scholarly journals Optogenetic activation of the inhibitory nigro-collicular circuit evokes orienting movements in mice

2020 ◽  
Author(s):  
C.A. Villalobos ◽  
M.A. Basso
Keyword(s):  
Basal Ganglia ◽  
Substantia Nigra ◽  
High Frequency ◽  
Current Model ◽  
Optogenetic Stimulation ◽  
Output Neurons ◽  
Rebound Spiking ◽  
Stimulation Of

ABSTRACTIn contrast to predictions from the current model of basal ganglia (BG) function, we report here that increasing inhibition from the BG to the superior colliculus (SC) through the substantia nigra (nigra) using in vivo optogenetic activation of GABAergic terminals in mice, produces contralateral orienting movements. Orienting movements resulting from activation of inhibitory nigral terminals are unexpected because decreases and not increases, in nigral activity are generally associated with orienting movements. To determine how orienting movements may result from activation of inhibitory terminals, we performed a series of slice experiments and found that the same optogenetic stimulation of nigral terminals used in vivo, evoked post-inhibitory rebound depolarization and spiking in SC output neurons in vitro. Only high frequency (100Hz) stimulation evoked contralateral movements in vivo and triggered rebound spiking in vitro. The latency of orienting movements relative to the stimulation in vivo was similar to the latency of rebound spiking in vitro. Taken together, our results point toward a novel hypothesis that inhibition from the BG may play an active rather than passive role in the generation of orienting movements in mice.

scholarly journals Ventral pallidal GABAergic neurons control wakefulness associated with motivation through the ventral tegmental pathway

2020 ◽  
Author(s):  
Ya-Dong Li ◽  
Yan-Jia Luo ◽  
Wei Xu ◽  
Jing Ge ◽  
Yoan Cherasse ◽  
...  
Keyword(s):  
Dopaminergic Neurons ◽  
Gabaergic Neurons ◽  
Population Activity ◽  
Lateral Habenula ◽  
Optogenetic Stimulation ◽  
Ventral Tegmental ◽  
Stimulation Of

Abstract The ventral pallidum (VP) regulates motivation, drug addiction, and several behaviors that rely on heightened arousal. However, the role and underlying neural circuits of the VP in the control of wakefulness remain poorly understood. In the present study, we sought to elucidate the specific role of VP GABAergic neurons in controlling sleep–wake behaviors in mice. Fiber photometry revealed that the population activity of VP GABAergic neurons was increased during physiological transitions from non-rapid eye movement (non-REM, NREM) sleep to either wakefulness or REM sleep. Moreover, chemogenetic and optogenetic manipulations were leveraged to investigate a potential causal role of VP GABAergic neurons in initiating and/or maintaining arousal. In vivo optogenetic stimulation of VP GABAergic neurons innervating the ventral tegmental area (VTA) strongly promoted arousal via disinhibition of VTA dopaminergic neurons. Functional in vitro mapping revealed that VP GABAergic neurons, in principle, inhibited VTA GABAergic neurons but also inhibited VTA dopaminergic neurons. In addition, optogenetic stimulation of terminals of VP GABAergic neurons revealed that they promoted arousal by innervating the lateral hypothalamus, but not the mediodorsal thalamus or lateral habenula. The increased wakefulness chemogenetically evoked by VP GABAergic neuronal activation was completely abolished by pretreatment with dopaminergic D1 and D2/D3 receptor antagonists. Furthermore, activation of VP GABAergic neurons increased exploration time in both the open-field and light–dark box tests but did not modulate depression-like behaviors or food intake. Finally, chemogenetic inhibition of VP GABAergic neurons decreased arousal. Taken together, our findings indicate that VP GABAergic neurons are essential for arousal related to motivation.

scholarly journals Development of the Wireless Instantaneous Neurotransmitter Concentration System for intraoperative neurochemical monitoring using fast-scan cyclic voltammetry

2009 ◽  
Vol 111 (4) ◽  
pp. 712-723 ◽  
Author(s):  
Jonathan M. Bledsoe ◽  
Christopher J. Kimble ◽  
Daniel P. Covey ◽  
Charles D. Blaha ◽  
Filippo Agnesi ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Fiber ◽  
Flow Injection ◽  
High Frequency ◽  
Dopamine Release ◽  
Functional Neurosurgery ◽  
Fast Scan Cyclic Voltammetry ◽  
Stimulation Of

Object Emerging evidence supports the hypothesis that modulation of specific central neuronal systems contributes to the clinical efficacy of deep brain stimulation (DBS) and motor cortex stimulation (MCS). Real-time monitoring of the neurochemical output of targeted regions may therefore advance functional neurosurgery by, among other goals, providing a strategy for investigation of mechanisms, identification of new candidate neurotransmitters, and chemically guided placement of the stimulating electrode. The authors report the development of a device called the Wireless Instantaneous Neurotransmitter Concentration System (WINCS) for intraoperative neurochemical monitoring during functional neurosurgery. This device supports fast-scan cyclic voltammetry (FSCV) at a carbon-fiber microelectrode (CFM) for real-time, spatially and chemically resolved neurotransmitter measurements in the brain. Methods The FSCV study consisted of a triangle wave scanned between −0.4 and 1 V at a rate of 300 V/second and applied at 10 Hz. All voltages were compared with an Ag/AgCl reference electrode. The CFM was constructed by aspirating a single carbon fiber (r = 2.5 μm) into a glass capillary and pulling the capillary to a microscopic tip by using a pipette puller. The exposed carbon fiber (that is, the sensing region) extended beyond the glass insulation by ~ 100 μm. The neurotransmitter dopamine was selected as the analyte for most trials. Proof-of-principle tests included in vitro flow injection and noise analysis, and in vivo measurements in urethane-anesthetized rats by monitoring dopamine release in the striatum following high-frequency electrical stimulation of the medial forebrain bundle. Direct comparisons were made to a conventional hardwired system. Results The WINCS, designed in compliance with FDA-recognized consensus standards for medical electrical device safety, consisted of 4 modules: 1) front-end analog circuit for FSCV (that is, current-to-voltage transducer); 2) Bluetooth transceiver; 3) microprocessor; and 4) direct-current battery. A Windows-XP laptop computer running custom software and equipped with a Universal Serial Bus–connected Bluetooth transceiver served as the base station. Computer software directed wireless data acquisition at 100 kilosamples/second and remote control of FSCV operation and adjustable waveform parameters. The WINCS provided reliable, high-fidelity measurements of dopamine and other neurochemicals such as serotonin, norepinephrine, and ascorbic acid by using FSCV at CFM and by flow injection analysis. In rats, the WINCS detected subsecond striatal dopamine release at the implanted sensor during high-frequency stimulation of ascending dopaminergic fibers. Overall, in vitro and in vivo testing demonstrated comparable signals to a conventional hardwired electrochemical system for FSCV. Importantly, the WINCS reduced susceptibility to electromagnetic noise typically found in an operating room setting. Conclusions Taken together, these results demonstrate that the WINCS is well suited for intraoperative neurochemical monitoring. It is anticipated that neurotransmitter measurements at an implanted chemical sensor will prove useful for advancing functional neurosurgery.

074 Basal Forebrain GABAergic Neurons Promote Arousal by Disinhibiting the Orexin Neurons via Local GABAergic Interneurons

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A31-A31
Author(s):  
Michela Cristofolini ◽  
Roberto De Luca ◽  
Anne Venner ◽  
Loris Ferrari ◽  
Kevin Grace ◽  
...  
Keyword(s):  
Basal Forebrain ◽  
Viral Vector ◽  
Brain Slices ◽  
Nrem Sleep ◽  
Gabaergic Neurons ◽  
Gabaergic Interneurons ◽  
Optogenetic Stimulation ◽  
Stimulation Of

Abstract Introduction Optogenetic and chemogenetic studies have shown that activation of basal forebrain (BF) GABAergic neurons rapidly wakes up mice from non-REM (NREM) sleep. These wake-promoting responses have been attributed to BF GABAergic neurons projecting to the cerebral cortex and more specifically to the inhibition of cortical fast-spiking interneurons. Tracing studies have however found that BF GABAergic neurons also densely innervate the lateral hypothalamus (LH) perifornical area, although the role of this pathway in behavioral state control remains mostly unexplored. Methods We conducted in vivo and in vitro optogenetic studies. We selectively expressed channelrhodopsin-2 (ChR2) in BF GABAergic neurons by injecting a cre-dependent viral vector encoding for ChR2 into the BF of VGAT-cre mice. We photostimulated the BF GABAergic input to the LH with optical fibers placed into the LH of EEG instrumented mice. For in vitro recordings we expressed ChR2 in BF GABAergic neurons and we fluorescently labeled orexin or LH GABAergic neurons. We recorded in brain slices from identified orexin neurons or GABA neurons while photostimulating the BF GABAergic input. Results Optogenetic stimulation of the BF GABAergic fibers in the LH produced rapid arousals from NREM sleep. The same stimulation however did not wake up the mice if they were in REM sleep. We conducted additional studies in brain slices to identify the postsynaptic neurons in the LH targeted by the BF GABAergic input. We found that while optogenetic stimulation of the BF GABAergic input did not produce opto-evoked synaptic responses in the orexin neurons, it produced short-latency opto-evoked inhibitory postsynaptic currents (IPSCs) in LH GABAergic neurons. These opto-evoked IPSCs were GABAA receptor-mediated and were maintained in tetrodotoxin (TTX) indicating monosynaptic connectivity. We have previously found that orexin neurons are inhibited by local LH GABAergic neurons. Our hypothesis is that these local GABAergic interneurons are the target of the BF GABAergic arousal input. Conclusion BF GABAergic neurons drive arousal through projections to the LH. We propose that this arousal response is due to the inhibition of local GABAergic interneurons which in turn disinhibit the LH wake-promoting neurons including the orexin neurons. Support (if any) NS091126 and HL149630

scholarly journals Basal ganglia and cortical control of thalamic rebound spikes

2018 ◽  
Author(s):  
Mohammadreza Mohagheghi Nejad ◽  
Stefan Rotter ◽  
Robert Schmidt
Keyword(s):  
Basal Ganglia ◽  
Neural Activity ◽  
Output Neurons ◽  
Cortical Excitation ◽  
Sensory Responses ◽  
Rebound Spiking ◽  
Motor Thalamus ◽  
The Impact ◽  
Motor Signals

AbstractBasal ganglia output neurons transmit motor signals by decreasing their firing rate during movement. This decrease can lead to post-inhibitory rebound spikes in thalamocortical neurons in motor thalamus. While in healthy animals neural activity in the basal ganglia is markedly uncorrelated, in Parkinson’s disease neural activity becomes pathologically correlated. Here we investigated the impact of correlations in the basal ganglia output on the transmission of motor signals to motor thalamus using a Hodgkin-Huxley model of a thalamocortical neuron. We found that correlations in the basal ganglia output disrupt the transmission of motor signals via rebound spikes by decreasing the signal-to-noise ratio and increasing the trial-to-trial variability. We further examined the role of brief sensory responses in basal ganglia output neurons and the effect of cortical excitation of motor thalamus in modulating rebound spiking. Interestingly, both the sensory responses and cortical inputs could either promote or suppress the generation of rebound spikes depending on their timing relative to the motor signal. Finally, in the model rebound spiking occurred despite the presence of moderate levels of excitation, indicating that rebound spiking might be feasible in a parameter regime relevant also in vivo. Overall, our model provides novel insights into the transmission of motor signals from the basal ganglia to motor thalamus by suggesting new functional roles for active decorrelation and sensory responses in the basal ganglia, as well as cortical excitation of motor thalamus.

scholarly journals Comonitoring of adenosine and dopamine using the Wireless Instantaneous Neurotransmitter Concentration System: proof of principle

2010 ◽  
Vol 112 (3) ◽  
pp. 539-548 ◽  
Author(s):  
Young-Min Shon ◽  
Su-Youne Chang ◽  
Susannah J. Tye ◽  
Christopher J. Kimble ◽  
Kevin E. Bennet ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Carbon Fiber ◽  
High Frequency ◽  
High Frequency Stimulation ◽  
Frequency Stimulation ◽  
Dopamine Efflux ◽  
Proof Of Principle ◽  
Stimulation Of

Object The authors of previous studies have demonstrated that local adenosine efflux may contribute to the therapeutic mechanism of action of thalamic deep brain stimulation (DBS) for essential tremor. Real-time monitoring of the neurochemical output of DBS-targeted regions may thus advance functional neurosurgical procedures by identifying candidate neurotransmitters and neuromodulators involved in the physiological effects of DBS. This would in turn permit the development of a method of chemically guided placement of DBS electrodes in vivo. Designed in compliance with FDA-recognized standards for medical electrical device safety, the authors report on the utility of the Wireless Instantaneous Neurotransmitter Concentration System (WINCS) for real-time comonitoring of electrical stimulation–evoked adenosine and dopamine efflux in vivo, utilizing fast-scan cyclic voltammetry (FSCV) at a polyacrylonitrile-based (T-650) carbon fiber microelectrode (CFM). Methods The WINCS was used for FSCV, which consisted of a triangle wave scanned between −0.4 and +1.5 V at a rate of 400 V/second and applied at 10 Hz. All voltages applied to the CFM were with respect to an Ag/AgCl reference electrode. The CFM was constructed by aspirating a single T-650 carbon fiber (r = 2.5 μm) into a glass capillary and pulling to a microscopic tip using a pipette puller. The exposed carbon fiber (the sensing region) extended beyond the glass insulation by ~ 50 μm. Proof of principle tests included in vitro measurements of adenosine and dopamine, as well as in vivo measurements in urethane-anesthetized rats by monitoring adenosine and dopamine efflux in the dorsomedial caudate putamen evoked by high-frequency electrical stimulation of the ventral tegmental area and substantia nigra. Results The WINCS provided reliable, high-fidelity measurements of adenosine efflux. Peak oxidative currents appeared at +1.5 V and at +1.0 V for adenosine, separate from the peak oxidative current at +0.6 V for dopamine. The WINCS detected subsecond adenosine and dopamine efflux in the caudate putamen at an implanted CFM during high-frequency stimulation of the ventral tegmental area and substantia nigra. Both in vitro and in vivo testing demonstrated that WINCS can detect adenosine in the presence of other easily oxidizable neurochemicals such as dopamine comparable to the detection abilities of a conventional hardwired electrochemical system for FSCV. Conclusions Altogether, these results demonstrate that WINCS is well suited for wireless monitoring of high-frequency stimulation-evoked changes in brain extracellular concentrations of adenosine. Clinical applications of selective adenosine measurements may prove important to the future development of DBS technology.

scholarly journals Incerto-thalamic modulation of fear via GABA and dopamine

2021 ◽  
Author(s):  
Archana Venkataraman ◽  
Sarah C. Hunter ◽  
Maria Dhinojwala ◽  
Diana Ghebrezadik ◽  
JiDong Guo ◽  
...  
Keyword(s):  
Brain Regions ◽  
Zona Incerta ◽  
Dependent Manner ◽  
Post Traumatic Stress ◽  
Functional Roles ◽  
Functional Connections ◽  
Optogenetic Stimulation ◽  
Fear Generalization ◽  
Stimulation Of

AbstractFear generalization and deficits in extinction learning are debilitating dimensions of Post-Traumatic Stress Disorder (PTSD). Most understanding of the neurobiology underlying these dimensions comes from studies of cortical and limbic brain regions. While thalamic and subthalamic regions have been implicated in modulating fear, the potential for incerto-thalamic pathways to suppress fear generalization and rescue deficits in extinction recall remains unexplored. We first used patch-clamp electrophysiology to examine functional connections between the subthalamic zona incerta and thalamic reuniens (RE). Optogenetic stimulation of GABAergic ZI → RE cell terminals in vitro induced inhibitory post-synaptic currents (IPSCs) in the RE. We then combined high-intensity discriminative auditory fear conditioning with cell-type-specific and projection-specific optogenetics in mice to assess functional roles of GABAergic ZI → RE cell projections in modulating fear generalization and extinction recall. In addition, we used a similar approach to test the possibility of fear generalization and extinction recall being modulated by a smaller subset of GABAergic ZI → RE cells, the A13 dopaminergic cell population. Optogenetic stimulation of GABAergic ZI → RE cell terminals attenuated fear generalization and enhanced extinction recall. In contrast, optogenetic stimulation of dopaminergic ZI → RE cell terminals had no effect on fear generalization but enhanced extinction recall in a dopamine receptor D1-dependent manner. Our findings shed new light on the neuroanatomy and neurochemistry of ZI-located cells that contribute to adaptive fear by increasing the precision and extinction of learned associations. In so doing, these data reveal novel neuroanatomical substrates that could be therapeutically targeted for treatment of PTSD.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Selective elimination of immunosuppressive T cells in patients with multiple myeloma

Leukemia ◽  
2021 ◽  
Author(s):  
Mohamed H. S. Awwad ◽  
Abdelrahman Mahmoud ◽  
Heiko Bruns ◽  
Hakim Echchannaoui ◽  
Katharina Kriegsmann ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
Immune Responses ◽  
High Frequency ◽  
Surface Markers ◽  
Selective Elimination ◽  
Related Transcription Factor ◽  
Cell Membrane Protein

AbstractElimination of suppressive T cells may enable and enhance cancer immunotherapy. Here, we demonstrate that the cell membrane protein SLAMF7 was highly expressed on immunosuppressive CD8+CD28-CD57+ Tregs in multiple myeloma (MM). SLAMF7 expression associated with T cell exhaustion surface markers and exhaustion-related transcription factor signatures. T cells from patients with a high frequency of SLAMF7+CD8+ T cells exhibited decreased immunoreactivity towards the MART-1aa26–35*A27L antigen. A monoclonal anti-SLAMF7 antibody (elotuzumab) specifically depleted SLAMF7+CD8+ T cells in vitro and in vivo via macrophage-mediated antibody-dependent cellular phagocytosis (ADCP). Anti-SLAMF7 treatment of MM patients depleted suppressive T cells in peripheral blood. These data highlight SLAMF7 as a marker for suppressive CD8+ Treg and suggest that anti-SLAMF7 antibodies can be used to boost anti-tumoral immune responses in cancer patients.

scholarly journals Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 146-158 ◽  
Author(s):  
KS Zuckerman ◽  
PJ Quesenberry ◽  
J Levin ◽  
R Sullivan
Keyword(s):  
Significant Inhibition ◽  
Erythropoietic Activity ◽  
Limulus Amebocyte Lysate ◽  
Endogenous Erythropoietin ◽  
Significant Change ◽  
In Vitro Effects ◽  
Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

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