The central complex is a prominent structure in the Drosophila brain. Visual learning experiments in the flight simulator, with flies with genetically altered brains, revealed that two groups of horizontal neurons in one of its substructures, the fan-shaped body, were required for Drosophila visual pattern memory. However, little is known about the role of other components of the central complex for visual pattern memory. Here we show that a small set of neurons in the ellipsoid body, which is another substructure of the central complex and connected to the fan-shaped body, is also required for visual pattern memory. Localized expression of rutabaga adenylyl cyclase in either the fan-shaped body or the ellipsoid body is sufficient to rescue the memory defect of the rut(2080) mutant. We then performed RNA interference of rutabaga in either structure and found that they both were required for visual pattern memory. Additionally, we tested the above rescued flies under several visual pattern parameters, such as size, contour orientation, and vertical compactness, and revealed differential roles of the fan-shaped body and the ellipsoid body for visual pattern memory. Our study defines a complex neural circuit in the central complex for Drosophila visual pattern memory.

In a genetic screen for active zone defective mutants in Caenorhabditis elegans, we isolated a loss-of-function allele of unc-7, a gene encoding an innexin/pannexin family gap junction protein. Innexin UNC-7 regulates the size and distribution of active zones at C. elegans neuromuscular junctions. Loss-of-function mutations in another innexin, UNC-9, cause similar active zone defects as unc-7 mutants. In addition to presumptive gap junction localizations, both UNC-7 and UNC-9 are also localized perisynaptically throughout development and required in presynaptic neurons to regulate active zone differentiation. Our mosaic analyses, electron microscopy, as well as expression studies suggest a novel and likely nonjunctional role of specific innexins in active zone differentiation in addition to gap junction formations.

Input comparison is thought to occur in many neuronal circuits, including the hippocampus, where functionally important interactions between the Schaffer collateral and perforant pathways have been hypothesized. We investigated this idea using multisite, whole-cell recordings and Ca2+ imaging and found that properly timed, repetitive stimulation of both pathways results in the generation of large plateau potentials in distal dendrites of CA1 pyramidal neurons. These dendritic plateau potentials produce widespread Ca2+ influx, large after-depolarizations, burst firing output, and long-term potentiation of perforant path synapses. Plateau duration is directly related to the strength and temporal overlap of pathway activation and involves back-propagating action potentials and both NMDA receptors and voltage-gated Ca2+ channels. Thus, the occurrence of highly correlated SC and PP input to CA1 is signaled by a dramatic change in output mode and an increase in input efficacy, all induced by a large plateau potential in the distal dendrites of CA1 pyramidal neurons.

This paper demonstrates that patient driving habits lead to homogenous congested flow while impatient driving habits lead to wide-moving jam flow in the high density region based on the numerical simulation of the intelligent driver model proposed by M.Treiber [M. Treiber, A.Hennecke, D. Helbing, Phys. Rev. E 62 (2) (2000), 1805–1824]. In a circular one lane traffic system which includes homogeneous drivers, we obtain the stable condition of homogenous flow and the phase diagram of traffic flow based on the linearization analysis. The phase diagram shows three possible pathways of phase transition along with the increase of global density: from the homogenous free flow to the homogenous congested flow directly, from the homogenous free flow to the synchronized flow then to the homogenous congested flow, or from the homogenous free flow to synchronized flow then to the wide-moving jam flow. The paper also analyzes the traffic flow including heterogenous drivers, and the results indicate that homogenous congested flow will lose its stability when the proportion of impatient drivers reaches a critical value and some new kinds of traffic flow emerge: wide-moving jam flow or a mixture of synchronized flow and wide-moving jam flow.

Camera networks are widely used for tasks such as surveillance, monitoring and tracking. In order to accomplish these tasks, knowledge of localization information such as camera locations and other geometric constraints about the environment (e.g. walls, rooms, and building layout) are typically considered to be essential. However, this information is not always required for many tasks such as estimating the topology of camera network coverage, or coordinate-free object tracking and navigation. In this paper, we propose a simplicial representation (called CN- complex) that can be constructed from discrete local observations from cameras, and utilize this novel representation to recover the topological information of the network coverage. We prove that our representation captures the correct topological information from network coverage for 2.5-D layouts, and demonstrate their utility in simulations as well as a real-world experimental set-up. Our proposed approach is particularly useful in the context of ad-hoc camera networks in indoor/outdoor urban environments with distributed but limited computational power and energy.

BACKGROUND: The genetic analysis of behavior in Drosophila melanogaster has linked genes controlling neuronal connectivity and physiology to specific neuronal circuits underlying a variety of innate behaviors. We investigated the circuitry underlying the adult startle response, using photoexcitation of neurons that produce the abnormal chemosensory jump 6 (acj6) transcription factor. This transcription factor has previously been shown to play a role in neuronal pathfinding and neurotransmitter modality, but the role of acj6 neurons in the adult startle response was largely unknown. PRINCIPAL FINDINGS: We show that the activity of these neurons is necessary for a wild-type startle response and that excitation is sufficient to generate a synthetic escape response. Further, we show that this synthetic response is still sensitive to the dose of acj6 suggesting that that acj6 mutation alters neuronal activity as well as connectivity and neurotransmitter production. RESULTS/SIGNIFICANCE: These results extend the understanding of the role of acj6 and of the adult startle response in general. They also demonstrate the usefulness of activity-dependent characterization of neuronal circuits underlying innate behaviors in Drosophila, and the utility of integrating genetic analysis into modern circuit analysis techniques.

We introduce a method based on machine vision for automatically measuring aggression and courtship in Drosophila melanogaster. The genetic and neural circuit bases of these innate social behaviors are poorly understood. High-throughput behavioral screening in this genetically tractable model organism is a potentially powerful approach, but it is currently very laborious. Our system monitors interacting pairs of flies and computes their location, orientation and wing posture. These features are used for detecting behaviors exhibited during aggression and courtship. Among these, wing threat, lunging and tussling are specific to aggression; circling, wing extension (courtship ’song’) and copulation are specific to courtship; locomotion and chasing are common to both. Ethograms may be constructed automatically from these measurements, saving considerable time and effort. This technology should enable large-scale screens for genes and neural circuits controlling courtship and aggression.

We report the preparation and structure-activity relationships of phosphorus-containing histone deacetylase inhibitors. A strong trend between decreasing phosphorus functional group size and superior mouse pharmacokinetic properties was identified. In addition, optimized candidates showed tumor growth inhibition in xenograft studies.

The gene SSO0495 (proC), which encodes pyrroline-5-carboxylate reductase (P5CR) from the thermoacidophilic archeon Sulfolobus solfataricus P2 (Ss-P5CR), was cloned and expressed. The purified recombinant enzyme catalyzes the thioproline dehydrogenase with concomitant oxidation of NAD(P)H to NAD(P)+. This archeal enzyme has an optimal alkaline pH in this reversible reaction and is thermostable with a half-life of approximately 30 min at 80 degrees C. At pH 9.0, the reverse activation rate is nearly 3-fold higher than at pH 7.0. The homopolymer was characterized by cross-linking and size exclusion gel filtration chromatography. Ss-P5CR was crystallized by the hanging-drop vapor-diffusion method at 37 degrees C. Diffraction data were obtained to a resolution of 3.5A and were suitable for X-ray structure determination.