TY - JOUR AU - Harris, K D AU - Henze, D A AU - Hirase, H AU - Leinekugel, X AU - Dragoi, G AU - Czurkó, András AU - Buzsáki, György TI - Spike train dynamics predicts theta-related phase precession in hippocampal pyramidal cells. JF - NATURE J2 - NATURE VL - 417 PY - 2002 IS - 6890 SP - 738 EP - 741 PG - 4 SN - 0028-0836 DO - 10.1038/nature00808 UR - https://m2.mtmt.hu/api/publication/1031123 ID - 1031123 AB - According to the temporal coding hypothesis, neurons encode information by the exact timing of spikes. An example of temporal coding is the hippocampal phase precession phenomenon, in which the timing of pyramidal cell spikes relative to the theta rhythm shows a unidirectional forward precession during spatial behaviour. Here we show that phase precession occurs in both spatial and non-spatial behaviours. We found that spike phase correlated with instantaneous discharge rate, and processed unidirectionally at high rates, regardless of behaviour. The spatial phase precession phenomenon is therefore a manifestation of a more fundamental principle governing the timing of pyramidal cell discharge. We suggest that intrinsic properties of pyramidal cells have a key role in determining spike times, and that the interplay between the magnitude of dendritic excitation and rhythmic inhibition of the somatic region is responsible for the phase assignment of spikes. LA - English DB - MTMT ER - TY - JOUR AU - Kiss, Tamás AU - Orbán, Gergő AU - Lengyel, M AU - Érdi, Péter TI - Intrahippocampal gamma and theta rhythm generation in a network model of inhibitory interneurons JF - NEUROCOMPUTING J2 - NEUROCOMPUTING VL - 38-40 PY - 2001 SP - 713 EP - 719 PG - 7 SN - 0925-2312 DO - 10.1016/S0925-2312(01)00358-7 UR - https://m2.mtmt.hu/api/publication/1228630 ID - 1228630 LA - English DB - MTMT ER - TY - JOUR AU - Orbán, Gergő AU - Kiss, Tamás AU - Lengyel, M AU - Érdi, Péter TI - Hippocampal rhythm generation: Gamma-related theta-frequency resonance in CA3 interneurons JF - BIOLOGICAL CYBERNETICS J2 - BIOL CYBERN VL - 84 PY - 2001 IS - 2 SP - 123 EP - 132 PG - 10 SN - 0340-1200 DO - 10.1007/s004220000199 UR - https://m2.mtmt.hu/api/publication/1228244 ID - 1228244 AB - During different behavioral states different population activities are present in the hippocampal formation. These activities are not independent: sharp waves often occur together with high-frequency ripples, and gamma-frequency activity is usually superimposed on theta oscillations. There is both experimental and theoretical evidence supporting the notion that gamma oscillation is generated intrahippocampally, but there is no generally accepted view about the origin of theta waves. Precise timing of population bursts of pyramidal cells may be due to a synchronized external drive. Membrane potential oscillations recorded in the septum are unlikely to fulfill this purpose because they are not coherent enough. We investigated the prospects of an intrahippocampal mechanism supplying pyramidal cells with theta frequency periodic inhibition, by studying a model of a network of hippocampal inhibitory interneurons. As shown previously, interneurons are capable of generating synchronized gamma-frequency action potential oscillations. Exciting the neurons by periodic current injection, the system could either be entrained in an oscillation with the frequency of the inducing current or exhibit in-phase periodic changes at the frequency of single cell (and network) activity. Simulations that used spatially inhomogeneous stimulus currents showed antiphase frequency changes across cells, which resulted in a periodic decrease in the synchrony of the network. As this periodic change in synchrony occurred in the theta frequency range, our network should be able to exhibit the theta-frequency weakening of inhibition of pyramidal cells, thus offering a possible mechanism for intrahippocampal theta generation. LA - English DB - MTMT ER - TY - JOUR AU - Csicsvari, J AU - Hirase, H AU - Czurkó, András AU - Mamiya, A AU - Buzsáki, György TI - Oscillatory coupling of hippocampal pyramidal cells and interneurons in the behaving Rat. JF - JOURNAL OF NEUROSCIENCE J2 - J NEUROSCI VL - 19 PY - 1999 IS - 1 SP - 274 EP - 287 PG - 14 SN - 0270-6474 DO - 10.1523/jneurosci.19-01-00274.1999 UR - https://m2.mtmt.hu/api/publication/1031133 ID - 1031133 AB - We examined whether excitation and inhibition are balanced in hippocampal cortical networks. Extracellular field and single-unit activity were recorded by multiple tetrodes and multisite silicon probes to reveal the timing of the activity of hippocampal CA1 pyramidal cells and classes of interneurons during theta waves and sharp wave burst (SPW)-associated field ripples. The somatic and dendritic inhibition of pyramidal cells was deduced from the activity of interneurons in the pyramidal layer [int(p)] and in the alveus and st. oriens [int(a/o)], respectively. Int(p) and int(a/o) discharged an average of 60 and 20 degrees before the population discharge of pyramidal cells during the theta cycle, respectively. SPW ripples were associated with a 2.5-fold net increase of excitation. The discharge frequency of int(a/o) increased, decreased ("anti-SPW" cells), or did not change ("SPW-independent" cells) during SPW, suggesting that not all interneurons are innervated by pyramidal cells. Int(p) either fired together with (unimodal cells) or both before and after (bimodal cells) the pyramidal cell burst. During fast-ripple oscillation, the activity of interneurons in both the int(p) and int(a/o) groups lagged the maximum discharge probability of pyramidal neurons by 1-2 msec. Network state changes, as reflected by field activity, covaried with changes in the spike train dynamics of single cells and their interactions. Summed activity of parallel-recorded interneurons, but not of pyramidal cells, reliably predicted theta cycles, whereas the reverse was true for the ripple cycles of SPWs. We suggest that network-driven excitability changes provide temporal windows of opportunity for single pyramidal cells to suppress, enable, or facilitate selective synaptic inputs. LA - English DB - MTMT ER - TY - JOUR AU - Katona, István AU - Acsády, László AU - Freund, Tamás TI - Postsynaptic targets of somatostatin-immunoreactive interneurons in the rat hippocampus JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 88 PY - 1999 IS - 1 SP - 37 EP - 55 PG - 19 SN - 0306-4522 DO - 10.1016/S0306-4522(98)00302-9 UR - https://m2.mtmt.hu/api/publication/108648 ID - 108648 N1 - Cited By :169 Export Date: 22 June 2023 CODEN: NRSCD Correspondence Address: Freund, T.F.; Institute of Experimental Medicine, P.O. Box 67, Budapest H-1450, Hungary Chemicals/CAS: gamma-Aminobutyric Acid, 56-12-2; Somatostatin, 51110-01-1 Funding details: Howard Hughes Medical Institute, HHMI Funding details: National Institute of Mental Health, NIMH, MH54671 Funding details: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, SNF Funding details: Hungarian Scientific Research Fund, OTKA, T16942 Funding text 1: We are grateful to Dr T. J. Görcs for antisera against somatostatin, vasoactive intestinal polypeptide and cholecystokinin, to Dr K. G. Baimbridge and to Dr J. H. Rogers for antisera against parvalbumin and calretinin, respectively, and to Dr P. Somogyi for antisera against GABA. The valuable discussions with Drs A. M. Thomson, Gy. Buzsáki, H. Markram and R. Miles concerning the activation of O-LM cells, and the time-course of back-propagating action potentials and disynaptic IPSPs are highly appreciated. The authors wish to thank for preparation of the colour figure Ms Á. L. Bodor. The excellent technical assistance of Mrs E. Borók, Mrs A. Zöldi Szabóné and Mr Gy. Goda is also acknowledged. This work was supported by the Howard Hughes Medical Institute, the Swiss National Science Foundation, NIMH (MH54671) and OTKA (T16942) Hungary. LA - English DB - MTMT ER - TY - JOUR AU - Kamondi, Anita AU - Acsády, László AU - Wang, XJ AU - Buzsáki, György TI - Theta oscillations in somata and dendrites of hippocampal pyramidal cells in vivo: activity-dependent phase-precession of action potentials JF - HIPPOCAMPUS J2 - HIPPOCAMPUS VL - 8 PY - 1998 IS - 3 SP - 244 EP - 261 PG - 18 SN - 1050-9631 DO - 10.1002/(SICI)1098-1063(1998)8:3<244::AID-HIPO7>3.0.CO;2-J UR - https://m2.mtmt.hu/api/publication/108577 ID - 108577 LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Katalin AU - Freund, Tamás AU - Miles, R TI - Disinhibition of rat hippocampal pyramidal cells by GABAergic afferents from the septum JF - JOURNAL OF PHYSIOLOGY-LONDON J2 - J PHYSIOL-LONDON VL - 500 PY - 1997 SP - 463 EP - 474 PG - 12 SN - 0022-3751 DO - 10.1113/jphysiol.1997.sp022033 UR - https://m2.mtmt.hu/api/publication/107892 ID - 107892 N1 - Lab. de Neurobiologie Cellulaire, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450 Budapest, Hungary Cited By :325 Export Date: 3 August 2023 CODEN: JPHYA Correspondence Address: Miles, R.; Lab. Neurobiologie Cellulaire, 25 rue du Dr Roux, 75724 Paris cedex 15, France; email: rmiles@pasteur.fr Chemicals/CAS: acetic acid, 127-08-2, 127-09-3, 64-19-7, 71-50-1; cesium chloride, 7647-17-8; picrotoxin, 124-87-8 LA - English DB - MTMT ER - TY - JOUR AU - Freund, Tamás AU - Buzsáki, György TI - Interneurons of the hippocampus JF - HIPPOCAMPUS J2 - HIPPOCAMPUS VL - 6 PY - 1996 SP - 347 EP - 470 PG - 124 SN - 1050-9631 DO - 10.1002/(SICI)1098-1063(1996)6:4<347::AID-HIPO1>3.0.CO;2-I UR - https://m2.mtmt.hu/api/publication/107931 ID - 107931 LA - English DB - MTMT ER - TY - JOUR AU - R U, Muller AU - M, Stead AU - Pach, János TI - The hippocampus as a cognitive graph JF - JOURNAL OF GENERAL PHYSIOLOGY J2 - J GEN PHYSIOL VL - 107 PY - 1996 IS - 6 SP - 663 EP - 694 PG - 32 SN - 0022-1295 DO - 10.1085/jgp.107.6.663 UR - https://m2.mtmt.hu/api/publication/1263778 ID - 1263778 N1 - Cited By :223 Export Date: 20 September 2021 CODEN: JGPLA Correspondence Address: Muller, R.U.; Department of Physiology, 450 Clarkson Ave., Brooklyn, NY 11203, United States Funding details: National Institute of Neurological Disorders and Stroke, NINDS, R01NS014497, R01NS020686 AB - A theory of cognitive mapping is developed that depends only on accepted properties of hippocampal function, namely, long-term potentiation, the place cell phenomenon, and the associative or recurrent connections made among CA3 pyramidal cells. It is proposed that the distance between the firing fields of connected pairs of CA3 place cells is encoded as synaptic resistance (reciprocal synaptic strength). The encoding occurs because pairs of cells with coincident or overlapping fields will tend to fire together in time, thereby causing a decrease in synaptic resistance via long-term potentiation; in contrast, cells with widely separated fields will tend never to fire together, causing no change or perhaps (via long-term depression) an increase in synaptic resistance. A network whose connection pattern mimics that of CA3 and whose connection weights are proportional to synaptic resistance can be formally treated as a weighted, directed graph. In such a graph, a ''node'' is assigned to each CA3 cell and two nodes are connected by a ''directed edge'' if and only if the two corresponding cells are connected by a synapse. Weighted, directed graphs can be searched for an optimal path between any pair of nodes with standard algorithms. Here, we are interested in finding the path along which the sum of the synaptic resistances from one cell to another is minimal. Since each cell is a place cell, such a path also corresponds to a path in two-dimensional space. Our basic finding is that minimizing the sum of the synaptic resistances along a path in neural space yields the shortest (optimal) path in unobstructed two-dimensional space, so long as the connectivity of the network is great enough. Zn addition to being able to find geodesics in unobstructed space, the same network enables solutions to the ''detour'' and ''shortcut'' problems, in which it is necessary to find an optimal path around a newly introduced barrier and to take a Shorter path through a hole opened up in a preexisting barrier, respectively. We argue that the ability to solve such problems qualifies the proposed hippocampal object as a cognitive map. Graph theory thus provides a sort of existence proof demonstrating that the hippocampus contains the necessary information to function as a map, in the sense postulated by others (O'Keefe,J., and L. Nadel. 1978. The Hippocampus as a Cognitive Map. Clarendon Press, Oxford, UK). It is also possible that the cognitive map ping functions of the hippocampus are carried out by parallel graph searching algorithms implemented as neural processes. This possibility has the great attraction that the hippocampus could then operate in much the same way to find paths in general problem space; it would only be necessary for pyramidal cells to exhibit a strong nonpositional firing correlate. LA - English DB - MTMT ER - TY - JOUR AU - YLINEN, A AU - Soltesz, Ivan AU - BRAGIN, A AU - PENTTONEN, M AU - Sík, Attila AU - BUZSAKI, G TI - INTRACELLULAR CORRELATES OF HIPPOCAMPAL THETA-RHYTHM IN IDENTIFIED PYRAMIDAL CELLS, GRANULE CELLS, AND BASKET CELLS JF - HIPPOCAMPUS J2 - HIPPOCAMPUS VL - 5 PY - 1995 IS - 1 SP - 78 EP - 90 PG - 13 SN - 1050-9631 DO - 10.1002/hipo.450050110 UR - https://m2.mtmt.hu/api/publication/2941574 ID - 2941574 AB - The cellular-synaptic generation of rhythmic slow activity (RSA or theta) in the hippocampus has been investigated by intracellular recording from principal cells and basket cells in anesthetized rats. In addition, the voltage-, coherence-, and phase versus depth profiles were examined by simultaneously recording field activity at 16 sites in the intact rat, during urethane anesthesia, and after bilateral entorhinal cortex lesion. In the extracellular experiments the large peak of theta at the hippocampal fissure was attenuated by urethane anesthesia and abolished by entorhinal cortex lesion. The phase versus depth profiles were similar during urethane anesthesia and following entorhinal cortex lesion but distinctly different in the intact, awake rat. These observations suggest that dendritic currents underlying theta in the awake rat may not be revealed under urethane anesthesia. The frequency of theta-related membrane potential oscillation was voltage-independent in pyramidal neurons, granule cells, and basket cells. On the other hand, the phase and amplitude of intracellular theta were voltage-dependent in all three cell types with an almost complete phase reversal at chloride equilibrium potential in pyramidal cells and basket cells. At strong depolarization levels (less than 30 mV) pyramidal cells emitted calcium spike oscillations, phase-locked to theta. Basket cells possessed the most regular membrane oscillations of the three cell types. All neurons of this study were verified by intracellular injection of biocytin. The observations provide direct evidence that theta-related rhythmic hyperpolarization of principal cells is brought about by the rhythmically discharging basket neurons. Furthermore, the finding that basket cells were also paced by rhythmic inhibitory postsynaptic potentials during theta suggest that they were periodically hyperpolarized by their GABAergic septal afferents. (C) 1995 Wiley-Liss, Inc. LA - English DB - MTMT ER - TY - JOUR AU - Freund, Tamás AU - Antal, Miklós TI - GABA-containing neurons in the septum control inhibitory interneurons in the hippocampus JF - NATURE J2 - NATURE VL - 336 PY - 1988 SP - 170 EP - 173 PG - 4 SN - 0028-0836 DO - 10.1038/336170a0 UR - https://m2.mtmt.hu/api/publication/107532 ID - 107532 LA - English DB - MTMT ER -