TY - JOUR AU - Schomburg, EW AU - Fernandez-Ruiz, A AU - Mizuseki, K AU - Berényi, Antal AU - Anastassiou, CA AU - Koch, C AU - Buzsaki, G TI - Theta Phase Segregation of Input-Specific Gamma Patterns in Entorhinal-Hippocampal Networks. JF - NEURON J2 - NEURON VL - 84 PY - 2014 SP - 470 EP - 485 PG - 16 SN - 0896-6273 DO - 10.1016/j.neuron.2014.08.051 UR - https://m2.mtmt.hu/api/publication/2782611 ID - 2782611 AB - Precisely how rhythms support neuronal communication remains obscure. We investigated interregional coordination of gamma oscillations using high-density electrophysiological recordings in the rat hippocampus and entorhinal cortex. We found that 30-80 Hz gamma dominated CA1 local field potentials (LFPs) on the descending phase of CA1 theta waves during navigation, with 60-120 Hz gamma at the theta peak. These signals corresponded to CA3 and entorhinal input, respectively. Above 50 Hz, interregional phase-synchronization of principal cell spikes occurred mostly for LFPs in the axonal target domain. CA1 pyramidal cells were phase-locked mainly to fast gamma (>100 Hz) LFP patterns restricted to CA1, which were strongest at the theta trough. While theta phase coordination of spiking across entorhinal-hippocampal regions depended on memory demands, LFP gamma patterns below 100 Hz in the hippocampus were consistently layer specific and largely reflected afferent activity. Gamma synchronization as a mechanism for interregional communication thus rapidly loses efficacy at higher frequencies. LA - English DB - MTMT ER - TY - JOUR AU - Varga, Edina AU - Juhász, Gábor AU - Bozsó, Zsolt AU - Penke, Botond AU - Fülöp, Lívia AU - Szegedi, Viktor TI - Abeta(1-42) Enhances Neuronal Excitability in the CA1 via NR2B Subunit-Containing NMDA Receptors JF - NEURAL PLASTICITY J2 - NEURAL PLAST VL - 2014 PY - 2014 PG - 12 SN - 2090-5904 DO - 10.1155/2014/584314 UR - https://m2.mtmt.hu/api/publication/2755870 ID - 2755870 AB - Neuronal hyperexcitability is a phenomenon associated with early Alzheimer's disease. The underlying mechanism is considered to involve excessive activation of glutamate receptors; however, the exact molecular pathway remains to be determined. Extracellular recording from the CA1 of hippocampal slices is a long-standing standard for a range of studies both in basic research and in neuropharmacology. Evoked field potentials (fEPSPs) are regarded as the input, while spiking rate is regarded as the output of the neuronal network; however, the relationship between these two phenomena is not fully clear. We investigated the relationship between spontaneous spiking and evoked fEPSPs using mouse hippocampal slices. Blocking AMPA receptors (AMPARs) with CNQX abolished fEPSPs, but left firing rate unchanged. NMDA receptor (NMDAR) blockade with MK801 decreased neuronal spiking dose dependently without altering fEPSPs. Activating NMDARs by small concentration of NMDA induced a trend of increased firing. These results suggest that fEPSPs are mediated by synaptic activation of AMPARs, while spontaneous firing is regulated by the activation of extrasynaptic NMDARs. Synaptotoxic Abeta(1-42) increased firing activity without modifying evoked fEPSPs. This hyperexcitation was prevented by ifenprodil, an antagonist of the NR2B NMDARs. Overall, these results suggest that Abeta(1-42) induced neuronal overactivity is not dependent on AMPARs but requires NR2B. LA - English DB - MTMT ER - TY - JOUR AU - Scott, L AU - Feng, J AU - Kiss, Tamás AU - Needle, E AU - Atchison, K AU - Kawabe, TT AU - Milici, AJ AU - Hajos-Korcsok, E AU - Riddell, D AU - Hajos, M TI - Age-dependent disruption in hippocampal theta oscillation in amyloid-beta overproducing transgenic mice JF - NEUROBIOLOGY OF AGING: AGE-RELATED PHENOMENA NEURODEGENERATION AND NEUROPATHOLOGY J2 - NEUROBIOL AGING VL - 33 PY - 2012 IS - 7 SP - 1481.e13 EP - 1481.e23 PG - 10 SN - 0197-4580 DO - 10.1016/j.neurobiolaging.2011.12.010 UR - https://m2.mtmt.hu/api/publication/2783420 ID - 2783420 LA - English DB - MTMT ER - TY - JOUR AU - Minkeviciene, R AU - Rheims, S AU - Dobszay, Márton Benedek AU - Zilberter, M AU - Hartikainen, J AU - Fülöp, Lívia AU - Penke, Botond AU - Zilberter, Y AU - Harkany, T AU - Pitkanen, A AU - Tanila, H TI - Amyloid beta-Induced Neuronal Hyperexcitability Triggers Progressive Epilepsy JF - JOURNAL OF NEUROSCIENCE J2 - J NEUROSCI VL - 29 PY - 2009 IS - 11 SP - 3453 EP - 3462 PG - 10 SN - 0270-6474 DO - 10.1523/JNEUROSCI.5215-08.2009 UR - https://m2.mtmt.hu/api/publication/246935 ID - 246935 AB - Alzheimer's disease is associated with an increased risk of unprovoked seizures. However, the underlying mechanisms of seizure induction remain elusive. Here, we performed video-EEG recordings in mice carrying mutant human APPswe and PS1dE9 genes (APdE9 mice) and their wild-type littermates to determine the prevalence of unprovoked seizures. In two recording episodes at the onset of amyloid beta (A beta) pathogenesis (3 and 4.5 months of age), at least one unprovoked seizure was detected in 65% of APdE9 mice, of which 46% had multiple seizures and 38% had a generalized seizure. None of the wild-type mice had seizures. In a subset of APdE9 mice, seizure phenotype was associated with a loss of calbindin-D28k immunoreactivity in dentate granular cells and ectopic expression of neuropeptide Y in mossy fibers. In APdE9 mice, persistently decreased resting membrane potential in neocortical layer 2/3 pyramidal cells and dentate granule cells underpinned increased network excitability as identified by patch-clamp electrophysiology. At stimulus strengths evoking single-component EPSPs in wild-type littermates, APdE9 mice exhibited decreased action potential threshold and burst firing of pyramidal cells. Bath application (1h) of A beta 1-42 or A beta 25-35 (proto-) fibrils but not oligomers induced significant membrane depolarization of pyramidal cells and increased the activity of excitatory cell populations as measured by extracellular field recordings in the juvenile rodent brain, confirming the pathogenic significance of bath-applied A beta(proto-) fibrils. Overall, these data identify fibrillar A beta as a pathogenic entity powerfully altering neuronal membrane properties such that hyperexcitability of pyramidal cells culminates in epileptiform activity. LA - English DB - MTMT ER - TY - JOUR AU - Czigler, Balázs AU - Csikós, Dóra AU - Hidasi, Zoltán AU - Gaál, Zsófia Anna AU - Csibri, É AU - Kiss, É AU - Salacz, Pál AU - Molnár, Márk TI - Quantitative EEG in early Alzheimer's patients - power spectrum and complexity features JF - INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY J2 - INT J PSYCHOPHYSIOL VL - 68 PY - 2008 IS - 1 SP - 75 EP - 80 PG - 6 SN - 0167-8760 DO - 10.1016/j.ijpsycho.2007.11.002 UR - https://m2.mtmt.hu/api/publication/207985 ID - 207985 LA - English DB - MTMT ER - TY - JOUR AU - Arabadzisz, D AU - Antal, Károly AU - Parpan, F AU - Emri, Zsuzsa AU - Fritschy, JM TI - Epileptogenesis and chronic seizures in a mouse model of temporal lobe epilepsy are associated with distinct EEG patterns and selective neurochemical alterations in the contralateral hippocampus JF - EXPERIMENTAL NEUROLOGY J2 - EXP NEUROL VL - 194 PY - 2005 IS - 1 SP - 76 EP - 90 PG - 15 SN - 0014-4886 DO - 10.1016/j.expneurol.2005.01.029 UR - https://m2.mtmt.hu/api/publication/112923 ID - 112923 N1 - [049/2005] Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland Department of Neurochemistry, Chemical Research Center, Budapest, Hungary Cited By :98 Export Date: 6 April 2021 CODEN: EXNEA Correspondence Address: Fritschy, J.-M.; Institute of Pharmacology and Toxicology, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; email: fritschy@pharma.unizh.ch Chemicals/CAS: galanin, 88813-36-9; glutamic acid, 11070-68-1, 138-15-8, 56-86-0, 6899-05-4; kainic acid, 487-79-6; neuropeptide Y, 82785-45-3, 83589-17-7; calbindin; Calcium-Binding Protein, Vitamin D-Dependent; Galanin, 88813-36-9; Kainic Acid, 487-79-6; Neuropeptide Y; Neurotoxins; Sincalide, 25126-32-3 Funding details: QLK2-CT-2002-90436 Funding details: Magyar Tudományos Akadémia, MTA Funding text 1: This study was supported by the National Center of Competence in Research in Neuroscience (NCCR-Neuro) and the Center of Excellence on Biomolecular Chemistry (Project CBCH, QLK2-CT-2002-90436). Zs. Emri was supported by grant János Bolyai of Hungarian Academy of Sciences. We are grateful to Corinne Sidler and Karl Wüthrich for excellent technical assistance, to Dr. Véronique Riban for help with the EEG recordings, and to Dr. Jozsef Janszky for stimulating discussions. LA - English DB - MTMT ER - TY - JOUR AU - Buzsáki, György AU - Buhl, D L AU - Harris, K D AU - Csicsvari, J AU - Czéh, Boldizsár AU - Morozov, A TI - Hippocampal network patterns of activity in the mouse JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 116 PY - 2003 IS - 1 SP - 201 EP - 211 PG - 11 SN - 0306-4522 DO - 10.1016/S0306-4522(02)00669-3 UR - https://m2.mtmt.hu/api/publication/1486567 ID - 1486567 AB - Genetic engineering of the mouse brain allows investigators to address novel hypotheses in vivo. Because of the paucity of information on the network patterns of the mouse hippocampus, we investigated the electrical patterns in the behaving animal using multisite silicon probes and wire tetrodes. Theta (6-9 Hz) and gamma (40-100 Hz) oscillations were present during exploration and rapid eye movement sleep. Gamma power and theta power were comodulated and gamma power varied as a function of the theta cycle. Pyramidal cells and putative interneurons were phase-locked to theta oscillations. During immobility, consummatory behaviors and slow-wave sleep, sharp waves were present in cornu ammonis region CA1 of the hippocampus stratum radiatum associated with 140-200-Hz "ripples" in the pyramidal cell layer and population burst of CA1 neurons. In the hilus, large-amplitude "dentate spikes" occurred in association with increased discharge of hilar neurons. The amplitude of field patterns was larger in the mouse than in the rat, likely reflecting the higher neuron density in a smaller brain. We suggest that the main hippocampal network patterns are mediated by similar pathways and mechanisms in mouse and rat. © 2003 IBRO. Published by Elsevier Science Ltd. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - BRAGIN, A AU - Jandó, Gábor AU - Nádasdy, Zoltán AU - HETKE, J AU - WISE, K AU - Buzsáki, György TI - GAMMA (40-100-HZ) OSCILLATION IN THE HIPPOCAMPUS OF THE BEHAVING RAT JF - JOURNAL OF NEUROSCIENCE J2 - J NEUROSCI VL - 15 PY - 1995 IS - 1 SP - 47 EP - 60 PG - 14 SN - 0270-6474 DO - 10.1523/jneurosci.15-01-00047.1995 UR - https://m2.mtmt.hu/api/publication/1428428 ID - 1428428 AB - The cellular generation and spatial distribution of gamma frequency (40-100 Hz) activity was examined in the hippocampus of the awake rat. Field potentials and unit activity were recorded by multiple site silicon probes (5- and 16-site shanks) and wire electrode arrays. Gamma waves were highly coherent along the long axis of the dentate hilus, but average coherence decreased rapidly in the CA3 and CA1 directions. Analysis of short epochs revealed large fluctuations in coherence values between the dentate and CA1 gamma waves, Current source density analysis revealed large sinks and sources in the dentate gyrus with spatial distribution similar to the dipoles evoked by stimulation of the perforant path, The frequency changes of gamma and theta waves positively correlated (40-100 Hz and 5-10 Hz, respectively), Putative interneurons in the dentate gyrus discharged at gamma frequency and were phase-locked to the ascending part of the gamma waves recorded from the hilus, Following bilateral lesion of the entorhinal cortex the power and frequency of hilar gamma activity significantly decreased or disappeared. Instead, a large amplitude but slower gamma pattern (25-50 Hz) emerged in the CA3-CA1 network, We suggest that gamma oscillation emerges from an interaction between intrinsic oscillatory properties of interneurons and the network properties of the dentate gyrus. We also hypothesize that under physiological conditions the hilar gamma oscillation may be entrained by the entorhinal rhythm and that gamma oscillation in the CA3-CA1 circuitry is suppressed by either the hilar region or the entorhinal cortex. LA - English DB - MTMT ER - TY - JOUR AU - Soltesz, Ivan AU - DESCHENES, M TI - LOW-FREQUENCY AND HIGH-FREQUENCY MEMBRANE-POTENTIAL OSCILLATIONS DURING THETA ACTIVITY IN CA1 AND CA3 PYRAMIDAL NEURONS OF THE RAT HIPPOCAMPUS UNDER KETAMINE-XYLAZINE ANESTHESIA JF - JOURNAL OF NEUROPHYSIOLOGY J2 - J NEUROPHYSIOL VL - 70 PY - 1993 IS - 1 SP - 97 EP - 116 PG - 20 SN - 0022-3077 DO - 10.1152/jn.1993.70.1.97 UR - https://m2.mtmt.hu/api/publication/2941583 ID - 2941583 AB - 1. Intracellularly recorded low- and high-frequency (4-6 and 25-50 Hz, respectively), rhythmic, spontaneous membrane potential oscillations were investigated in pyramidal neurons of the rat hippocampus in vivo, during theta(THETA, 4-6 Hz)electroencephalographic (EEG) activity, under ketamine-xylazine anesthesia. 2. The EEG activity showed two spectral peaks, one in the THETA range. the other at higher frequencies (25-50 Hz). On the basis of their electrophysiological and pharmacological properties, it was concluded that the EEG THETA-waves, and the fast EEG rhythm, recorded during ketamine-xylazine anesthesia, share the basic properties of those THETA and fast rhythms that are recorded under the effects of other types of anesthetics. 3. When intracellular recordings (n = 32) were made with electrodes filled with potassium-acetate (K-acetate), the only CA1 and CA3 pyramidal cells (PCs) considered for further analysis were those that did not fire rhythmically at most or each cycle of the THETA rhythm at the resting membrane potential. During EEG-THETA, the membrane potential (V(m)) of these cells showed a prominent oscillation (3-15 mV) with frequencies similar to those of the EEG-THETA (the intracellular THETA rhythm, intra-THETA). 4. The frequency of the intra-THETA was independent of the V(m). However, the phase difference between the intra-THETA and the EEG-THETA was voltage dependent in both types of cells. CA1 PCs showed a large ( 120-180-degrees, where 360-degrees is the full cycle), gradual shift in the phase difference between the intra-THETA and the EEG-THETA, when the membrane was hyperpolarized to -85 from -65 mV. Although CA3 PCs displayed a larger variability in their phase-voltage relations. a voltage-dependent phase shift (90-180-degrees) could be observed in CA3 PCs as well. 5. Although the amplitude of the intra-THETA in both CA1 and CA3 PCs could display large, sudden, spontaneous changes at a given V(m), the amplitude-V(m) plots tended to show a minimum between -70 and -80 mV. Spontaneous changes in the amplitude of the intra-THETA did not affect the phase difference between the intra- and the EEG-THETA rhythms. 6. Intracellular injection of QX-314 (50-100 mM) did not change the phase-V(m) or the amplitude-V(m) relationships of CA1 PCs. 7. Intracellular injection of chloride (Cl-) ions greatly reduced the voltage dependency of the phase difference and revealed fast (duration: 20-25 ms), depolarizing potentials (5-20 mV), which appeared at high frequencies (25-50 Hz), amplitude modulated at THETA-frequencies. 8. These findings are consistent with the hypothesis that rhythmic, high-frequency, gamma-aminobutyric acid-A (GABA(A))-receptor-mediated inhibitory postsynaptic potentials have an important role in the generation of both the THETA and the fast hippocampal rhythms. LA - English DB - MTMT ER -