Here, we have developed DIAMonDS (Drosophila Individual Activity Monitoring and Detection System) comprising time-lapse imaging by a charge-coupled device (CCD) flatbed scanner and Sapphire, a novel algorithm and web application. DIAMonDS automatically and sequentially identified the transition time points of multiple life cycle events such as pupariation, eclosion, and death in individual flies at high temporal resolution and on a large scale. DIAMonDS performed simultaneous multiple scans to measure individual deaths (≤1152 flies per scanner) and pupariation and eclosion timings (≤288 flies per scanner) under various chemical exposures, environmental conditions, and genetic backgrounds. DIAMonDS correctly identified 74–85% of the pupariation and eclosion events and ~ 92% of the death events within ± 10 scanning frames. This system is a powerful tool for studying the influences of genetic and environmental factors on fruit flies and efficient, high-throughput genetic and chemical screening in drug discovery.
An asymmetric total synthesis of picrotoxinin was achieved, with a Mizoroki-Heck reaction of an enantioenriched tricyclic lactone with isopropenyl bromide as the key transformation, enabling the highly diastereoselective introduction of the requisite C4-isopropenyl group. After functional group manipulations including carbonylation, bromoetherification, epoxidation and dihydroxylation, picrotoxinin was obtained in moderate to good yield.
Here, we have developed DIAMonDS (Drosophila Individual Activity Monitoring and Detection System) comprising time-lapse imaging by a charge-coupled device (CCD) flatbed scanner and Sapphire, a novel algorithm and web application. DIAMonDS automatically and sequentially identified the transition time points of multiple life cycle events such as pupariation, eclosion, and death in individual flies at high temporal resolution and on a large scale. DIAMonDS performed simultaneous multiple scans to measure individual deaths (≤ 1,152 flies per scanner) and pupariation and eclosion timings (≤ 288 flies per scanner) under various chemical exposures, environmental conditions, and genetic backgrounds. DIAMonDS correctly identified 74–85% of the pupariation and eclosion events and ∼92% of the death events within ±10 scanning frames. This system is a powerful tool for studying the influences of genetic and environmental factors on fruit flies and efficient, high-throughput genetic and chemical screening in drug discovery.
Rhythmic activities were widely observed in many brain regions. Human EEG recording revealed several frequency modulation of the oscillation reflecting internal brain states such as attentional modulation in visual systems. On the other hand, in vivo intracellular recordings suggested that individual neurons showed persistent membrane fluctuations and global oscillation originated from the activity of the neuronal fluctuations.Furthermore, it was found that some types of neuron showed membrane resonance in their subthreshold level. However, functional roles of the subthreshold resonance in a recurrent neural network are still unknown. Here, we computationally examined the behavior of resonator network driven by external inputs and organized through the spike-timing-dependent plasticity (STDP) under oscillatory background and noise. As a result, it was shown how the resonator network modified its responsiveness depending on frequency modulation and its connectivity through the STDP.
Cortical neurons exhibit membrane fluctuations and spontaneous transitions between distinct different two states characterized by subthreshold level of membrane potential. It has been known by modeling study that the mechanism of the spontaneous fluctuation originates from not only reverberation in a cortical circuit but intrinsic factor at a single neuron level. The two-state transitions are widely found in many brain regions and these transitions typically occurred spontaneously and synchronously. However, its computational advantage is still unclear. In this study, we investigated synaptic learning for external inputs in a model neuron whose dynamics of membrane potential fluctuation was modulated through the modification of ionic channel dynamics. It was observed that the membrane fluctuation could modulate the learning property to sequential inputs through the spike-timing-dependent plasticity.
Recent in vivo multiunit recording revealed that spontaneous activity (SA) and evoked activity (EA) of neural population in primary visual cortex (V1) show the similar spatiotemporal patterns. Furthermore, the similarity gradually increases depending on visual experience during development. However, it is still unclear how such a network dynamics is organized through the learning of local circuit in cerebral cortex. Through the computational modeling study, it was demonstrated that cortical network could generate precise spike sequences that repetitively occur during both SA and EA, and such the repetitive spatiotemporal patterns are organized through synaptic learning mediated by the spike-timing-dependent plasticity (STDP). As a result, it was found that the model network could acquire the internal representation for external sensory experience described as the spatiotemporal pattern of population firings. It was also provided that the circuit structure for such kind of the visual experience-dependent organization of population dynamics that is recently observed by in vivo multiunit recording study in V1 during development.
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