TY - JOUR AU - Hangya, Balázs AU - Tihanyi, Benedek AU - Entz, László AU - Fabó, Dániel AU - Erőss, Loránd AU - Wittner, Lucia AU - Jakus, R AU - Varga, Viktor AU - Freund, Tamás AU - Ulbert, István TI - Complex Propagation Patterns Characterize Human Cortical Activity during Slow-Wave Sleep JF - JOURNAL OF NEUROSCIENCE J2 - J NEUROSCI VL - 31 PY - 2011 IS - 24 SP - 8770 EP - 8779 PG - 10 SN - 0270-6474 DO - 10.1523/JNEUROSCI.1498-11.2011 UR - https://m2.mtmt.hu/api/publication/1611469 ID - 1611469 N1 - Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary National Institute of Neuroscience, Budapest, Hungary Institute for Psychology, Hungarian Academy of Sciences, Budapest, Hungary Faculty of Information Technology, Péter Pázmány Catholic University, Budapest, Hungary Cited By :23 Export Date: 2 February 2021 CODEN: JNRSD Correspondence Address: Hangya, B.; Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, United States; email: bhangya@cshl.edu Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary National Institute of Neuroscience, Budapest, Hungary Institute for Psychology, Hungarian Academy of Sciences, Budapest, Hungary Faculty of Information Technology, Péter Pázmány Catholic University, Budapest, Hungary Cited By :23 Export Date: 27 July 2021 CODEN: JNRSD Correspondence Address: Hangya, B.; Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, United States; email: bhangya@cshl.edu AB - Cortical electrical activity during nonrapid eye movement (non- REM) sleep is dominated by slow-wave activity (SWA). At larger spatial scales ( approximately 2-30 cm), investigated by scalp EEG recordings, SWA has been shown to propagate globally over wide cortical regions as traveling waves, which has been proposed to serve as a temporal framework for neural plasticity. However, whether SWA dynamics at finer spatial scales also reflects the orderly propagation has not previously been investigated in humans. To reveal the local, finer spatial scale ( approximately 1-6 cm) patterns of SWA propagation during non- REM sleep, electrocorticographic (ECoG) recordings were conducted from subdurally implanted electrode grids and a nonlinear correlation technique [mutual information (MI)] was implemented. MI analysis revealed spatial maps of correlations between cortical areas demonstrating SWA propagation directions, speed, and association strength. Highest correlations, indicating significant coupling, were detected during the initial positive-going deflection of slow waves. SWA propagated predominantly between adjacent cortical areas, albeit spatial noncontinuities were also frequently observed. MI analysis further uncovered significant convergence and divergence patterns. Areas receiving the most convergent activity were similar to those with high divergence rate, while reciprocal and circular propagation of SWA was also frequent. We hypothesize that SWA is characterized by distinct attributes depending on the spatial scale observed. At larger spatial scales, the orderly SWA propagation dominates; at the finer scale of the ECoG recordings, non-REM sleep is characterized by complex SWA propagation patterns. LA - English DB - MTMT ER - TY - JOUR AU - Keller, CJ AU - Bickel, S AU - Entz, László AU - Ulbert, István AU - Milham, MP AU - Kelly, C AU - Mehta, AD TI - Intrinsic functional architecture predicts electrically evoked responses in the human brain. JF - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA J2 - P NATL ACAD SCI USA VL - 108 PY - 2011 IS - 25 SP - 10308 EP - 10313 PG - 6 SN - 0027-8424 DO - 10.1073/pnas.1019750108 UR - https://m2.mtmt.hu/api/publication/1606036 ID - 1606036 AB - Adaptive brain function is characterized by dynamic interactions within and between neuronal circuits, often occurring at the time scale of milliseconds. These complex interactions between adjacent and noncontiguous brain areas depend on a functional architecture that is maintained even in the absence of input. Functional MRI studies carried out during rest (R-fMRI) suggest that this architecture is represented in low-frequency (<0.1 Hz) spontaneous fluctuations in the blood oxygen level-dependent signal that are correlated within spatially distributed networks of brain areas. These networks, collectively referred to as the brain's intrinsic functional architecture, exhibit a remarkable correspondence with patterns of task-evoked coactivation as well as maps of anatomical connectivity. Despite this striking correspondence, there is no direct evidence that this intrinsic architecture forms the scaffold that gives rise to faster processes relevant to information processing and seizure spread. Here, we demonstrate that the spatial distribution and magnitude of temporally correlated low-frequency fluctuations observed with R-fMRI during rest predict the pattern and magnitude of corticocortical evoked potentials elicited within 500 ms after single-pulse electrical stimulation of the cerebral cortex with intracranial electrodes. Across individuals, this relationship was found to be independent of the specific regions and functional systems probed. Our findings bridge the immense divide between the temporal resolutions of these distinct measures of brain function and provide strong support for the idea that the low-frequency signal fluctuations observed with R-fMRI maintain and update the intrinsic architecture underlying the brain's repertoire of functional responses. LA - English DB - MTMT ER - TY - JOUR AU - Csercsa, Richárd AU - Dombovári, Balázs Gábor AU - Fabó, Dániel AU - Wittner, Lucia AU - Erőss, Loránd AU - Entz, László AU - Solyom, A AU - Rasonyi, G AU - Szűcs, Anna AU - Kelemen, Anna AU - Jakus, R AU - Juhos, V AU - Grand, László AU - Magony, Andor Dániel AU - Halász, Péter AU - Freund, Tamás AU - Maglóczky, Zsófia AU - Cash, SS AU - Papp, L AU - Karmos, György AU - Halgren, E AU - Ulbert, István TI - Laminar analysis of slow wave activity in humans JF - BRAIN J2 - BRAIN VL - 133 PY - 2010 IS - 9 SP - 2814 EP - 2829 PG - 16 SN - 0006-8950 DO - 10.1093/brain/awq169 UR - https://m2.mtmt.hu/api/publication/1362087 ID - 1362087 N1 - Institute for Psychology, Hungarian Academy of Sciences, Budapest, Hungary Pázmány Péter Catholic University, Faculty of Information Technology, Budapest, Hungary National Institute of Neuroscience, Budapest, Hungary Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary Department of Neurology, Szent István Hospital, Budapest, Hungary School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom Department of Neurology, Massachusetts General Hospital, Boston, MA, United States Neuronelektród Kft, Budapest, Hungary Departments of Radiology, Neuroscience and Psychiatry, University of California, San Diego, CA, United States Cited By :167 Export Date: 13 March 2024 CODEN: BRAIA Correspondence Address: Ulbert, I.; MTA PKI, Szondi u. 83-85, Budapest 1068, Hungary; email: ulbert@cogpsyphy.hu Funding details: National Institutes of Health, NIH Funding details: National Institute of Neurological Disorders and Stroke, NINDS, R01NS062092 AB - Brain electrical activity is largely composed of oscillations at characteristic frequencies. These rhythms are hierarchically organized and are thought to perform important pathological and physiological functions. The slow wave is a fundamental cortical rhythm that emerges in deep non-rapid eye movement sleep. In animals, the slow wave modulates delta, theta, spindle, alpha, beta, gamma and ripple oscillations, thus orchestrating brain electrical rhythms in sleep. While slow wave activity can enhance epileptic manifestations, it is also thought to underlie essential restorative processes and facilitate the consolidation of declarative memories. Animal studies show that slow wave activity is composed of rhythmically recurring phases of widespread, increased cortical cellular and synaptic activity, referred to as active- or up-state, followed by cellular and synaptic inactivation, referred to as silent- or down-state. However, its neural mechanisms in humans are poorly understood, since the traditional intracellular techniques used in animals are inappropriate for investigating the cellular and synaptic/transmembrane events in humans. To elucidate the intracortical neuronal mechanisms of slow wave activity in humans, novel, laminar multichannel microelectrodes were chronically implanted into the cortex of patients with drug-resistant focal epilepsy undergoing cortical mapping for seizure focus localization. Intracortical laminar local field potential gradient, multiple-unit and single-unit activities were recorded during slow wave sleep, related to simultaneous electrocorticography, and analysed with current source density and spectral methods. We found that slow wave activity in humans reflects a rhythmic oscillation between widespread cortical activation and silence. Cortical activation was demonstrated as increased wideband (0.3-200 Hz) spectral power including virtually all bands of cortical oscillations, increased multiple- and single-unit activity and powerful inward transmembrane currents, mainly localized to the supragranular layers. Neuronal firing in the up-state was sparse and the average discharge rate of single cells was less than expected from animal studies. Action potentials at up-state onset were synchronized within +/-10 ms across all cortical layers, suggesting that any layer could initiate firing at up-state onset. These findings provide strong direct experimental evidence that slow wave activity in humans is characterized by hyperpolarizing currents associated with suppressed cell firing, alternating with high levels of oscillatory synaptic/transmembrane activity associated with increased cell firing. Our results emphasize the major involvement of supragranular layers in the genesis of slow wave activity. LA - English DB - MTMT ER - TY - JOUR AU - Cash, SS AU - Halgren, E AU - Dehghani, N AU - Rossetti, AO AU - Thesen, T AU - Wang, C AU - Devinsky, O AU - Kuzniecky, R AU - Doyle, W AU - Madsen, JR AU - Bromfield, E AU - Erőss, Loránd AU - Halász, Péter AU - Karmos, György AU - Csercsa, Richárd AU - Wittner, Lucia AU - Ulbert, István TI - The human K-complex represents an isolated cortical down-state. JF - SCIENCE J2 - SCIENCE VL - 324 PY - 2009 IS - 5930 SP - 1084 EP - 1087 PG - 4 SN - 0036-8075 DO - 10.1126/science.1169626 UR - https://m2.mtmt.hu/api/publication/1234812 ID - 1234812 AB - The electroencephalogram (EEG) is a mainstay of clinical neurology and is tightly correlated with brain function, but the specific currents generating human EEG elements remain poorly specified because of a lack of microphysiological recordings. The largest event in healthy human EEGs is the K- complex (KC), which occurs in slow-wave sleep. Here, we show that KCs are generated in widespread cortical areas by outward dendritic currents in the middle and upper cortical layers, accompanied by decreased broadband EEG power and decreased neuronal firing, which demonstrate a steep decline in network activity. Thus, KCs are isolated "down-states," a fundamental cortico-thalamic processing mode already characterized in animals. This correspondence is compatible with proposed contributions of the KC to sleep preservation and memory consolidation. LA - English DB - MTMT ER - TY - JOUR AU - Erőss, Loránd AU - Bagó, Attila György AU - Entz, László AU - Fabó, Dániel AU - Halász, Péter AU - Balogh, Attila AU - Fedorcsák, Imre TI - Neuronavigation and fluoroscopy-assisted subdural strip electrode positioning: a simple method to increase intraoperative accuracy of strip localization in epilepsy surgery JF - JOURNAL OF NEUROSURGERY J2 - J NEUROSURG VL - 110 PY - 2009 IS - 2 SP - 327 EP - 331 PG - 5 SN - 0022-3085 DO - 10.3171/2008.6.JNS17611 UR - https://m2.mtmt.hu/api/publication/208107 ID - 208107 LA - English DB - MTMT ER -