Neural processing of imminent collision in humans

Detecting a looming object and its imminent collision is imperative to survival. For most humans, it is a fundamental aspect of daily activities such as driving, road crossing and participating in sport, yet little is known about how the brain both detects and responds to such stimuli. Here we use functional magnetic resonance imaging to assess neural response to looming stimuli in comparison with receding stimuli and motion-controlled static stimuli. We demonstrate for the first time that, in the human, the superior colliculus and the pulvinar nucleus of the thalamus respond to looming in addition to cortical regions associated with motor preparation. We also implicate the anterior insula in making timing computations for collision events

An fMRI study of parietal cortex involvement in the visual guidance of locomotion

Locomoting through the environment typically involves anticipating impending changes in heading trajectory in addition to maintaining the current direction of travel. We explored the neural systems involved in the “far road” and “near road” mechanisms proposed by Land and Horwood (1995) using simulated forward or backward travel where participants were required to gauge their current direction of travel (rather than directly control it). During forward egomotion, the distant road edges provided future path information, which participants used to improve their heading judgments. During backward egomotion, the road edges did not enhance performance because they no longer provided prospective information. This behavioral dissociation was reflected at the neural level, where only simulated forward travel increased activation in a region of the superior parietal lobe and the medial intraparietal sulcus. Providing only near road information during a forward heading judgment task resulted in activation in the motion complex. We propose a complementary role for the posterior parietal cortex and motion complex in detecting future path information and maintaining current lane positioning, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved

Hershey Arena: Anton Tedesko’s Pioneering Form

Civil engineering structures are part of our cultural heritage. The story of who we are can be told, in part, by what we have built. There have been pivotal moments in civil engineering design history wherein a master engineer creates a pioneering structure. One major example is Anton Tedesko’s 1936 Hershey Ice Arena, the first large-scale thin shell concrete roof in the United States. Tedesko left all his papers, including the original design and analysis calculations of the Hershey shell, to the Princeton Maillart Archives. These documents, as well as other archival materials and photographs, provide insight into the design history of Hershey, and the transfer of thin shell technology to America. In this paper, we retrace the design and analysis calculations performed by Tedesko, and compare them to modern computer models. We show that the hand calculations are sufficiently accurate, and in fact are necessary for initial form finding. We close by pointing out the enormous impact that this design had in thin shell concrete construction, and argue for the preservation of this remarkable structure

A versatile high resolution objective for imaging quantum gases

We present a high resolution objective lens made entirely from catalog singlets that has a numerical aperture of 0.36. It corrects for aberrations introduced by a glass window and has a long working distance of 35mm, making it suitable for imaging objects within a vacuum system. This offers simple high resolution imaging for many in the quantum gas community. The objective achieves a resolution of 1.3{\mu}m at the design wavelength of 780nm, and a diffraction-limited field of view of 360{\mu}m when imaging through a 5mm window. Images of a resolution target and a pinhole show quantitative agreement with the simulated lens performance. The objective is suitable for diffraction-limited imaging on the D2 line of all the alkalis by changing only the aperture diameter, retaining numerical apertures above 0.32. The design corrects for window thicknesses of up to 15mm if the singlet spacings are modified

Real time analysis of β2-adrenoceptor-mediated signaling kinetics in Human Primary Airway Smooth Muscle Cells reveals both ligand and dose dependent differences

BACKGROUND: β(2)-adrenoceptor agonists elicit bronchodilator responses by binding to β(2)-adrenoceptors on airway smooth muscle (ASM). In vivo, the time between drug administration and clinically relevant bronchodilation varies significantly depending on the agonist used. Our aim was to utilise a fluorescent cyclic AMP reporter probe to study the temporal profile of β(2)-adrenoceptor-mediated signaling induced by isoproterenol and a range of clinically relevant agonists in human primary ASM (hASM) cells by using a modified Epac protein fused to CFP and a variant of YFP. METHODS: Cells were imaged in real time using a spinning disk confocal system which allowed rapid and direct quantification of emission ratio imaging following direct addition of β(2)-adrenoceptor agonists (isoproterenol, salbutamol, salmeterol, indacaterol and formoterol) into the extracellular buffer. For pharmacological comparison a radiolabeling assay for whole cell cyclic AMP formation was used. RESULTS: Temporal analysis revealed that in hASM cells the β(2)-adrenoceptor agonists studied did not vary significantly in the onset of initiation. However, once a response was initiated, significant differences were observed in the rate of this response with indacaterol and isoproterenol inducing a significantly faster response than salmeterol. Contrary to expectation, reducing the concentration of isoproterenol resulted in a significantly faster initiation of response. CONCLUSIONS: We conclude that confocal imaging of the Epac-based probe is a powerful tool to explore β(2)-adrenoceptor signaling in primary cells. The ability to analyse the kinetics of clinically used β(2)-adrenoceptor agonists in real time and at a single cell level gives an insight into their possible kinetics once they have reached ASM cells in vivo