The Human K-Complex Represents an Isolated Cortical Down-State

Cash, Sydney S.; Halgren, Eric; Dehghani, Nima; Rossetti, Andrea O.; Thesen, Thomas; Wang, Chunmao; Devinsky, Orrin; Kuzniecky, Ruben; Doyle, Werner; Madsen, Joseph R.; Bromfield, Edward B; Erőss, Lóránd; Halász, Péter; Karmos, G.; Csercsa, Richard; Wittner, Lúcia; Ulbert, István

doi:10.1126/science.1169626

Cited by 347 publications

(330 citation statements)

References 26 publications

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“…The decrease in synaptic activity together with current outflow from the neuronal elements (source) suggests the role of non-synaptic regulations, such as disfacilitation (regulated by ion channels) [87]. This profile of decreased deep multi-unit activity and current sources in middle-to-deep layers mimics slow-wave-sleep [88] and K-complexes [89] and suggests that the N2 slow wave of the CCEP represents prolonged inhibition. In summary, single and multi-unit data support the interpretation of the N1 of the CCEP to represent excitation of pyramidal cells, while the N2 represents long-lasting inhibition.…”

Section: Relationship Between Anatomical Functionalmentioning

confidence: 99%

Mapping human brain networks with cortico-cortical evoked potentials

Keller

Honey

Mégevand

et al. 2014

Phil. Trans. R. Soc. B

188

212

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The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex.

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Section: Relationship Between Anatomical Functionalmentioning

confidence: 99%

Mapping human brain networks with cortico-cortical evoked potentials

Keller

Honey

Mégevand

et al. 2014

Phil. Trans. R. Soc. B

188

212

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“…Modern electrode systems provide the possibility of extracellular recordings of neuronal ensembles by using either microwires (7) or high-density microelectrode arrays (8,9). Prior efforts have demonstrated excellent recordings of single-neuron activity in human cerebral cortex (10)(11)(12).…”

mentioning

confidence: 99%

Spatiotemporal dynamics of neocortical excitation and inhibition during human sleep

Peyrache

Dehghani

Eskandar

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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176

229

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Intracranial recording is an important diagnostic method routinely used in a number of neurological monitoring scenarios. In recent years, advancements in such recordings have been extended to include unit activity of an ensemble of neurons. However, a detailed functional characterization of excitatory and inhibitory cells has not been attempted in human neocortex, particularly during the sleep state. Here, we report that such feature discrimination is possible from high-density recordings in the neocortex by using 2D multielectrode arrays. Successful separation of regular-spiking neurons (or bursting cells) from fast-spiking cells resulted in well-defined clusters that each showed unique intrinsic firing properties. The high density of the array, which allowed recording from a large number of cells (up to 90), helped us to identify apparent monosynaptic connections, confirming the excitatory and inhibitory nature of regular-spiking and fast-spiking cells, thus categorized as putative pyramidal cells and interneurons, respectively. Finally, we investigated the dynamics of correlations within each class. A marked exponential decay with distance was observed in the case of excitatory but not for inhibitory cells. Although the amplitude of that decline depended on the timescale at which the correlations were computed, the spatial constant did not. Furthermore, this spatial constant is compatible with the typical size of human columnar organization. These findings provide a detailed characterization of neuronal activity, functional connectivity at the microcircuit level, and the interplay of excitation and inhibition in the human neocortex.spontaneous activity | ensemble recordings | single unit | functional dynamics F rom columnar microcircuits (1-3) to higher-order neuronal functional units, neocortical dynamics are characterized by a large range of spatial and temporal scales (4, 5). Recent technical improvements have allowed the nature of these dynamics in the human brain to be directly explored: Single-neuron activity in conjunction with local field potentials (LFPs) can be detected from the cerebral cortex and hippocampus in the course of intense monitoring of brain activity before surgical treatment of epileptic foci (6). Modern electrode systems provide the possibility of extracellular recordings of neuronal ensembles by using either microwires (7) or high-density microelectrode arrays (8,9). Prior efforts have demonstrated excellent recordings of single-neuron activity in human cerebral cortex (10-12).Separation of units between "regular-spiking" (RS) and "fastspiking" (FS) neurons, presumably excitatory (pyramidal) and inhibitory (interneuron) cells, respectively, is commonly practiced in animal experiments. In the neocortex of various mammalian species, RS and FS cells can be reliably separated based on spike waveform, duration, and firing rates (13,14). Similar criteria were also used to successfully separate units into putative pyramidal (Pyr) cells and inhibitory interneurons (Int) in human hippocampus...

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“…Advances in the fabrication of tetrodes and the increased availability of manufactured solutions will further facilitate the movement of this technology into addressing human diseases and ailments 19,20 . And while the penetration of electrodes into brain tissue is invasive in nature, these recordings offer invaluable information from individual neurons that cannot be obtained with technologies such as functional imaging.…”

Section: Discussionmentioning

confidence: 99%

Construction of Microdrive Arrays for Chronic Neural Recordings in Awake Behaving Mice

Chang

Frattini

Robbiati

et al. 2013

JoVE

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State-of-the-art electrophysiological recordings from the brains of freely behaving animals allow researchers to simultaneously examine local field potentials (LFPs) from populations of neurons and action potentials from individual cells, as the animal engages in experimentally relevant tasks. Chronically implanted microdrives allow for brain recordings to last over periods of several weeks. Miniaturized drives and lightweight components allow for these long-term recordings to occur in small mammals, such as mice. By using tetrodes, which consist of tightly braided bundles of four electrodes in which each wire has a diameter of 12.5 μm, it is possible to isolate physiologically active neurons in superficial brain regions such as the cerebral cortex, dorsal hippocampus, and subiculum, as well as deeper regions such as the striatum and the amygdala. Moreover, this technique insures stable, high-fidelity neural recordings as the animal is challenged with a variety of behavioral tasks. This manuscript describes several techniques that have been optimized to record from the mouse brain. First, we show how to fabricate tetrodes, load them into driveable tubes, and gold-plate their tips in order to reduce their impedance from MΩ to KΩ range. Second, we show how to construct a custom microdrive assembly for carrying and moving the tetrodes vertically, with the use of inexpensive materials. Third, we show the steps for assembling a commercially available microdrive (Neuralynx VersaDrive) that is designed to carry independently movable tetrodes. Finally, we present representative results of local field potentials and single-unit signals obtained in the dorsal subiculum of mice. These techniques can be easily modified to accommodate different types of electrode arrays and recording schemes in the mouse brain. Video LinkThe video component of this article can be found at

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The Human K-Complex Represents an Isolated Cortical Down-State

Cited by 347 publications

References 26 publications

Mapping human brain networks with cortico-cortical evoked potentials

Mapping human brain networks with cortico-cortical evoked potentials

Spatiotemporal dynamics of neocortical excitation and inhibition during human sleep

Construction of Microdrive Arrays for Chronic Neural Recordings in Awake Behaving Mice

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