TY - JOUR AU - Szőnyi, András AU - Sós, Katalin Eszter AU - Nyilas, Rita AU - Schlingloff, Dániel AU - Domonkos, Andor AU - Tresóné Takács, Virág AU - Pósfai, Balázs AU - Hegedüs, Panna AU - Priestley, James B. AU - Gundlach, Andrew L. AU - Gulyás, Attila AU - Varga, Viktor AU - Losonczy, Attila AU - Freund, Tamás AU - Nyíri, Gábor TI - Brainstem nucleus incertus controls contextual memory formation JF - SCIENCE J2 - SCIENCE VL - 364 PY - 2019 IS - 6442 PG - 13 SN - 0036-8075 DO - 10.1126/science.aaw0445 UR - https://m2.mtmt.hu/api/publication/30725513 ID - 30725513 AB - Hippocampal pyramidal cells encode memory engrams, which guide adaptive behavior. Selection of engram-forming cells is regulated by somatostatin-positive dendrite-targeting interneurons, which inhibit pyramidal cells that are not required for memory formation. Here, we found that gamma-aminobutyric acid ( GABA)-releasing neurons of the mouse nucleus incertus (NI) selectively inhibit somatostatin-positive interneurons in the hippocampus, both monosynaptically and indirectly through the inhibition of their subcortical excitatory inputs. We demonstrated that NI GABAergic neurons receive monosynaptic inputs from brain areas processing important environmental information, and their hippocampal projections are strongly activated by salient environmental inputs in vivo. Optogenetic manipulations of NI GABAergic neurons can shift hippocampal network state and bidirectionally modify the strength of contextual fear memory formation. Our results indicate that brainstem NI GABAergic cells are essential for controlling contextual memories. LA - English DB - MTMT ER - TY - JOUR AU - Losonczy, Attila AU - Bíró, Ágota AU - Nusser, Zoltán TI - Persistently active cannabinoid receptors mute a subpopulation of hippocampal interneurons JF - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA J2 - P NATL ACAD SCI USA VL - 101 PY - 2004 SP - 1362 EP - 1367 PG - 6 SN - 0027-8424 DO - 10.1073/pnas.0304752101 UR - https://m2.mtmt.hu/api/publication/109461 ID - 109461 LA - English DB - MTMT ER - TY - JOUR AU - Ábrahám, Hajnalka AU - Losonczy, Attila AU - Czéh, Gábor AU - Lázár, Gyula TI - Potassium channel blockers tetraethylammonium and 4-aminopyridine fail to prevent microglial activation induced by elevated potassium concentration. JF - ACTA BIOLOGICA HUNGARICA (1983-2018) J2 - ACTA BIOL HUNG VL - 54 PY - 2003 IS - 1 SP - 63 EP - 78 PG - 16 SN - 0236-5383 DO - 10.1556/ABiol.54.2003.1.7 UR - https://m2.mtmt.hu/api/publication/1006362 ID - 1006362 N1 - Export Date: 27 January 2024; CODEN: ABHUE AB - The effect of potassium channel blocker tetraethylammonium and 4-aminopyridine was examined on the elevated K+ concentration-induced microglial activation on rat hippocampal slice preparations. Microglial cells were detected by immunohistochemisty with a monoclonal antibody (OX 42) raised against a type 3 complement receptor. During activation the morphology of the microglial cells changes and the staining intensity increases. The degree of microglial activation was determined by measuring the integrated optical density of the cells. Tetraethylammonium and 4-aminopyridine failed to reduce the elevated K+ concentration-induced microglial activation. Both potassium channel blockers, when applied on the hippocampal slices without K+, caused significantly increased microglial activation as compared to the control slices. In order to check whether the functional alteration of the neuronal population induced by 4-aminopyridine caused the activation of the microglial cells, Schaffer collaterals were cut to block spreading of epileptiform hyperactivity of the CA3 pyramidal cells to the CA1 region. No significant differences were found in microglial activation between the CA3 and CA1 regions, indicating that the effect of 4-aminopyridine on microglial cells is independent of the epileptiform activity caused by the drug. LA - English DB - MTMT ER - TY - JOUR AU - Losonczy, Attila AU - Somogyi, Péter Pál AU - Nusser, Zoltán TI - Reduction of excitatory postsynaptic responses by persistently active metabotropic glutamate receptors in the hippocampus JF - JOURNAL OF NEUROPHYSIOLOGY J2 - J NEUROPHYSIOL VL - 89 PY - 2003 SP - 1910 EP - 1919 PG - 10 SN - 0022-3077 DO - 10.1152/jn.00842.2002 UR - https://m2.mtmt.hu/api/publication/109255 ID - 109255 LA - English DB - MTMT ER - TY - JOUR AU - Losonczy, Attila AU - Zhang, L AU - Shigemoto, R AU - Somogyi, Péter Pál AU - Nusser, Zoltán TI - Cell type dependence and variability in the short-term plasticity of EPSCs in identified mouse hippocampal interneurones JF - JOURNAL OF PHYSIOLOGY-LONDON J2 - J PHYSIOL-LONDON VL - 542 PY - 2002 SP - 193 EP - 210 PG - 18 SN - 0022-3751 DO - 10.1113/jphysiol.2002.020024 UR - https://m2.mtmt.hu/api/publication/109138 ID - 109138 LA - English DB - MTMT ER - TY - JOUR AU - Ábrahám, Hajnalka AU - Losonczy, Attila AU - Czéh, Gábor AU - Lázár, Gyula TI - Rapid activation of microglial cells by hypoxia, kainic acid, and potassium ions in slice preparations of the rat hippocampus. JF - BRAIN RESEARCH J2 - BRAIN RES VL - 906 PY - 2001 IS - 1-2 SP - 115 EP - 126 PG - 12 SN - 0006-8993 DO - 10.1016/S0006-8993(01)02569-0 UR - https://m2.mtmt.hu/api/publication/1006448 ID - 1006448 AB - Microglial activation induced by hypoxia, kainic acid and elevated potassium concentration, all of which alter neuronal function, was studied in hippocampal slices. The activation of microglia was detected by immunostaining with a monoclonal antibody (OX-42) raised against a type 3 complement receptor (CD11b). During activation the phenotype of microglia changes and the intensity of staining of individual cells increases. Oxygen deprivation depressed the focal responses of CA1 neurons to stratum radiatum volleys. Microglial activation was time dependent. Ten minute hypoxia caused mild activation, and after 20 min, a strong microglial reaction could be observed. Although neuronal function returned during reoxygenation, the morphological signs of microglial activation remained. Epileptiform activity of hippocampal neurons, followed by depression, was induced by application of 0.5 mM kainic acid, in a time and dose dependent manner. Washing out kainic acid did not alter microglial reaction. Elevated concentrations of potassium ions induced microglial changes similar to those induced by hypoxia and kainic acid. It is therefore suggested that an elevated extracellular potassium ion concentration may be the common factor in microglial activation observed in these experiments since this is raised both in hypoxia and under the effect of excitotoxins. LA - English DB - MTMT ER - TY - JOUR AU - Losonczy, Attila AU - Ábrahám, Hajnalka AU - Czéh, Gábor AU - Seress, László TI - Development of mossy cells in the rat dentate hilus JF - JOURNAL OF PHYSIOLOGY-LONDON J2 - J PHYSIOL-LONDON VL - 526 PY - 2000 IS - Suppl. SP - 63P EP - 64P SN - 0022-3751 UR - https://m2.mtmt.hu/api/publication/1579836 ID - 1579836 LA - English DB - MTMT ER - TY - JOUR AU - Losonczy, Attila AU - Ábrahám, Hajnalka AU - Czéh, Gábor AU - Seress, László TI - Development of mossy cells in the rat dentate hilus JF - EUROPEAN JOURNAL OF NEUROSCIENCE J2 - EUR J NEUROSCI VL - 12 PY - 2000 SP - 160 EP - 160 PG - 1 SN - 0953-816X UR - https://m2.mtmt.hu/api/publication/1411489 ID - 1411489 LA - English DB - MTMT ER - TY - JOUR AU - Losonczy, Attila AU - Ábrahám, Hajnalka AU - Czéh, Gábor AU - Seress, László TI - Postnatal development of CA3 pyramidal and hilar mossy cells using combined intracellular recording and filling techniques. JF - EUROPEAN JOURNAL OF NEUROSCIENCE J2 - EUR J NEUROSCI VL - 11 PY - 2000 SP - 160 SN - 0953-816X UR - https://m2.mtmt.hu/api/publication/1008736 ID - 1008736 LA - English DB - MTMT ER - TY - GEN AU - Losonczy, Attila AU - Ábrahám, Hajnalka AU - Czéh, Gábor AU - Lázár, Gyula TI - The mechanism of microglial activation studied on rat hippocampal slices exposed to elevated concentration of potassium and 4-aminopyridine. PY - 1999 UR - https://m2.mtmt.hu/api/publication/1008749 ID - 1008749 LA - English DB - MTMT ER -