@article{HuggenbergerVaterDeisz2009, author = {Huggenberger, Stefan and Vater, Marianne and Deisz, Rudolf A.}, title = {Interlaminar differences of intrinsic properties of pyramidal neurons in the auditory cortex of mice}, issn = {1047-3211}, doi = {10.1093/cercor/bhn143}, year = {2009}, abstract = {Cortical information processing depends crucially upon intrinsic neuronal properties modulating a given synaptic input, in addition to integration of excitatory and inhibitory inputs. These intrinsic mechanisms are poorly understood in sensory cortex areas. We therefore investigated neuronal properties in slices of the auditory cortex (AC) of normal hearing mice using whole-cell patch-clamp recordings of pyramidal neurons in layers II/III, IV, V, and VI in the current- and voltage clamp mode. A total of 234 pyramidal neurons were included in the analysis revealing distinct laminar differences. Regular spiking (RS) neurons in layer II/III have significantly lower resting membrane potential, higher threshold for action potential generation, and larger K-ir and I-h amplitudes compared with layer V and VI RS neurons. These currents could improve temporal resolution in the upper layers of the AC. Additionally, the presence of a T-type Ca2+ current could be an important factor of RS neurons in these upper layers to amplify temporally closely correlated inputs. Compared with upper layers, lower layers (V and VI) exhibit a higher relative abundance of intrinsic bursting neurons. These neurons may provide layer-specific transfer functions for interlaminar, intercortical, and corticofugal information processing.}, language = {en} } @article{HuggenbergerRidgwayOelschlageretal.2006, author = {Huggenberger, Stefan and Ridgway, Sam H. and Oelschlager, Helmut H.A. and Kirschenbauer, Irmgard and Vogl, Thomas J. and Klima, Milan}, title = {Histological analysis of the nasal roof cartilage in a neonate sperm whale (Physeter macrocephalus : Mammalia, Odontoceti)}, issn = {0044-5231}, doi = {10.1016/j.jcz.2006.01.001}, year = {2006}, abstract = {The nasal roof cartilage of a neonate sperm whale (Physeter macrocephalus) was examined by gross dissection and routine histology. This cartilage is part of the embryonic Tectum nasi and is a critical feature in the formation of the massive sperm whale forehead. In neonates as well as in adults, the blade-like nasal roof cartilage extends diagonally through the huge nasal complex from the bony nares to the blowhole on the left side of the rostral apex of the head. It accompanies the left nasal passage along its entire length, which may reach several meters in adult males. The tissue of the nasal roof cartilage in the neonate whale shows an intermediate state of development. For example, in embryos and fetuses, the nasal roof cartilage consists of hyaline cartilage, but in adult sperm whales, it also includes elastic fibers. In our neonate sperm whale, the nasal roof cartilage already consisted of adult-like elastic cartilage. In addition, the active or growing, layer of the perichondrium was relatively thick compared to that of fetuses, and a large number of straight, elastic fibers that were arranged perpendicularly to the long axis of the nasal roof cartilage were present. These neonatal features call be interpreted as characteristics of immature and growing cartilaginous tissue. An important function of the nasal roof cartilage may be the stabilization of the left nasal passage, which is embedded within the soft tissue of the nasal complex. The nasal roof cartilage with its elastic fibers may keep the nasal passage open and prevent its collapse from Bernoulli forces during inhalation. Additionally, the intrinsic tension of the massive nasal musculature may be a source of compression on the nasal roof cartilage and could explain its hyaline character in the adult. In our neonate specimen, in contrast, the cartilaginous rostrum (i.e., mesorostral cartilage) consisted of hyaline cartilage with an ample blood supply. The cartilaginous rostrum does not change its histological characteristics during development, but its function In adults is still not understood.}, language = {en} } @article{RauschmannHuggenbergerKossatzetal.2006, author = {Rauschmann, Michael A. and Huggenberger, Stefan and Kossatz, Lars Swen and Oelschl{\"a}ger, Helmut H. A.}, title = {Head morphology in perinatal dolphins: A window into phylogeny and ontogeny}, series = {Journal of morphology}, volume = {267}, journal = {Journal of morphology}, number = {11}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0362-2525}, doi = {10.1002/jmor.10477}, pages = {1295 -- 1315}, year = {2006}, abstract = {In this paper on the ontogenesis and evolutionary biology of odontocete cetaceans (toothed whales), we investigate the head morphology of three perinatal pantropical spotted dolphins (Stenella attenuata) with the following methods: computer-assisted tomography, magnetic resonance imaging, conventional X-ray imaging, cryo-sectioning as well as gross dissection. Comparison of these anatomical methods reveals that for a complete structural analysis, a combination of modern imaging techniques and conventional morphological methods is needed. In addition to the perinatal dolphins, we include series of microslides of fetal odontocetes (S. attenuata, common dolphin Delphinus delphis, narwhal Monodon monoceros). In contrast to other mammals, newborn cetaceans represent an extremely precocial state of development correlated to the fact that they have to swim and surface immediately after birth. Accordingly, the morphology of the perinatal dolphin head is very similar to that of the adult. Comparison with early fetal stages of dolphins shows that the ontogenetic change from the general mammalian bauplan to cetacean organization was characterized by profound morphological transformations of the relevant organ systems and roughly seems to parallel the phylogenetic transition. from terrestrial ancestors to modern odontocetes.}, language = {en} }