@article{11765, abstract = {This paper presents insertions-only algorithms for maintaining the exact and/or approximate size of the minimum edge cut and the minimum vertex cut of a graph. The algorithms output the approximate or exact sizekin timeO(1) and a cut of sizekin time linear in its size. For the minimum edge cut problem and for any 0 < ε ≤ 1, the amortized time per insertion isO(1/ε2) for a (2 + ε)-approximation,O((log λ)((log n)/ε)2) for a (1 + ε)-approximation, andO(λ log n) for the exact size, wherenis the number of nodes in the graph and λ is the size of the minimum cut. The (2 + ε)-approximation algorithm and the exact algorithm are deterministic; the (1 + ε)-approximation algorithm is randomized. We also present a static 2-approximation algorithm for the size κ of the minimum vertex cut in a graph, which takes time. This is a factor of κ faster than the best algorithm for computing the exact size, which takes time. We give an insertions-only algorithm for maintaining a (2 + ε)-approximation of the minimum vertex cut with amortized insertion timeO(n/ε).}, author = {Henzinger, Monika H}, issn = {0196-6774}, journal = {Journal of Algorithms}, number = {1}, pages = {194--220}, publisher = {Elsevier}, title = {{A static 2-approximation algorithm for vertex connectivity and incremental approximation algorithms for edge and vertex connectivity}}, doi = {10.1006/jagm.1997.0855}, volume = {24}, year = {1997}, } @article{11767, abstract = {We give a linear-time algorithm for single-source shortest paths in planar graphs with nonnegative edge-lengths. Our algorithm also yields a linear-time algorithm for maximum flow in a planar graph with the source and sink on the same face. For the case where negative edge-lengths are allowed, we give an algorithm requiringO(n4/3 log(nL)) time, whereLis the absolute value of the most negative length. This algorithm can be used to obtain similar bounds for computing a feasible flow in a planar network, for finding a perfect matching in a planar bipartite graph, and for finding a maximum flow in a planar graph when the source and sink are not on the same face. We also give parallel and dynamic versions of these algorithms.}, author = {Henzinger, Monika H and Klein, Philip and Rao, Satish and Subramanian, Sairam}, issn = {0022-0000}, journal = {Journal of Computer and System Sciences}, number = {1}, pages = {3--23}, publisher = {Elsevier}, title = {{Faster shortest-path algorithms for planar graphs}}, doi = {10.1006/jcss.1997.1493}, volume = {55}, year = {1997}, } @article{8527, abstract = {We introduce a new potential-theoretic definition of the dimension spectrum of a probability measure for q > 1 and explain its relation to prior definitions. We apply this definition to prove that if and is a Borel probability measure with compact support in , then under almost every linear transformation from to , the q-dimension of the image of is ; in particular, the q-dimension of is preserved provided . We also present results on the preservation of information dimension and pointwise dimension. Finally, for and q > 2 we give examples for which is not preserved by any linear transformation into . All results for typical linear transformations are also proved for typical (in the sense of prevalence) continuously differentiable functions.}, author = {Hunt, Brian R and Kaloshin, Vadim}, issn = {0951-7715}, journal = {Nonlinearity}, keywords = {Mathematical Physics, General Physics and Astronomy, Applied Mathematics, Statistical and Nonlinear Physics}, number = {5}, pages = {1031--1046}, publisher = {IOP Publishing}, title = {{How projections affect the dimension spectrum of fractal measures}}, doi = {10.1088/0951-7715/10/5/002}, volume = {10}, year = {1997}, } @article{8528, abstract = {In the present paper, we give a definition of prevalent ("metrically prevalent" ) sets in nonlinear function spaces. A subset of a Euclidean space is said to be metrically prevalent if its complement has measure zero. There is no natural way to generalize the definition of a set of measure zero in a finite-dimensional space to the infinite-dimensional case [6]. Therefore, it is necessary to give a special definition of a metrically prevalent set (set of full measure) in an infinite-dimensional space. There are various ways to do so. We suggest one of the possible ways to define the class of metrically prevalent sets in the space of smooth maps of one smooth manifold into another. It is shown in this paper that the class of metrically prevalent sets has natural properties; in particular, the intersection of finitely many metrically prevalent sets is metrically prevalent. The main result of the paper is a prevalent version of Thorn's transversality theorem. It is common practice in singularity theory and the theory of dynamical systems to say that a property holds for "almost every" map (or flow) if it holds for a residual set, i.e., a set that contains a countable intersection of open dense sets in the corresponding function space. However, even in finite-dimensional spaces such a set can have arbitrarily small (say, zero) Lebesgue measure. We prove that Thorn's transversality theorem holds for an essentially "thicker" set than a residual set. It seems reasonable to revise from the prevalent point of view the classical results of singularity theory and theory of dynamical systems, including the multijet transversality theorem, Mather's stability theorem, Kupka-Smale's theorem for dynamical systems, etc. We shall do this elsewhere. The notion of prevalence in linear Banach spaces was introduced and investigated in [8]. One of the possible ways to define a class of prevalent sets in the space of smooth maps of manifolds, which essentially differs from that presented in this paper, is given in [7]. Definitions of typicalness based on the Lebesgue measure in a finite-dimensional space were suggested by Kolmogorov [10] and Arnold [11]. These definitions were cited and discussed in [9]. Here we only point out that the finite-dimensional analog of Arnold's definition allows prevalent sets to have arbitrarily small measure, whereas the prevalent sets in the sense of the finite-dimensional analog of the definition given in the present paper are necessarily of full measure. Our definition is a modification of that due to Arnold. I wish to thank Yu. S. Illyashenko for constant attention to this work and useful discussions and R. I. Bogdanov for help in the preparation of this paper. }, author = {Kaloshin, Vadim}, issn = {0016-2663}, journal = {Functional Analysis and Its Applications}, keywords = {Applied Mathematics, Analysis}, number = {2}, pages = {95--99}, publisher = {Springer Nature}, title = {{Prevalence in the space of finitely smooth maps}}, doi = {10.1007/bf02466014}, volume = {31}, year = {1997}, } @inproceedings{4583, abstract = {In a trace-based world, the modular specification, verification, and control of live systems require each module to be receptive; that is, each module must be able to meet its liveness assumptions no matter how the other modules behave. In a real-time world, liveness is automatically present in the form of diverging time. The receptiveness condition, then, translates to the requirement that a module must be able to let time diverge no matter how the environment behaves. We study the receptiveness condition for real-time systems by extending the model of reactive modules to timed and hybrid modules. We define the receptiveness of such a module as the existence of a winning strategy in a game of the module against its environment. By solving the game on region graphs, we present an (optimal) Exptime algorithm for checking the receptiveness of prepositional timed modules. By giving a fixpoint characterization of the game, we present a symbolic procedure for checking the receptiveness of linear hybrid modules. Finally, we present an assume-guarantee principle for reasoning about timed and hybrid modules, and a method for synthesizing receptive controllers of timed and hybrid modules.}, author = {Alur, Rajeev and Henzinger, Thomas A}, booktitle = {8th International Conference on Concurrency Theory}, isbn = {9783540691884}, location = {Warsaw, Poland}, pages = {74 -- 88}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Modularity for timed and hybrid systems}}, doi = {10.1007/3-540-63141-0_6}, volume = {1243}, year = {1997}, } @article{4584, abstract = {This paper introduces, gently but rigorously, the clock approach to real-time programming. We present with mathematical precision, assuming no prerequisites other than familiarity with logical and programming notations, the concepts that are necessary for understanding, writing, and executing clock programs. In keeping with an expository style, all references are clustered in bibliographic remarks at the end of each section. The first appendix presents proof rules for verifying temporal properties of clock programs. The second appendix points to selected literature on formal methods and tools for programming with clocks. In particular, the timed automaton, which is a finite-state machine equipped with clocks, has become a standard paradigm for real-time model checking; it underlies the tools HyTech, Kronos, and Uppaal, which are discussed elsewhere in this volume.}, author = {Alur, Rajeev and Henzinger, Thomas A}, issn = {1433-2779}, journal = {Software Tools For Technology Transfer}, number = {1-2}, pages = {86 -- 109}, publisher = {Springer}, title = {{Real-time system = discrete system + clock variables}}, doi = {10.1007/s100090050007}, volume = {1}, year = {1997}, } @inproceedings{4605, abstract = {A hybrid system is a dynamical system whose behavior exhibits both discrete and continuous change. A hybrid automaton is a mathematical model for hybrid systems, which combines, in a single formalism, automaton transitions for capturing discrete change with differential equations for capturing continuous change. In this survey, we demonstrate symbolic algorithms for the verification of and controller synthesis for linear hybrid automata, a subclass of hybrid automata that can be analyzed automatically}, author = {Alur, Rajeev and Henzinger, Thomas A and Wong Toi, Howard}, booktitle = {Proceedings of the 36th IEEE Conference on Decision and Control}, isbn = {0780341872}, location = {San Diego, CA, USA}, pages = {702 -- 707}, publisher = {IEEE}, title = {{Symbolic analysis of hybrid systems}}, doi = {10.1109/CDC.1997.650717 }, year = {1997}, } @article{4607, abstract = {We present a verification algorithm for duration properties of real-time systems. While simple real-time properties constrain the total elapsed time between events, duration properties constrain the accumulated satisfaction time of state predicates. We formalize the concept of durations by introducing duration measures for timed automata. A duration measure assigns to each finite run of a timed automaton a real number —the duration of the run— which may be the accumulated satisfaction time of a state predicate along the run. Given a timed automaton with a duration measure, an initial and a final state, and an arithmetic constraint, the duration-bounded reachability problem asks if there is a run of the automaton from the initial state to the final state such that the duration of the run satisfies the constraint. Our main result is an (optimal) PSPACE decision procedure for the duration-bounded reachability problem.}, author = {Alur, Rajeev and Courcoubetis, Costas and Henzinger, Thomas A}, issn = {0925-9856}, journal = {Formal Methods in System Design}, number = {2}, pages = {137 -- 156}, publisher = {Springer}, title = {{Computing accumulated delays in real-time systems}}, doi = {10.1023/A:1008626013578}, volume = {11}, year = {1997}, } @inproceedings{4608, abstract = {State space explosion is a fundamental obstacle in formal verification of designs and protocols. Several techniques for combating this problem have emerged in the past few years, among which two are significant: partial-order reductions and symbolic state space search. In asynchronous systems, interleavings of independent concurrent events are equivalent, and only a representative interleaving needs to be explored to verify local properties. Partial-order methods exploit this redundancy and visit only a subset of the reachable states. Symbolic techniques, on the other hand, capture the transition relation of a system and the set of reachable states as boolean functions. In many cases, these functions can be represented compactly using binary decision diagrams (BDDs). Traditionally, the two techniques have been practiced by two different schools—partial-order methods with enumerative depth-first search for the analysis of asynchronous network protocols, and symbolic breadth-first search for the analysis of synchronous hardware designs. We combine both approaches and develop a method for using partial-order reduction techniques in symbolic BDD-based invariant checking. We present theoretical results to prove the correctness of the method, and experimental results to demonstrate its efficacy.}, author = {Alur, Rajeev and Brayton, Robert and Henzinger, Thomas A and Qadeer, Shaz and Rajamani, Sriram}, booktitle = {9th International Conference on Computer Aided Verification}, isbn = {9783540631668}, location = {Haifa, Israel}, pages = {340 -- 351}, publisher = {Springer}, title = {{Partial-order reduction in symbolic state-space exploration}}, doi = {10.1007/3-540-63166-6_34}, volume = {1254}, year = {1997}, } @inproceedings{4609, abstract = {Temporal logic comes in two varieties: linear-time temporal logic assumes implicit universal quantification over all paths that are generated by system moves; branching-time temporal logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of temporal logic: alternating-time temporal logic offers selective quantification over those paths that are possible outcomes of games, such as the game in which the system and the environment alternate moves. While linear-time and branching-time logics are natural specification languages for closed systems, alternating-time logics are natural specification languages for open systems. For example, by preceding the temporal operator “eventually” with a selective path quantifier, we can specify that in the game between the system and the environment, the system has a strategy to reach a certain state. Also the problems of receptiveness, realizability, and controllability can be formulated as model-checking problems for alternating-time formulas}, author = {Alur, Rajeev and Henzinger, Thomas A and Kupferman, Orna}, booktitle = {Proceedings of the 38th Annual Symposium on Foundations of Computer Science}, issn = {0004-5411}, location = {Washington, DC, United States}, pages = {100 -- 109}, publisher = {Association for Computing Machinery (ACM)}, title = {{Alternating-time temporal logic}}, doi = {10.1145/585265.585270}, year = {1997}, } @inproceedings{11803, abstract = {We present the first fully dynamic algorithm for maintaining a minimum spanning tree in time o(√n) per operation. To be precise, the algorithm uses O(n 1/3 log n) amortized time per update operation. The algorithm is fairly simple and deterministic. An immediate consequence is the first fully dynamic deterministic algorithm for maintaining connectivity and, bipartiteness in amortized time O(n 1/3 log n) per update, with O(1) worst case time per query.}, author = {Henzinger, Monika H and King, Valerie}, booktitle = {24th International Colloquium on Automata, Languages and Programming}, isbn = {9783540631651}, issn = {1611-3349}, location = {Bologna, Italy}, pages = {594–604}, publisher = {Springer Nature}, title = {{Maintaining minimum spanning trees in dynamic graphs}}, doi = {10.1007/3-540-63165-8_214}, volume = {1256}, year = {1997}, } @article{11849, abstract = {This paper describes the DIGlTAL Continuous Profiling Infrastmcture, a sampling-based profiling system designed to run continuously on production systems. The system supports multiprocessors, works on unmodified executable& and collects profiles for entire systems, including user programs, shared libraries, and the operating system kernel. Samples are collected at a high rate (over 5200 samples/secper333-MHz processor), yet with low overhead (l-3% slowdown for most workloads). Analysis tools supplied with the profiling system use the sample data to produce an accurate accounting, down to the level of pipeline stalls incurred by individual instructions, of where time is being spent. When instructions incur stalls, the tools identify possible reasons, such as cache misses, branch mispredictions, and functional unit contention. The fine-grained instruction-level analysis guides users and automated optimizers to the causes of performance problems and provides important insights for fixing them. }, author = {Anderson, Jennifer M. and Berc, Lance M. and Dean, Jeffrey and Ghemawat, Sanjay and Henzinger, Monika H and Leung, Shun-Tak A. and Sites, Richard L. and Vandevoorde, Mark T. and Waldspurger, Carl A. and Weihl, William E.}, issn = {0163-5980}, journal = {ACM SIGOPS Operating Systems Review}, number = {5}, pages = {1--14}, publisher = {Association for Computing Machinery}, title = {{Continuous profiling: Where have all the cycles gone?}}, doi = {10.1145/269005.266637}, volume = {31}, year = {1997}, } @article{11883, abstract = {In dynamic graph algorithms the following provide-or-bound problem has to be solved quickly: Given a set S containing a subset R and a way of generating random elements from S testing for membership in R, either (i) provide an element of R, or (ii) give a (small) upper bound on the size of R that holds with high probability. We give an optimal algorithm for this problem. This algorithm improves the time per operation for various dynamic graph algorithms by a factor of O(log n). For example, it improves the time per update for fully dynamic connectivity from O(log3n) to O(log2n).}, author = {Henzinger, Monika H and Thorup, Mikkel}, issn = {1098-2418}, journal = {Random Structures and Algorithms}, number = {4}, pages = {369--379}, publisher = {Wiley}, title = {{Sampling to provide or to bound: With applications to fully dynamic graph algorithms}}, doi = {10.1002/(sici)1098-2418(199712)11:4<369::aid-rsa5>3.0.co;2-x}, volume = {11}, year = {1997}, } @article{3482, abstract = {AMPA- and NMDA-type glutamate receptors (AMPARs and NMDARs) mediate excitatory synoptic transmission in the basal ganglia and may contribute to excitotoxic injury. We investigated the functional properties of AMPARs and NMDARs expressed by six main types of basal ganglia neurons in acute rat brain slices (principal neurons and cholinergic interneurons of striatum, GABAergic and dopaminergic neurons of substantia nigra, globus pallidus neurons, and subthalamic nucleus neurons) using fast application of glutamate to nucleated and outside-out membrane patches, AMPARs in different types of basal ganglia neurons were functionally distinct. Those expressed in striatal principal neurons exhibited the slowest gating (desensitization time constant τ = 11.5 msec, 1 mM glutamate, 22°C), whereas those in striatal cholinergic interneurons showed the fastest gating (desensitization time constant τ = 3.6 msec). The lowest Ca2+ permeability of AMPARs was observed in nigral dopaminergic neurons (P(CA)/P(NA) = 0.10), whereas the highest Ca2+ permeability was found in subthalamic nucleus neurons (P(Ca)/P(Na) = 1.17). NMDARs of different types of basal ganglia neurons were less variable in their functional properties; those expressed in nigral dopaminergic neurons exhibited the slowest gating (deactivation time constant of predominant fast component τ1 150 msec, 100 μM glutamate), and those of globus pallidus neurons showed the fastest gating (τ1 = 67 msec). The Mg2+ block of NMDARs was similar; the average chord conductance ratio g(+60mv)/g(+40mV) was 0.18-0.22 in 100 μM external Mg2+. Hence, AMPARs expressed in different types of basal ganglia neurons are markedly diverse, whereas NMDARs are less variable in functional properties that are relevant for excitatory synoptic transmission and neuronal vulnerability.}, author = {Götz, Thomas and Kraushaar, Udo and Geiger, Jörg and Lubke, Joachim and Berger, Thomas and Jonas, Peter M}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {1}, pages = {204 -- 215}, publisher = {Society for Neuroscience}, title = {{Functional properties of AMPA and NMDA receptors expressed in identified types of basal ganglia neurons}}, doi = {10.1523/JNEUROSCI.17-01-00204.1997}, volume = {17}, year = {1997}, } @article{3483, abstract = {The main excitatory pathway of the hippocampal formation is controlled by a network of morphologically distinct populations of GABAergic interneurons. Here we describe a novel type of GABAergic interneuron located in the outer molecular layer (OML) of the rat dentate gyrus with a long- range forward projection from the dentate gyrus to the subiculum across the hippocampal fissure, OML interneurons were recorded in hippocampal slices by using the whole-cell patch-clamp configuration. During recording, cells were filled with biocytin for subsequent light and electron microscopic analysis. Neurons projecting to the subiculum were distributed throughout the entire OML. They had round or ovoid somata and a multipolar dendritic morphology. Two axonal domains could be distinguished: an extensive, tangential distribution within the OML and a long-range vertical and tangential projection to layer 1 and stratum pyramidale of the subiculum. Symmetric synaptic contacts were established by these interneurons on dendritic shafts in the OML and subiculum. OML interneurons were characterized physiologically by short action potential duration and marked afterhyperpolarization that followed the spike. On sustained current injection, they generated high- frequency (up to 130 Hz, 34°C) trains of action potentials with only little adaptation. In situ hybridization and single-call RT-PCR analysis for GAD67 mRNA confirmed the GABAergic nature of OML interneurons. GABAergic interneurons in the OML projecting to the subiculum connect the input and output regions of the hippocampus. Hence, they could mediate long-range feed- forward inhibition and may participate in an oscillating cross-regional interneuron network that may synchronize the activity of spatially distributed principal neurons in the dentate gyrus and the subiculum.}, author = {Ceranik, Katya and Bender, Roland and Geiger, Jörg and Monyer, Hannah and Jonas, Peter M and Frotscher, Michael and Lubke, Joachim}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {14}, pages = {5380 -- 5394}, publisher = {Society for Neuroscience}, title = {{A novel type of GABAergic interneuron connecting the input and the output regions of the hippocampus.}}, doi = {10.1523/JNEUROSCI.17-14-05380.1997}, volume = {17}, year = {1997}, } @article{3484, abstract = {Glutamatergic transmission at a principal neuroninterneuron synapse was investigated by dual whole-cell patch-clamp recording in rat hippocampal slices combined with morphological analysis. Evoked EPSPs with rapid time course (half duration ≃ 4 ms; 34°C) were generated at multiple synaptic contacts established on the interneuron dendrites close to the soma. The underlying postsynaptic conductance change showed a submillisecond rise and decay, due to the precise timing of glutamate release and the rapid deactivation of the postsynaptic AMPA receptors. Simulations based on a compartmental model of the interneuron indicated that the rapid postsynaptic conductance change determines the shape and the somatodendritic integration of EPSPs, thus enabling interneurons to detect synchronous principal neuron activity.}, author = {Geiger, Jörg and Lubke, Joachim and Roth, Arnd and Frotscher, Michael and Jonas, Peter M}, issn = {0896-6273}, journal = {Neuron}, number = {6}, pages = {1009 -- 1023}, publisher = {Elsevier}, title = {{Submillisecond AMPA receptor-mediated signaling at a principal neuron-interneuron synapse}}, doi = {10.1016/S0896-6273(00)80339-6}, volume = {18}, year = {1997}, } @article{3485, abstract = {1. GABAergic interneurones differ from glutamatergic principal neurones in their ability to discharge high-frequency trains of action potentials without adaptation. To examine whether Na+ channel gating contributed to these differences, Na+ currents were recorded in nucleated patches from interneurones (dentate gyrus basket cells, BCs) and principal neurones (CA1 pyramidal cells, PCs) of rat hippocampal slices. 2. The voltage dependence of Na+ channel activation in BCs and PCs was similar. The slope factors of the activation curves, fitted with Boltzmann functions raised to the third power, were 11.5 and 11.8 mV, and the mid-point potentials were -25.1 and -23.9 mV, respectively. 3. Whereas the time course of Na+ channel activation (-30 to +40 mV) was similar, the deactivation kinetics (-100 to -40 mV) were faster in BCs than in PCs (tail current decay time constants, 0.13 and 0.20 ms, respectively, at -40 mV). 4. Na+ channels in BCs and PCs differed in the voltage dependence of inactivation. The slope factors of the steady-state inactivation curves fitted with Boltzmann functions were 6.7 and 10.7 mV, and the mid-point potentials were -58.3 and -62.9 mV, respectively. 5. The onset of Na+ channel inactivation at -55 mV was slower in BC's than in PCs; the inactivation time constants were 18.6 and 9.3 ms, respectively. At more positive potentials the differences in inactivation onset were smaller. 6. The time course of recovery of Na+ channels from inactivation induced by a 30 ms pulse was fast and mono-exponential (τ = 2.0 ms at -120 mV) in BCs, whereas it was slower and biexponential in PCs (τ1 = 2.0 ms and τ2 = 133 ms; amplitude contribution of the slow component, 15%). 7. We conclude that Na+ channels of BCs and PCs differ in gating properties that contribute to the characteristic action potential patterns of the two types of neurones.}, author = {Martina, Marco and Jonas, Peter M}, issn = {0022-3751}, journal = {Journal of Physiology}, number = {3}, pages = {593 -- 603}, publisher = {Wiley-Blackwell}, title = {{Functional differences in Na+ channel gating between fast-spiking interneurones and principal neurones in rat hippocampus}}, doi = {10.1111/j.1469-7793.1997.593ba.x}, volume = {505}, year = {1997}, } @article{3486, abstract = {1. Dendritic patch-clamp recordings were obtained from mitral cells in rat olfactory bulb slices, up to 350 μm from the soma. Simultaneous dendritic and somatic whole-cell recordings indicated that action potentials (APs) evoked by somatic or dendritic current injection were initiated near the soma. Both the large amplitude (100.7 ± 1.1 mV) and the short duration (1.38 ± 0.07 ms) of the AP were maintained as the AP propagated back into the primary mitral cell dendrites. 2. Outside-out patches isolated from mitral cell dendrites contained voltage-gated Na+ channels (peak conductance density, 90 pS μm-2 at -10 mV). When an AP was used as a somatic voltage-clamp command in the presence of 1 μM tetrodotoxin (TTX), the amplitude of the dendritic potential was attenuated to 48 ± 14 mV. This shows that dendritic Na+ channels support the active back-propagation of APs. 3. Dendritic patches contained voltage-gated K+ channels with high density (conductance density, 513 pS μm-2 at 30 mV. Dendritic K+ currents were reduced to 35% by 1 mM external tetraethylammonium chloride (TEACl). When an AP was used as a somatic voltage clamp command in the presence of TEACl, the dendritic potential was markedly prolonged. This indicates that dendritic K+ channels mediate the fast repolarization of dendritic APs. 4. We conclude that voltage gated Na+ and K+ channels support dendritic APs with large amplitudes and short durations that may trigger fast transmitter release at dendrodendritic synapses in the olfactory bulb.}, author = {Bischofberger, Joseph and Jonas, Peter M}, issn = {0022-3751}, journal = {Journal of Physiology}, number = {Pt 2}, pages = {359 -- 365}, publisher = {Wiley-Blackwell}, title = {{Action potential propagation into the presynaptic dendrites of rat mitral cells}}, doi = {10.1111/j.1469-7793.1997.359be.x}, volume = {504}, year = {1997}, } @article{3541, abstract = {The contribution of the various hippocampal regions to the maintenance of epileptic activity, induced by stimulation of the perforant path or commissural system, was examined in the awake rat. Combination of multiple-site recordings with silicon probes, current source density analysis and unit recordings allowed for a high spatial resolution of the field events. Following perforant path stimulation, seizures began in the dentate gyrus, followed by events in the CA3-CA1 regions. After commissural stimulation, rhythmic bursts in the CA3-CA1 circuitry preceded the activation of the dentate gyrus. Correlation of events in the different subregions indicated that the sustained rhythmic afterdischarge (2-6 Hz) could not be explained by a cycle-by-cycle excitation of principal cell populations in the hippocampal-entorhinal loop. The primary afterdischarge always terminated in the CA1 region, followed by the dentate gyrus, CA3 region and the entorhinal cortex. The duration and pattern of the hippocampal afterdischarge was essentially unaffected by removal of the entorhinal cortex. The emergence of large population spike bursts coincided with a decreased discharge of interneurons in both CAI and hilar regions. The majority of hilar interneurons displayed a strong amplitude decrement prior to the onset of population spike phase of the afterdischarge. These findings suggest that (i) afterdischarges can independently arise in the CA3-CA1 and entorhinal-dentate gyrus circuitries, (ii) reverberation of excitation in the hippocampal-entorhinal loop is not critical for the maintenance of afterdischarges and (iii) decreased activity of the interneuronal network may release population bursting of principal cells. }, author = {Bragin, Anatol and Csicsvari, Jozsef L and Penttonen, Markku and Buzsáki, György}, issn = {0306-4522}, journal = {Neuroscience}, number = {4}, pages = {1187 -- 1203}, publisher = {Elsevier}, title = {{Epileptic afterdischarge in the hippocampal-entorhinal system: Current source density and unit studies}}, doi = {10.1016/S0306-4522(96)00446-0}, volume = {76}, year = {1997}, } @article{3630, abstract = {This paper derives the long-term effective size, Ne, for a general model of population subdivision, allowing for differential deme fitness, variable emigration and immigration rates, extinction, colonization, and correlations across generations in these processes. We show that various long-term measures of Ne are equivalent. The effective size of a metapopulation can be expressed in a variety of ways. At a demographic equilibrium, Ne can be derived from the demography by combining information about the ultimate contribution of each deme to the future genetic make-up of the population and Wright's FST's. The effective size is given by Ne = 1/(1 + var (upsilon) ((1 - FST)/Nin), where n is the number of demes, theta i is the eventual contribution of individuals in deme i to the whole population (scaled such that sigma theta i = n), and < > denotes an average weighted by theta i. This formula is applied to a catastrophic extinction model (where sites are either empty or at carrying capacity) and to a metapopulation model with explicit dynamics, where extinction is caused by demographic stochasticity and by chaos. Contrary to the expectation from the standard island model, the usual effect of population subdivision is to decrease the effective size relative to a panmictic population living on the same resource.}, author = {Whitlock, Michael and Barton, Nicholas H}, issn = {0016-6731}, journal = {Genetics}, number = {1}, pages = {427 -- 441}, publisher = {Genetics Society of America}, title = {{The effective size of a subdivided population}}, doi = {10.1093/genetics/146.1.427}, volume = {146}, year = {1997}, }