Developmental dynamics of occipital and cervical somites.

Development of somites leading to somite compartments, sclerotome, dermomyotome and myotome, has been intensely investigated. Most knowledge on somite development, including the commonly used somite maturation stages, is based on data from somites at thoracic and lumbar levels. Potential regional differences in somite maturation dynamics have been indicated by a number of studies, but have not yet been comprehensively examined. Here, we present an overview on the developmental dynamics of somites at occipital and cervical levels in the chicken embryo. We show that in these regions, the onset of sclerotomal and myotomal compartment formation is later than at thoracolumbar levels, and is initiated simultaneously in multiple somites, which is in contrast to the serial cranial- to- caudal progression of somite maturation in the trunk. Our data suggest a variant spatiotemporal regulation of somite development in occipitocervical somites.

Auditory Profiles of Classical, Jazz, and Rock Musicians: Genre-Specific Sensitivity to Musical Sound Features.

When compared with individuals without explicit training in music, adult musicians have facilitated neural functions in several modalities. They also display structural changes in various brain areas, these changes corresponding to the intensity and duration of their musical training. Previous studies have focused on investigating musicians with training in Western classical music. However, musicians involved in different musical genres may display highly differentiated auditory profiles according to the demands set by their genre, i.e., varying importance of different musical sound features. This hypothesis was tested in a novel melody paradigm including deviants in tuning, timbre, rhythm, melody transpositions, and melody contour. Using this paradigm while the participants were watching a silent video and instructed to ignore the sounds, we compared classical, jazz, and rock musicians' and non-musicians' accuracy of neural encoding of the melody. In all groups of participants, all deviants elicited an MMN response, which is a cortical index of deviance discrimination. The strength of the MMN and the subsequent attentional P3a responses reflected the importance of various sound features in each music genre: these automatic brain responses were selectively enhanced to deviants in tuning (classical musicians), timing (classical and jazz musicians), transposition (jazz musicians), and melody contour (jazz and rock musicians). Taken together, these results indicate that musicians with different training history have highly specialized cortical reactivity to sounds which violate the neural template for melody content.

Checklist of earthworms (Oligochaeta: Lumbricidae) from Germany.

A checklist of the German earthworm fauna (Oligochaeta: Lumbricidae) is presented, including published data, data from reports, diploma- and PhD- theses as well as unpublished data from museum collections, research institutions and private persons. Overall, 16,000 datasets were analyzed to produce the first German checklist of Lumbricidae. The checklist comprises 46 earthworm species from 15 genera and provides ecological information, zoogeographical distribution type and information on the species distribution in Germany. Only one species, Lumbricus badensis Michaelsen, 1907, is endemic to Germany, whereas 41% are peregrine. As there are 14 species occurring exclusively in the southern or eastern part of Germany, the species numbers in German regions increase from north to south.

First clinical experiences with a direct acoustic cochlear stimulator in comparison to preoperative fitted conventional hearing aids.

OBJECTIVE: Patients with moderate-to-severe mixed hearing losses (MHLs) are hard to provide sufficient benefit with currently available conventional hearing aids. Here, the long-term safety of a direct acoustic cochlear stimulator (DACS) and the effectiveness compared with conventional "high-performance" hearing aids were investigated. STUDY DESIGN: Prospective, within patient reference, nonrandomized, interventional multicenter clinical study performed at these 3 centers: Medical University Hannover, University of Heidelberg, and Helios Hospital Krefeld. PATIENTS AND INTERVENTION: Ten otosclerosis patients with severe-to-profound MHL were preoperatively fitted with state-of-the-art conventional hearing aids (HA). After 2 months of testing conventional HA, 9 of the patients decided to be implanted with a DACS. MAIN OUTCOME MEASURES: Air conduction (AC) and bone conduction (BC) aided and unaided thresholds, speech discrimination before and after implantation and at 3, 6, and 12 months after activation. The subjective benefit was assessed by the Abbreviated Profile of Hearing Aid Benefit (APHAB). RESULTS: Preoperative hearing thresholds were preserved over the 12 month observation time after activation. Average functional gain (0.5-4 kHz) achieved with conventional HA was 47 dB compared with 56 dB with the DACS. Speech-in-noise tests revealed a lower SNR for DACS (3.1 dB) than for the HA (6.6 dB) and patients were more satisfied with the DACS. CONCLUSION: The DACS significantly improved hearing, speech intelligibility, and satisfaction in patients with a severe-to-profound mixed hearing loss and can be considered a safe and useful alternative to conventional hearing aids.

Development of somites, muscle, and skeleton is independent of signals from the Wolffian duct.

BACKGROUND: In the vertebrate embryo, skeletal muscle and the axial skeleton arise from the somites. Patterning of the somites into the respective somite compartments, namely dermomyotome, myotome, and sclerotome, depends on molecular signals from neighboring structures, including surface ectoderm, neural tube, notochord, and lateral plate mesoderm. A potential role of the intermediate mesoderm, notably the Wolffian or nephric duct, in somite development is poorly understood. RESULTS: We studied somite compartmentalization as well as muscular and skeletal development after surgical ablation of the early Wolffian duct anlage, which lead to loss of the Wolffian duct and absence of the mesonephros, whereas Pax2 expression in the nephrogenic mesenchyme was temporarily maintained. We show that somite compartments, as well as the somite derivatives, skeletal muscle and the cartilaginous skeleton, develop normally in the absence of the Wolffian duct. CONCLUSIONS: Our results indicate that development of the musculoskeletal system is independent of the Wolffian duct as a signaling center.

Divergent regulation of Wnt-mediated development of the dorsomedial and ventrolateral dermomyotomal lips.

The dermomyotome is the dorsal compartment of the somite which gives rise to multiple cell fates including skeletal muscle, connective tissue, and endothelia. It consists of a pseudostratified, roughly rectangular epithelial sheet, the margins of which are called the dermomyotomal lips. The dermomyotomal lips are blastema-like epithelial growth zones, which continuously give rise to resident dermomyotomal cells and emigrating muscle precursor cells, which populate the subjacent myotomal compartment. Wnt signaling has been shown to regulate both dermomyotome formation and maintenance of the dermomyotomal lips. Whereas the epithelialization of the dermomyotome is regulated via canonical, ß-catenin-dependent Wnt signaling, the downstream signaling mechanisms suppressing epithelial-mesenchymal transition (EMT) in the mature dermomyotomal lips have been unknown. Here, we present evidence that dermomyotomal lip sustainment is differentially regulated. Whereas the dorsomedial dermomyotomal lip is maintained by canonical Wnt signaling, development of the ventrolateral dermomyotomal lip is regulated by non-canonical, PCP-like Wnt signaling. We discuss our results in the light of the different developmental prerequisites in the dorsomedial and ventrolateral lips, respectively, thus providing a new perspective on the regulation of dermomyotomal EMT.

Cystathionine gamma-lyase expression during avian embryogenesis.

Cystathionine gamma-lyase (CSE) is a key enzyme in the trans-sulphuration pathway for the biosynthesis of cysteine from methionine and catalyses the hydrolysis of cystathionine into cysteine. It has been reported to be expressed in mammalian liver and kidney but so far no comprehensive developmental expression analysis of CSE has been available. We cloned a 600 bp fragment of chick CSE cDNA and analysed its expression pattern during avian embryonic development until embryonic day 13. We found CSE expression in various developing organs including the notochord, eye, neural tube, limb bud mesenchyme and sclerotomal compartment of the somites. Notably, prominent expression was found in renal epithelia throughout kidney development, i.e. in the tubular structures of pronephros, mesonephros and metanephros. Our data introduce CSE as a novel marker gene to study avian kidney development.

From air oscillations to music and speech: functional magnetic resonance imaging evidence for fine-tuned neural networks in audition.

In the auditory modality, music and speech have high informational and emotional value for human beings. However, the degree of the functional specialization of the cortical and subcortical areas in encoding music and speech sounds is not yet known. We investigated the functional specialization of the human auditory system in processing music and speech by functional magnetic resonance imaging recordings. During recordings, the subjects were presented with saxophone sounds and pseudowords /ba:ba/ with comparable acoustical content. Our data show that areas encoding music and speech sounds differ in the temporal and frontal lobes. Moreover, slight variations in sound pitch and duration activated thalamic structures differentially. However, this was the case with speech sounds only while no such effect was evidenced with music sounds. Thus, our data reveal the existence of a functional specialization of the human brain in accurately representing sound information at both cortical and subcortical areas. They indicate that not only the sound category (speech/music) but also the sound parameter (pitch/duration) can be selectively encoded.