects who reported phosphene size while stimulation current was varied. Phosphene size increased as the stimulation current was initially raised above threshold, but then rapidly reached saturation. Phosphene size also depended on the location of the stimulated site, with size increasing with distance from the foveal representation. We developed a model relating phosphene size to the amount of activated cortex and its location within the retinotopic map. First, a sigmoidal curve was used to predict the amount of activated cortex at a given current. Second, the amount of active cortex was converted to degrees of visual angle by multiplying by the inverse cortical magnification factor for that retinotopic location. This simple model accurately predicted phosphene size for a broad range of stimulation currents and cortical locations. The unexpected saturation in phosphene sizes suggests that the functional architecture of cerebral cortex may impose fundamental restrictions on the spread of artificially evoked activity and this may be an important consideration in the design of cortical prosthetic devices.SIGNIFICANCE STATEMENT Understanding the neural basis for phosphenes, the visual percepts created by electrical stimulation of visual cortex, is fundamental to the development of a visual cortical prosthetic. Our experiments in human subjects implanted with electrodes over visual cortex show that it is the activity of a large population of cells spread out across several millimeters of tissue that supports the perception of a phosphene. In addition, we describe an important feature of the production of phosphenes by electrical stimulation: phosphene size saturates at a relatively low current level. This finding implies that, with current methods, visual prosthetics will have a limited dynamic range available to control the production of spatial forms and that more advanced stimulation methods may be required.
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Intracortical microstimulation differentially activates cortical layers based on stimulation depth. Brain Stimul 2017; 10:684-694. [DOI: 10.1016/j.brs.2017.02.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/23/2017] [Accepted: 02/24/2017] [Indexed: 12/22/2022] Open
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Hao Y, Riehle A, Brochier TG. Mapping Horizontal Spread of Activity in Monkey Motor Cortex Using Single Pulse Microstimulation. Front Neural Circuits 2016; 10:104. [PMID: 28018182 PMCID: PMC5159418 DOI: 10.3389/fncir.2016.00104] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 12/01/2016] [Indexed: 12/13/2022] Open
Abstract
Anatomical studies have demonstrated that distant cortical points are interconnected through long range axon collaterals of pyramidal cells. However, the functional properties of these intrinsic synaptic connections, especially their relationship with the cortical representations of body movements, have not been systematically investigated. To address this issue, we used multielectrode arrays chronically implanted in the motor cortex of two rhesus monkeys to analyze the effects of single-pulse intracortical microstimulation (sICMS) applied at one electrode on the neuronal activities recorded at all other electrodes. The temporal and spatial distribution of the evoked responses of single and multiunit activities was quantified to determine the properties of horizontal propagation. The typical responses were characterized by a brief excitatory peak followed by inhibition of longer duration. Significant excitatory responses to sICMS could be evoked up to 4 mm away from the stimulation site, but the strength of the response decreased exponentially and its latency increased linearly with the distance. We then quantified the direction and strength of the propagation in relation to the somatotopic organization of the motor cortex. We observed that following sICMS the propagation of neural activity is mainly directed rostro-caudally near the central sulcus but follows medio-lateral direction at the most anterior electrodes. The fact that these interactions are not entirely symmetrical may characterize a critical functional property of the motor cortex for the control of upper limb movements. Overall, these results support the assumption that the motor cortex is not functionally homogeneous but forms a complex network of interacting subregions.
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Affiliation(s)
- Yaoyao Hao
- Institut de Neurosciences de la Timone, CNRS - Aix-Marseille Université, UMR7289 Marseille, France
| | - Alexa Riehle
- Institut de Neurosciences de la Timone, CNRS - Aix-Marseille Université, UMR7289Marseille, France; RIKEN Brain Science InstituteSaitama, Japan; Institute of Neuroscience and Medicine, Forschungszentrum JülichJülich, Germany
| | - Thomas G Brochier
- Institut de Neurosciences de la Timone, CNRS - Aix-Marseille Université, UMR7289 Marseille, France
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Overstreet CK, Hellman RB, Ponce Wong RD, Santos VJ, Helms Tillery SI. Discriminability of Single and Multichannel Intracortical Microstimulation within Somatosensory Cortex. Front Bioeng Biotechnol 2016; 4:91. [PMID: 27995126 PMCID: PMC5133427 DOI: 10.3389/fbioe.2016.00091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 11/14/2016] [Indexed: 11/13/2022] Open
Abstract
The addition of tactile and proprioceptive feedback to neuroprosthetic limbs is expected to significantly improve the control of these devices. Intracortical microstimulation (ICMS) of somatosensory cortex is a promising method of delivering this sensory feedback. To date, the main focus of somatosensory ICMS studies has been to deliver discriminable signals, corresponding to varying intensity, to a single location in cortex. However, multiple independent and simultaneous streams of sensory information will need to be encoded by ICMS to provide functionally relevant feedback for a neuroprosthetic limb (e.g., encoding contact events and pressure on multiple digits). In this study, we evaluated the ability of an awake, behaving non-human primate (Macaca mulatta) to discriminate ICMS stimuli delivered on multiple electrodes spaced within somatosensory cortex. We delivered serial stimulation on single electrodes to evaluate the discriminability of sensations corresponding to ICMS of distinct cortical locations. Additionally, we delivered trains of multichannel stimulation, derived from a tactile sensor, synchronously across multiple electrodes. Our results indicate that discrimination of multiple ICMS stimuli is a challenging task, but that discriminable sensory percepts can be elicited by both single and multichannel ICMS on electrodes spaced within somatosensory cortex.
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Affiliation(s)
- Cynthia K Overstreet
- SensoriMotor Research Group, School of Biological and Health Systems Engineering, Arizona State University , Tempe, AZ , USA
| | - Randall B Hellman
- Biomechatronics Lab, Department of Mechanical and Aerospace Engineering, Arizona State University , Tempe, AZ , USA
| | - Ruben D Ponce Wong
- Biomechatronics Lab, Department of Mechanical and Aerospace Engineering, Arizona State University , Tempe, AZ , USA
| | - Veronica J Santos
- Biomechatronics Lab, Department of Mechanical and Aerospace Engineering, Arizona State University , Tempe, AZ , USA
| | - Stephen I Helms Tillery
- SensoriMotor Research Group, School of Biological and Health Systems Engineering, Arizona State University , Tempe, AZ , USA
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Ethological Action Maps: A Paradigm Shift for the Motor Cortex. Trends Cogn Sci 2016; 20:121-132. [PMID: 26628112 DOI: 10.1016/j.tics.2015.10.008] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 10/20/2015] [Accepted: 10/28/2015] [Indexed: 11/21/2022]
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Chernov MM, Chen G, Torre-Healy LA, Friedman RM, Roe AW. Microelectrode array stimulation combined with intrinsic optical imaging: A novel tool for functional brain mapping. J Neurosci Methods 2016; 263:7-14. [PMID: 26820903 DOI: 10.1016/j.jneumeth.2016.01.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 12/24/2015] [Accepted: 01/16/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND Functional brain mapping via cortical microstimulation is a widely used clinical and experimental tool. However, data are traditionally collected point by point, making the technique very time consuming. Moreover, even in skilled hands, consistent penetration depths are difficult to achieve. Finally, the effects of microstimulation are assessed behaviorally, with no attempt to capture the activity of the local cortical circuits being stimulated. NEW METHOD We propose a novel method for functional brain mapping, which combines the use of a microelectrode array with intrinsic optical imaging. The precise spacing of electrodes allows for fast, accurate mapping of the area of interest in a regular grid. At the same time, the optical window allows for visualization of local neural connections when stimulation is combined with intrinsic optical imaging. RESULTS We demonstrate the efficacy of our technique using the primate motor cortex as a sample application, using a combination of microstimulation, imaging and electrophysiological recordings during wakefulness and under anesthesia. Comparison with current method: We find the data collected with our method is consistent with previous data published by others. We believe that our approach enables data to be collected faster and in a more consistent fashion and makes possible a number of studies that would be difficult to carry out with the traditional approach. CONCLUSIONS Our technique allows for simultaneous modulation and imaging of cortical sensorimotor networks in wakeful subjects over multiple sessions which is highly desirable for both the study of cortical organization and the design of brain machine interfaces.
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Affiliation(s)
- Mykyta M Chernov
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States.
| | - Gang Chen
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
| | - Luke A Torre-Healy
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
| | - Robert M Friedman
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
| | - Anna W Roe
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
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Spatiotemporal Profile of Voltage-Sensitive Dye Responses in the Visual Cortex of Tree Shrews Evoked by Electric Microstimulation of the Dorsal Lateral Geniculate and Pulvinar Nuclei. J Neurosci 2015; 35:11891-6. [PMID: 26311771 DOI: 10.1523/jneurosci.0717-15.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The primary visual cortex (V1) receives its main thalamic drive from the dorsal lateral geniculate nucleus (dLGN) through synaptic contacts terminating primarily in cortical layer IV. In contrast, the projections from the pulvinar nucleus to the cortex are less clearly defined. The pulvinar projects predominantly to layer I in V1, and layer IV in extrastriate areas. These projection patterns suggest that the pulvinar nucleus most strongly influences (drives) activity in cortical areas beyond V1. Should this hypothesis be true, one would expect the spatiotemporal responses evoked by pulvinar activation to be different in V1 and extrastriate areas, reflecting the different connectivity patterns. We investigated this issue by analyzing the spatiotemporal dynamics of cortical visual areas' activity following thalamic electrical microstimulation in tree shrews, using optical imaging and voltage-sensitive dyes. As expected, electrical stimulation of the dLGN induced fast and local responses in V1, as well as in extrastriate and contralateral cortical areas. In contrast, electrical stimulation of the pulvinar induced fast and local responses in extrastriate areas, followed by weak and diffuse activation in V1 and contralateral cortical areas. This study highlights spatiotemporal cortical activation characteristics induced by stimulation of first (dLGN) and high-order (pulvinar) thalamic nuclei. SIGNIFICANCE STATEMENT The pulvinar nucleus represents the main extrageniculate thalamic visual structure in higher-order mammals, but its exact role remains enigmatic. The pulvinar receive prominent inputs from virtually all visual cortical areas. Cortico-thalamo-cortical pathways through the pulvinar nuclei may then provide a complementary route for corticocortical information flow. One step toward the understanding of the role of transthalamic corticocortical pathways is to determine the nature of the signals transmitted between the cortex and the thalamus. By performing, for the first time, high spatiotemporal mesoscopic imaging on tree shrews (the primate's closest relative) through the combination of voltage-sensitive dye recordings and brain stimulation, we revealed clear evidence of distinct thalamocortical functional connectivity pattern originating from the geniculate nucleus and the pulvinar nuclei.
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Roe AW, Chernov MM, Friedman RM, Chen G. In Vivo Mapping of Cortical Columnar Networks in the Monkey with Focal Electrical and Optical Stimulation. Front Neuroanat 2015; 9:135. [PMID: 26635539 PMCID: PMC4644798 DOI: 10.3389/fnana.2015.00135] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/12/2015] [Indexed: 11/30/2022] Open
Abstract
There are currently largescale efforts to understand the brain as a connection machine. However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns. Here, we review development and application of focal electrical and optical stimulation methods combined with optical imaging and fMRI mapping in the non-human primate. These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns. Such functionally specific network data can provide accurate views of brain network topology.
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Affiliation(s)
- Anna Wang Roe
- Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China
| | - Mykyta M Chernov
- Department of Psychology, Vanderbilt University, Nashville TN, USA
| | | | - Gang Chen
- Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China
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Paffi A, Camera F, Apollonio F, d'Inzeo G, Liberti M. Restoring the encoding properties of a stochastic neuron model by an exogenous noise. Front Comput Neurosci 2015; 9:42. [PMID: 25999845 PMCID: PMC4422033 DOI: 10.3389/fncom.2015.00042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 03/19/2015] [Indexed: 11/13/2022] Open
Abstract
Here we evaluate the possibility of improving the encoding properties of an impaired neuronal system by superimposing an exogenous noise to an external electric stimulation signal. The approach is based on the use of mathematical neuron models consisting of stochastic HH-like circuit, where the impairment of the endogenous presynaptic inputs is described as a subthreshold injected current and the exogenous stimulation signal is a sinusoidal voltage perturbation across the membrane. Our results indicate that a correlated Gaussian noise, added to the sinusoidal signal can significantly increase the encoding properties of the impaired system, through the Stochastic Resonance (SR) phenomenon. These results suggest that an exogenous noise, suitably tailored, could improve the efficacy of those stimulation techniques used in neuronal systems, where the presynaptic sensory neurons are impaired and have to be artificially bypassed.
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Affiliation(s)
- Alessandra Paffi
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems Genova, Italy
| | - Francesca Camera
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems Genova, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems Genova, Italy
| | - Guglielmo d'Inzeo
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems Genova, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome Rome, Italy ; Italian Inter-University Center for the Study of Electromagnetic Fields and Biological Systems Genova, Italy
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Premereur E, Van Dromme IC, Romero MC, Vanduffel W, Janssen P. Effective connectivity of depth-structure-selective patches in the lateral bank of the macaque intraparietal sulcus. PLoS Biol 2015; 13:e1002072. [PMID: 25689048 PMCID: PMC4331519 DOI: 10.1371/journal.pbio.1002072] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/09/2015] [Indexed: 12/04/2022] Open
Abstract
Extrastriate cortical areas are frequently composed of subpopulations of neurons encoding specific features or stimuli, such as color, disparity, or faces, and patches of neurons encoding similar stimulus properties are typically embedded in interconnected networks, such as the attention or face-processing network. The goal of the current study was to examine the effective connectivity of subsectors of neurons in the same cortical area with highly similar neuronal response properties. We first recorded single- and multi-unit activity to identify two neuronal patches in the anterior part of the macaque intraparietal sulcus (IPS) showing the same depth structure selectivity and then employed electrical microstimulation during functional magnetic resonance imaging in these patches to determine the effective connectivity of these patches. The two IPS subsectors we identified-with the same neuronal response properties and in some cases separated by only 3 mm-were effectively connected to remarkably distinct cortical networks in both dorsal and ventral stream in three macaques. Conversely, the differences in effective connectivity could account for the known visual-to-motor gradient within the anterior IPS. These results clarify the role of the anterior IPS as a pivotal brain region where dorsal and ventral visual stream interact during object analysis. Thus, in addition to the anatomical connectivity of cortical areas and the properties of individual neurons in these areas, the effective connectivity provides novel key insights into the widespread functional networks that support behavior.
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Affiliation(s)
- Elsie Premereur
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
| | | | - Maria C. Romero
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
| | - Wim Vanduffel
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter Janssen
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
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Mesoscale transcranial spontaneous activity mapping in GCaMP3 transgenic mice reveals extensive reciprocal connections between areas of somatomotor cortex. J Neurosci 2015; 34:15931-46. [PMID: 25429135 DOI: 10.1523/jneurosci.1818-14.2014] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transgenic mice expressing genetically encoded activity indicators are an attractive means of mapping mesoscopic regional functional cortical connectivity given widespread stable and cell-specific expression compatible with chronic recordings. Cortical functional connectivity was evaluated using wide-field imaging in lightly anesthetized Emx1-creXRosa26-GCaMP3 mice expressing calcium sensor in cortical neurons. Challenges exist because green fluorescence signals overlap with endogenous activity-dependent autofluorescence and are affected by changes in blood volume and oxygenation. Under the conditions used for imaging and analysis (0.1-1 Hz frequency band), autofluorescence and hemodynamic effects contributed 3% and 8% of the SD of spontaneous activity-dependent GCaMP3 fluorescence when signals were recorded through intact bone. To evaluate the accuracy and sensitivity of this approach, the topology of functional connections between somatomotor cortex (primary S1 and secondary S2 somatosensory, and primary motor cortex M1) was estimated. During sequences of spontaneous activity, calcium signals recorded at each location of area S1 were correlated with activity in contralateral area S1, ipsilateral area S2, and bilateral areas M1. Reciprocal results were observed when "seed pixels" were placed in S2 and M1. Coactivation of areas implies functional connections but could also be attributed to both regions receiving common upstream drive. These apparent connections revealed during spontaneous activity coactivation by GCaMP3 were confirmed by intracortical microstimulation but were more difficult to detect using intrinsic signals from reflected red light. We anticipate GCAMP wide-field imaging will enable longitudinal studies during plasticity paradigms or after models of CNS disease, such as stroke, where the weighting within these connectivity maps may be altered.
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Chernov M, Roe AW. Infrared neural stimulation: a new stimulation tool for central nervous system applications. NEUROPHOTONICS 2014; 1:011011. [PMID: 26157967 PMCID: PMC4478761 DOI: 10.1117/1.nph.1.1.011011] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 05/08/2023]
Abstract
The traditional approach to modulating brain function (in both clinical and basic science applications) is to tap into the neural circuitry using electrical currents applied via implanted electrodes. However, it suffers from a number of problems, including the risk of tissue trauma, poor spatial specificity, and the inability to selectively stimulate neuronal subtypes. About a decade ago, optical alternatives to electrical stimulation started to emerge in order to address the shortcomings of electrical stimulation. We describe the use of one optical stimulation technique, infrared neural stimulation (INS), during which short (of the order of a millisecond) pulses of infrared light are delivered to the neural tissue. Very focal stimulation is achieved via a thermal mechanism and stimulation location can be quickly adjusted by redirecting the light. After describing some of the work done in the peripheral nervous system, we focus on the use of INS in the central nervous system to investigate functional connectivity in the visual and somatosensory areas, target specific functional domains, and influence behavior of an awake nonhuman primate. We conclude with a positive outlook for INS as a tool for safe and precise targeted brain stimulation.
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Affiliation(s)
- Mykyta Chernov
- Vanderbilt University, Department of Psychology, 111 21st Avenue South, Nashville, Tennessee 37240, United States
| | - Anna Wang Roe
- Vanderbilt University, Department of Psychology, 111 21st Avenue South, Nashville, Tennessee 37240, United States
- Address all correspondence to: Anna Wang Roe, E-mail:
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