scholarly journals Subgroups of parvalbumin-expressing interneurons in layers 2/3 of the visual cortex

2013 ◽  
Vol 109 (6) ◽  
pp. 1600-1613 ◽  
Author(s):  
Jessica Helm ◽  
Gulcan Akgul ◽  
Lonnie P. Wollmuth
Keyword(s):  
Visual Cortex ◽  
Pyramidal Neurons ◽  
Neural Circuit ◽  
Membrane Properties ◽  
Shape Information ◽  
Firing Patterns ◽  
Excitatory Synaptic Input ◽  
Flow Through ◽  
The Difference ◽  
Output Characteristics

The input, processing, and output characteristics of inhibitory interneurons help shape information flow through layers 2/3 of the visual cortex. Parvalbumin (PV)-positive interneurons modulate and synchronize the gain and dynamic responsiveness of pyramidal neurons. To define the diversity of PV interneurons in layers 2/3 of the developing visual cortex, we characterized their passive and active membrane properties. Using Ward's and k-means multidimensional clustering, we identified four PV interneuron subgroups. The most notable difference between the subgroups was their firing patterns in response to moderate stimuli just above rheobase. Two subgroups showed regular and continuous firing at all stimulus intensities above rheobase. The difference between these two continuously firing subgroups was that one fired at much higher frequencies and transitioned into this high-frequency firing rate at or near rheobase. The two other subgroups showed irregular, stuttering firing patterns just above rheobase. Both of these subgroups typically transitioned to regular and continuous firing at intense stimulations, but one of these subgroups, the strongly stuttering subgroup, showed irregular firing across a wider range of stimulus intensities and firing frequencies. The four subgroups also differed in excitatory synaptic input, providing independent support for the classification of subgroups. The subgroups of PV interneurons identified here would respond differently to inputs of varying intensity and frequency, generating diverse patterns of PV inhibition in the developing neural circuit.

scholarly journals Asymmetric Temporal Integration of Layer 4 and Layer 2/3 Inputs in Visual Cortex

2011 ◽  
Vol 105 (1) ◽  
pp. 347-355 ◽  
Author(s):  
Giao B. Hang ◽  
Yang Dan
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Pyramidal Neurons ◽  
Temporal Integration ◽  
Cortical Inhibition ◽  
Multiple Sources ◽  
Layer 2 ◽  
Layer 4 ◽  
The Difference

Neocortical neurons in vivo receive concurrent synaptic inputs from multiple sources, including feedforward, horizontal, and feedback pathways. Layer 2/3 of the visual cortex receives feedforward input from layer 4 and horizontal input from layer 2/3. Firing of the pyramidal neurons, which carries the output to higher cortical areas, depends critically on the interaction of these pathways. Here we examined synaptic integration of inputs from layer 4 and layer 2/3 in rat visual cortical slices. We found that the integration is sublinear and temporally asymmetric, with larger responses if layer 2/3 input preceded layer 4 input. The sublinearity depended on inhibition, and the asymmetry was largely attributable to the difference between the two inhibitory inputs. Interestingly, the asymmetric integration was specific to pyramidal neurons, and it strongly affected their spiking output. Thus via cortical inhibition, the temporal order of activation of layer 2/3 and layer 4 pathways can exert powerful control of cortical output during visual processing.

Different voltage dependence of transient and persistent Na+ currents is compatible with modal-gating hypothesis for sodium channels

1994 ◽  
Vol 71 (6) ◽  
pp. 2562-2565 ◽  
Author(s):  
A. M. Brown ◽  
P. C. Schwindt ◽  
W. E. Crill
Keyword(s):  
Pyramidal Neurons ◽  
Voltage Dependence ◽  
Sufficient Evidence ◽  
Na Channel ◽  
Na Channels ◽  
Activation Curve ◽  
Neocortical Neurons ◽  
Na Currents ◽  
Flow Through ◽  
The Difference

1. These experiments tested the hypothesis that the differing voltage dependence of the transient (INa) and persistent (INaP) Na+ currents in neocortical neurons results from the state of inactivation of one type of Na+ channel rather than from the existence of different types of Na+ channels. This question was examined in acutely isolated pyramidal neurons from the sensorimotor cortex of rats by using papain to remove inactivation from INa and comparing the resulting activation curve with that of INaP. 2. In control cells, INaP activated at more negative potentials than INa. Inclusion of papain in the recording pipette removed inactivation from INa and caused the INa activation curve to be shifted leftward to the position of the curve for INaP measured in control cells. Papain greatly increased both INa amplitude and the time to reach peak INa during smaller depolarizations, whereas the difference between control and test currents was reduced during large depolarizations. 3. We conclude that differences in the voltage dependence of INa and INaP activation does not provide sufficient evidence that these currents flow through separate sets of Na+ channels. Instead, our results are consistent with the idea that INaP largely arises from a fraction of the transient Na+ channels that intermittently lose their inactivation.

scholarly journals Developmental Regulation of Homeostatic Plasticity in Mouse Primary Visual Cortex

2021 ◽  
Author(s):  
Wei Wen ◽  
Gina Turrigiano
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Pyramidal Neurons ◽  
Neural Circuit ◽  
Developmental Regulation ◽  
Visual Deprivation ◽  
Homeostatic Plasticity ◽  
Designer Drugs ◽  
Inhibitory Input ◽  
Synaptic Scaling

Homeostatic plasticity maintains network stability by adjusting excitation, inhibition, or the intrinsic excitability of neurons, but the developmental regulation and coordination of these distinct forms of homeostatic plasticity remains poorly understood. A major contributor to this information gap is the lack of a uniform paradigm for chronically manipulating activity at different developmental stages. To overcome this limitation, we utilized Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to directly suppress neuronal activity in layer (L) 2/3 of mouse primary visual cortex (V1) at two important developmental timepoints: the classic visual system critical period (CP, P24-29), and adulthood (P45-55). We show that 24 hours of DREADD-mediated activity suppression simultaneously induces excitatory synaptic scaling up and intrinsic homeostatic plasticity in L2/3 pyramidal neurons during the CP, consistent with previous observations using prolonged visual deprivation. Importantly, manipulations known to block these forms of homeostatic plasticity when induced pharmacologically or via visual deprivation also prevented DREADD-induced homeostatic plasticity. We next used the same paradigm to suppress activity in adult animals. Surprisingly, while excitatory synaptic scaling persisted into adulthood, intrinsic homeostatic plasticity was completely absent. Finally, we found that homeostatic changes in quantal inhibitory input onto L2/3 pyramidal neurons were absent during the CP but present in adults. Thus, the same population of neurons can express distinct sets of homeostatic plasticity mechanisms at different development stages. Our findings suggest that homeostatic forms of plasticity can be recruited in a modular manner according to the evolving needs of a developing neural circuit.

scholarly journals Reliable sensory processing in mouse visual cortex through inhibitory interactions between Somatostatin and Parvalbumin interneurons

2017 ◽  
Author(s):  
Rajeev V. Rikhye ◽  
Ming Hu ◽  
Murat Yildirim ◽  
Mriganka Sur
Keyword(s):  
Visual Cortex ◽  
Cortical Neurons ◽  
Neural Coding ◽  
Computational Models ◽  
Pyramidal Neurons ◽  
Neural Circuit ◽  
Large Variability ◽  
Sensory Stimuli ◽  
Parvalbumin Interneurons ◽  
Mouse Visual Cortex

ABSTRACTCortical neurons often respond to identical sensory stimuli with large variability. However, under certain conditions, the same neurons can also respond highly reliably. The circuit mechanisms that contribute to this modulation, and their influence on behavior remains unknown. Here we used novel double transgenic mice, dual-wavelength calcium imaging and temporally selective optical perturbation to identify an inhibitory neural circuit in visual cortex that can modulate the reliability of pyramidal neurons to naturalistic visual stimuli. Our results, supported by computational models, suggest that somatostatin interneurons (SST-INs) increase pyramidal neuron reliability by suppressing parvalbumin interneurons (PV-INs) via the inhibitory SST→PV circuit. Using a novel movie classification task, we further show that, by reducing variability, activating SST-INs can improve the ability of mice to discriminate between ambiguous stimuli. Together, these findings reveal a novel role of the SST→PV circuit in modulating the fidelity of neural coding critical for visual perception.

Study of pumping effect in flow-through electrolysers

1983 ◽  
Vol 48 (8) ◽  
pp. 2232-2248 ◽  
Author(s):  
Ivo Roušar ◽  
Michal Provazník ◽  
Pavel Stuhl
Keyword(s):  
Natural Convection ◽  
Balance Equation ◽  
Volume Fraction ◽  
Industrial Applications ◽  
Pumping Effect ◽  
Flow Through ◽  
The Mean ◽  
The Difference

In electrolysers with recirculation, where a gas is evolved, the pumping of electrolyte from a lower to a higher level can be effected by natural convection due to the difference between the densities of the inlet electrolyte and the gaseous emulsion at the outlet. An accurate balance equation for calculation of the rate of flow of the pumped liquid is derived. An equation for the calculation of the mean volume fraction of bubbles in the space between the electrodes is proposed and verified experimentally on a pilot electrolyser. Two examples of industrial applications are presented.

scholarly journals 3D Ultrastructure of Synaptic Inputs to Distinct GABAergic Neurons in the Mouse Primary Visual Cortex

2020 ◽  
Author(s):  
Yang-Sun Hwang ◽  
Catherine Maclachlan ◽  
Jérôme Blanc ◽  
Anaëlle Dubois ◽  
Carl C H Petersen ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Pyramidal Neuron ◽  
Cell Types ◽  
Gabaergic Neurons ◽  
Inhibitory Synapses ◽  
Synaptic Inputs ◽  
Neuronal Types ◽  
The Difference ◽  
Ultrastructure Of Synapses

Abstract Synapses are the fundamental elements of the brain’s complicated neural networks. Although the ultrastructure of synapses has been extensively studied, the difference in how synaptic inputs are organized onto distinct neuronal types is not yet fully understood. Here, we examined the cell-type-specific ultrastructure of proximal processes from the soma of parvalbumin-positive (PV+) and somatostatin-positive (SST+) GABAergic neurons in comparison with a pyramidal neuron in the mouse primary visual cortex (V1), using serial block-face scanning electron microscopy. Interestingly, each type of neuron organizes excitatory and inhibitory synapses in a unique way. First, we found that a subset of SST+ neurons are spiny, having spines on both soma and dendrites. Each of those spines has a highly complicated structure that has up to eight synaptic inputs. Next, the PV+ and SST+ neurons receive more robust excitatory inputs to their perisoma than does the pyramidal neuron. Notably, excitatory synapses on GABAergic neurons were often multiple-synapse boutons, making another synapse on distal dendrites. On the other hand, inhibitory synapses near the soma were often single-targeting multiple boutons. Collectively, our data demonstrate that synaptic inputs near the soma are differentially organized across cell types and form a network that balances inhibition and excitation in the V1.

scholarly journals Septohippocampal transmission from parvalbumin-positive neurons features rapid recovery from synaptic depression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Feng Yi ◽  
Tavita Garrett ◽  
Karl Deisseroth ◽  
Heikki Haario ◽  
Emily Stone ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Synaptic Depression ◽  
Medial Septum ◽  
Membrane Properties ◽  
Projection Neurons ◽  
Calcium Dependent ◽  
Light Pulses ◽  
Diagonal Band ◽  
Initial Release ◽  
Intrinsic Membrane Properties

AbstractParvalbumin-containing projection neurons of the medial-septum-diagonal band of Broca ($$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB ) are essential for hippocampal rhythms and learning operations yet are poorly understood at cellular and synaptic levels. We combined electrophysiological, optogenetic, and modeling approaches to investigate $$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB neuronal properties. $$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB neurons had intrinsic membrane properties distinct from acetylcholine- and somatostatin-containing MS-DBB subtypes. Viral expression of the fast-kinetic channelrhodopsin ChETA-YFP elicited action potentials to brief (1–2 ms) 470 nm light pulses. To investigate $$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB transmission, light pulses at 5–50 Hz frequencies generated trains of inhibitory postsynaptic currents (IPSCs) in CA1 stratum oriens interneurons. Using a similar approach, optogenetic activation of local hippocampal PV ($$\hbox {PV}_{\text{HC}}$$ PV HC ) neurons generated trains of $$\hbox {PV}_{\text{HC}}$$ PV HC -mediated IPSCs in CA1 pyramidal neurons. Both synapse types exhibited short-term depression (STD) of IPSCs. However, relative to $$\hbox {PV}_{\text{HC}}$$ PV HC synapses, $$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB synapses possessed lower initial release probability, transiently resisted STD at gamma (20–50 Hz) frequencies, and recovered more rapidly from synaptic depression. Experimentally-constrained mathematical synapse models explored mechanistic differences. Relative to the $$\hbox {PV}_{\text{HC}}$$ PV HC model, the $$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB model exhibited higher sensitivity to calcium accumulation, permitting a faster rate of calcium-dependent recovery from STD. In conclusion, resistance of $$\hbox {PV}_{\text{MS-DBB}}$$ PV MS-DBB synapses to STD during short gamma bursts enables robust long-range GABAergic transmission from MS-DBB to hippocampus.

scholarly journals Firing responses mediated via distinct nicotinic acetylcholine receptor subtypes in rat prepositus hypoglossi nuclei neurons

2018 ◽  
Vol 120 (4) ◽  
pp. 1525-1533
Author(s):  
Yue Zhang ◽  
Yuchio Yanagawa ◽  
Yasuhiko Saito
Keyword(s):  
Acetylcholine Receptor ◽  
Nicotinic Acetylcholine Receptor ◽  
Firing Frequency ◽  
Membrane Properties ◽  
Receptor Subtypes ◽  
Nicotinic Acetylcholine ◽  
Firing Patterns ◽  
Prepositus Hypoglossi ◽  
Specific Antagonist ◽  
The Relationship

We previously reported that cholinergic current responses mediated via nicotinic acetylcholine (ACh) receptors (nAChRs) in the prepositus hypoglossi nucleus (PHN), which participates in gaze control, can be classified into distinct types based on different kinetics and are mainly composed of α7- and/or non-α7-subtypes: fast (F)-, slow (S)-, and fast and slow (FS)-type currents. In this study, to clarify how each current type is related to neuronal activities, we investigated the relationship between the current types and the membrane properties and the firing responses that were induced by each current type. The proportion of the current types differed in neurons that exhibited different afterhyperpolarization (AHP) profiles and firing patterns, suggesting that PHN neurons show a preference for specific current types dependent on the membrane properties. In response to ACh, F-type neurons showed either one action potential (AP) or multiple APs with a short firing duration, and S-type neurons showed multiple APs with a long firing duration. The firing frequency of F-type neurons was significantly higher than that of S-type and FS-type neurons. An α7-subtype-specific antagonist abolished the firing responses of F-type neurons and reduced the responses of FS-type neurons but had little effect on the responses of S-type neurons, which were reduced by a non-α7-subtype-specific antagonist. These results suggest that the different properties of the current types and the distinct expression of the nAChR subtypes in PHN neurons with different membrane properties produce unique firing responses via the activation of nAChRs. NEW & NOTEWORTHY Prepositus hypoglossi nucleus (PHN) neurons show distinct nicotinic acetylcholine receptor (nAChR)-mediated current responses. The proportion of the current types differed in the neurons that exhibited different afterhyperpolarization profiles and firing patterns. The nAChR-mediated currents with different kinetics induced firing responses of the neurons that were distinct in the firing frequency and duration. These results suggest that the different properties of the current types in PHN neurons with different membrane properties produce unique firing responses via the activation of nAChRs.

Effect of small doses of 5-hydroxytryptamine (serotonin) on pulmonary circulation in the closed-chest dog

1959 ◽  
Vol 197 (5) ◽  
pp. 963-967 ◽  
Author(s):  
John T. Shepherd ◽  
David E. Donald ◽  
Erland Linder ◽  
H. J. C. Swan
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Blood Flow ◽  
Pulmonary Veins ◽  
Pulmonary Vessels ◽  
Isolated Perfused Lung ◽  
Small Doses ◽  
Perfused Lung ◽  
Anesthetized Dogs ◽  
Flow Through ◽  
The Difference

5-Hydroxytryptamine (serotonin) was infused into anesthetized dogs at a rate of 20 µg/kg/min. In nine sets of observations on three dogs the increase in the difference of pressure between the pulmonary artery and the left atrium, which averaged 55%, consistently exceeded the increase in pulmonary blood flow, which averaged 16%. 5-HT therefore is a potent constrictor of pulmonary vessels, even in small concentrations. No changes in the pulmonary-artery wedge and pulmonary-vein pressures were detected during the infusions of 5-HT, nor was there any change in the volume of blood between the pulmonary artery and the root of the aorta. With this dose of 5-HT the principal site of the increased resistance to flow through the lungs appeared to be in the precapillary vessels. In the isolated perfused lung, moderate constriction of pulmonary veins also was produced by large doses of 5-HT.

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