68,682 research outputs found
Neuronal representation of visual motion and orientation in the fly medulla
Get PDFSpalthoff C, Gerdes R, Kurtz R. Neuronal representation of visual motion and orientation in the fly medulla. Frontiers in Neural Circuits. 2012;6:72.In insects, the first extraction of motion and direction clues from local brightness modulations is thought to take place in the medulla. However, whether and how these computations are represented in the medulla stills remain widely unknown, because electrical recording of the neurons in the medulla is difficult. As an effort to overcome this difficulty, we employed local electroporation in vivo in the medulla of the blowfly (Calliphora vicina) to stain small ensembles of neurons with a calcium-sensitive dye. We studied the responses of these neuronal ensembles to spatial and temporal brightness modulations and found selectivity for grating orientation. In contrast, the responses to the two opposite directions of motion of a grating with the same orientation were similar in magnitude, indicating that strong directional selectivity is either not present in the types of neurons covered by our data set, or that direction-selective signals are too closely spaced to be distinguished by our calcium imaging. The calcium responses also showed a bell-shaped dependency on the temporal frequency of drifting gratings, with an optimum higher than that observed in one of the subsequent processing stages, i.e., the lobula plate. Medulla responses were elicited by on- as well as off-stimuli with some spatial heterogeneity in the sensitivity for “on” and “off”, and in the polarity of the responses. Medulla neurons thus show similarities to some established principles of motion and edge detection in the vertebrate visual system
Application of multiline two-photon microscopy to functional in vivo imaging
Get PDFKurtz R, Fricke M, Kalb J, Tinnefeld P, Sauer M. Application of multiline two-photon microscopy to functional in vivo imaging. Journal of Neuroscience Methods. 2006;151(2):276-286
Adaptation accentuates responses of fly motion-sensitive visual neurons to sudden stimulus changes
Get PDFKurtz R, Egelhaaf M, Meyer HG, Kern R. Adaptation accentuates responses of fly motion-sensitive visual neurons to sudden stimulus changes. Proceedings of The Royal Society B: Biological Sciences. 2009;276(1673):3711-3719
Wahrhafftige Erklärung Ihrer Kön. Majestät/ In Groß-Britannien/ wieder Das unrechtmässige verfahren der Fairfaxischen Armee/ So sie selbst einem Ihrer Diener kurtz vor Ihrem End gegeben/ und zu Befriedigung ihres Volcks aufgehen wollen lassen / [C. R.]
Get PDFWAHRHAFFTIGE ERKLÄRUNG IHRER KÖN. MAJESTÄT/ IN GROSS-BRITANNIEN/ WIEDER DAS UNRECHTMÄSSIGE VERFAHREN DER FAIRFAXISCHEN ARMEE/ SO SIE SELBST EINEM IHRER DIENER KURTZ VOR IHREM END GEGEBEN/ UND ZU BEFRIEDIGUNG IHRES VOLCKS AUFGEHEN WOLLEN LASSEN / [C. R.]
Wahrhafftige Erklärung Ihrer Kön. Majestät/ In Groß-Britannien/ wieder Das unrechtmässige verfahren der Fairfaxischen Armee/ So sie selbst einem Ihrer Diener kurtz vor Ihrem End gegeben/ und zu Befriedigung ihres Volcks aufgehen wollen lassen / [C. R.] (1)
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Dendritic calcium accumulation associated with direction-selective adaptation in visual motion-sensitive neurons in vivo
Get PDFKurtz R, Dürr V, Egelhaaf M. Dendritic calcium accumulation associated with direction-selective adaptation in visual motion-sensitive neurons in vivo. Journal of Neurophysiology. 2000;84(4):1914-1923
Distinct alterations in the guanylate cyclase-C/cGMP pathway are evident across different subtypes of irritable bowel syndrome patients
No full textPoster presentation PP097A. M. Harrington, J. Castro, R. L. Young, C. Kurtz, A. Silos-Santiago, N. Nguyen, J. M. Andrews and S. M. Brierle
Efficient implementation of lazy suffix trees
Get PDFGiegerich R, Kurtz S, Stoye J. Efficient implementation of lazy suffix trees. SOFTWARE-PRACTICE & EXPERIENCE. 2003;33(11):1035-1049.We present an efficient implementation of a write-only top-down construction for suffix trees. Our implementation is based on a new, space-efficient representation of suffix trees that requires only 12 bytes per input character in the worst case, and 8.5 bytes per input character on average for a collection of files of different type. We show how to efficiently implement the lazy evaluation of suffix trees such that a subtree is evaluated only when it is traversed for the first time. Our experiments show that for the problem of searching many exact patterns in a fixed input string, the lazy top-down construction is often faster and more space efficient than other methods. Copyright (C) 2003 John Wiley Sons, Ltd
Examination of fly motion vision by functional fluorescence techniques
Get PDFKurtz R, Kalb J, Spalthoff C. Examination of fly motion vision by functional fluorescence techniques. FRONTIERS IN BIOSCIENCE. 2008;13:3009-3021
Maturation and myotonia influence the abundance of cation channels K-DR, K-IR and C-IR differently: a patch-clamp study on mouse interosseus muscle fibres
No full textKurtz R, Schirm T, Jockusch H. Maturation and myotonia influence the abundance of cation channels K-DR, K-IR and C-IR differently: a patch-clamp study on mouse interosseus muscle fibres. PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY. 1999;438(4):516-524
Analysis of chromosome/allele loss in genetically unstable yeast by quantitative real-time PCR.
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