J C Durack | PubMed Health

PubMed2001

Structured data management--the design and implementation of a web-based video archive prototype.

In response to the lack of readily available multimedia rich medical knowledge sources to support medical education and patient care, we designed and implemented a web-based video publishing platform. In order to promote the development of high-quality, up-to-date educational content, we have devised a scalable structure that allows online submissions and continuous updating of video and accompanying textual descriptions. Our goal is to enable experts in varied medical domains to collaborate in the construction of a video library using an intuitive web-based interface. Neurologists at Stanford built a well-annotated neurology video collection that initially emphasized childhood and adult movement disorders. The collection may be accessed either as a stand-alone resource or as part of the Stanford Skolar MD, an integrated online medical knowledge provider. This manuscript discusses the design framework and implementation details of structured media content development. We present examples illustrating media data collection, content indexing using UMLS concepts, media storage, and web presentation.

Abstracting and Indexing↗

PubMedDate not supplied

Development of horizontal projections in layer 2/3 of ferret visual cortex.

Pyramidal cells in layer 2/3 of cat striate cortex extend long axons that form clustered projections linking iso-orientation columns. Using extracellular biocytin injections in brain slices, the formation of these projections was examined in the ferret to determine whether horizontal projections exhibit similar patterns of development in the ferret and the cat, and to relate the time course of horizontal projection formation to the onset of patterned visual experience and orientation selectivity. Soon after the first appearance of axon collaterals in layer 2/3, around postnatal day 22 (P22), pyramidal cell axons were uniformly distributed and unbranched for up to 1 mm from the cell body. By P26, axons began to form secondary branches 1-2 mm from the cell body, with little evidence for distinct clusters. The first indication of selective elaboration of secondary branches and retraction of unbranched collaterals occurred around P28. By P34, patchy regions of axon branches emerged, though unbranched collaterals were still present, followed by distinct, adult-like clusters by P45. Although the general pattern of horizontal projection formation closely resembles that seen in the cat (Callaway and Katz, 1990), the ferret circuitry matures earlier than that of the cat relative to the time of eye opening. Since eye opening in ferrets occurs between P30 and P32, this system of orientation-specific patches begins to develop in the absence of patterned visual input and when most cortical cells are not yet orientation selective, suggesting a prominent role for spontaneous activity in initiating cluster formation. The refinement of clustered connections, however, does occur synchronously with the maturation of orientation-selective responses (Chapman and Stryker, 1993).

Age Factors↗