Lmo4 in the Basolateral Complex of the Amygdala Modulates Fear Learning

Pavlovian fear conditioning is an associative learning paradigm in which mice learn to associate a neutral conditioned stimulus with an aversive unconditioned stimulus. In this study, we demonstrate a novel role for the transcriptional regulator Lmo4 in fear learning. LMO4 is predominantly expressed in pyramidal projection neurons of the basolateral complex of the amygdala (BLC). Mice heterozygous for a genetrap insertion in the Lmo4 locus (Lmo4gt/+), which express 50% less Lmo4 than their wild type (WT) counterparts display enhanced freezing to both the context and the cue in which they received the aversive stimulus. Small-hairpin RNA-mediated knockdown of Lmo4 in the BLC, but not the dentate gyrus region of the hippocampus recapitulated this enhanced conditioning phenotype, suggesting an adult- and brain region-specific role for Lmo4 in fear learning. Immunohistochemical analyses revealed an increase in the number of c-Fos positive puncta in the BLC of Lmo4gt/+ mice in comparison to their WT counterparts after fear conditioning. Lastly, we measured anxiety-like behavior in Lmo4gt/+ mice and in mice with BLC-specific downregulation of Lmo4 using the elevated plus maze, open field, and light/dark box tests. Global or BLC-specific knockdown of Lmo4 did not significantly affect anxiety-like behavior. These results suggest a selective role for LMO4 in the BLC in modulating learned but not unlearned fear

Input and output of the central complex related to polarized light in the nervous system of the desert locust Schistocerca gregaria

Animal species from nearly all major taxa show migratory behavior, and some of these animals cover remarkable distances. Well studied examples are migratory birds like the arctic tern Sterna paradisaea that migrates from boreal and high Arctic breeding grounds to the Southern Ocean (Egevang et al., 2009). Insects also attain excellent achievements in annual migration as shown by the monarch butterfly Danaus plexippus which changes its habitat between eastern North America and central Mexico (Kyriacou, 2009). How can these animals perform such remarkable migrations? Which mechanisms underlie such a performance? Foraging ants and bees use navigational strategies similar to those of birds and mammals to reach a goal. To navigate through familiar terrain, all of these species use path integration and memories of visual landmarks (Collett & Collett, 2002). During path integration, an animal permanently updates a homing vector resulting from all angular and translational movements so that it can always take a direct path back to its starting point (Collett & Collett, 2000). To compute resulting novel routes out of several single homing flights, bees use a map-like navigation strategy that allows targetoriented decisions at any place and toward any intended location within the familiar terrain (Menzel et al., 2006). These mechanisms are used for near-range navigation, termed as "homing", rather than for long-distance navigation tasks. Animals that navigate through unknown space are forced to use cues of a global nature, such as the geomagnetic field, the stars, and cues related to the position of the sun (Frost & Mouritsen, 2006). Like diverse marine animals, e.g. marine turtles, lobsters, and molluscs, the green sea-turtle Chelonia mydas has a magnetic map sense for navigation to specific targets (Cain et al., 2005; Lohmann et al., 2004). Many diurnal species use a time-compensated sun-compass, other sky compass cues like polarized light, or stars for steering toward distant targets (Wehner, 1984; Homberg, 2004; Frost & Mouritsen, 2006)

Identification of distinct tyraminergic and octopaminergic neurons innervating the central complex of the desert locust, Schistocerca gregaria

The central complex is a group of modular neuropils in the insect brain with a key role in visual memory, spatial orientation, and motor control. In desert locusts the neurochemical organization of the central complex has been investigated in detail, including the distribution of dopamine-, serotonin-, and histamine-immunoreactive neurons. In the present study we identified neurons immunoreactive with antisera against octopamine, tyramine, and the enzymes required for their synthesis, tyrosine decarboxylase (TDC) and tyramine beta-hydroxylase (TBH). Octopamine- and tyramine immunostaining in the central complex differed strikingly. In each brain hemisphere tyramine immunostaining was found in four neurons innervating the noduli, 12-15 tangential neurons of the protocerebral bridge, and about 17 neurons that supplied the anterior lip region and parts of the central body. In contrast, octopamine immunostaining was present in two bilateral pairs of ascending fibers innervating the upper division of the central body and a single pair of neurons with somata near the esophageal foramen that gave rise to arborizations in the protocerebral bridge. Immunostaining for TDC, the enzyme converting tyrosine to tyramine, combined the patterns seen with the tyramine- and octopamine antisera. Immunostaining for TBH, the enzyme converting tyramine to octopamine, in contrast, was strikingly similar to octopamine immunolabeling. We conclude that tyramine and octopamine act as neurotransmitters/modulators in distinct sets of neurons of the locust central complex with TBH likely being the rate-limiting enzyme for octopamine synthesis in a small subpopulation of TDC-containing neurons

Linux-Klienten in Workstation-Gruppen

In den letzten Jahren ist Linux eine ernsthafte Alternative zu Microsoft's Windows-Betriebssystemen auf PCs geworden.Ziel des Projekts war zu untersuchen, ob und mit welchem Aufwand es müglich ist, Linux-Klienten auf Intel-Plattformen in existierende homogene AIX- bzw. Compaq/AXP-Workstationgruppen zu integrieren.Neben der Einbindung und Anpassung in das bestehende Konzept wurden auch zusätzliche Produkte wie Windows unter Linux und alternative Funktionen wie die Benutzeroberflächen KDE und GNOME betrachtet. Weiterhin wurde untersucht, wie die Performance im Vergleich zu Unix-Workstations anderer Hersteller aussieht