scholarly journals Calcium activation of cortical neurons by continuous electrical stimulation: Frequency-dependence, temporal fidelity and activation density

2018 ◽  
Author(s):  
Nicholas J. Michelson ◽  
James R. Eles ◽  
Alberto L. Vazquez ◽  
Kip A Ludwig ◽  
Takashi DY Kozai
Keyword(s):  
Electrical Stimulation ◽  
Cortical Neurons ◽  
Local Population ◽  
Stimulation Frequency ◽  
Neural Element ◽  
Dependent Manner ◽  
Frequency Dependent ◽  
Two Photon Microscopy ◽  
Neuroscience Research

AbstractElectrical stimulation of the brain has become a mainstay of fundamental neuroscience research and an increasingly prevalent clinical therapy. Despite decades of use in basic neuroscience research and the growing prevalence of neuromodulation therapies, gaps in knowledge regarding activation or inactivation of neural elements over time have limited its ability to adequately interpret evoked downstream responses or fine-tune stimulation parameters to focus on desired responses. In this work, in vivo two-photon microscopy was used to image neuronal calcium activity in layer 2/3 neurons of somatosensory cortex (S1) in male C57BL/6J-Tg(Thy1-GCaMP6s)GP4.3Dkim/J mice during 30 s of continuous electrical stimulation at varying frequencies. We show frequency-dependent differences in spatial and temporal somatic responses during continuous stimulation. Our results elucidate conflicting results from prior studies reporting either dense spherical activation of somas biased towards those near the electrode, or sparse activation of somas at a distance via axons near the electrode. These findings indicate that the neural element specific temporal response local to the stimulating electrode changes as a function of applied charge density and frequency. These temporal responses need to be considered to properly interpret downstream circuit responses or determining mechanisms of action in basic science experiments or clinical therapeutic applications.Significance StatementMicrostimulation of small populations of neurons has the potential to ameliorate symptoms associated with several neurological disorders. However, the specific mechanisms by which microstimulation elicits therapeutic responses are unclear. This work examines the effects of continuous microstimulation on the local population of neurons surrounding the implanted electrode. Stimulation was found to elicit spatiotemporal neuronal responses in a frequency dependent manner. These findings suggest that stimulation frequency may be an important consideration for applications in research or therapy. Further research aimed at understanding these neuronal activation properties may provide insight into the mechanistic mode of action of continuous microstimulation.

Dynorphin A Elicits an Increase in Intracellular Calcium in Cultured Neurons Via a Non-Opioid, Non-NMDA Mechanism

2000 ◽  
Vol 83 (5) ◽  
pp. 2610-2615 ◽  
Author(s):  
Qingbo Tang ◽  
Ronald M. Lynch ◽  
Frank Porreca ◽  
Josephine Lai
Keyword(s):  
Nmda Receptor ◽  
Nmda Receptors ◽  
Intracellular Calcium ◽  
Cortical Neurons ◽  
Excitatory Amino Acid ◽  
Receptor Activation ◽  
Dependent Manner ◽  
Dynorphin A ◽  
Excitatory Effect

The opioid peptide dynorphin A is known to elicit a number of pathological effects that may result from neuronal excitotoxicity. An up-regulation of this peptide has also been causally related to the dysesthesia associated with inflammation and nerve injury. These effects of dynorphin A are not mediated through opioid receptor activation but can be effectively blocked by pretreatment with N-methyl-d-aspartate (NMDA) receptor antagonists, thus implicating the excitatory amino acid system as a mediator of the actions of dynorphin A and/or its fragments. A direct interaction between dynorphin A and the NMDA receptors has been well established; however the physiological relevance of this interaction remains equivocal. This study examined whether dynorphin A elicits a neuronal excitatory effect that may underlie its activation of the NMDA receptors. Calcium imaging of individual cultured cortical neurons showed that the nonopioid peptide dynorphin A(2-17) induced a time- and dose-dependent increase in intracellular calcium. This excitatory effect of dynorphin A(2-17) was insensitive to (+)-5-methyl-10,11-dihydro-5 H-dibenzo[ a,d]-cyclohepten-5,10-imine (MK-801) pretreatment in NMDA-responsive cells. Thus dynorphin A stimulates neuronal cells via a nonopioid, non-NMDA mechanism. This excitatory action of dynorphin A could modulate NMDA receptor activity in vivo by enhancing excitatory neurotransmitter release or by potentiating NMDA receptor function in a calcium-dependent manner. Further characterization of this novel site of action of dynorphin A may provide new insight into the underlying mechanisms of dynorphin excitotoxicity and its pathological role in neuropathy.

scholarly journals A novel Netrin-1–sensitive mechanism promotes local SNARE-mediated exocytosis during axon branching

2014 ◽  
Vol 205 (2) ◽  
pp. 217-232 ◽  
Author(s):  
Cortney C. Winkle ◽  
Leslie M. McClain ◽  
Juli G. Valtschanoff ◽  
Charles S. Park ◽  
Christopher Maglione ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cortical Neurons ◽  
Direct Interaction ◽  
Vesicle Fusion ◽  
Dependent Manner ◽  
Axon Branching ◽  
Spatial Regulation ◽  
Novel Model

Developmental axon branching dramatically increases synaptic capacity and neuronal surface area. Netrin-1 promotes branching and synaptogenesis, but the mechanism by which Netrin-1 stimulates plasma membrane expansion is unknown. We demonstrate that SNARE-mediated exocytosis is a prerequisite for axon branching and identify the E3 ubiquitin ligase TRIM9 as a critical catalytic link between Netrin-1 and exocytic SNARE machinery in murine cortical neurons. TRIM9 ligase activity promotes SNARE-mediated vesicle fusion and axon branching in a Netrin-dependent manner. We identified a direct interaction between TRIM9 and the Netrin-1 receptor DCC as well as a Netrin-1–sensitive interaction between TRIM9 and the SNARE component SNAP25. The interaction with SNAP25 negatively regulates SNARE-mediated exocytosis and axon branching in the absence of Netrin-1. Deletion of TRIM9 elevated exocytosis in vitro and increased axon branching in vitro and in vivo. Our data provide a novel model for the spatial regulation of axon branching by Netrin-1, in which localized plasma membrane expansion occurs via TRIM9-dependent regulation of SNARE-mediated vesicle fusion.

scholarly journals Gene Deletion Mutants Reveal a Role for Semaphorin Receptors of the Plexin-B Family in Mechanisms Underlying Corticogenesis

2009 ◽  
Vol 30 (3) ◽  
pp. 764-780 ◽  
Author(s):  
A. Hirschberg ◽  
S. Deng ◽  
A. Korostylev ◽  
E. Paldy ◽  
M. R. Costa ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Ex Vivo ◽  
Time Windows ◽  
Expression Patterns ◽  
Cortical Development ◽  
Critical Time ◽  
Dependent Manner ◽  
Semaphorin 4D ◽  
Developing Neurons

ABSTRACT Semaphorins and their receptors, plexins, are emerging as key regulators of various aspects of neural and nonneural development. Semaphorin 4D (Sema4D) and B-type plexins demonstrate distinct expression patterns over critical time windows during the development of the murine neocortex. Here, analysis of mice genetically lacking plexin-B1 or plexin-B2 revealed the significance of Sema4D-plexin-B signaling in cortical development. Deficiency of plexin-B2 resulted in abnormal cortical layering and defective migration and differentiation of several subtypes of cortical neurons, including Cajal-Retzius cells, GABAergic interneurons, and principal cells in vivo. In contrast, a lack of plexin-B1 did not impact on cortical development in vivo. In various ex vivo assays on embryonic forebrain, Sema4D enhanced the radial and tangential migration of developing neurons in a plexin-B2-dependent manner. These results suggest that Sema4D-plexin-B2 interactions regulate mechanisms underlying cell specification, differentiation, and migration during corticogenesis.

scholarly journals Histidine–Tryptophan-–Ketoglutarate Solution as a Neuroprotective Against Ischemia/Reperfusion Injury

2018 ◽  
Author(s):  
Jiun Hsu ◽  
Chih-Hsien Wang ◽  
Shu-Chien Huang ◽  
Yung-Wei Chen ◽  
Shengpin Yu ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
In Vitro Study ◽  
Dependent Manner ◽  
Sterile Saline ◽  
Nadph Oxidase 4 ◽  
H2o2 Level

Ischemic neuron loss contributes to brain dysfunction in patients with cardiac arrest (CA). Histidine–tryptophan–ketoglutarate (HTK) solution is a preservative used during organ transplantation. Can HTK also protect neurons from severe hypoxia (SH) following CA? We isolated rat primary cortical neurons and induced SH with or without HTK. Changes in caspase-3, hypoxia-inducible factor 1-alpha (HIF-1α), and NADPH oxidase-4 (NOX4) expression were evaluated at different time points till 72 h. Using a rat asphyxia model, we induced CA-mediated brain damage and then completed resuscitation. HTK or sterile saline was administered into the left carotid artery. Neurological deficit scoring and mortality were evaluated for 3 days. Then the rats were sacrificed for evaluating NOX4 and H2O2 level in blood and brain. In the in vitro study, HTK attenuated SH- and H2O2-mediated cytotoxicity in a volume- and time-dependent manner, associated with persisted HIF-1α expression, reductions in procaspase-3 activation and NOX4 expression. The inhibition of HIF-1α abrogated HTK’s effect on NOX4. In the in vivo study, neurological scores were significantly improved by HTK. H2O2 level, NOX4 activity and NOX4 gene expression were all decreased in the brain specimen of HTK-treated rats. Our results suggest that HTK acts as an effective neuroprotective solution.

scholarly journals Robust RBM3 and β-klotho expression in developing neurons in the human brain

2019 ◽  
Vol 39 (12) ◽  
pp. 2355-2367 ◽  
Author(s):  
Travis C Jackson ◽  
Keri Janesko-Feldman ◽  
Shaun W Carlson ◽  
Shawn E Kotermanski ◽  
Patrick M Kochanek
Keyword(s):  
Cortical Neurons ◽  
Rna Binding ◽  
Transmembrane Protein ◽  
Adult Brain ◽  
Human Infant ◽  
Fibroblast Growth Factor 21 ◽  
Binding Motif ◽  
Dependent Manner ◽  
Neuroprotective Effects

RNA binding motif 3 (RBM3) is a powerful neuroprotectant that inhibits neurodegenerative cell death in vivo and is a promising therapeutic target in brain ischemia. RBM3 is increased by the hormone fibroblast growth factor 21 (FGF21) in an age- and temperature-dependent manner in rat cortical neurons. FGF21 receptor binding is controlled by the transmembrane protein β-klotho, which is mostly absent in the adult brain. We discovered that RBM3/β-klotho is unexpectedly high in the human infant vs. adult brain (hippocampus/prefrontal cortex). The use of tissue homogenates in that study precluded a comparison of RBM3/β-klotho expression among different CNS cell-types, thus, omitted key evidence (i.e. confirmation of neuronal expression) that would otherwise provide a critical link to support their possible direct neuroprotective effects in humans. This report addresses that knowledge gap. High-quality fixed human hippocampus, cortex, and hypothalamic tissues were acquired from the NIH Neurobiobank (<1 yr (premature born) infants, 1 yr, 4 yr, and 34 yr). Dual labeling of cell-type markers vs. RBM3/β-klotho revealed enriched staining of targets in neurons in the developing brain. Identifying that RBM3/β-klotho is abundant in neurons in the immature brain is fundamentally important to guide protocol design and conceptual frameworks germane to future testing of these neuroprotective pathways in humans.

scholarly journals c-Jun NH2-terminal Kinase (JNK)-interacting Protein-3 (JIP3) Regulates Neuronal Axon Elongation in a Kinesin- and JNK-dependent Manner

2013 ◽  
Vol 288 (20) ◽  
pp. 14531-14543 ◽  
Author(s):  
Tao Sun ◽  
Nuo Yu ◽  
Lu-Kai Zhai ◽  
Na Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Neuronal Development ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Anterograde Transport ◽  
Interacting Protein ◽  
Axon Elongation

The development of neuronal polarity is essential for the establishment of the accurate patterning of neuronal circuits in the brain. However, little is known about the underlying molecular mechanisms that control rapid axon elongation during neuronal development. Here, we report that c-Jun NH2-terminal kinase (JNK)-interacting protein-3 (JIP3) is highly expressed at axon tips during the critical period for axon development. Using gain- and loss-of-function approaches, immunofluorescence analysis, and in utero electroporation, we find that JIP3 can enhance axon elongation in primary hippocampal neurons and cortical neurons in vivo. We further demonstrate that JIP3 promotes axon elongation in a kinesin- and JNK-dependent manner using several deletion mutants of JIP3. Next, we demonstrate that the successful transportation of JIP3 to axon tips by kinesin is a prerequisite for enhancing JNK phosphorylation in this area and therefore promotes axon elongation, constituting a novel mechanism for coupling JIP3 anterograde transport with JNK signaling at the distal axons and axon elongation. Finally, our immunofluorescence data suggest that the activation of JNK at axon tips facilitates axon elongation by modulating cofilin activity and actin filament dynamics. These findings may have important implications for our understanding of neuronal axon elongation during development.

scholarly journals Spatiotemporal constraints on optogenetic inactivation in cortical circuits

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Nuo Li ◽  
Susu Chen ◽  
Zengcai V Guo ◽  
Han Chen ◽  
Yan Huo ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Pyramidal Neurons ◽  
Inhibitory Neurons ◽  
Dependent Manner ◽  
Cortical Circuits ◽  
Neuronal Populations ◽  
Multiple Length Scales ◽  
Dose Dependent ◽  
Reduced Activity

Optogenetics allows manipulations of genetically and spatially defined neuronal populations with excellent temporal control. However, neurons are coupled with other neurons over multiple length scales, and the effects of localized manipulations thus spread beyond the targeted neurons. We benchmarked several optogenetic methods to inactivate small regions of neocortex. Optogenetic excitation of GABAergic neurons produced more effective inactivation than light-gated ion pumps. Transgenic mice expressing the light-dependent chloride channel GtACR1 produced the most potent inactivation. Generally, inactivation spread substantially beyond the photostimulation light, caused by strong coupling between cortical neurons. Over some range of light intensity, optogenetic excitation of inhibitory neurons reduced activity in these neurons, together with pyramidal neurons, a signature of inhibition-stabilized neural networks ('paradoxical effect'). The offset of optogenetic inactivation was followed by rebound excitation in a light dose-dependent manner, limiting temporal resolution. Our data offer guidance for the design of in vivo optogenetics experiments.

scholarly journals A binocular synaptic network supports interocular response alignment in visual cortical neurons

2021 ◽  
Author(s):  
Benjamin Scholl ◽  
Clara Tepohl ◽  
Melissa A Ryan ◽  
Connon I Thomas ◽  
Naomi Kamasawa ◽  
...  
Keyword(s):  
Synaptic Input ◽  
Cortical Neurons ◽  
Visual Stimulation ◽  
Light And Electron Microscopy ◽  
Orientation Tuning ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Layer 2 ◽  
Visual Cortical

In the visual system, signals from the two eyes are combined to form a coherent representation through the convergence of synaptic input populations onto individual cortical neurons. As individual synapses originate from either monocular (representing one eye) or binocular (representing both eyes) cortical networks, it has been unclear how these inputs are integrated coherently. Here, we imaged dendritic spines on layer 2/3 binocular cells in ferret visual cortex with in vivo two-photon microscopy to examine how monocular and binocular synaptic networks contribute to the interocular alignment of orientation tuning. We found that binocular synapses varied in degree of "congruency", namely response correlation between left and right eye visual stimulation. Binocular congruent inputs were functionally distinct from binocular noncongruent and monocular inputs, exhibiting greater tuning selectivity and connection specificity. Using correlative light and electron microscopy, we found no difference in ultrastructural anatomy and instead, observed strength in numbers using a simple model simulating aggregate synaptic input. This model demonstrated a predominate contribution of binocular congruent inputs in sculpting somatic orientation preference and interocular response alignment. Our study suggests that, in layer 2/3 cortical neurons, a binocular network is responsible for forming a coherent representation in individual neurons through recurrent intracortical interactions.

scholarly journals Serotonin regulates mitochondrial biogenesis and function in rodent cortical neurons via the 5-HT2A receptor and SIRT1-PGC-1α axis

2018 ◽  
Author(s):  
Sashaina Fanibunda ◽  
Sukrita Deb ◽  
Babukrishna Maniyadath ◽  
Samir Gupta ◽  
Noelia Weisstaub ◽  
...  
Keyword(s):  
Mitochondrial Biogenesis ◽  
Cortical Neurons ◽  
Neuronal Excitability ◽  
In Vivo Studies ◽  
Primary Role ◽  
Dependent Manner ◽  
Atp Levels ◽  
And Function ◽  
Neuroprotective Action

Mitochondria in neurons in addition to their primary role in bioenergetics also contribute to specialized functions including regulation of synaptic transmission, Ca2+ homeostasis, neuronal excitability and stress adaptation. However, the factors that influence mitochondrial biogenesis and function in neurons remain poorly elucidated. Here, we identify an important role for serotonin (5-HT) as a regulator of mitochondrial biogenesis and function in rodent cortical neurons, via a 5-HT2A receptor-mediated recruitment of the SIRT1-PGC-1α axis, which is relevant to the neuroprotective action of 5-HT. 5-HT increased mitochondrial biogenesis, reflected through enhanced mtDNA levels, mitotracker staining, and expression of mitochondrial genes. This was accompanied by increased cellular ATP levels, basal and maximal respiration, as well as spare respiratory capacity. Mechanistically the effects of 5-HT were mediated via the 5-HT2A receptor and master modulators of mitochondrial biogenesis, SIRT1 and PGC-1α. SIRT1 was required to mediate the effects of 5-HT on mitochondrial biogenesis and function in cortical neurons. In vivo studies revealed that 5-HT2A receptor stimulation increased cortical mtDNA and ATP levels, in a SIRT1 dependent manner. In cortical neurons, 5-HT enhanced expression of anti-oxidant enzymes, decreased cellular reactive oxygen species, and exhibited neuroprotection against excitotoxic and oxidative stress, an effect that required SIRT1. These findings identify 5-HT as a novel upstream regulator of mitochondrial biogenesis and function in cortical neurons, and implicate the mitochondrial effects of 5-HT in its neuroprotective action.

scholarly journals Local field potentials reflect cortical population dynamics in a region-specific and frequency-dependent manner

2021 ◽  
Author(s):  
Cecilia Gallego-Carracedo ◽  
Matthew G. Perich ◽  
Raeed H. Chowdhury ◽  
Lee E. Miller ◽  
Juan A. Gallego
Keyword(s):  
Local Field ◽  
Cortical Neurons ◽  
Local Field Potentials ◽  
Neural Correlates ◽  
Movement Planning ◽  
Neural Population ◽  
Dependent Manner ◽  
Field Potentials ◽  
Frequency Dependent ◽  
The Relationship

The spiking activity of populations of cortical neurons is well described by a small number of population-wide covariance patterns, the "latent dynamics". These latent dynamics are largely driven by the same correlated synaptic currents across the circuit that determine the generation of local field potentials (LFP). Yet, the relationship between latent dynamics and LFPs remains largely unexplored. Here, we characterised this relationship for three different regions of primate sensorimotor cortex during reaching. The correlation between latent dynamics and LFPs was frequency-dependent and varied across regions. However, for any given region, this relationship remained stable across behaviour: in each of primary motor and premotor cortices, the LFP-latent dynamics correlation profile was remarkably similar between movement planning and execution. These robust associations between LFPs and neural population latent dynamics help bridge the wealth of studies reporting neural correlates of behaviour using either type of recordings.

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