Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extrastriate areas TEO and V4 have been associated with form and color vision. Area V4 has also been suggested to participate in processes concerned with attention, stimulus salience, and perceptual learning. In a continuing effort to elucidate the connectional interactions and microcircuitry of these areas, we describe in this report the pattern of feedback connections from TEO and V4. Connections were demonstrated by injections of the high-resolution anterograde tracers PHA-L or biocytin and further analyzed by reconstruction of 25 individual axons through serial sections. This analysis yielded several new results: (1) Both areas TEO and V4 have widespread feedback connections (defined by their preferential termination in layer 1 and avoidance of layer 4). From TEO, there are dense projections to area V4 and moderate ones to V2 and V1. From V4, there are dense projections to V2 and moderate ones to V3 and V1. (2) Terminal fields span large territories in area V1, up to 6.0 mm in the case of axons originating from TEO; up to 5.0 mm in the case of axons originating from V4. In V2, fields tend to be smaller, between 3.0-5.0 mm. (3) Many axons from TEO and some from V4 have terminations in both areas V1 and V2. (4) Because individual terminal clusters and segments are often larger than cytochrome oxidase compartments, especially in V1, we suggest they may not be correlated with this compartmental organization. These results are consistent with the hypothesis that feedback connections may contribute to processes other than perceptual discrimination.
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PMID:Divergent feedback connections from areas V4 and TEO in the macaque. 803 30

The lateral geniculate nucleus (LGN) of primates contains three classes of relay cells, the magnocellular (M), parvocellular (P), and koniocellular (K) cells. At present, very little is known about either the structure or function of the K relay cells in New or Old World monkeys (simian primates). In monkeys, K cells are located between the main LGN layers and adjacent to the optic tract. For convenience, these intercalated cell layers are numbered K1-K4 starting closest to the optic tract with K1. The objective of this study was to examine the details of K axon morphology in the primary visual cortex (V1) of owl monkeys and to determine if different K layers give rise to distinct axon types. For this purpose, injections of WGA-HRP or PHA-L were made into specific K LGN layers and the distribution and morphology of the resulting labeled axons were analyzed. Injections of fluorescent tracers also were made within the superficial layers of V1 to further document connections via analysis of the patterns of retrogradely labeled cells in the LGN. Our main finding is that K axons in owl monkeys terminate as delicate focused arbors within single cytochrome oxidase (CO) blob columns in cortical layer III and within cortical layer I. Overall, the morphology of the K axons in these monkeys is quite similar to what we described previously for K geniculocortical axons in the distantly related bush baby (prosimian primate), suggesting that the basic features of this pathway are common to all primates. Our results also provide evidence that the axon arbors from different K layers are morphologically distinct; axons from LGN layer K1 project mainly to cortical layer I, while axons from LGN layer K3 chiefly terminate in cortical layer III. Taken together, these results imply that the basic features of axons within the K pathway are conserved across primates, and that the K axons from different K layers are likely to differ in function based upon their different morphologies.
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PMID:The distribution and morphology of LGN K pathway axons within the layers and CO blobs of owl monkey V1. 927 98