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Qiao X, Grieco SF, Yu Z, Holmes TC, Xu X. Intranasal Delivery of Ketamine Induces Cortical Disinhibition. eNeuro 2024; 11:ENEURO.0107-23.2023. [PMID: 38164560 PMCID: PMC10849039 DOI: 10.1523/eneuro.0107-23.2023] [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: 03/27/2023] [Revised: 11/02/2023] [Accepted: 11/21/2023] [Indexed: 01/03/2024] Open
Abstract
Our previous studies find that subcutaneously administered (s.c.) subanesthetic ketamine promotes sustained cortical disinhibition and plasticity in adult mouse binocular visual cortex (bV1). We hypothesized that intranasal delivery (i.n.) of subanesthetic ketamine may have similar actions. To test this, we delivered ketamine (10 mg/kg, i.n.) to adult mice and then recorded excitatory pyramidal neurons or PV+ interneurons in L2/3 of bV1 slices. In pyramidal neurons the baseline IPSC amplitudes from mice treated with ketamine are significantly weaker than those in control mice. Acute bath application of neuregulin-1 (NRG1) to cortical slices increases these IPSC amplitudes in mice treated with ketamine but not in controls. In PV+ interneurons, the baseline EPSC amplitudes from mice treated with ketamine are significantly weaker than those in control mice. Acute bath application of NRG1 to cortical slices increases these EPSC amplitudes in mice treated with ketamine but not in controls. We also found that mice treated with ketamine exhibit increased pCREB staining in L2/3 of bV1. Together, our results show that a single intranasal delivery of ketamine reduces PV+ interneuron excitation and reduces pyramidal neuron inhibition and that these effects are acutely reversed by NRG1. These results are significant as they show that intranasal delivery of ketamine induces cortical disinhibition, which has implications for the treatment of psychiatric, neurologic, and ophthalmic disorders.
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Affiliation(s)
- Xin Qiao
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine 92697, California
| | - Steven F Grieco
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine 92697, California
- Center for Neural Circuit Mapping, University of California, Irvine 92697, California
| | - Zhaoxia Yu
- Center for Neural Circuit Mapping, University of California, Irvine 92697, California
- Department of Statistics, Donald Bren School of Information and Computer Sciences, Irvine 92697, California
| | - Todd C Holmes
- Center for Neural Circuit Mapping, University of California, Irvine 92697, California
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine 92697, California
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine 92697, California
- Center for Neural Circuit Mapping, University of California, Irvine 92697, California
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Grieco SF, Qiao X, Johnston KG, Chen L, Nelson RR, Lai C, Holmes TC, Xu X. Neuregulin signaling mediates the acute and sustained antidepressant effects of subanesthetic ketamine. Transl Psychiatry 2021; 11:144. [PMID: 33627623 PMCID: PMC7904825 DOI: 10.1038/s41398-021-01255-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/09/2021] [Accepted: 02/01/2021] [Indexed: 01/03/2023] Open
Abstract
Subanesthetic ketamine evokes rapid antidepressant effects in human patients that persist long past ketamine's chemical half-life of ~2 h. Ketamine's sustained antidepressant action may be due to modulation of cortical plasticity. We find that ketamine ameliorates depression-like behavior in the forced swim test in adult mice, and this depends on parvalbumin-expressing (PV) neuron-directed neuregulin-1 (NRG1)/ErbB4 signaling. Ketamine rapidly downregulates NRG1 expression in PV inhibitory neurons in mouse medial prefrontal cortex (mPFC) following a single low-dose ketamine treatment. This NRG1 downregulation in PV neurons co-tracks with the decreases in synaptic inhibition to mPFC excitatory neurons for up to a week. This results from reduced synaptic excitation to PV neurons, and is blocked by exogenous NRG1 as well as by PV targeted ErbB4 receptor knockout. Thus, we conceptualize that ketamine's effects are mediated through rapid and sustained cortical disinhibition via PV-specific NRG1 signaling. Our findings reveal a novel neural plasticity-based mechanism for ketamine's acute and long-lasting antidepressant effects.
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Affiliation(s)
- Steven F. Grieco
- grid.266093.80000 0001 0668 7243Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275 USA
| | - Xin Qiao
- grid.266093.80000 0001 0668 7243Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275 USA
| | - Kevin G. Johnston
- grid.266093.80000 0001 0668 7243Department of Mathematics, University of California, Irvine, CA 92697-3875 USA
| | - Lujia Chen
- grid.266093.80000 0001 0668 7243Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275 USA
| | - Renetta R. Nelson
- grid.266093.80000 0001 0668 7243Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275 USA
| | - Cary Lai
- grid.411377.70000 0001 0790 959XDepartment of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7000 USA
| | - Todd C. Holmes
- grid.19006.3e0000 0000 9632 6718Department of Physiology and Biophysics, School of Medicine, Universityof California, Irvine, CA 92697- 4560 USA ,grid.266093.80000 0001 0668 7243The Center for Neural Circuit Mapping, University of California, Irvine, CA 92697 USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697-1275, USA. .,The Center for Neural Circuit Mapping, University of California, Irvine, CA, 92697, USA. .,Department of Biomedical Engineering, University of California, Irvine, CA, 92697-2715, USA. .,Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, 92697-4025, USA. .,Department of Computer Science, University of California, Irvine, CA, 92697-3435, USA.
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Microglia Elimination Increases Neural Circuit Connectivity and Activity in Adult Mouse Cortex. J Neurosci 2020; 41:1274-1287. [PMID: 33380470 DOI: 10.1523/jneurosci.2140-20.2020] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/16/2020] [Accepted: 12/13/2020] [Indexed: 12/21/2022] Open
Abstract
Microglia have crucial roles in sculpting synapses and maintaining neural circuits during development. To test the hypothesis that microglia continue to regulate neural circuit connectivity in adult brain, we have investigated the effects of chronic microglial depletion, via CSF1R inhibition, on synaptic connectivity in the visual cortex in adult mice of both sexes. We find that the absence of microglia dramatically increases both excitatory and inhibitory synaptic connections to excitatory cortical neurons assessed with functional circuit mapping experiments in acutely prepared adult brain slices. Microglia depletion leads to increased densities and intensities of perineuronal nets. Furthermore, in vivo calcium imaging across large populations of visual cortical neurons reveals enhanced neural activities of both excitatory neurons and parvalbumin-expressing interneurons in the visual cortex following microglia depletion. These changes recover following adult microglia repopulation. In summary, our new results demonstrate a prominent role of microglia in sculpting neuronal circuit connectivity and regulating subsequent functional activity in adult cortex.SIGNIFICANCE STATEMENT Microglia are the primary immune cell of the brain, but recent evidence supports that microglia play an important role in synaptic sculpting during development. However, it remains unknown whether and how microglia regulate synaptic connectivity in adult brain. Our present work shows chronic microglia depletion in adult visual cortex induces robust increases in perineuronal nets, and enhances local excitatory and inhibitory circuit connectivity to excitatory neurons. Microglia depletion increases in vivo neural activities of both excitatory neurons and parvalbumin inhibitory neurons. Our new results reveal new potential avenues to modulate adult neural plasticity by microglia manipulation to better treat brain disorders, such as Alzheimer's disease.
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Grieco SF, Qiao X, Zheng X, Liu Y, Chen L, Zhang H, Yu Z, Gavornik JP, Lai C, Gandhi SP, Holmes TC, Xu X. Subanesthetic Ketamine Reactivates Adult Cortical Plasticity to Restore Vision from Amblyopia. Curr Biol 2020; 30:3591-3603.e8. [PMID: 32822611 PMCID: PMC7925140 DOI: 10.1016/j.cub.2020.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/07/2020] [Accepted: 07/01/2020] [Indexed: 12/09/2022]
Abstract
Subanesthetic ketamine evokes rapid and long-lasting antidepressant effects in human patients. The mechanism for ketamine's effects remains elusive, but ketamine may broadly modulate brain plasticity processes. We show that single-dose ketamine reactivates adult mouse visual cortical plasticity and promotes functional recovery of visual acuity defects from amblyopia. Ketamine specifically induces downregulation of neuregulin-1 (NRG1) expression in parvalbumin-expressing (PV) inhibitory neurons in mouse visual cortex. NRG1 downregulation in PV neurons co-tracks both the fast onset and sustained decreases in synaptic inhibition to excitatory neurons, along with reduced synaptic excitation to PV neurons in vitro and in vivo following a single ketamine treatment. These effects are blocked by exogenous NRG1 as well as PV targeted receptor knockout. Thus, ketamine reactivation of adult visual cortical plasticity is mediated through rapid and sustained cortical disinhibition via downregulation of PV-specific NRG1 signaling. Our findings reveal the neural plasticity-based mechanism for ketamine-mediated functional recovery from adult amblyopia.
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Affiliation(s)
- Steven F Grieco
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, USA
| | - Xin Qiao
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, USA
| | - Xiaoting Zheng
- Department of Neurobiology and Behavior, School of Biology, University of California, Irvine, CA 92697-1275, USA
| | - Yongjun Liu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, USA; Key Laboratory of Pollinating Insect Biology, Institute of Agricultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - Lujia Chen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, USA
| | - Hai Zhang
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, USA
| | - Zhaoxia Yu
- Department of Statistics, University of California, Irvine, CA 92697-1250, USA
| | | | - Cary Lai
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7000, USA
| | - Sunil P Gandhi
- Department of Neurobiology and Behavior, School of Biology, University of California, Irvine, CA 92697-1275, USA
| | - Todd C Holmes
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697- 4560, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, USA; Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, USA; Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697-4025, USA.
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Morales C, Morici JF, Miranda M, Gallo FT, Bekinschtein P, Weisstaub NV. Neurophotonics Approaches for the Study of Pattern Separation. Front Neural Circuits 2020; 14:26. [PMID: 32587504 PMCID: PMC7298152 DOI: 10.3389/fncir.2020.00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/20/2020] [Indexed: 11/26/2022] Open
Abstract
Successful memory involves not only remembering over time but also keeping memories distinct. Computational models suggest that pattern separation appears as a highly efficient process to discriminate between overlapping memories. Furthermore, lesion studies have shown that the dentate gyrus (DG) participates in pattern separation. However, these manipulations did not allow identifying the neuronal mechanism underlying pattern separation. The development of different neurophotonics techniques, together with other genetic tools, has been useful for the study of the microcircuit involved in this process. It has been shown that less-overlapped information would generate distinct neuronal representations within the granule cells (GCs). However, because glutamatergic or GABAergic cells in the DG are not functionally or structurally homogeneous, identifying the specific role of the different subpopulations remains elusive. Then, understanding pattern separation requires the ability to manipulate a temporal and spatially specific subset of cells in the DG and ideally to analyze DG cells activity in individuals performing a pattern separation dependent behavioral task. Thus, neurophotonics and calcium imaging techniques in conjunction with activity-dependent promoters and high-resolution microscopy appear as important tools for this endeavor. In this work, we review how different neurophotonics techniques have been implemented in the elucidation of a neuronal network that supports pattern separation alone or in combination with traditional techniques. We discuss the limitation of these techniques and how other neurophotonic techniques could be used to complement the advances presented up to this date.
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Affiliation(s)
- Cristian Morales
- Departamento de Psiquiatria, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Facundo Morici
- Instituto de Neurociencias Cognitiva y Traslacional (INCYT), Concejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Instituto de Neurología Cognitiva (INECO), Universidad Favaloro, Buenos Aires, Argentina
| | - Magdalena Miranda
- Instituto de Neurociencias Cognitiva y Traslacional (INCYT), Concejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Instituto de Neurología Cognitiva (INECO), Universidad Favaloro, Buenos Aires, Argentina
| | - Francisco Tomás Gallo
- Instituto de Neurociencias Cognitiva y Traslacional (INCYT), Concejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Instituto de Neurología Cognitiva (INECO), Universidad Favaloro, Buenos Aires, Argentina
| | - Pedro Bekinschtein
- Instituto de Neurociencias Cognitiva y Traslacional (INCYT), Concejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Instituto de Neurología Cognitiva (INECO), Universidad Favaloro, Buenos Aires, Argentina
| | - Noelia V. Weisstaub
- Instituto de Neurociencias Cognitiva y Traslacional (INCYT), Concejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Instituto de Neurología Cognitiva (INECO), Universidad Favaloro, Buenos Aires, Argentina
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Functional Reorganization of Local Circuit Connectivity in Superficial Spinal Dorsal Horn with Neuropathic Pain States. eNeuro 2019; 6:ENEURO.0272-19.2019. [PMID: 31533959 PMCID: PMC6787342 DOI: 10.1523/eneuro.0272-19.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 08/27/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023] Open
Abstract
The spinal dorsal horn is the first relay structure coding for pain transmission and modulation. Previous anatomical and electrophysiological studies have examined spinal dorsal horn circuit connections and network activity. Further work is required to understand spinal cord sensory information processing that underlies pathological neuropathic pain states. Our previous studies suggest that peripheral nerve injury enhances presynaptic excitatory input onto spinal superficial dorsal horn neurons, which in turn contributes to pathologic nociception. The potential changes in local postsynaptic circuits in the dorsal horn that lead to pathologically heightened behavioral responses to pain remain largely unexplored. We combined whole-cell electrophysiological recordings with laser-scanning photostimulation to test whether peripheral nerve injury in the spinal nerve ligation (SNL) mouse model of neuropathic pain leads to alterations in the functional connectivity of spinal cord circuits including lamina II excitatory interneurons. Here we show that SNL enhances excitation and decreases inhibition to lamina II excitatory interneurons along with their increased glutamate-evoked excitability. The enhanced excitatory postsynaptic input and connectivity evoked by SNL eventually return to normal levels concurrently with the resolution of the neuropathic pain states. The physiological pattern highly correlates with mouse pain behaviors following SNL, supporting a neurophysiological mechanism of central sensitization and neuropathic pain that is functionally localized to the spinal dorsal horn. Together, these data support that SNL induces functional changes in synaptic input and connectivity to lamina II excitatory interneurons that code for pain perception, and thus provide new insights into the mechanism and locus of pain hypersensitivity.
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Lazaro MT, Taxidis J, Shuman T, Bachmutsky I, Ikrar T, Santos R, Marcello GM, Mylavarapu A, Chandra S, Foreman A, Goli R, Tran D, Sharma N, Azhdam M, Dong H, Choe KY, Peñagarikano O, Masmanidis SC, Rácz B, Xu X, Geschwind DH, Golshani P. Reduced Prefrontal Synaptic Connectivity and Disturbed Oscillatory Population Dynamics in the CNTNAP2 Model of Autism. Cell Rep 2019; 27:2567-2578.e6. [PMID: 31141683 PMCID: PMC6553483 DOI: 10.1016/j.celrep.2019.05.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/20/2019] [Accepted: 04/30/2019] [Indexed: 11/25/2022] Open
Abstract
Loss-of-function mutations in CNTNAP2 cause a syndromic form of autism spectrum disorder in humans and produce social deficits, repetitive behaviors, and seizures in mice. However, the functional effects of these mutations at cellular and circuit levels remain elusive. Using laser-scanning photostimulation, whole-cell recordings, and electron microscopy, we found a dramatic decrease in excitatory and inhibitory synaptic inputs onto L2/3 pyramidal neurons of the medial prefrontal cortex (mPFC) of Cntnap2 knockout (KO) mice, concurrent with reduced spines and synapses, despite normal dendritic complexity and intrinsic excitability. Moreover, recording of mPFC local field potentials (LFPs) and unit spiking in vivo revealed increased activity in inhibitory neurons, reduced phase-locking to delta and theta oscillations, and delayed phase preference during locomotion. Excitatory neurons showed similar phase modulation changes at delta frequencies. Finally, pairwise correlations increased during immobility in KO mice. Thus, reduced synaptic inputs can yield perturbed temporal coordination of neuronal firing in cortical ensembles.
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Affiliation(s)
- Maria T Lazaro
- Interdepartmental Program for Neuroscience, UCLA, Los Angeles, CA, USA; Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Jiannis Taxidis
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Tristan Shuman
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Iris Bachmutsky
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - Rommel Santos
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - G Mark Marcello
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Apoorva Mylavarapu
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Swasty Chandra
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Allison Foreman
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Rachna Goli
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Duy Tran
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Nikhil Sharma
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Michelle Azhdam
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Hongmei Dong
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Katrina Y Choe
- Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA
| | - Olga Peñagarikano
- Department of Pharmacology, School of Medicine, University of the Basque Country (UPV/EHU), Vizcaya, Spain; Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Madrid, Spain
| | - Sotiris C Masmanidis
- Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - Daniel H Geschwind
- Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Center for Autism Research and Treatment, Semel Institute, UCLA, Los Angeles, CA, USA; Intellectual Development and Disabilities Research Center, UCLA, Los Angeles, CA, USA.
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA; Intellectual Development and Disabilities Research Center, UCLA, Los Angeles, CA, USA; West Los Angeles VA Medical Center, Los Angeles, CA.
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Development of Local Circuit Connections to Hilar Mossy Cells in the Mouse Dentate Gyrus. eNeuro 2019; 6:eN-NWR-0370-18. [PMID: 30937358 PMCID: PMC6439204 DOI: 10.1523/eneuro.0370-18.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 02/15/2019] [Accepted: 02/22/2019] [Indexed: 12/14/2022] Open
Abstract
Hilar mossy cells in the dentate gyrus (DG) shape the firing and function of the hippocampal circuit. However, the neural circuitry providing afferent input to mossy cells is incompletely understood, and little is known about the development of these inputs. Thus, we used whole-cell recording and laser scanning photostimulation (LSPS) to characterize the developmental trajectory of local excitatory and inhibitory synaptic inputs to mossy cells in the mouse hippocampus. Hilar mossy cells were targeted by visualizing non-red fluorescent cells in the dentate hilus of GAD2-Cre; Ai9 mice that expressed tdTomato in GAD+ neurons, and were confirmed by post hoc morphological characterization. Our results show that at postnatal day (P)6–P7, mossy cells received more excitatory input from neurons in the proximal CA3 versus those in the DG. In contrast, at P13–P14 and P21–P28, the largest source of excitatory input originated in DG cells, while the strength of CA3 and hilar inputs declined. A developmental trend was also evident for inhibitory inputs. Overall inhibitory input at P6–P7 was weak, while inhibitory inputs from the DG cell layer and the hilus predominated at P13–P14 and P21–P28. The strength of local DG excitation and inhibition to mossy cells peaked at P13–P14 and decreased slightly in older P21–P28 mice. Together, these data provide new detailed information on the development of local synaptic connectivity of mossy cells, and suggests mechanisms through which developmental changes in local circuit inputs to hilar mossy cells shape their physiology and vulnerability to injury during postnatal periods.
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Tanaka Y, Nomoto T, Shiki T, Sakata Y, Shimada Y, Hayashida Y, Yagi T. Focal activation of neuronal circuits induced by microstimulation in the visual cortex. J Neural Eng 2019; 16:036007. [PMID: 30818288 DOI: 10.1088/1741-2552/ab0b80] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Microstimulation to the cortical tissue applied with penetrating electrodes delivers current that spreads concentrically around the electrode tip and is known to evoke focal visual sensations, i.e. phosphenes. However, to date, there is no direct evidence depicting the spatiotemporal properties of neuronal activity induced immediately after microstimulation and how such activity drives the subsequent local cortical circuits. APPROACH In the present study, we imaged the spatiotemporal distribution of action potentials (APs) directly induced by microstimulation and the subsequent trans-synaptic signal propagation using a voltage-sensitive dye (VSD) and a calcium-sensitive dye (CaSD) in slice preparations of the mouse primary visual cortex. MAIN RESULTS The directly induced APs were confined to the close vicinity of the electrode tip, and the effective distance of excitation was proportional to the square root of the current intensity. The excitation around the electrode tip in layer IV mainly propagated to layer II/III to further induce the subsequent focal activation in downstream local cortical circuits. The extent of activation in the downstream circuits was restrained by competitive interactions between excitatory and inhibitory signals. Namely, the spread of the excitation to lateral neighbor neurons along the layer II/III was confined by the delayed inhibition that also spread laterally at a faster rate. SIGNIFICANCE These observations indicate that dynamic interactions between excitatory and inhibitory signals play a critical role in the focal activation of a cortical circuit in response to intracortical microstimulation and, therefore, in evoking a localized phosphene.
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Affiliation(s)
- Yuta Tanaka
- Division of Electrical, Electronic, and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
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Opposing and Complementary Topographic Connectivity Gradients Revealed by Quantitative Analysis of Canonical and Noncanonical Hippocampal CA1 Inputs. eNeuro 2018; 5:eN-NWR-0322-17. [PMID: 29387780 PMCID: PMC5790753 DOI: 10.1523/eneuro.0322-17.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 01/07/2023] Open
Abstract
Physiological studies suggest spatial representation gradients along the CA1 proximodistal axis. To determine the underlying anatomical basis, we quantitatively mapped canonical and noncanonical inputs to excitatory neurons in dorsal hippocampal CA1 along the proximal-distal axis in mice of both sexes using monosynaptic rabies tracing. Our quantitative analyses show comparable strength of subiculum complex and entorhinal cortex (EC) inputs to CA1, significant inputs from presubiculum and parasubiculum to CA1, and a threefold stronger input to proximal versus distal CA1 from CA3. Noncanonical subicular complex inputs exhibit opposing topographic connectivity gradients whereby the subiculum-CA1 input strength systematically increases but the presubiculum-CA1 input strength decreases along the proximal-distal axis. The subiculum input strength cotracks that of the lateral EC, known to be less spatially selective than the medial EC. The functional significance of this organization is verified physiologically for subiculum-to-CA1 inputs. These results reveal a novel anatomical framework by which to determine the circuit bases for CA1 representations.
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11
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Passlick S, Kramer PF, Richers MT, Williams JT, Ellis-Davies GCR. Two-color, one-photon uncaging of glutamate and GABA. PLoS One 2017; 12:e0187732. [PMID: 29117230 PMCID: PMC5678877 DOI: 10.1371/journal.pone.0187732] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/24/2017] [Indexed: 12/28/2022] Open
Abstract
Neuronal cells receive a variety of excitatory and inhibitory signals which they process to generate an output signal. In order to study the interaction between excitatory and inhibitory receptors with exogenously applied transmitters in the same preparation, two caging chromophores attached to glutamate and GABA were developed that were selectively photolyzed by different wavelengths of light. This technique has the advantage that the biologically inactive caged compound can be applied at equilibrium prior to the near instantaneous release of the transmitters. This method therefore mimics the kinetics of endogenously released transmitters that is otherwise not possible in brain slice preparations. Repeated photolysis with either of the two wavelengths resulted in GABA- or glutamate-induced activation of both ionotropic and metabotropic receptors to evoke reproducible currents. With these compounds, the interaction between inhibitory and excitatory receptors was examined using whole field photolysis.
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Affiliation(s)
- Stefan Passlick
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Paul F. Kramer
- Vollum Institute, Oregon Health and Sciences University, Portland, Oregon, United States of America
| | - Matthew T. Richers
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - John T. Williams
- Vollum Institute, Oregon Health and Sciences University, Portland, Oregon, United States of America
| | - Graham C. R. Ellis-Davies
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
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12
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Nogo Receptor 1 Confines a Disinhibitory Microcircuit to the Critical Period in Visual Cortex. J Neurosci 2017; 36:11006-11012. [PMID: 27798181 DOI: 10.1523/jneurosci.0935-16.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/02/2016] [Indexed: 11/21/2022] Open
Abstract
A characteristic of the developing mammalian visual system is a brief interval of plasticity, termed the "critical period," when the circuitry of primary visual cortex is most sensitive to perturbation of visual experience. Depriving one eye of vision (monocular deprivation [MD]) during the critical period alters ocular dominance (OD) by shifting the responsiveness of neurons in visual cortex to favor the nondeprived eye. A disinhibitory microcircuit involving parvalbumin-expressing (PV) interneurons initiates this OD plasticity. The gene encoding the neuronal nogo-66-receptor 1 (ngr1/rtn4r) is required to close the critical period. Here we combined mouse genetics, electrophysiology, and circuit mapping with laser-scanning photostimulation to investigate whether disinhibition is confined to the critical period by ngr1 We demonstrate that ngr1 mutant mice retain plasticity characteristic of the critical period as adults, and that ngr1 operates within PV interneurons to restrict the loss of intracortical excitatory synaptic input following MD in adult mice, and this disinhibition induces a "lower PV network configuration" in both critical-period wild-type mice and adult ngr1-/- mice. We propose that ngr1 limits disinhibition to close the critical period for OD plasticity and that a decrease in PV expression levels reports the diminished recent cumulative activity of these interneurons. SIGNIFICANCE STATEMENT Life experience refines brain circuits throughout development during specified critical periods. Abnormal experience during these critical periods can yield enduring maladaptive changes in neural circuits that impair brain function. In the developing visual system, visual deprivation early in life can result in amblyopia (lazy-eye), a prevalent childhood disorder comprising permanent deficits in spatial vision. Here we identify that the nogo-66 receptor 1 gene restricts an early and essential step in OD plasticity to the critical period. These findings link the emerging circuit-level description of OD plasticity to the genetic regulation of the critical period. Understanding how plasticity is confined to critical periods may provide clues how to better treat amblyopia.
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13
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Local and Long-Range Circuit Connections to Hilar Mossy Cells in the Dentate Gyrus. eNeuro 2017; 4:eN-NWR-0097-17. [PMID: 28451637 PMCID: PMC5396130 DOI: 10.1523/eneuro.0097-17.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 01/04/2023] Open
Abstract
Hilar mossy cells are the prominent glutamatergic cell type in the dentate hilus of the dentate gyrus (DG); they have been proposed to have critical roles in the DG network. To better understand how mossy cells contribute to DG function, we have applied new viral genetic and functional circuit mapping approaches to quantitatively map and compare local and long-range circuit connections of mossy cells and dentate granule cells in the mouse. The great majority of inputs to mossy cells consist of two parallel inputs from within the DG: an excitatory input pathway from dentate granule cells and an inhibitory input pathway from local DG inhibitory neurons. Mossy cells also receive a moderate degree of excitatory and inhibitory CA3 input from proximal CA3 subfields. Long range inputs to mossy cells are numerically sparse, and they are only identified readily from the medial septum and the septofimbrial nucleus. In comparison, dentate granule cells receive most of their inputs from the entorhinal cortex. The granule cells receive significant synaptic inputs from the hilus and the medial septum, and they also receive direct inputs from both distal and proximal CA3 subfields, which has been underdescribed in the existing literature. Our slice-based physiological mapping studies further supported the identified circuit connections of mossy cells and granule cells. Together, our data suggest that hilar mossy cells are major local circuit integrators and they exert modulation of the activity of dentate granule cells as well as the CA3 region through "back-projection" pathways.
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14
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Magnuson ME, Thompson GJ, Schwarb H, Pan WJ, McKinley A, Schumacher EH, Keilholz SD. Errors on interrupter tasks presented during spatial and verbal working memory performance are linearly linked to large-scale functional network connectivity in high temporal resolution resting state fMRI. Brain Imaging Behav 2016; 9:854-67. [PMID: 25563228 DOI: 10.1007/s11682-014-9347-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The brain is organized into networks composed of spatially separated anatomical regions exhibiting coherent functional activity over time. Two of these networks (the default mode network, DMN, and the task positive network, TPN) have been implicated in the performance of a number of cognitive tasks. To directly examine the stable relationship between network connectivity and behavioral performance, high temporal resolution functional magnetic resonance imaging (fMRI) data were collected during the resting state, and behavioral data were collected from 15 subjects on different days, exploring verbal working memory, spatial working memory, and fluid intelligence. Sustained attention performance was also evaluated in a task interleaved between resting state scans. Functional connectivity within and between the DMN and TPN was related to performance on these tasks. Decreased TPN resting state connectivity was found to significantly correlate with fewer errors on an interrupter task presented during a spatial working memory paradigm and decreased DMN/TPN anti-correlation was significantly correlated with fewer errors on an interrupter task presented during a verbal working memory paradigm. A trend for increased DMN resting state connectivity to correlate to measures of fluid intelligence was also observed. These results provide additional evidence of the relationship between resting state networks and behavioral performance, and show that such results can be observed with high temporal resolution fMRI. Because cognitive scores and functional connectivity were collected on nonconsecutive days, these results highlight the stability of functional connectivity/cognitive performance coupling.
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Affiliation(s)
- Matthew Evan Magnuson
- Georgia Institute of Technology and Biomedical Engineering, Emory University, 1760 Haygood Dr, HSRB W230, Atlanta, GA, USA, 30322
| | - Garth John Thompson
- Georgia Institute of Technology and Biomedical Engineering, Emory University, 1760 Haygood Dr, HSRB W230, Atlanta, GA, USA, 30322
| | - Hillary Schwarb
- Georgia Institute of Technology School of Psychology, 654 Cherry Street, Atlanta, GA, USA, 30313
| | - Wen-Ju Pan
- Georgia Institute of Technology and Biomedical Engineering, Emory University, 1760 Haygood Dr, HSRB W230, Atlanta, GA, USA, 30322
| | - Andy McKinley
- Air Force Research Laboratory Wright-Patterson Air Force Base, Atlanta, OH, USA, 45433
| | - Eric H Schumacher
- Georgia Institute of Technology School of Psychology, 654 Cherry Street, Atlanta, GA, USA, 30313
| | - Shella Dawn Keilholz
- Georgia Institute of Technology and Biomedical Engineering, Emory University, 1760 Haygood Dr, HSRB W230, Atlanta, GA, USA, 30322.
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15
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Xu X, Ikrar T, Sun Y, Santos R, Holmes TC, Francesconi W, Berton F. High-resolution and cell-type-specific photostimulation mapping shows weak excitatory vs. strong inhibitory inputs in the bed nucleus of the stria terminalis. J Neurophysiol 2016; 115:3204-16. [PMID: 27052587 DOI: 10.1152/jn.01148.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 04/04/2016] [Indexed: 11/22/2022] Open
Abstract
The bed nucleus of the stria terminalis (BNST) is a key component of the extended amygdala and has been implicated in anxiety and addiction. As individual neurons function within neural circuits, it is important to understand local microcircuits and larger network connections of identified neuronal types and understand how maladaptive changes in the BNST neural networks are induced by stress and drug abuse. However, due to limitations of classic anatomical and physiological methods, the local circuit organization of synaptic inputs to specific BNST neuron types is not well understood. In this study, we report on the application of high-resolution and cell-type-specific photostimulation methodology developed in our laboratory to local circuit mapping in the BNST. Under calibrated experimental conditions, laser photostimulation via glutamate uncaging or channelrhodopsin-2 photoactivation evokes spiking of BNST neurons perisomatically, without activating spikes from axons of passage or distal dendrites. Whole cell recordings, combined with spatially restricted photostimulation of presynaptic neurons at many different locations over a large region, allow high-resolution mapping of presynaptic input sources to single recorded neurons in the BNST. We constructed maps of synaptic inputs impinging onto corticotrophin-releasing hormone-expressing (CRH+) BNST neurons in the dorsolateral BNST and found that the CRH+ neurons receive predominant local inhibitory synaptic connections with very weak excitatory connections. Through cell-type-specific optogenetic stimulation mapping, we generated maps of somatostatin-expressing neuron-specific inhibitory inputs to BNST neurons. Taken together, the photostimulation-based techniques offer us powerful tools for determining the functional organization of local circuits of specific BNST neuron types.
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Affiliation(s)
- Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California; Department of Biomedical Engineering, University of California, Irvine, California; Department of Microbiology and Molecular Genetics, University of California, Irvine, California;
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California
| | - Yanjun Sun
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California
| | - Rommel Santos
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California
| | - Todd C Holmes
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
| | - Walter Francesconi
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California; and
| | - Fulvia Berton
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California
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16
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Xu X, Olivas ND, Ikrar T, Peng T, Holmes TC, Nie Q, Shi Y. Primary visual cortex shows laminar-specific and balanced circuit organization of excitatory and inhibitory synaptic connectivity. J Physiol 2016; 594:1891-910. [PMID: 26844927 DOI: 10.1113/jp271891] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 01/27/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Using functional mapping assays, we conducted a quantitative assessment of both excitatory and inhibitory synaptic laminar connections to excitatory neurons in layers 2/3-6 of the mouse visual cortex (V1). Laminar-specific synaptic wiring diagrams of excitatory neurons were constructed on the basis of circuit mapping. The present study reveals that that excitatory and inhibitory synaptic connectivity is spatially balanced across excitatory neuronal networks in V1. ABSTRACT In the mammalian neocortex, excitatory neurons provide excitation in both columnar and laminar dimensions, which is modulated further by inhibitory neurons. However, our understanding of intracortical excitatory and inhibitory synaptic inputs in relation to principal excitatory neurons remains incomplete, and it is unclear how local excitatory and inhibitory synaptic connections to excitatory neurons are spatially organized on a layer-by-layer basis. In the present study, we combined whole cell recordings with laser scanning photostimulation via glutamate uncaging to map excitatory and inhibitory synaptic inputs to single excitatory neurons throughout cortical layers 2/3-6 in the mouse primary visual cortex (V1). We find that synaptic input sources of excitatory neurons span the radial columns of laminar microcircuits, and excitatory neurons in different V1 laminae exhibit distinct patterns of layer-specific organization of excitatory inputs. Remarkably, the spatial extent of inhibitory inputs of excitatory neurons for a given layer closely mirrors that of their excitatory input sources, indicating that excitatory and inhibitory synaptic connectivity is spatially balanced across excitatory neuronal networks. Strong interlaminar inhibitory inputs are found, particularly for excitatory neurons in layers 2/3 and 5. This differs from earlier studies reporting that inhibitory cortical connections to excitatory neurons are generally localized within the same cortical layer. On the basis of the functional mapping assays, we conducted a quantitative assessment of both excitatory and inhibitory synaptic laminar connections to excitatory cells at single cell resolution, establishing precise layer-by-layer synaptic wiring diagrams of excitatory neurons in the visual cortex.
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Affiliation(s)
- Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine.,Department of Biomedical Engineering
| | - Nicholas D Olivas
- Department of Anatomy and Neurobiology, School of Medicine.,Present address: Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, School of Medicine
| | - Tao Peng
- Department of Mathematics.,Center for Complex Biological Systems
| | - Todd C Holmes
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Qing Nie
- Department of Biomedical Engineering.,Department of Mathematics.,Center for Complex Biological Systems
| | - Yulin Shi
- Department of Anatomy and Neurobiology, School of Medicine
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17
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Shi Y, Ikrar T, Olivas ND, Xu X. Bidirectional global spontaneous network activity precedes the canonical unidirectional circuit organization in the developing hippocampus. J Comp Neurol 2015; 522:2191-208. [PMID: 24357090 PMCID: PMC4293468 DOI: 10.1002/cne.23528] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 11/22/2013] [Accepted: 12/17/2013] [Indexed: 11/27/2022]
Abstract
Spontaneous network activity is believed to sculpt developing neural circuits. Spontaneous giant depolarizing potentials (GDPs) were first identified with single-cell recordings from rat CA3 pyramidal neurons, but here we identify and characterize a large-scale spontaneous network activity we term global network activation (GNA) in the developing mouse hippocampal slices, which is measured macroscopically by fast voltage-sensitive dye imaging. The initiation and propagation of GNA in the mouse is largely GABA-independent and dominated by glutamatergic transmission via AMPA receptors. Despite the fact that signal propagation in the adult hippocampus is strongly unidirectional through the canonical trisynaptic circuit (dentate gyrus [DG] to CA3 to CA1), spontaneous GNA in the developing hippocampus originates in distal CA3 and propagates both forward to CA1 and backward to DG. Photostimulation-evoked GNA also shows prominent backward propagation in the developing hippocampus from CA3 to DG. Mouse GNA is strongly correlated to electrophysiological recordings of highly localized single-cell and local field potential events. Photostimulation mapping of neural circuitry demonstrates that the enhancement of local circuit connections to excitatory pyramidal neurons occurs over the same time course as GNA and reveals the underlying pathways accounting for GNA backward propagation from CA3 to DG. The disappearance of GNA coincides with a transition to the adult-like unidirectional circuit organization at about 2 weeks of age. Taken together, our findings strongly suggest a critical link between GNA activity and maturation of functional circuit connections in the developing hippocampus.
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Affiliation(s)
- Yulin Shi
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California, 92697-1275
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18
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Shi Y, Veidenbaum AV, Nicolau A, Xu X. Large-scale neural circuit mapping data analysis accelerated with the graphical processing unit (GPU). J Neurosci Methods 2014; 239:1-10. [PMID: 25277633 DOI: 10.1016/j.jneumeth.2014.09.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 09/19/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Modern neuroscience research demands computing power. Neural circuit mapping studies such as those using laser scanning photostimulation (LSPS) produce large amounts of data and require intensive computation for post hoc processing and analysis. NEW METHOD Here we report on the design and implementation of a cost-effective desktop computer system for accelerated experimental data processing with recent GPU computing technology. A new version of Matlab software with GPU enabled functions is used to develop programs that run on Nvidia GPUs to harness their parallel computing power. RESULTS We evaluated both the central processing unit (CPU) and GPU-enabled computational performance of our system in benchmark testing and practical applications. The experimental results show that the GPU-CPU co-processing of simulated data and actual LSPS experimental data clearly outperformed the multi-core CPU with up to a 22× speedup, depending on computational tasks. Further, we present a comparison of numerical accuracy between GPU and CPU computation to verify the precision of GPU computation. In addition, we show how GPUs can be effectively adapted to improve the performance of commercial image processing software such as Adobe Photoshop. COMPARISON WITH EXISTING METHOD(S) To our best knowledge, this is the first demonstration of GPU application in neural circuit mapping and electrophysiology-based data processing. CONCLUSIONS Together, GPU enabled computation enhances our ability to process large-scale data sets derived from neural circuit mapping studies, allowing for increased processing speeds while retaining data precision.
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Affiliation(s)
- Yulin Shi
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, United States
| | - Alexander V Veidenbaum
- Department of Computer Science, University of California, Irvine, CA 92697-3435, United States
| | - Alex Nicolau
- Department of Computer Science, University of California, Irvine, CA 92697-3435, United States
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, United States; Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, United States; Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697-2625, United States.
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19
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Ozkan ED, Creson TK, Kramár EA, Rojas C, Seese RR, Babyan AH, Shi Y, Lucero R, Xu X, Noebels JL, Miller CA, Lynch G, Rumbaugh G. Reduced cognition in Syngap1 mutants is caused by isolated damage within developing forebrain excitatory neurons. Neuron 2014; 82:1317-33. [PMID: 24945774 DOI: 10.1016/j.neuron.2014.05.015] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2014] [Indexed: 01/10/2023]
Abstract
Syngap1 haploinsufficiency is a common cause of sporadic intellectual disability. Syngap1 mutations disrupt developing pyramidal neurons, although it remains unclear if this process contributes to cognitive abnormalities. Here, we found that haploinsufficiency restricted to forebrain glutamatergic neurons was sufficient to disrupt cognition and removing mutations from this population prevented cognitive abnormalities. In contrast, manipulating Syngap1 function in GABAergic neurons had no effect on cognition, excitability, or neurotransmission, highlighting the specificity of Syngap1 mutations within forebrain excitatory neurons. Interestingly, cognitive abnormalities were reliably predicted by the emergence of enhanced excitatory synaptic function in mature superficial cortical pyramidal cells, which was a neurophysiological disruption caused by Syngap1 dysfunction in developing, but not adult, forebrain neurons. We conclude that reduced cognition in Syngap1 mutants is caused by isolated damage to developing forebrain glutamatergic neurons. This damage triggers secondary disruptions to synaptic homeostasis in mature cortical pyramidal cells, which perpetuates brain dysfunction into adulthood.
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Affiliation(s)
- Emin D Ozkan
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Thomas K Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Enikö A Kramár
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Camilo Rojas
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Ron R Seese
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Alex H Babyan
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Yulin Shi
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Rocco Lucero
- Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Jeffrey L Noebels
- Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Courtney A Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Gary Lynch
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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20
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Sun Y, Nguyen AQ, Nguyen JP, Le L, Saur D, Choi J, Callaway EM, Xu X. Cell-type-specific circuit connectivity of hippocampal CA1 revealed through Cre-dependent rabies tracing. Cell Rep 2014; 7:269-80. [PMID: 24656815 DOI: 10.1016/j.celrep.2014.02.030] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 01/06/2014] [Accepted: 02/20/2014] [Indexed: 10/25/2022] Open
Abstract
We developed and applied a Cre-dependent, genetically modified rabies-based tracing system to map direct synaptic connections to specific CA1 neuron types in the mouse hippocampus. We found common inputs to excitatory and inhibitory CA1 neurons from CA3, CA2, the entorhinal cortex (EC), the medial septum (MS), and, unexpectedly, the subiculum. Excitatory CA1 neurons receive inputs from both cholinergic and GABAergic MS neurons, whereas inhibitory neurons receive a great majority of inputs from GABAergic MS neurons. Both cell types also receive weaker input from glutamatergic MS neurons. Comparisons of inputs to CA1 PV+ interneurons versus SOM+ interneurons showed similar strengths of input from the subiculum, but PV+ interneurons received much stronger input than SOM+ neurons from CA3, the EC, and the MS. Thus, rabies tracing identifies hippocampal circuit connections and maps how the different input sources to CA1 are distributed with different strengths on each of its constituent cell types.
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Affiliation(s)
- Yanjun Sun
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA
| | - Amanda Q Nguyen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA
| | - Joseph P Nguyen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA
| | - Luc Le
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA
| | - Dieter Saur
- II. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Jiwon Choi
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Edward M Callaway
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA; Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697-2715, USA; Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA 92697-4025, USA.
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21
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Parks GS, Olivas ND, Ikrar T, Sanathara NM, Wang L, Wang Z, Civelli O, Xu X. Histamine inhibits the melanin-concentrating hormone system: implications for sleep and arousal. J Physiol 2014; 592:2183-96. [PMID: 24639485 DOI: 10.1113/jphysiol.2013.268771] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Melanin-concentrating hormone (MCH)-producing neurons are known to regulate a wide variety of physiological functions such as feeding, metabolism, anxiety and depression, and reward. Recent studies have revealed that MCH neurons receive projections from several wake-promoting brain regions and are integral to the regulation of rapid eye movement (REM) sleep. Here, we provide evidence in both rats and mice that MCH neurons express histamine-3 receptors (H3R), but not histamine-1 (H1R) or histamine-2 (H2R) receptors. Electrophysiological recordings in brain slices from a novel line of transgenic mice that specifically express the reporter ZsGreen in MCH neurons show that histamine strongly inhibits MCH neurons, an effect which is TTX insensitive, and blocked by the intracellular presence of GDP-β-S. A specific H3R agonist, α-methylhistamine, mimicks the inhibitory effects of histamine, and a specific neutral H3R antagonist, VUF 5681, blocks this effect. Tertiapin Q (TPQ), a G protein-dependent inwardly rectifying potassium (GIRK) channel inhibitor, abolishes histaminergic inhibition of MCH neurons. These results indicate that histamine directly inhibits MCH neurons through H3R by activating GIRK channels and suggest that that inhibition of the MCH system by wake-active histaminergic neurons may be responsible for silencing MCH neurons during wakefulness and thus may be directly involved in the regulation of sleep and arousal.
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Affiliation(s)
- Gregory S Parks
- Department of Pharmacology, University of California Irvine, Irvine, CA, 92697, USA Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697, USA
| | - Nicholas D Olivas
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, CA, 92697, USA
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, CA, 92697, USA
| | - Nayna M Sanathara
- Department of Pharmacology, University of California Irvine, Irvine, CA, 92697, USA
| | - Lien Wang
- Department of Pharmacology, University of California Irvine, Irvine, CA, 92697, USA
| | - Zhiwei Wang
- Department of Pharmacology, University of California Irvine, Irvine, CA, 92697, USA
| | - Olivier Civelli
- Department of Pharmacology, University of California Irvine, Irvine, CA, 92697, USA Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697, USA Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, CA, 92697, USA
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22
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Wilkinson NM, Metta G. Capture of fixation by rotational flow; a deterministic hypothesis regarding scaling and stochasticity in fixational eye movements. Front Syst Neurosci 2014; 8:29. [PMID: 24616670 PMCID: PMC3935396 DOI: 10.3389/fnsys.2014.00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/09/2014] [Indexed: 11/13/2022] Open
Abstract
Visual scan paths exhibit complex, stochastic dynamics. Even during visual fixation, the eye is in constant motion. Fixational drift and tremor are thought to reflect fluctuations in the persistent neural activity of neural integrators in the oculomotor brainstem, which integrate sequences of transient saccadic velocity signals into a short term memory of eye position. Despite intensive research and much progress, the precise mechanisms by which oculomotor posture is maintained remain elusive. Drift exhibits a stochastic statistical profile which has been modeled using random walk formalisms. Tremor is widely dismissed as noise. Here we focus on the dynamical profile of fixational tremor, and argue that tremor may be a signal which usefully reflects the workings of oculomotor postural control. We identify signatures reminiscent of a certain flavor of transient neurodynamics; toric traveling waves which rotate around a central phase singularity. Spiral waves play an organizational role in dynamical systems at many scales throughout nature, though their potential functional role in brain activity remains a matter of educated speculation. Spiral waves have a repertoire of functionally interesting dynamical properties, including persistence, which suggest that they could in theory contribute to persistent neural activity in the oculomotor postural control system. Whilst speculative, the singularity hypothesis of oculomotor postural control implies testable predictions, and could provide the beginnings of an integrated dynamical framework for eye movements across scales.
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Affiliation(s)
| | - Giorgio Metta
- iCub Facility, Fondazione Istituto Italiano di TecnologiaGenova, Italy
- Centre for Robotics and Neural Systems, School of Computing and Mathematics, University of PlymouthPlymouth, UK
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23
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Magnuson ME, Thompson GJ, Pan WJ, Keilholz SD. Effects of severing the corpus callosum on electrical and BOLD functional connectivity and spontaneous dynamic activity in the rat brain. Brain Connect 2014; 4:15-29. [PMID: 24117343 DOI: 10.1089/brain.2013.0167] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Functional networks, defined by synchronous spontaneous blood oxygenation level-dependent (BOLD) oscillations between spatially distinct brain regions, appear to be essential to brain function and have been implicated in disease states, cognitive capacity, and sensing and motor processes. While the topographical extent and behavioral function of these networks has been extensively investigated, the neural functions that create and maintain these synchronizations remain mysterious. In this work callosotomized rodents are examined, providing a unique platform for evaluating the influence of structural connectivity via the corpus callosum on bilateral resting state functional connectivity. Two experimental groups were assessed, a full callosotomy group, in which the corpus callosum was completely sectioned, and a sham callosotomy group, in which the gray matter was sectioned but the corpus callosum remained intact. Results indicated a significant reduction in interhemispheric connectivity in the full callosotomy group as compared with the sham group in primary somatosensory cortex and caudate-putamen regions. Similarly, electrophysiology revealed significantly reduced bilateral correlation in band limited power. Bilateral gamma Band-limited power connectivity was most strongly affected by the full callosotomy procedure. This work represents a robust finding indicating the corpus callosum's influence on maintaining integrity in bilateral functional networks; further, functional magnetic resonance imaging (fMRI) and electrophysiological connectivity share a similar decrease in connectivity as a result of the callosotomy, suggesting that fMRI-measured functional connectivity reflects underlying changes in large-scale coordinated electrical activity. Finally, spatiotemporal dynamic patterns were evaluated in both groups; the full callosotomy rodents displayed a striking loss of bilaterally synchronous propagating waves of cortical activity.
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Affiliation(s)
- Matthew E Magnuson
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia
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Krook-Magnuson E, Ledri M, Soltesz I, Kokaia M. How might novel technologies such as optogenetics lead to better treatments in epilepsy? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 813:319-36. [PMID: 25012388 DOI: 10.1007/978-94-017-8914-1_26] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Recent technological advances open exciting avenues for improving the understanding of mechanisms in a broad range of epilepsies. This chapter focuses on the development of optogenetics and on-demand technologies for the study of epilepsy and the control of seizures. Optogenetics is a technique which, through cell-type selective expression of light-sensitive proteins called opsins, allows temporally precise control via light delivery of specific populations of neurons. Therefore, it is now possible not only to record interictal and ictal neuronal activity, but also to test causality and identify potential new therapeutic approaches. We first discuss the benefits and caveats to using optogenetic approaches and recent advances in optogenetics related tools. We then turn to the use of optogenetics, including on-demand optogenetics in the study of epilepsies, which highlights the powerful potential of optogenetics for epilepsy research.
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Affiliation(s)
- Esther Krook-Magnuson
- Department of Anatomy and Neurobiology, University of California, 192 Irvine Hall, Irvine, CA, 92697, USA,
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Ikrar T, Guo N, He K, Besnard A, Levinson S, Hill A, Lee HK, Hen R, Xu X, Sahay A. Adult neurogenesis modifies excitability of the dentate gyrus. Front Neural Circuits 2013; 7:204. [PMID: 24421758 PMCID: PMC3872742 DOI: 10.3389/fncir.2013.00204] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 12/10/2013] [Indexed: 01/24/2023] Open
Abstract
Adult-born dentate granule neurons contribute to memory encoding functions of the dentate gyrus (DG) such as pattern separation. However, local circuit-mechanisms by which adult-born neurons partake in this process are poorly understood. Computational, neuroanatomical and electrophysiological studies suggest that sparseness of activation in the granule cell layer (GCL) is conducive for pattern separation. A sparse coding scheme is thought to facilitate the distribution of similar entorhinal inputs across the GCL to decorrelate overlapping representations and minimize interference. Here we used fast voltage-sensitive dye (VSD) imaging combined with laser photostimulation and electrical stimulation to examine how selectively increasing adult DG neurogenesis influences local circuit activity and excitability. We show that DG of mice with more adult-born neurons exhibits decreased strength of neuronal activation and more restricted excitation spread in GCL while maintaining effective output to CA3c. Conversely, blockade of adult hippocampal neurogenesis changed excitability of the DG in the opposite direction. Analysis of GABAergic inhibition onto mature dentate granule neurons in the DG of mice with more adult-born neurons shows a modest readjustment of perisomatic inhibitory synaptic gain without changes in overall inhibitory tone, presynaptic properties or GABAergic innervation pattern. Retroviral labeling of connectivity in mice with more adult-born neurons showed increased number of excitatory synaptic contacts of adult-born neurons onto hilar interneurons. Together, these studies demonstrate that adult hippocampal neurogenesis modifies excitability of mature dentate granule neurons and that this non-cell autonomous effect may be mediated by local circuit mechanisms such as excitatory drive onto hilar interneurons. Modulation of DG excitability by adult-born dentate granule neurons may enhance sparse coding in the GCL to influence pattern separation.
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Affiliation(s)
- Taruna Ikrar
- Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, CA, USA
| | - Nannan Guo
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
| | - Kaiwen He
- Department of Biology, University of Maryland College Park, MD, USA ; The Solomon H. Snyder Department of Neuroscience, The Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University Baltimore, MD, USA
| | - Antoine Besnard
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
| | - Sally Levinson
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
| | - Alexis Hill
- Division of Integrative Neuroscience, Departments of Neuroscience and Psychiatry, Department of Pharmacology, Columbia University New York, NY, USA
| | - Hey-Kyoung Lee
- Department of Biology, University of Maryland College Park, MD, USA ; The Solomon H. Snyder Department of Neuroscience, The Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University Baltimore, MD, USA
| | - Rene Hen
- Division of Integrative Neuroscience, Departments of Neuroscience and Psychiatry, Department of Pharmacology, Columbia University New York, NY, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, CA, USA ; Department of Biomedical Engineering, University of California Irvine, CA, USA
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA ; Harvard Stem Cell Institute, Harvard University Boston, MA, USA ; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
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Kuhlman SJ, Olivas ND, Tring E, Ikrar T, Xu X, Trachtenberg JT. A disinhibitory microcircuit initiates critical-period plasticity in the visual cortex. Nature 2013; 501:543-6. [PMID: 23975100 PMCID: PMC3962838 DOI: 10.1038/nature12485] [Citation(s) in RCA: 291] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 07/17/2013] [Indexed: 11/29/2022]
Abstract
Early sensory experience instructs the maturation of neural circuitry in cortex 1,2. This has been extensively studied in the primary visual cortex where loss of vision to one eye permanently degrades cortical responsiveness to that eye 3,4, a phenomenon known as ocular dominance plasticity (ODP). Cortical inhibition mediates this process 4-6, but the precise role of specific classes of inhibitory neurons in ODP is controversial. Here we report that evoked firing rates of binocular excitatory neurons in primary visual cortex immediately drop by half when vision is restricted to one eye, but gradually return to normal over the following 24 hours, despite the fact that vision remains restricted to one eye. This restoration of binocular-like excitatory firing rates following monocular deprivation results from a rapid, though transient reduction in the firing rates of fast-spiking, parvalbumin-positive (PV) interneurons, which in turn can be attributed to a decrease in local excitatory circuit input onto PV interneurons. This reduction in PV cell evoked responses following monocular lid suture is restricted to the critical period for ODP and appears to be necessary for subsequent shifts in excitatory ODP. Pharmacologically enhancing inhibition at the time of sight deprivation blocks ODP and, conversely, pharmaco-genetic reduction of PV cell firing rates can extend the critical period for ODP. These findings define the microcircuit changes initiating competitive plasticity during critical periods of cortical development. Moreover, they show that the restoration of evoked firing rates of L2/3 pyramidal neurons by PV-specific disinhibition is a key step in the progression of ocular dominance plasticity.
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Affiliation(s)
- Sandra J Kuhlman
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California 90048, USA
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Chandrasekaran L, Xiao Y, Sivaramakrishnan S. Functional architecture of the inferior colliculus revealed with voltage-sensitive dyes. Front Neural Circuits 2013; 7:41. [PMID: 23518906 PMCID: PMC3602642 DOI: 10.3389/fncir.2013.00041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 02/28/2013] [Indexed: 11/22/2022] Open
Abstract
We used optical imaging with voltage-sensitive dyes to investigate the spatio-temporal dynamics of synaptically evoked activity in brain slices of the inferior colliculus (IC). Responses in transverse slices which preserve cross-frequency connections and in modified sagittal slices that preserve connections within frequency laminae were evoked by activating the lateral lemniscal tract. Comparing activity between small and large populations of cells revealed response areas in the central nucleus of the IC that were similar in magnitude but graded temporally. In transverse sections, these response areas are summed to generate a topographic response profile. Activity through the commissure to the contralateral IC required an excitation threshold that was reached when GABAergic inhibition was blocked. Within laminae, module interaction created temporal homeostasis. Diffuse activity evoked by a single lemniscal shock re-organized into distinct spatial and temporal compartments when stimulus trains were used, and generated a directional activity profile within the lamina. Using different stimulus patterns to activate subsets of microcircuits in the central nucleus of the IC, we found that localized responses evoked by low-frequency stimulus trains spread extensively when train frequency was increased, suggesting recruitment of silent microcircuits. Long stimulus trains activated a circuit specific to post-inhibitory rebound neurons. Rebound microcircuits were defined by a focal point of initiation that spread to an annular ring that oscillated between inhibition and excitation. We propose that much of the computing power of the IC is derived from local circuits, some of which are cell-type specific. These circuits organize activity within and across frequency laminae, and are critical in determining the stimulus-selectivity of auditory coding.
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Affiliation(s)
- Lakshmi Chandrasekaran
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University Rootstown, OH, USA
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Ahrar S, Nguyen TV, Shi Y, Ikrar T, Xu X, Hui EE. Optical stimulation and imaging of functional brain circuitry in a segmented laminar flow chamber. LAB ON A CHIP 2013; 13:536-41. [PMID: 23044655 PMCID: PMC3554874 DOI: 10.1039/c2lc40689f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Microfluidic technology is emerging as a useful tool for the study of brain slices, offering precise delivery of chemical factors along with robust oxygen and nutrient transport. However, continued reliance upon electrode-based physiological recording poses inherent limitations in terms of physical access, as well as the number of sites that can be sampled simultaneously. In the present study, we combine a microfluidic laminar flow chamber with fast voltage-sensitive dye imaging and laser photostimulation via caged glutamate to map neural network activity across large cortical regions in living brain slices. We find that the closed microfluidic chamber results in greatly improved signal-to-noise performance for optical measurements of neural signaling. These optical tools are also leveraged to characterize laminar flow interfaces within the device, demonstrating a functional boundary width of less than 100 μm. Finally, we utilize this integrated platform to investigate the mechanism of signal propagation for spontaneous neural activity in the developing mouse hippocampus. Through the use of localized Ca(2+) depletion, we provide evidence for Ca(2+)-dependent synaptic transmission.
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Affiliation(s)
- Siavash Ahrar
- Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, United States. Fax: 01 949 824 1727; Tel: 01 949 824 1727
| | - Transon V. Nguyen
- Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, United States. Fax: 01 949 824 1727; Tel: 01 949 824 1727
| | - Yulin Shi
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, United States
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, United States
| | - Xiangmin Xu
- Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, United States. Fax: 01 949 824 1727; Tel: 01 949 824 1727
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-1275, United States
- To whom correspondence should be addressed
| | - Elliot E. Hui
- Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, United States. Fax: 01 949 824 1727; Tel: 01 949 824 1727
- To whom correspondence should be addressed
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Haettig J, Sun Y, Wood MA, Xu X. Cell-type specific inactivation of hippocampal CA1 disrupts location-dependent object recognition in the mouse. Learn Mem 2013; 20:139-46. [PMID: 23418393 DOI: 10.1101/lm.027847.112] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The allatostatin receptor (AlstR)/ligand inactivation system enables potent regulation of neuronal circuit activity. To examine how different cell types participate in memory formation, we have used this system through Cre-directed, cell-type specific expression in mouse hippocampal CA1 in vivo and examined functional effects of inactivation of excitatory vs. inhibitory neurons on memory formation. We chose to use a hippocampus-dependent behavioral task involving location-dependent object recognition (LOR). The double transgenic mice, with the AlstRs selectively expressed in excitatory pyramidal neurons or inhibitory interneurons, were cannulated, targeting dorsal hippocampus to allow the infusion of the receptor ligand (the allatostatin [AL] peptide) in a time dependent manner. Compared to control animals, AL-infused animals showed no long-term memory for object location. While inactivation of excitatory or inhibitory neurons produced opposite effects on hippocampal circuit activity in vitro, the effects in vivo were similar. Both types of inactivation experiments resulted in mice exhibiting no long-term memory for object location. Together, these results demonstrate that the Cre-directed, AlstR-based system is a powerful tool for cell-type specific manipulations in a behaving animal and suggest that activity of either excitatory neurons or inhibitory interneurons is essential for proper long-term object location memory formation.
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Affiliation(s)
- Jakob Haettig
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-3800, USA
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Clement JP, Aceti M, Creson TK, Ozkan ED, Shi Y, Reish NJ, Almonte AG, Miller BH, Wiltgen BJ, Miller CA, Xu X, Rumbaugh G. Pathogenic SYNGAP1 mutations impair cognitive development by disrupting maturation of dendritic spine synapses. Cell 2013; 151:709-723. [PMID: 23141534 DOI: 10.1016/j.cell.2012.08.045] [Citation(s) in RCA: 263] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 07/21/2012] [Accepted: 08/20/2012] [Indexed: 01/28/2023]
Abstract
Mutations that cause intellectual disability (ID) and autism spectrum disorder (ASD) are commonly found in genes that encode for synaptic proteins. However, it remains unclear how mutations that disrupt synapse function impact intellectual ability. In the SYNGAP1 mouse model of ID/ASD, we found that dendritic spine synapses develop prematurely during the early postnatal period. Premature spine maturation dramatically enhanced excitability in the developing hippocampus, which corresponded with the emergence of behavioral abnormalities. Inducing SYNGAP1 mutations after critical developmental windows closed had minimal impact on spine synapse function, whereas repairing these pathogenic mutations in adulthood did not improve behavior and cognition. These data demonstrate that SynGAP protein acts as a critical developmental repressor of neural excitability that promotes the development of life-long cognitive abilities. We propose that the pace of dendritic spine synapse maturation in early life is a critical determinant of normal intellectual development.
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Affiliation(s)
- James P Clement
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Massimiliano Aceti
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Thomas K Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Emin D Ozkan
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yulin Shi
- Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Nicholas J Reish
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Antoine G Almonte
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Brooke H Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Brian J Wiltgen
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - Courtney A Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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Olivas ND, Quintanar-Zilinskas V, Nenadic Z, Xu X. Laminar circuit organization and response modulation in mouse visual cortex. Front Neural Circuits 2012; 6:70. [PMID: 23060751 PMCID: PMC3464489 DOI: 10.3389/fncir.2012.00070] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 09/12/2012] [Indexed: 01/03/2023] Open
Abstract
The mouse has become an increasingly important animal model for visual system studies, but few studies have investigated local functional circuit organization of mouse visual cortex. Here we used our newly developed mapping technique combining laser scanning photostimulation (LSPS) with fast voltage-sensitive dye (VSD) imaging to examine the spatial organization and temporal dynamics of laminar circuit responses in living slice preparations of mouse primary visual cortex (V1). During experiments, LSPS using caged glutamate provided spatially restricted neuronal activation in a specific cortical layer, and evoked responses from the stimulated layer to its functionally connected regions were detected by VSD imaging. In this study, we first provided a detailed analysis of spatiotemporal activation patterns at specific V1 laminar locations and measured local circuit connectivity. Then we examined the role of cortical inhibition in the propagation of evoked cortical responses by comparing circuit activity patterns in control and in the presence of GABAa receptor antagonists. We found that GABAergic inhibition was critical in restricting layer-specific excitatory activity spread and maintaining topographical projections. In addition, we investigated how AMPA and NMDA receptors influenced cortical responses and found that blocking AMPA receptors abolished interlaminar functional projections, and the NMDA receptor activity was important in controlling visual cortical circuit excitability and modulating activity propagation. The NMDA receptor antagonist reduced neuronal population activity in time-dependent and laminar-specific manners. Finally, we used the quantitative information derived from the mapping experiments and presented computational modeling analysis of V1 circuit organization. Taken together, the present study has provided important new information about mouse V1 circuit organization and response modulation.
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Affiliation(s)
- Nicholas D Olivas
- Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, CA, USA
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Ikrar T, Olivas ND, Shi Y, Xu X. Mapping inhibitory neuronal circuits by laser scanning photostimulation. J Vis Exp 2011:3109. [PMID: 22006064 DOI: 10.3791/3109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Inhibitory neurons are crucial to cortical function. They comprise about 20% of the entire cortical neuronal population and can be further subdivided into diverse subtypes based on their immunochemical, morphological, and physiological properties. Although previous research has revealed much about intrinsic properties of individual types of inhibitory neurons, knowledge about their local circuit connections is still relatively limited. Given that each individual neuron's function is shaped by its excitatory and inhibitory synaptic input within cortical circuits, we have been using laser scanning photostimulation (LSPS) to map local circuit connections to specific inhibitory cell types. Compared to conventional electrical stimulation or glutamate puff stimulation, LSPS has unique advantages allowing for extensive mapping and quantitative analysis of local functional inputs to individually recorded neurons. Laser photostimulation via glutamate uncaging selectively activates neurons perisomatically, without activating axons of passage or distal dendrites, which ensures a sub-laminar mapping resolution. The sensitivity and efficiency of LSPS for mapping inputs from many stimulation sites over a large region are well suited for cortical circuit analysis. Here we introduce the technique of LSPS combined with whole-cell patch clamping for local inhibitory circuit mapping. Targeted recordings of specific inhibitory cell types are facilitated by use of transgenic mice expressing green fluorescent proteins (GFP) in limited inhibitory neuron populations in the cortex, which enables consistent sampling of the targeted cell types and unambiguous identification of the cell types recorded. As for LSPS mapping, we outline the system instrumentation, describe the experimental procedure and data acquisition, and present examples of circuit mapping in mouse primary somatosensory cortex. As illustrated in our experiments, caged glutamate is activated in a spatially restricted region of the brain slice by UV laser photolysis; simultaneous voltage-clamp recordings allow detection of photostimulation-evoked synaptic responses. Maps of either excitatory or inhibitory synaptic input to the targeted neuron are generated by scanning the laser beam to stimulate hundreds of potential presynaptic sites. Thus, LSPS enables the construction of detailed maps of synaptic inputs impinging onto specific types of inhibitory neurons through repeated experiments. Taken together, the photostimulation-based technique offers neuroscientists a powerful tool for determining the functional organization of local cortical circuits.
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Affiliation(s)
- Taruna Ikrar
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, USA
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Shi Y, Nenadic Z, Xu X. Novel use of matched filtering for synaptic event detection and extraction. PLoS One 2010; 5:e15517. [PMID: 21124805 PMCID: PMC2991367 DOI: 10.1371/journal.pone.0015517] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 10/04/2010] [Indexed: 12/05/2022] Open
Abstract
Efficient and dependable methods for detection and measurement of synaptic events are important for studies of synaptic physiology and neuronal circuit connectivity. As the published methods with detection algorithms based upon amplitude thresholding and fixed or scaled template comparisons are of limited utility for detection of signals with variable amplitudes and superimposed events that have complex waveforms, previous techniques are not applicable for detection of evoked synaptic events in photostimulation and other similar experimental situations. Here we report on a novel technique that combines the design of a bank of approximate matched filters with the detection and estimation theory to automatically detect and extract photostimluation-evoked excitatory postsynaptic currents (EPSCs) from individually recorded neurons in cortical circuit mapping experiments. The sensitivity and specificity of the method were evaluated on both simulated and experimental data, with its performance comparable to that of visual event detection performed by human operators. This new technique was applied to quantify and compare the EPSCs obtained from excitatory pyramidal cells and fast-spiking interneurons. In addition, our technique has been further applied to the detection and analysis of inhibitory postsynaptic current (IPSC) responses. Given the general purpose of our matched filtering and signal recognition algorithms, we expect that our technique can be appropriately modified and applied to detect and extract other types of electrophysiological and optical imaging signals.
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Affiliation(s)
- Yulin Shi
- Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Zoran Nenadic
- Department of Biomedical Engineering, University of California Irvine, Irvine, California, United States of America
- * E-mail: (XX); (ZN)
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California Irvine, Irvine, California, United States of America
- Department of Biomedical Engineering, University of California Irvine, Irvine, California, United States of America
- * E-mail: (XX); (ZN)
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Suter BA, O'Connor T, Iyer V, Petreanu LT, Hooks BM, Kiritani T, Svoboda K, Shepherd GMG. Ephus: multipurpose data acquisition software for neuroscience experiments. Front Neural Circuits 2010; 4:100. [PMID: 21960959 PMCID: PMC3176413 DOI: 10.3389/fncir.2010.00100] [Citation(s) in RCA: 196] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Accepted: 07/01/2010] [Indexed: 12/03/2022] Open
Abstract
Physiological measurements in neuroscience experiments often involve complex stimulus paradigms and multiple data channels. Ephus (http://www.ephus.org) is an open-source software package designed for general-purpose data acquisition and instrument control. Ephus operates as a collection of modular programs, including an ephys program for standard whole-cell recording with single or multiple electrodes in typical electrophysiological experiments, and a mapper program for synaptic circuit mapping experiments involving laser scanning photostimulation based on glutamate uncaging or channelrhodopsin-2 excitation. Custom user functions allow user-extensibility at multiple levels, including on-line analysis and closed-loop experiments, where experimental parameters can be changed based on recently acquired data, such as during in vivo behavioral experiments. Ephus is compatible with a variety of data acquisition and imaging hardware. This paper describes the main features and modules of Ephus and their use in representative experimental applications.
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Affiliation(s)
- Benjamin A Suter
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
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