Dataset Information

Development of the mouse cochlea database (MCD).

ABSTRACT: The mouse cochlea database (MCD) provides an interactive, image database of the mouse cochlea for learning its anatomy and data mining of its resources. The MCD website is hosted on a centrally maintained, high-speed server at the following URL: (http://mousecochlea.umn.edu). The MCD contains two types of image resources, serial 2D image stacks and 3D reconstructions of cochlear structures. Complete image stacks of the cochlea from two different mouse strains were obtained using orthogonal plane fluorescence optical microscopy (OPFOS). 2D images of the cochlea are presented on the MCD website as: viewable images within a stack, 2D atlas of the cochlea, orthogonal sections, and direct volume renderings combined with isosurface reconstructions. In order to assess cochlear structures quantitatively, "true" cross-sections of the scala media along the length of the basilar membrane were generated by virtual resectioning of a cochlea orthogonal to a cochlear structure, such as the centroid of the basilar membrane or the scala media. 3D images are presented on the MCD website as: direct volume renderings, movies, interactive QuickTime VRs, flythrough, and isosurface 3D reconstructions of different cochlear structures. 3D computer models can also be used for solid model fabrication by rapid prototyping and models from different cochleas can be combined to produce an average 3D model. The MCD is the first comprehensive image resource on the mouse cochlea and is a new paradigm for understanding the anatomy of the cochlea, and establishing morphometric parameters of cochlear structures in normal and mutant mice.

SUBMITTER: Santi PA

PROVIDER: S-EPMC2628570 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature

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Development of the mouse cochlea database (MCD).

Santi Peter A PA Rapson Ian I Voie Arne A

Hearing research 20080525 1-2

The mouse cochlea database (MCD) provides an interactive, image database of the mouse cochlea for learning its anatomy and data mining of its resources. The MCD website is hosted on a centrally maintained, high-speed server at the following URL: (http://mousecochlea.umn.edu). The MCD contains two types of image resources, serial 2D image stacks and 3D reconstructions of cochlear structures. Complete image stacks of the cochlea from two different mouse strains were obtained using orthogonal plane ...[more]

PMID: 18603386

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Project description:Cochlear implants (CIs) provide sound and speech sensations for patients with severe to profound hearing loss by electrically stimulating the auditory nerve. While most CI users achieve some degree of open set word recognition under quiet conditions, hearing that utilizes complex neural coding (e.g., appreciating music) has proved elusive, probably because of the inability of CIs to create narrow regions of spectral activation. Several novel approaches have recently shown promise for improving spatial selectivity, but substantial design differences from conventional CIs will necessitate much additional safety and efficacy testing before clinical viability is established. Outside the cochlea, magnetic stimulation from small coils (micro-coils) has been shown to confine activation more narrowly than that from conventional microelectrodes, raising the possibility that coil-based stimulation of the cochlea could improve the spectral resolution of CIs. To explore this, we delivered magnetic stimulation from micro-coils to multiple locations of the cochlea and measured the spread of activation utilizing a multielectrode array inserted into the inferior colliculus; responses to magnetic stimulation were compared to analogous experiments with conventional microelectrodes as well as to responses when presenting auditory monotones. Encouragingly, the extent of activation with micro-coils was ~60% narrower compared to electric stimulation and largely similar to the spread arising from acoustic stimulation. The dynamic range of coils was more than three times larger than that of electrodes, further supporting a smaller spread of activation. While much additional testing is required, these results support the notion that magnetic micro-coil CIs can produce a larger number of independent spectral channels and may therefore improve auditory outcomes. Further, because coil-based devices are structurally similar to existing CIs, fewer impediments to clinical translational are likely to arise.

Project description:BACKGROUND:To support healthcare professionals in dealing with ethically difficult situations, Clinical Ethics Support (CES) services like Moral Case Deliberation (MCD) are increasingly implemented. To assess the impact of CES, it is important to evaluate outcomes. Despite general claims about outcomes from MCD experts and some qualitative research, there exists no conceptual analysis of outcomes yet. Therefore, the aim of this study was to systematically define and categorize MCD outcomes. An additional aim was to compare these outcomes with the outcomes in the Euro-MCD Instrument from 2014, to further validate this Instrument. METHODS:The concept mapping method was used and involves qualitative and quantitative steps including brainstorming, individual structuring, computation of concept maps (by principal component analysis and cluster analysis), group interpretation and utilization. In total, 12 experienced MCD participants from a variety of professional backgrounds participated in two sessions. RESULTS:The focus group brainstorm resulted in a list of 85 possible MCD outcomes, of which a point map and concept maps were constructed. After a thorough discussion of each cluster, final consensus was reached on the names and position of 8 clusters of MCD outcomes: 1) Organisation and Policy; 2) Team development; 3) Personal development focused on the Other Person; 4) Personal development as Professional, focused on Skills; 5) Personal development as Professional, focused on Knowledge; 6) Personal development as an Individual; 7) Perception and Connection; and 8) Concrete action. CONCLUSIONS:This study explored and categorized MCD outcomes in a concept mapping focus group. When comparing the results with the Euro-MCD Instrument, our study confirms that outcomes of MCD can be categorized in clusters referring to the organisational level, team development, personal development (both as an individual and a professional) and the concrete case-level. In developing CES evaluation tools, it is important to be explicit if an outcome refers to the individual or the team, to knowledge or skills, to the organisation or the specific case. The findings will be used in the further validation of the Euro-MCD Instrument. The current study further contributes to the field of evaluating CES in general and defining outcomes of MCD in particular.

Project description:Mutations in the genes encoding for gap junction proteins connexin 26 (Cx26) and connexin 30 (Cx30) have been linked to syndromic and nonsyndromic hearing loss in mice and humans. The release of ATP from connexin hemichannels in cochlear nonsensory cells has been proposed to be the main trigger for action potential activity in immature sensory inner hair cells (IHCs), which is crucial for the refinement of the developing auditory circuitry. Using connexin knock-out mice, we show that IHCs fire spontaneous action potentials even in the absence of ATP-dependent intercellular Ca2+ signaling in the nonsensory cells. However, this signaling from nonsensory cells was able to increase the intrinsic IHC firing frequency. We also found that connexin expression is key to IHC functional maturation. In Cx26 conditional knock-out mice (Cx26Sox10-Cre), the maturation of IHCs, which normally occurs at approximately postnatal day 12, was partially prevented. Although Cx30 has been shown not to be required for hearing in young adult mice, IHCs from Cx30 knock-out mice exhibited a comprehensive brake in their development, such that their basolateral membrane currents and synaptic machinery retain a prehearing phenotype. We propose that IHC functional differentiation into mature sensory receptors is initiated in the prehearing cochlea provided that the expression of either connexin reaches a threshold level. As such, connexins regulate one of the most crucial functional refinements in the mammalian cochlea, the disruption of which contributes to the deafness phenotype observed in mice and DFNB1 patients. SIGNIFICANCE STATEMENT:The correct development and function of the mammalian cochlea relies not only on the sensory hair cells, but also on the surrounding nonsensory cells. Although the nonsensory cells have been largely implicated in the general homeostasis in the mature cochlea, their involvement in the initial functional differentiation of the sensory inner hair cells is less clear. Using mutant mouse models for the most common form of congenital deafness in humans, which are knock-outs for the gap-junction channels connexin 26 and connexin 30 genes, we show that defects in nonsensory cells prevented the functional maturation of inner hair cells. In connexin knock-outs, inner hair cells remained stuck at a prehearing stage of development and, as such, are unable to process sound information.

Dataset Information

Development of the mouse cochlea database (MCD).

Publications

Development of the mouse cochlea database (MCD).

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