The role of H-current in regulating strength and frequency of thalamic network oscillations

Synchronized neural activity is believed to be essential for many CNS functions, including neuronal development, sensory perception, and memory formation. In several brain areas GABAA receptor–mediated synaptic inhibition is thought to be important for the generation of synchronous network activity. We have used GABAA receptor β3 subunit deficient mice (β3−/−) to study the role of GABAergic inhibition in the generation of network oscillations in the olfactory bulb (OB) and to reveal the role of such oscillations in olfaction. The expression of functional GABAA receptors was drastically reduced (>93%) in β3−/− granule cells, the local inhibitory interneurons of the OB. This was revealed by a large reduction of muscimol-evoked whole-cell current and the total current mediated by spontaneous, miniature inhibitory postsynaptic currents (mIPSCs). In β3−/− mitral/tufted cells (principal cells), there was a two-fold increase in mIPSC amplitudes without any significant change in their kinetics or frequency. In parallel with the altered inhibition, there was a significant increase in the amplitude of theta (80% increase) and gamma (178% increase) frequency oscillations in β3−/− OBs recorded in vivo from freely moving mice. In odor discrimination tests, we found β3−/− mice to be initially the same as, but better with experience than β3+/+ mice in distinguishing closely related monomolecular alcohols. However, β3−/− mice were initially better and then worse with practice than control mice in distinguishing closely related mixtures of alcohols. Our results indicate that the disruption of GABAAreceptor–mediated synaptic inhibition of GABAergic interneurons and the augmentation of IPSCs in principal cells result in increased network oscillations in the OB with complex effects on olfactory discrimination, which can be explained by an increase in the size or effective power of oscillating neural cell assemblies among the mitral cells of β3−/− mice.

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The role of electrical signaling via gap junctions in the generation of fast network oscillations

Brain Research Bulletin ◽

10.1016/j.brainresbull.2003.07.004 ◽

2003 ◽

Vol 62 (1) ◽

pp. 3-13 ◽

Cited By ~ 53

Author(s):

Fiona E.N. LeBeau ◽

Roger D. Traub ◽

Hannah Monyer ◽

Miles A. Whittington ◽

Eberhard H. Buhl

Keyword(s):

Gap Junctions ◽

Network Oscillations ◽

Fast Network ◽

Electrical Signaling

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Modeling of sustained spontaneous network oscillations of a sexually dimorphic brainstem nucleus: the role of potassium equilibrium potential

Journal of Computational Neuroscience ◽

10.1007/s10827-021-00789-2 ◽

2021 ◽

Author(s):

Daniel Hartman ◽

Dávid Lehotzky ◽

Iulian Ilieş ◽

Mariana Levi ◽

Günther K. H. Zupanc

Keyword(s):

Equilibrium Potential ◽

Sexually Dimorphic ◽

Network Oscillations ◽

Brainstem Nucleus

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Ih interacts with somato-dendritic structure to determine frequency response to weak alternating electric field stimulation

Journal of Neurophysiology ◽

10.1152/jn.00541.2017 ◽

2018 ◽

Vol 119 (3) ◽

pp. 1029-1036 ◽

Cited By ~ 9

Author(s):

Enrique H. S. Toloza ◽

Ehsan Negahbani ◽

Flavio Fröhlich

Keyword(s):

Electric Field ◽

Electric Fields ◽

Cellular Response ◽

Current Injection ◽

Field Stimulation ◽

Electric Field Stimulation ◽

Cation Current ◽

Network Oscillations ◽

Alternating Electric Field

Transcranial current stimulation (tCS) modulates brain dynamics using weak electric fields. Given the pathological changes in brain network oscillations in neurological and psychiatric illnesses, using alternating electric field waveforms that engage rhythmic activity has been proposed as a targeted, network-level treatment approach. Previous studies have investigated the effects of electric fields at the neuronal level. However, the biophysical basis of the cellular response to electric fields has remained limited. Here, we characterized the frequency-dependent response of different compartments in a layer V pyramidal neuron to exogenous electric fields to dissect the relative contributions of voltage-gated ion channels and neuronal morphology. Hyperpolarization-activated cation current (Ih) in the distal dendrites was the primary ionic mechanism shaping the model’s response to electric field stimulation and caused subthreshold resonance in the tuft at 20 ± 4 Hz. In contrast, subthreshold Ih-mediated resonance in response to local sinusoidal current injection was present in all model compartments at 11 ± 2 Hz. The frequencies of both resonance responses were modulated by Ih conductance density. We found that the difference in resonance frequency between the two stimulation types can be explained by the fact that exogenous electric fields simultaneously polarize the membrane potentials at the distal ends of the neuron (relative to field direction) in opposite directions. Our results highlight the role of Ih in shaping the cellular response to electric field stimulation and suggest that the common model of tCS as a weak somatic current injection fails to capture the cellular effects of electric field stimulation. NEW & NOTEWORTHY Modulation of cortical oscillation by brain stimulation serves as a tool to understand the causal role of network oscillations in behavior and is a potential treatment modality that engages impaired network oscillations in disorders of the central nervous system. To develop targeted stimulation paradigms, cellular-level effects must be understood. We demonstrate that hyperpolarization-activated cation current (Ih) and cell morphology cooperatively shape the response to applied alternating electric fields.

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Parvalbumin interneuron dendrites enhance gamma oscillations

10.1101/2021.06.22.449483 ◽

2021 ◽

Author(s):

Birgit Kriener ◽

Hua Hu ◽

Koen Vervaeke

Keyword(s):

Network Models ◽

Gamma Oscillations ◽

Input Output ◽

Basket Cells ◽

Gamma Frequency ◽

Network Oscillations ◽

In Silico Modeling ◽

Parvalbumin Interneuron ◽

Relationship Of

Dendrites are important determinants of the input-output relationship of single neurons, but their role in network computations is not well understood. Here, we used a combination of dendritic patch-clamp recordings and in silico modeling to determine how dendrites of parvalbumin (PV)- expressing basket cells contribute to network oscillations in the gamma frequency band. Simultaneous soma-dendrite recordings from PV basket cells in the dentate gyrus revealed that the slope, or gain, of the dendritic input-output relationship is exceptionally low, thereby reducing the cell's sensitivity to changes in its input. By simulating gamma oscillations in detailed network models, we demonstrate that the low gain is key to increase spike synchrony in PV neuron assemblies when cells are driven by spatially and temporally heterogeneous synaptic input. These results highlight the role of dendritic computations in synchronized network oscillations.

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Role of GABAergic inhibition in hippocampal network oscillations

Trends in Neurosciences ◽

10.1016/j.tins.2007.05.003 ◽

2007 ◽

Vol 30 (7) ◽

pp. 343-349 ◽

Cited By ~ 228

Author(s):

Edward O. Mann ◽

Ole Paulsen

Keyword(s):

Gabaergic Inhibition ◽

Network Oscillations ◽

Hippocampal Network

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CA2 neuronal activity controls hippocampal low gamma and ripple oscillations

eLife ◽

10.7554/elife.38052 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 9

Author(s):

Georgia M Alexander ◽

Logan Y Brown ◽

Shannon Farris ◽

Daniel Lustberg ◽

Caroline Pantazis ◽

...

Keyword(s):

Neuronal Activity ◽

Cognitive Functions ◽

Social Memory ◽

Experimental System ◽

Gamma Oscillations ◽

Neuronal Populations ◽

Prefrontal Cortical ◽

Network Oscillations ◽

Hippocampal Area

Hippocampal oscillations arise from coordinated activity among distinct populations of neurons and are associated with cognitive functions. Much progress has been made toward identifying the contribution of specific neuronal populations in hippocampal oscillations, but less is known about the role of hippocampal area CA2, which is thought to support social memory. Furthermore, the little evidence on the role of CA2 in oscillations has yielded conflicting conclusions. Therefore, we sought to identify the contribution of CA2 to oscillations using a controlled experimental system. We used excitatory and inhibitory DREADDs to manipulate CA2 neuronal activity and studied resulting hippocampal-prefrontal cortical network oscillations. We found that modification of CA2 activity bidirectionally regulated hippocampal and prefrontal cortical low-gamma oscillations and inversely modulated hippocampal ripple oscillations in mice. These findings support a role for CA2 in low-gamma generation and ripple modulation within the hippocampus and underscore the importance of CA2 in extrahippocampal oscillations.

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