The brain’s response to sensory input is strikingly modulated by behavioral state. Notably, the visual response of mouse primary visual cortex (V1) is enhanced by locomotion, a tractable and accessible example of a time-locked change in cortical state. The neural circuits that transmit behavioral state to sensory cortex to produce this modulation are unknown. In vivo calcium imaging of behaving animals revealed that locomotion activates vasoactive intestinal peptide (VIP)-positive neurons in mouse V1 independent of visual stimulation and largely through nicotinic inputs from basal forebrain. Optogenetic activation of VIP neurons increased V1 visual responses in stationary awake mice, artificially mimicking the effect of locomotion, and photolytic damage of VIP neurons abolished the enhancement of V1 responses by locomotion. These findings establish a cortical circuit for the enhancement of visual response by locomotion and provide a potential common circuit for the modulation of sensory processing by behavioral state.
This study presents new ignition delay data recorded in a rapid compression machine over a wide range temperature, pressure and fuel/air ratio. This data is an extension of that recorded previously (D. Darcy, C.J. Tobin, K. Yasunaga, J.M. Simmie, J. Würmel, T. Niass, O. Mathieu, S.S. Ahmed, C.K. Westbrook, H.J. Curran, Combust. Flame, 159 (2012) 2219-2232 for the oxidation of n-propylbenzene in a high-pressure shock tube. The data was obtained for equivalence ratios of 0.29, 0.48, 0.96, and 1.92, at compressed gas pressures of 10, 30 and 50 atm, and over the temperature range of 650-1000 K. Experimental data was also obtained at 50 atm for all equivalence ratios in our new heated high-pressure shock tube and this is also presented here. Agreement between the data obtained in both the rapid compression machine and in the shock tube facilities showed excellent complementarity. A previously published chemical kinetic mechanism has been updated in attempt to simulate ignition delay times at the lower temperature conditions of this study by adding the appropriate species and reactions including alkyl-peroxyl and hydroperoxy-alkyl radical chemistry. In general, good agreement was obtained between the model and experiments and consistent trends were observed * address: Combustion Chemistry Centre, School of Chemistry, NUI Galway, Ireland. Phone: 00353-91-493856. Email: email@example.com URL: http://c3.nuigalway.ie/ (H.J. Curran)Preprint submitted to Combustion and Flame February 5, 2013 and these are discussed. Comparisons are also made with experimental data obtained for n-butylbenzene over the same range of conditions and common trends are highlighted. It was found that, in general, n-butylbenzene was faster to ignite over the lower temperature range of 650-1000 K.
Abstract-We present a survey of psychophysiology-based assessment for Quality of Experience (QoE) in advanced multimedia technologies. We provide a classification of methods relevant to QoE and describe related psychological processes, experimental design considerations, and signal analysis techniques. We summarise multimodal techniques and discuss several important aspects of psychophysiology-based QoE assessment, including the synergies with psychophysical assessment and the need for standardised experimental design. This survey is not considered to be exhaustive but serves as a guideline for those interested to further explore this emerging field of research.
Newborn inhibitory neurons migrate into existing neural circuitry in the olfactory bulb throughout the lifetime of adult mammals. While many factors contribute to the maturation of neural circuits, intracellular calcium is believed to play an important role in regulating cell migration and the development of neural systems. However, the factors underlying calcium signaling within newborn neurons in the postnatal olfactory bulb are not well understood. Here, we show that migrating, immature neurons in the olfactory bulb subependymal layer (SEL) undergo spontaneous and depolarization-evoked intracellular calcium transients mediated by high-voltage-activated L-type calcium channels. In contrast to migrating immature neurons in other brain regions, modulation of calcium transients in SEL cells does not alter their rate of migration.
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