Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ultrastructure of the lateroventral subcomponent of the visual dorsolateral anterior thalamic nucleus of the pigeon (DLLv) was analyzed using hodological techniques and GABA-immunocytochemistry. Two types of GABA-immunonegative hyperpalliopetal neurons and a single type of strongly GABA-immunoreactive (-ir) interneuron were identified, the latter displaying long dendrites with some containing synaptic vesicles (DCSV). Ten types of axon terminal were identified and divided into two categories. The first, GABA-immunonegative and making asymmetrical synaptic contact, contain round (RT1, RT2, RT3) or pleiomorphic synaptic and many dense-core vesicles (DCT). RT1 terminals are retinothalamic and RT2 terminals hyperpalliothalamic; both mainly contact dendrites of projection neurons (72% and 78% respectively), less frequently dendrites of interneurons and sometimes DCSV; RT1 terminals are rarely involved in synaptic triads. The second category are consistently GABA-immunopositive. Four types (PT1-4), distinguished by their pleiomorphic synaptic vesicles, make symmetrical synaptic contact essentially with dendrites of projection neurons, more rarely on dendrites of interneurons (PT2). PT1 terminals are very probably those of interneurons, whereas the rare PT4 terminals are of retinal origin. A fifth type (RgT) contains round synaptic vesicles and makes asymmetrical synaptic contact with dendrites of projection neurons and interneurons. PT2 and RgT terminals occasionally contact DCSV of interneurons, which are sometimes involved in synaptic triads. Two final subcategories (DCgT1-2) contain many dense-core vesicles. Our findings are compared with those of previous studies concerning the fine structure and neurochemical properties of the GLd of reptiles and mammals, with special reference to the origin of the extraretinal and extracortical projections to this structure.
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PMID:Fine structure of the visual dorsolateral anterior thalamic nucleus of the pigeon (Columba livia): a hodological and GABA-immunocytochemical study. 1818 7

Model-based vector quantization (MVQ) is introduced here as a variant of vector quantization (VQ). MVQ has the asymmetrical computational properties of conventional VQ, but does not require the use of pregenerated codebooks. This is a great advantage, since codebook generation is usually a computationally intensive process, and maintenance of codebooks for coding and decoding can pose difficulties. MVQ uses a simple mathematical model for mean removed errors combined with a human visual system model to generate parameterized codebooks. The error model parameter (lambda) is included with the compressed image as side information from which the same codebook is regenerated for decoding. As far as the user is concerned, MVQ is a codebookless VQ variant. After a brief introduction, the problems associated with codebook generation and maintenance are discussed. We then give a description of the MVQ algorithm, followed by an evaluation of the performance of MVQ on remotely sensed image data sets from NASA sources. The results obtained with MVQ are compared with other VQ techniques and JPEG/DCT. Finally, we demonstrate the performance of MVQ as a part of a progressive compression system suitable for use in an image archival and distribution installation.
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PMID:Model-based vector quantization with application to remotely sensed image data. 1826 61