Neural Representations of Airflow in Drosophila Mushroom Body

The Drosophila mushroom body (MB) is a higher olfactory center where olfactory and other sensory information are thought to be associated. However, how MB neurons of Drosophila respond to sensory stimuli other than odor is not known. Here, we characterized the responses of MB neurons to a change in airflow, a stimulus associated with odor perception. In vivo calcium imaging from MB neurons revealed surprisingly strong and dynamic responses to an airflow stimulus. This response was dependent on the movement of the 3rd antennal segment, suggesting that Johnston's organ may be detecting the airflow. The calyx, the input region of the MB, responded homogeneously to airflow on. However, in the output lobes of the MB, different types of MB neurons responded with different patterns of activity to airflow on and off. Furthermore, detailed spatial analysis of the responses revealed that even within a lobe that is composed of a single type of MB neuron, there are subdivisions that respond differently to airflow on and off. These subdivisions within a single lobe were organized in a stereotypic manner across flies. For the first time, we show that changes in airflow affect MB neurons significantly and these effects are spatially organized into divisions smaller than previously defined MB neuron types

Hemodynamic responses in human multisensory and auditory association cortex to purely visual stimulation

BACKGROUND: Recent findings of a tight coupling between visual and auditory association cortices during multisensory perception in monkeys and humans raise the question whether consistent paired presentation of simple visual and auditory stimuli prompts conditioned responses in unimodal auditory regions or multimodal association cortex once visual stimuli are presented in isolation in a post-conditioning run. To address this issue fifteen healthy participants partook in a "silent" sparse temporal event-related fMRI study. In the first (visual control) habituation phase they were presented with briefly red flashing visual stimuli. In the second (auditory control) habituation phase they heard brief telephone ringing. In the third (conditioning) phase we coincidently presented the visual stimulus (CS) paired with the auditory stimulus (UCS). In the fourth phase participants either viewed flashes paired with the auditory stimulus (maintenance, CS-) or viewed the visual stimulus in isolation (extinction, CS+) according to a 5:10 partial reinforcement schedule. The participants had no other task than attending to the stimuli and indicating the end of each trial by pressing a button. RESULTS: During unpaired visual presentations (preceding and following the paired presentation) we observed significant brain responses beyond primary visual cortex in the bilateral posterior auditory association cortex (planum temporale, planum parietale) and in the right superior temporal sulcus whereas the primary auditory regions were not involved. By contrast, the activity in auditory core regions was markedly larger when participants were presented with auditory stimuli. CONCLUSION: These results demonstrate involvement of multisensory and auditory association areas in perception of unimodal visual stimulation which may reflect the instantaneous forming of multisensory associations and cannot be attributed to sensation of an auditory event. More importantly, we are able to show that brain responses in multisensory cortices do not necessarily emerge from associative learning but even occur spontaneously to simple visual stimulation

CONCERNING THE ASSIGNMENT OF METHYLENE STRETCHING VIBRATIONS IN HYDROCARBONS

Author Institution: Polytechnic Institute of New YorkDespite extensive experimental and theoretical work, uncertainties about the approximate form of normal modes of vibrations of hydrocarbon chains in the CH stretching region persist. The experimental observations are complicated by the possibility of Fermi resonance with the overtone of $CH_{2}$ deformation vibrations. Recent work on the melting of hydrocarbon chains in phospholipids has led to a reexamination of these assignments. While force field calculations appear to show that there is only a very small amount of coupling between C-H stretching vibrations on adjacent carbons, the experimental results, when one includes both infrared and Raman spectra and when one further examines both all trans and trans-gauche segments for the same molecule, lead to a different conclusion. This is particularly true for the asymmetric $CH_{2}$ stretches, which are seen to extend from 2875 to $2930 cm^{-1}$. The conclusions will be substantiated through a series of infrared and Raman difference spectra

Technology and energy - 21st century outlook

For the past 150 years of energy production and consumption, technology has always exceeded our expectations. Sure, there have been some things that were speculated on thirty years ago as coming soon, and which have still not appeared, but this is probably less a failure of technology development than of speculation. And there is very little reason to believe that the next 150 years will be any different