TY - JOUR AU - COBB, SR AU - BUHL, EH AU - Halasy, Katalin AU - PAULSEN, O AU - Somogyi, Péter Pál TI - SYNCHRONIZATION OF NEURONAL-ACTIVITY IN HIPPOCAMPUS BY INDIVIDUAL GABAERGIC INTERNEURONS JF - NATURE J2 - NATURE VL - 378 PY - 1995 IS - 6552 SP - 75 EP - 78 PG - 4 SN - 0028-0836 DO - 10.1038/378075a0 UR - https://m2.mtmt.hu/api/publication/1661000 ID - 1661000 N1 - MRC Anatomical Neuropharmacology Unit, University Department of Pharmacology, Mansfield Road, Oxford, OX1 3TH, United Kingdom Department of Zoology & Cell Biology, Jozsef Attila University, Szeged, H-6722, Hungary Cited By :1114 Export Date: 6 April 2021 Chemicals/CAS: 4 aminobutyric acid, 28805-76-7, 56-12-2; gamma-Aminobutyric Acid, 56-12-2; Receptors, GABA-A AB - SYNCHRONIZATION Of neuronal activity is fundamental in the operation of cortical networks(1). With respect to an ongoing synchronized oscillation, the precise timing of action potentials is an attractive candidate mechanism for information coding(2-5) Networks of inhibitory interneurons have been proposed to have a role in entraining cortical, synchronized 40-Hz activity(6,7). Here we demonstrate that individual GABAergic interneurons(8) can effectively phase spontaneous firing and subthreshold oscillations in hippocampal pyramidal cells at theta frequencies (4-7 Hz). The efficiency of this entrainment is due to interaction of GABA(A)-receptor-mediated hyperpolarizing synaptic events with intrinsic oscillatory mechanisms tuned to this frequency range in pyramidal cells. Moreover, this GABAergic mechanism is sufficient to synchronize the firing of pyramidal cells. Thus, owing to the divergence of each GABAergic interneuron(9,10), more than a thousand pyramidal cells may share a common temporal reference established by an individual interneuron. LA - English DB - MTMT ER - TY - JOUR AU - Buhl, EH AU - Han, ZS AU - Lőrinczi, Zoltán AU - Stezhka, VV AU - Karnup, SV AU - Somogyi, Péter Pál TI - Physiological properties of anatomically identified axo-axonic cells in the rat hippocampus. JF - JOURNAL OF NEUROPHYSIOLOGY J2 - J NEUROPHYSIOL VL - 71 PY - 1994 IS - 4 SP - 1289 EP - 1307 PG - 19 SN - 0022-3077 UR - https://m2.mtmt.hu/api/publication/2138103 ID - 2138103 AB - 1. The properties of a well-defined type of GABAergic local circuit neuron, the axo-axonic cell (n = 17), were investigated in rat hippocampal slice preparations. During intracellular recording we injected axo-axonic cells with biocytin and subsequently identified them with correlated light and electron microscopy. Employing an immunogold-silver intensification technique we showed that one of the physiologically characterized cells was immunoreactive for gamma-aminobutyric acid (GABA). 2. Axo-axonic cells were encountered in the dentate gyrus (n = 5) as well as subfields CA3 (n = 2) and CA1 (n = 10). They generally had smooth, beaded dendrites that extended throughout all hippocampal layers. Their axons ramified densely in the cell body layers and in the subjacent stratum oriens or hilus, respectively. Tested with electron microscopy, labeled terminals (n = 53) established synapses exclusively with the axon initial segment of principal cells in strata oriens and pyramidale and rarely in lower radiatum. Within a 400-microns slice a single CA1 axo-axonic cell was estimated to be in synaptic contact with 686 pyramidal cells. 3. Axo-axonic cells (n = 14) had a mean resting membrane potential of -65.1 mV, an average input resistance of 73.9 M omega, and a mean time constant of 7.7 ms. Action potentials were of short duration (389-microseconds width at half-amplitude) and had a mean amplitude of 64.1 mV. 4. Nine of 10 tested cells showed a varying degree of spike frequency adaptation in response to depolarizing current injection. Current-evoked action potentials were usually curtailed by a deep (10.2 mV) short-latency afterhyperpolarization (AHP) with a mean duration of 28.1 ms. 5. Cells with strong spike frequency accommodation (n = 5) had a characteristic firing pattern with numerous spike doublets. These appeared to be triggered by an underlying depolarizing afterpotential. In the same cells, prolonged bursts of action potentials were followed by a prominent long-duration AHP with a mean time constant of 1.15 s. 6. Axo-axonic cells responded to the stimulation of afferent pathways with short-latency excitatory postsynaptic potentials (EPSPs) or at higher stimulation intensity with up to three action potentials. Axo-axonic cells in the dentate gyrus could be activated by stimulating the CA3 area as well as the perforant path, whereas in the CA1 area responses were elicited after shocks to the perforant path, Schaffer collaterals, and the stratum oriens-alveus border. 7. In the CA1 area the EPSP amplitude increased in response to membrane hyperpolarization.(ABSTRACT TRUNCATED AT 400 WORDS) LA - English DB - MTMT ER - TY - JOUR AU - Gulyás, Attila AU - Miles, R AU - Hájos, Norbert AU - Freund, Tamás TI - Precision and variability in postsynaptic target selection of inhibitory cells in the hippocampal CA3 region JF - EUROPEAN JOURNAL OF NEUROSCIENCE J2 - EUR J NEUROSCI VL - 5 PY - 1993 IS - 12 SP - 1729 EP - 1751 PG - 23 SN - 0953-816X DO - 10.1111/j.1460-9568.1993.tb00240.x UR - https://m2.mtmt.hu/api/publication/107599 ID - 107599 N1 - Institute of Experimental Medicine, Hungarian Academy of Sciences, PO Box 67, Budapest, H-1450, Hungary Laboratoire de Neurobiologie Cellulaire, Institut Pasteur, INSERM U261, 25 Rue de Dr Roux, Paris, 75264, France Cited By :180 Export Date: 6 April 2021 Correspondence Address: Freund, T.F. Chemicals/CAS: biocytin, 576-19-2; Lysine, 56-87-1 Institute of Experimental Medicine, Hungarian Academy of Sciences, PO Box 67, Budapest, H-1450, Hungary Laboratoire de Neurobiologie Cellulaire, Institut Pasteur, INSERM U261, 25 Rue de Dr Roux, Paris, 75264, France Cited By :180 Export Date: 7 April 2021 Correspondence Address: Freund, T.F. Chemicals/CAS: biocytin, 576-19-2; Lysine, 56-87-1 LA - English DB - MTMT ER - TY - JOUR AU - Sík, Attila AU - Tamamaki, N AU - Freund, Tamás TI - Complete axon arborization of a single CA3 pyramidal cell in the rat hippocampus, and its relationship with postsynaptic parvalbumin-containing interneurons JF - EUROPEAN JOURNAL OF NEUROSCIENCE J2 - EUR J NEUROSCI VL - 5 PY - 1993 SP - 1719 EP - 1728 PG - 10 SN - 0953-816X DO - 10.1111/j.1460-9568.1993.tb00239.x UR - https://m2.mtmt.hu/api/publication/107588 ID - 107588 LA - English DB - MTMT ER - TY - JOUR AU - Kisvárday, Zoltán AU - Eysel, UT TI - Cellular organization of reciprocal patchy networks in layer III of cat visual cortex (area 17). JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 46 PY - 1992 IS - 2 SP - 275 EP - 286 PG - 12 SN - 0306-4522 DO - 10.1016/0306-4522(92)90050-C UR - https://m2.mtmt.hu/api/publication/2379170 ID - 2379170 N1 - Hiányzó Besorolás: 'Journal Article\n\nResearch Support, Non-U.S. Gov\'t',24 AB - There is no direct information available concerning the exact spatial characteristics of long-range axons and their relationship with the patchy phenomena observed after extracellular injection of retrograde tracers. In the present study, using the recently introduced neuronal tracer biocytin, we demonstrate by detailed three-dimensional reconstruction of 10 pyramidal cells in layer III, that their clustered axonal terminals form a specific patchy network in layers II and III. The reconstructed network occupied an area of 6.5 x 3.5 mm parallel to the cortical surface elongated in an anteroposterior direction. The average centre-to-centre distance between patches within the network was 1.1 mm. On average, the axonal field of each of the 10 pyramidal cells contained a total of 417 boutons at four to eight distinct sites (patches), and in each patch, an average of 79 boutons was provided by the same cell. The identified connections between the patches were predominantly reciprocal. Detailed analyses have shown that many pyramidal cells of the network are directly interconnected so that each of them can receive one to four, chiefly axospinous, contacts onto the distal segment of its apical and basal dendrites from the axon of another pyramidal cell belonging to a different patch labelled from the same injection site. We hypothesize that the possible functional role of the network is to link remote sites with similar physiological characteristics, such as orientation preference, supporting the model of Mitchison and Crick [(1982) Proc. natn. Acad. Sci. U.S.A. 79, 3661-3665]. LA - English DB - MTMT ER - TY - JOUR AU - Kisvárday, Zoltán AU - Martin, KAC AU - Freund, Tamás AU - Maglóczky, Zsófia AU - Whitteridge, D AU - Somogyi, Péter Pál TI - Synaptic targets of HRP-filled layer III pyramidal cells in the cat striate cortex JF - EXPERIMENTAL BRAIN RESEARCH J2 - EXP BRAIN RES VL - 64 PY - 1986 SP - 541 EP - 552 PG - 12 SN - 0014-4819 DO - 10.1007/BF00340492 UR - https://m2.mtmt.hu/api/publication/107535 ID - 107535 LA - English DB - MTMT ER - TY - JOUR AU - Freund, Tamás AU - Martin, KAC AU - Smith, AD AU - Somogyi, Péter Pál TI - Glutamate decarboxylase-immunoreactive terminals of Golgi-impregnated axoaxonic cells and of presumed basket cells in synaptic contact with pyramidal neurons of the cat's visual cortex JF - JOURNAL OF COMPARATIVE NEUROLOGY J2 - J COMP NEUROL VL - 221 PY - 1983 SP - 263 EP - 278 PG - 16 SN - 0021-9967 DO - 10.1002/cne.902210303 UR - https://m2.mtmt.hu/api/publication/107687 ID - 107687 N1 - Cited By :231 Export Date: 6 April 2021 Correspondence Address: Freund, T.F.; University Department of Pharmacology, Oxford, OX1 3QT, United Kingdom Chemicals/CAS: 4 aminobutyric acid, 28805-76-7, 56-12-2; glutamate decarboxylase, 9024-58-2; gamma-Aminobutyric Acid, 56-12-2; Glutamate Decarboxylase, EC 4.1.1.15 LA - English DB - MTMT ER - TY - JOUR AU - Martin, KA AU - Somogyi, Péter Pál AU - Whitteridge, D TI - Physiological and morphological properties of identified basket cells in the cat's visual cortex. JF - EXPERIMENTAL BRAIN RESEARCH J2 - EXP BRAIN RES VL - 50 PY - 1983 IS - 2-3 SP - 193 EP - 200 PG - 8 SN - 0014-4819 DO - 10.1007/BF00239183 UR - https://m2.mtmt.hu/api/publication/2138124 ID - 2138124 N1 - Cited By :127 Export Date: 6 April 2021 CODEN: EXBRA Correspondence Address: Martin, K.A.C.; Dept. of Experimental Psychology, South Parks Road, Oxford, OX1 3UD, United Kingdom AB - In 87 cells studied physiologically, and filled intracellularly with horseradish peroxidase (HRP), we have found four cells which make multiple contacts with the perikarya of their post-synaptic targets. These cells are all multipolar non-pyramidal neurones with elongated smooth dendrites. Three resemble the classical "basket cells" of Ramon y Cajal (1911), having widely distributed axons which contribute to the "nids pericellulaires" around pyramidal cell perikarya. The fourth cell has a much more restricted axon virtually confined to layer 4 and appears to contact principally small, probably non-pyramidal, cells. Two of the basket cell axons have been examined by electron microscopy and make symmetrical, Gray's type II contacts with the perikarya and apical and basal dendrites of pyramidal cells. Ten percent of the synapses are on dendrites of non-pyramidal cells. The axon arborizations of all four cells are distributed in a patchy fashion. In two cells examined for the purpose, very few boutons were found within 100 micron of the cell body and a radially aligned cylinder of the same diameter extending from the cell body to the pial surface. The physiological properties of these structurally similar cells are far from uniform. They can be activated mono- or polysynaptically, by X- or Y-type lateral geniculate input, and can have S or C type receptive fields. Two were activated, probably monosynaptically, via callosal afferents. These cells may play an important role in the inhibitory mechanisms of the cortex. LA - English DB - MTMT ER - TY - JOUR AU - Somogyi, Péter Pál AU - Freund, Tamás AU - Cowey, A TI - The axo-axonic interneuron in the cerebral cortex of the rat, cat and monkey JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 7 PY - 1982 SP - 2577 EP - 2607 PG - 31 SN - 0306-4522 DO - 10.1016/0306-4522(82)90086-0 UR - https://m2.mtmt.hu/api/publication/107680 ID - 107680 LA - English DB - MTMT ER - TY - JOUR AU - Somogyi, Péter Pál AU - Cowey, A AU - Halász, Norbert AU - Freund, Tamás TI - Vertical organization of neurons accumulating 3H GABA in the visual cortex of the rhesus monkey JF - NATURE J2 - NATURE VL - 294 PY - 1981 IS - 5843 SP - 761 EP - 763 PG - 3 SN - 0028-0836 DO - 10.1038/294761a0 UR - https://m2.mtmt.hu/api/publication/104933 ID - 104933 LA - English DB - MTMT ER - TY - JOUR AU - Somogyi, Péter Pál AU - Smith, AD TI - Projection of neostriatal spiny neurons to the substantia nigra. Application of a combined Golgi-staining and horseradish peroxidase transport procedure at both light and electron microscopic levels. JF - BRAIN RESEARCH J2 - BRAIN RES VL - 178 PY - 1979 IS - 1 SP - 3 EP - 15 PG - 13 SN - 0006-8993 DO - 10.1016/0006-8993(79)90084-2 UR - https://m2.mtmt.hu/api/publication/2138566 ID - 2138566 AB - One type of striatonigral neuron in the rat has been characterized. Golgi impregnation of striatal neurons that had been retrogradely labeled by horseradish peroxidase has shown that the medium-sized, densely spiny neurons project to the substantia nigra. Some of the synapses on three of these identified striatonigral neurons have been studied in the electron microscope following replacement of the Golgi deposit by means of the 'gold-toning' method. Synapsing axonal boutons were found on the following sites: soma and axon initial segment (symmetrical, with flattened or pleomorphic vesicles); primary and secondary dendritic shafts (symmetrical with pleomorphic vesicles); dendritic spines (asymmetrical, with spheroidal vesicles). These findings show that new information concerning neuronal connectivity can be obtained by combining three classical procedures in the same material: first, the Golgi method, that characterizes the type of neuron on the basis of its dendritic morphology; second, a retrograde tracing method, that identifies the projection area of the neuron; and, third, ultrastructural analysis of the nature of afferent terminals on the neuron. LA - English DB - MTMT ER - TY - JOUR AU - Somogyi, Péter Pál TI - The study of Golgi stained cells and of experimental degeneration under the electron microscope: a direct method for the identification in the visual cortex of three successive links in a neuron chain. JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 3 PY - 1978 IS - 2 SP - 167 EP - 180 PG - 14 SN - 0306-4522 DO - 10.1016/0306-4522(78)90099-4 UR - https://m2.mtmt.hu/api/publication/2138570 ID - 2138570 LA - English DB - MTMT ER - TY - JOUR AU - Somogyi, Péter Pál TI - A specific 'axo-axonal' interneuron in the visual cortex of the rat. JF - BRAIN RESEARCH J2 - BRAIN RES VL - 136 PY - 1977 IS - 2 SP - 345 EP - 350 PG - 6 SN - 0006-8993 DO - 10.1016/0006-8993(77)90808-3 UR - https://m2.mtmt.hu/api/publication/2138571 ID - 2138571 LA - English DB - MTMT ER -