@article{6158, abstract = {Wild isolates of Caenorhabditis elegans can feed either alone or in groups1,2. This natural variation in behaviour is associated with a single residue difference in NPR-1, a predicted G-protein-coupled neuropeptide receptor related to Neuropeptide Y receptors2. Here we show that the NPR-1 isoform associated with solitary feeding acts in neurons exposed to the body fluid to inhibit social feeding. Furthermore, suppressing the activity of these neurons, called AQR, PQR and URX, using an activated K+ channel, inhibits social feeding. NPR-1 activity in AQR, PQR and URX neurons seems to suppress social feeding by antagonizing signalling through a cyclic GMP-gated ion channel encoded by tax-2 and tax-4. We show that mutations in tax-2 or tax-4 disrupt social feeding, and that tax-4 is required in several neurons for social feeding, including one or more of AQR, PQR and URX. The AQR, PQR and URX neurons are unusual in C. elegans because they are directly exposed to the pseudocoelomic body fluid3. Our data suggest a model in which these neurons integrate antagonistic signals to control the choice between social and solitary feeding behaviour.}, author = {Coates, Juliet C. and de Bono, Mario}, issn = {0028-0836}, journal = {Nature}, number = {6910}, pages = {925--929}, publisher = {Springer Nature}, title = {{Antagonistic pathways in neurons exposed to body fluid regulate social feeding in Caenorhabditis elegans}}, doi = {10.1038/nature01170}, volume = {419}, year = {2002}, } @article{6159, abstract = {Natural Caenorhabditis elegans isolates exhibit either social or solitary feeding on bacteria. We show here that social feeding is induced by nociceptive neurons that detect adverse or stressful conditions. Ablation of the nociceptive neurons ASH and ADL transforms social animals into solitary feeders. Social feeding is probably due to the sensation of noxious chemicals by ASH and ADL neurons; it requires the genes ocr-2 and osm-9, which encode TRP-related transduction channels, and odr-4 and odr-8, which are required to localize sensory chemoreceptors to cilia. Other sensory neurons may suppress social feeding, as social feeding in ocr-2 and odr-4 mutants is restored by mutations in osm-3, a gene required for the development of 26 ciliated sensory neurons. Our data suggest a model for regulation of social feeding by opposing sensory inputs: aversive inputs to nociceptive neurons promote social feeding, whereas antagonistic inputs from neurons that express osm-3 inhibit aggregation.}, author = {de Bono, Mario and Tobin, David M. and Davis, M. Wayne and Avery, Leon and Bargmann, Cornelia I.}, issn = {0028-0836}, journal = {Nature}, number = {6910}, pages = {899--903}, publisher = {Springer Nature}, title = {{Social feeding in Caenorhabditis elegans is induced by neurons that detect aversive stimuli}}, doi = {10.1038/nature01169}, volume = {419}, year = {2002}, } @article{204, abstract = {Let k⩾5 be an integer, and let x⩾1 be an arbitrary real number. We derive a bound[Formula presented] for the number of positive integers less than or equal to x which can be represented as a sum of two non-negative coprime kth powers, in essentially more than one way.}, author = {Browning, Timothy D}, issn = {0022-314X}, journal = {Journal of Number Theory}, number = {2}, pages = {293 -- 318}, publisher = {Academic Press}, title = {{Equal Sums of Two kth Powers}}, doi = {10.1006/jnth.2002.2800}, volume = {96}, year = {2002}, } @article{859, abstract = {The polymeric ubiquitin (poly-u) genes are composed of tandem 228-bp repeats with no spacer sequences between individual monomer units. Ubiquitin is one of the most conserved proteins known to date, and the individual units within a number of poly-u genes are significantly more similar to each other than would be expected if each unit evolved independently. It has been proposed that the rather striking similarity among poly-u monomers in some lineages is caused by a series of homogenization events. Here we report the sequences of the polyubiquitin-C (Ubc) genes in two mouse strains. Analysis of these sequences, as well as those of the previously reported Chinese hamster and rat poly-u genes, supports the assertion that the homogenization of the ubiquitin-C gene in rodents is due to unequal crossing-over events. The sequence divergence of noncoding DNA was used to estimate the frequency of unequal crossing-over events (6.3 x 10-5 events per generation) in the Ubc gene, as well as to provide evidence of apparent selection in the poly-u gene.}, author = {Perelygin, Andrey and Kondrashov, Fyodor and Rogozin, Igor and Brinton, Margo}, issn = {0022-2844}, journal = {Journal of Molecular Evolution}, number = {2}, pages = {202 -- 210}, publisher = {Springer}, title = {{Evolution of the mouse polyubiquitin C gene}}, doi = {10.1007/s00239-002-2318-0}, volume = {55}, year = {2002}, } @article{871, abstract = {BACKGROUND: Gene duplications have a major role in the evolution of new biological functions. Theoretical studies often assume that a duplication per se is selectively neutral and that, following a duplication, one of the gene copies is freed from purifying (stabilizing) selection, which creates the potential for evolution of a new function. RESULTS: In search of systematic evidence of accelerated evolution after duplication, we used data from 26 bacterial, six archaeal, and seven eukaryotic genomes to compare the mode and strength of selection acting on recently duplicated genes (paralogs) and on similarly diverged, unduplicated orthologous genes in different species. We find that the ratio of nonsynonymous to synonymous substitutions (Kn/Ks) in most paralogous pairs is <<1 and that paralogs typically evolve at similar rates, without significant asymmetry, indicating that both paralogs produced by a duplication are subject to purifying selection. This selection is, however, substantially weaker than the purifying selection affecting unduplicated orthologs that have diverged to the same extent as the analyzed paralogs. Most of the recently duplicated genes appear to be involved in various forms of environmental response; in particular, many of them encode membrane and secreted proteins. CONCLUSIONS: The results of this analysis indicate that recently duplicated paralogs evolve faster than orthologs with the same level of divergence and similar functions, but apparently do not experience a phase of neutral evolution. We hypothesize that gene duplications that persist in an evolving lineage are beneficial from the time of their origin, due primarily to a protein dosage effect in response to variable environmental conditions; duplications are likely to give rise to new functions at a later phase of their evolution once a higher level of divergence is reached.}, author = {Kondrashov, Fyodor and Rogozin, Igor and Wolf, Yuri and Koonin, Eugene}, issn = {1465-6906}, journal = {Genome Biology}, number = {2}, publisher = {BioMed Central}, title = {{Selection in the evolution of gene duplications }}, doi = {10.1186/gb-2002-3-2-research0008}, volume = {3}, year = {2002}, } @article{885, abstract = {We study fitness landscape in the space of protein sequences by relating sets of human pathogenic missense mutations in 32 proteins to amino acid substitutions that occurred in the course of evolution of these proteins. On average, ≈10% of deviations of a nonhuman protein from its human ortholog are compensated pathogenic deviations (CPDs), i.e., are caused by an amino acid substitution that, at this site, would be pathogenic to humans. Normal functioning of a CPD-containing protein must be caused by other, compensatory deviations of the nonhuman species from humans. Together, a CPD and the corresponding compensatory deviation form a Dobzhansky-Muller incompatibility that can be visualized as the corner on a fitness ridge. Thus, proteins evolve along fitness ridges which contain only ≈10 steps between sucessive corners. The fraction of CPDs among all deviations of a protein from its human ortholog does not increase with the evolutionary distance between the proteins, indicating that subtitutions that carry evolving proteins around these corners occur in rapid succession, driven by positive selection. Data on fitness of interspecies hybrids suggest that the compensatory change that makes a CPD fit usually occurs within the same protein. Data on protein structures and on cooccurrence of amino acids at different sites of multiple orthologous proteins often make it possible to provisionally identify the substitution that compensates a partiCUlar CPD.}, author = {Kondrashov, Alexey and Sunyaev, Shamil and Kondrashov, Fyodor}, issn = {0027-8424}, journal = {PNAS}, number = {23}, pages = {14878 -- 14883}, publisher = {National Academy of Sciences}, title = {{Dobzhansky-Muller incompatibilities in protein evolution}}, doi = {10.1073/pnas.232565499}, volume = {99}, year = {2002}, } @article{897, abstract = {Transcription is a slow and expensive process: in eukaryotes, approximately 20 nucleotides can be transcribed per second at the expense of at least two ATP molecules per nucleotide. Thus, at least for highly expressed genes, transcription of long introns, which are particularly common in mammals, is costly. Using data on the expression of genes that encode proteins in Caenorhabditis elegans and Homo sapiens, we show that introns in highly expressed genes are substantially shorter than those in genes that are expressed at low levels. This difference is greater in humans, such that introns are, on average, 14 times shorter in highly expressed genes than in genes with low expression, whereas in C. Elegans the difference in intron length is only twofold. In contrast, the density of introns in a gene does not strongly depend on the level of gene expression. Thus, natural selection appears to favor short introns in highly expressed genes to minimize the cost of transcription and other molecular processes, such as splicing. }, author = {Castillo Davis, Cristian and Mekhedov, Sergei and Hartl, Daniel and Koonin, Eugene and Kondrashov, Fyodor}, journal = {Nature Genetics}, number = {4}, pages = {415 -- 418}, publisher = {Nature Publishing Group}, title = {{Selection for short introns in highly expressed genes}}, doi = {10.1038/ng940}, volume = {31}, year = {2002}, } @article{3140, abstract = {The maturation of synaptic structures depends on inductive interactions between axons and their prospective targets. One example of such an interaction is the influence of proprioceptive sensory axons on the differentiation of muscle spindles. We have monitored the expression of three transcription factors, Egr3, Pea3, and Erm, that delineate early muscle spindle development in an assay of muscle spindle-inducing signals. We provide genetic evidence that Neuregulin1 (Nrg1) is required for proprioceptive afferent-evoked induction of muscle spindle differentiation in the mouse. Ig-Nrg1 isoforms are preferentially expressed by proprioceptive sensory neurons and are sufficient to induce muscle spindle differentiation in vivo, whereas CRD-Nrg1 isoforms are broadly expressed in sensory and motor neurons but are not required for muscle spindle induction.}, author = {Hippenmeyer, Simon and Shneider, Neil and Birchmeier, Carmen and Burden, Steven and Jessell, Thomas and Arber, Silvia}, issn = {0896-6273}, journal = {Neuron}, number = {6}, pages = {1035 -- 1049}, publisher = {Elsevier}, title = {{A role for Neuregulin1 signaling in muscle spindle differentiation}}, doi = {10.1016/S0896-6273(02)01101-7}, volume = {36}, year = {2002}, } @article{3421, abstract = {Single molecule experiments provide insight into the individuality of biological macromolecules, their unique function, reaction pathways, trajectories and molecular interactions. The exceptional signal-to-noise ratio of the atomic force microscope allows individual proteins to be imaged under physiologically relevant conditions at a lateral resolution of 0.5–1 nm and a vertical resolution of 0.1–0.2 nm. Recently, it has become possible to observe single molecule events using this technique. This capability is reviewed on various water-soluble and membrane proteins. Examples of the observation of function, variability, and assembly of single proteins are discussed. Statistical analysis is important to extend conclusions derived from single molecule experiments to protein species. Such approaches allow the classification of protein conformations and movements. Recent developments of probe microscopy techniques allow simultaneous measurement of multiple signals on individual macromolecules, and greatly extend the range of experiments possible for probing biological systems at the molecular level. Biologists exploring molecular mechanisms will benefit from a burgeoning of scanning probe microscopes and of their future combination with molecular biological experiments.}, author = {Mueller, Daniel and Janovjak, Harald L and Lehto, Tiina and Kuerschner, Lars and Anderson, Kurt}, issn = {0079-6107}, journal = {Progress in Biophysics and Molecular Biology}, number = {1-3}, pages = {1 -- 43}, publisher = {Elsevier}, title = {{Observing structure, function and assembly of single proteins by AFM}}, doi = {10.1016/S0079-6107(02)00009-3}, volume = {79}, year = {2002}, } @article{3422, abstract = {Quantitative real-time PCR represents a highly sensitive and powerful technique for the quantitation of nucleic acids. It has a tremendous potential for the high-throughput analysis of gene expression in research and routine diagnostics. However, the major hurdle is not the practical performance of the experiments themselves but rather the efficient evaluation and the mathematical and statistical analysis of the enormous amount of data gained by this technology, as these functions are not included in the software provided by the manufacturers of the detection systems. In this work, we focus on the mathematical evaluation and analysis of the data generated by quantitative real-time PCR, the calculation of the final results, the propagation of experimental variation of the measured values to the final results, and the statistical analysis. We developed a Microsoft Excel-based software application coded in Visual Basic for Applications, called Q-Gene, which addresses these points. Q-Gene manages and expedites the planning, performance, and evaluation of quantitative real-time PCR experiments, as well as the mathematical and statistical analysis, storage, and graphical presentation of the data. The Q-Gene software application is a tool to cope with complex quantitative real-time PCR experiments at a high-throughput scale and considerably expedites and rationalizes the experimental setup, data analysis, and data management while ensuring highest reproducibility.}, author = {Müller, Patrick and Janovjak, Harald L and Miserez, Andre and Dobbie, Zuzana}, issn = {0736-6205}, journal = {Biotechniques}, number = {6}, pages = {1372 -- 1379}, publisher = {Informa Healthcare}, title = {{Processing of gene expression data generated by quantitative real-time RT-PCR}}, volume = {32}, year = {2002}, } @inproceedings{3423, author = {Bauer, Wolfgang and Bollenbach, Mark Tobias and Kleine Berkenbusch, Marko and Harreis, Holger}, booktitle = {Proceedings of the 18th Winter Workshop on Nuclear Dynamics}, location = {Nassau, Bahamas}, pages = {111 -- 118}, publisher = {EP Systema}, title = {{The percolation interpretation of the nuclear fragmentation phase transition}}, year = {2002}, } @inproceedings{3424, abstract = {We give a brief overview of the current understanding of the explosion mechanism of core collapse supernovae. Our main focus is the impact of rotation on the explosion. Recent observations of the polarization of the light emitted by supernova explosions indicate that there are large deviations from spherical symmetry in the very heart of the explosion the origin of which is unknown. We use the new approach of a three dimensional test particle based simulation to simulate the infall phase of a supernova event. The underlying microphysics is simplified to make this computationally possible. A systematic study of the influence of rotation mainly during the infall phase of the collapse of a typical iron core is performed. Indications for significant deviations from spherical symmetry are found in our very rapidly rotating models. © 2002 American Institute of Physics }, author = {Bollenbach, Mark Tobias and Bauer, Wolfgang}, isbn = {9781510832008}, location = {Catania, Italy}, pages = {219 -- 232}, publisher = {American Institute of Physics}, title = {{3d supernovae collapse calculations}}, doi = {10.1063/1.1523196 }, volume = {644}, year = {2002}, } @inproceedings{3448, author = {Mallick, Sanhita and Krishnendu Chatterjee and Merchant, Arif N and Dasgupta, Pallab}, publisher = {Elsevier}, title = {{Implementation of shape grammar for plan analysis}}, year = {2002}, } @article{3497, abstract = {The use of advanced patch-clamp recording techniques in brain slices, such as simultaneous recording from multiple neurons and recording from dendrites or presynaptic terminals, demands slices of the highest quality. In this context the mechanics of the tissue slicer are an important factor. Ideally, a tissue slicer should generate large-amplitude and high-frequency movements of the cutting blade in a horizontal axis, with minimal vibrations in the vertical axis. We developed a vibroslicer that fulfils these in part conflicting requirements. The oscillator is a permanent-magnet-coil-leaf-spring system. Using an auto-resonant mechano-electrical feedback circuit, large horizontal oscillations (up to 3 mm peak-to-peak) with high frequency (,90 Hz) are generated. To minimize vertical vibrations, an adjustment mechanism was employed that allowed alignment of the cutting edge of the blade with the major axis of the oscillation. A vibroprobe device was used to monitor vertical vibrations during adjustment. The system is based on the shading of the light path between a light-emitting diode (LED) and a photodiode. Vibroprobe monitoring revealed that the vibroslicer, after appropriate adjustment, generated vertical vibrations of <1 µm, significantly less than many commercial tissue slicers. Light- and electron-microscopic analysis of surface layers of slices cut with the vibroslicer showed that cellular elements, dendritic processes and presynaptic terminals are well preserved under these conditions, as required for patch-clamp recording from these structures.}, author = {Geiger, Jörg and Bischofberger, Joseph and Vida, Imre and Fröbe, Ulrich and Pfitzinger, S and Weber, H. and Haverkampf, Klaus and Jonas, Peter M}, issn = {0031-6768}, journal = {Pflugers Archiv : European Journal of Physiology}, number = {3}, pages = {491 -- 501}, publisher = {Springer}, title = {{Patch-clamp recording in brain slices with improved slicer technology}}, doi = {10.1007/s00424-001-0735-3}, volume = {443}, year = {2002}, } @misc{3508, abstract = {A method of automatic conversion of a physical object into a three-dimensional digital model. The method acquires a set of measured data points on the surface of a physical model. From the measured data points, the method reconstructs a digital model of the physical object using a Delaunay complex of the points, a flow strcuture of the simplicies in the Delaunay complex and retracting the Delaunay complex into a digital model of the physical object using the flow structure. The method then outputs the digital model of the physical object.}, author = {Edelsbrunner, Herbert and Fu, Ping}, title = {{Methods of generating three-dimensional digital models of objects by wrapping point cloud data points}}, year = {2002}, } @article{3533, abstract = {Information in neuronal networks is thought to be represented by the rate of discharge and the temporal relationship between the discharging neurons. The discharge frequency of neurons is affected by their afferents and intrinsic properties, and shows great individual variability. The temporal coordination of neurons is greatly facilitated by network oscillations. In the hippocampus, population synchrony fluctuates during theta and gamma oscillations (10-100 ms scale) and can increase almost 10-fold during sharp wave bursts. Despite these large changes in excitability in the sub-second scale, longer-term (minute-scale) firing rates of individual neurons are relatively constant in an unchanging environment. As a result, mean hippocampal output remains stable over time. To understand the mechanisms responsible for this homeostasis, we address the following issues: (i) Can firing rates of single cells be modified? (ii) Once modified, what mechanism(s) can maintain the changes? We show that firing rates of hippocampal pyramidal cells can be altered in a novel environment and by Hebbian pairing of physiological input patterns with postsynaptic burst discharge. We also illustrate a competition between single spikes and the occurrence of spike bursts. Since spike-inducing (suprathreshold) inputs decrease the ability of strong ('teaching') inputs to induce a burst discharge, we propose that the single spike versus burst competition presents a homeostatic regulatory mechanism to maintain synaptic strength and, consequently, firing rate in pyramidal cells.}, author = {Buzsáki, György and Csicsvari, Jozsef L and Dragoi, George and Harris, Kenneth and Henze, D. and Hirase, Hajima}, issn = {1047-3211}, journal = {Cerebral Cortex}, number = {9}, pages = {893 -- 899}, publisher = {Oxford University Press}, title = {{Homeostatic maintenance of neuronal excitability by burst discharges in vivo}}, doi = {10.1093/cercor/12.9.893}, volume = {12}, year = {2002}, } @article{3621, abstract = {In 1991, Barton and Turelli developed recursions to describe the evolution of multilocus systems under arbitrary forms of selection. This article generalizes their approach to allow for arbitrary modes of inheritance, including diploidy, polyploidy, sex linkage, cytoplasmic inheritance, and genomic imprinting. The framework is also extended to allow for other deterministic evolutionary forces, including migration and mutation. Exact recursions that fully describe the state of the population are presented; these are implemented in a computer algebra package (available on the Web at http://helios.bto.ed.ac.uk/evolgen). Despite the generality of our framework, it can describe evolutionary dynamics exactly by just two equations. These recursions can be further simplified using a "quasi-linkage equilibrium" (QLE) approximation. We illustrate the methods by finding the effect of natural selection, sexual selection, mutation, and migration on the genetic composition of a population.}, author = {Kirkpatrick, Mark and Johnson, Toby and Barton, Nicholas H}, issn = {0016-6731}, journal = {Genetics}, number = {4}, pages = {1727 -- 1750}, publisher = {Genetics Society of America}, title = {{General models of multilocus evolution}}, doi = {10.1093/genetics/161.4.1727}, volume = {161}, year = {2002}, } @article{3757, abstract = {A central problem in biology is determining how genes interact as parts of functional networks. Creation and analysis of synthetic networks, composed of well-characterized genetic elements, provide a framework for theoretical modeling. Here, with the use of a combinatorial method, a library of networks with varying connectivity was generated in Escherichia coli. These networks were composed of genes encoding the transcriptional regulators Lacl, TetR, and lambda Cl, as well as the corresponding promoters. They displayed phenotypic behaviors resembling binary logical circuits, with two chemical “inputs” and a fluorescent protein “output.” Within this simple system, diverse computational functions arose through changes in network connectivity. Combinatorial synthesis provides an alternative approach for studying biological networks, as well as an efficient method for producing diverse phenotypes in vivo.}, author = {Guet, Calin C and Elowitz, Michael and Hsing, Weihong and Leibler, Stanislas}, issn = {0036-8075}, journal = {Science}, number = {5572}, pages = {1466 -- 1470}, publisher = {American Association for the Advancement of Science}, title = {{Combinatorial synthesis of genetic networks}}, doi = {10.1126/science.1067407}, volume = {296}, year = {2002}, } @article{3799, abstract = {GABAergic interneurones are diverse in their morphological and functional properties. Perisomatic inhibitory cells show fast spiking during sustained current injection, whereas dendritic inhibitory cells fire action potentials with lower frequency. We examined functional and molecular properties of K(+) channels in interneurones with horizontal dendrites in stratum oriens-alveus (OA) of the hippocampal CA1 region, which mainly comprise somatostatin-positive dendritic inhibitory cells. Voltage-gated K(+) currents in nucleated patches isolated from OA interneurones consisted of three major components: a fast delayed rectifier K(+) current component that was highly sensitive to external 4-aminopyridine (4-AP) and tetraethylammonium (TEA) (half-maximal inhibitory concentrations < 0.1 mM for both blockers), a slow delayed rectifier K(+) current component that was sensitive to high concentrations of TEA, but insensitive to 4-AP, and a rapidly inactivating A-type K(+) current component that was blocked by high concentrations of 4-AP, but resistant to TEA. The relative contributions of these components to the macroscopic K(+) current were estimated as 57 +/- 5, 25 +/- 6, and 19 +/- 2 %, respectively. Dendrotoxin, a selective blocker of Kv1 channels had only minimal effects on K(+) currents in nucleated patches. Coapplication of the membrane-permeant cAMP analogue 8-(4-chlorophenylthio)-adenosine 3':5'-cyclic monophosphate (cpt-cAMP) and the phosphodiesterase blocker isobutyl-methylxanthine (IBMX) resulted in a selective inhibition of the fast delayed rectifier K(+) current component. This inhibition was absent in the presence of the protein kinase A (PKA) inhibitor H-89, implying the involvement of PKA-mediated phosphorylation. Single-cell reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed a high abundance of Kv3.2 mRNA in OA interneurones, whereas the expression level of Kv3.1 mRNA was markedly lower. Similarly, RT-PCR analysis showed a high abundance of Kv4.3 mRNA, whereas Kv4.2 mRNA was undetectable. This suggests that the fast delayed rectifier K(+) current and the A-type K(+) current component are mediated predominantly by homomeric Kv3.2 and Kv4.3 channels. Selective modulation of Kv3.2 channels in OA interneurones by cAMP is likely to be an important factor regulating the activity of dendritic inhibitory cells in principal neurone-interneurone microcircuits.}, author = {Lien, Cheng and Martina, Marco and Schultz, Jobst and Ehmke, Heimo and Jonas, Peter M}, issn = {0022-3751}, journal = {Journal of Physiology}, number = {Pt 2}, pages = {405 -- 419}, publisher = {Wiley-Blackwell}, title = {{Gating, modulation and subunit composition of voltage-gated K(+) channels in dendritic inhibitory interneurones of rat hippocampus}}, doi = {10.1113/jphysiol.2001.013066}, volume = {538}, year = {2002}, } @article{3800, abstract = {Networks of GABAergic interneurons are of critical importance for the generation of gamma frequency oscillations in the brain. To examine the underlying synaptic mechanisms, we made paired recordings from "basket cells" (BCs) in different subfields of hippocampal slices, using transgenic mice that express enhanced green fluorescent protein (EGFP) under the control of the parvalbumin promoter. Unitary inhibitory postsynaptic currents (IPSCs) showed large amplitude and fast time course with mean amplitude-weighted decay time constants of 2.5, 1.2, and 1.8 ms in the dentate gyrus, and the cornu ammonis area 3 (CA3) and 1 (CA1), respectively (33-34 degrees C). The decay of unitary IPSCs at BC-BC synapses was significantly faster than that at BC-principal cell synapses, indicating target cell-specific differences in IPSC kinetics. In addition, electrical coupling was found in a subset of BC-BC pairs. To examine whether an interneuron network with fast inhibitory synapses can act as a gamma frequency oscillator, we developed an interneuron network model based on experimentally determined properties. In comparison to previous interneuron network models, our model was able to generate oscillatory activity with higher coherence over a broad range of frequencies (20-110 Hz). In this model, high coherence and flexibility in frequency control emerge from the combination of synaptic properties, network structure, and electrical coupling.}, author = {Bartos, Marlene and Vida, Imre and Frotscher, Michael and Meyer, Axel and Monyer, Hannah and Geiger, Jörg and Jonas, Peter M}, issn = {0027-8424}, journal = {PNAS}, number = {20}, pages = {13222 -- 13227}, publisher = {National Academy of Sciences}, title = {{Fast synaptic inhibition promotes synchronized gamma oscillations in hippocampal interneuron networks}}, doi = {10.1073/pnas.192233099}, volume = {99}, year = {2002}, }