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)

In the primate, connections between primary visual cortex (V1) and the second visual area (V2) are segregated according to the characteristic pattern of cytochrome oxidase (CO) activity in each of these cortical areas. Patches supply thin stripes, whereas interpatches supply pale stripes and thick stripes. Previously, the projection from patches to thin stripes was reported to arise exclusively from layer 2/3. In this present report, we made injections of a retrograde tracer, cholera toxin-B (CTB-Au), into macaque V2 thin stripes to re-examine the laminar origin of their input from V1. While the great majority of cells indeed resided in layer 2/3, small populations were also present in layers 4A, 4B, and 5/6. The location of CTB-filled cells in each layer was analyzed to determine the relationship with CO patches. Cells in layers 2/3, 4A, and 4B were aggregated into patches, forming columns that project to thin stripes. Surprisingly, cells in layer 5/6 were scattered, seemingly at random. These findings confirm that the main V1 projection to V2 stripes emanates from patches in layer 2/3. However, multiple V1 layers innervate V2 thin stripes, and the projection from layer 5/6 does not respect the patch/interpatch dichotomy.
Cereb Cortex 2007 Apr
PMID:Neurons in V1 patch columns project to V2 thin stripes. 1674 May 82

Previous studies of human primary visual cortex (V1) have demonstrated a significant eye-specific decrease in cytochrome oxidase (CO) staining following monocular enucleation. We have extended these results by examining CO staining and neurofilament labeling in V1 from a patient with long-standing monocular blindness. A pattern of reduced neurofilament reactivity was found to align with pale CO-stained ocular dominance columns. Neurons located within deprived ocular dominance columns were significantly smaller compared with those in nondeprived columns. A spatial analysis of the relationship between CO blobs and ocular dominance columns revealed that both deprived and nondeprived blobs tended to align with the centers of ocular dominance columns.
Cereb Cortex 2007 Jun
PMID:Cytochrome oxidase and neurofilament reactivity in monocularly deprived human primary visual cortex. 1683 56

The laminar and area patterning of the mammalian neocortex are two organizing principles that define its functional architecture. Members of the immunoglobulin (Ig) superfamily of cell adhesion molecules influence neural development by regulating cell adhesion, migration, and process growth. Here we describe the dynamic expression of the unique Ig-containing cell adhesion molecule, MAM domain-containing glycosylphosphatidylinositol anchor 1 (MDGA1), during forebrain development in mice and compare it with other markers. We show that MDGA1 is a layer-specific marker and an area-specific marker, being expressed in layers 2/3 throughout the neocortex, but within the primary somatosensory area (S1), MDGA1 is also uniquely expressed in layers 4 and 6a. Comparisons with other markers, including cadherins, serotonin, cytochrome oxidase, ROR beta, and COUP-TF1, reveal unique features of patterned expression of MDGA1 within cortex and S1 barrels. Further, our findings indicate that at earlier stages of development, MDGA1 is expressed by Reelin- and Tbr1-positive Cajal-Retzius neurons that originate from multiple sources outside of neocortex and emigrate into it. At even earlier stages, MDGA1 is expressed by the earliest diencephalic and mesencephalic neurons, which appear to migrate from a MDGA1-positive domain of progenitors in the diencephalon and form a "preplate." These findings show that MDGA1 is a unique marker for studies of cortical lamination and area patterning and together with recent reports suggest that MDGA1 has critical functions in forebrain/midbrain development.
Cereb Cortex 2007 Jul
PMID:Novel IgCAM, MDGA1, expressed in unique cortical area- and layer-specific patterns and transiently by distinct forebrain populations of Cajal-Retzius neurons. 1695 69

The key objective of this study was to determine the distribution and morphology of koniocellular (K) lateral geniculate nucleus (LGN) axons in primary visual cortex (V1) of the macaque monkey. In particular, we were interested in understanding whether subpopulations of K axons exist in this species and, if so, if these subpopulations arise from different K layers of the LGN. Restricted injections of the tracers, biotinilated dextran amine, or Phaseolus vulgaris leucoagglutinin were targeted to specific LGN K layers under electrophysiological guidance and immunocytochemistry was used to visualize labeled axons in cortex that were subsequently reconstructed through serial sections. A total of 36 complete axons and 166 axon segments were reconstructed. Our results identified at least 2 main subpopulations of K axons in macaque V1 based on branching patterns and bouton distribution. Axons that arise primarily from LGN layers K1 and K2 are morphologically simple and tend to branch in cortical layers 1 and 3A. These axons give rise to fewer boutons than seen in axons arising from the dorsal K LGN layers K3-K6. Axons that arise from LGN layers K3-K6 terminate as complex, focused arbors in the cytochrome oxidase (CO) blobs in layer 3Balpha, with only occasional simple projections to the more superficial layers of cortex. Combined with previous observations, our data suggest that there are at least 3 subclasses of K LGN axons in macaque monkey that are similar to K axons identified earlier in both nocturnal simian owl monkeys (Ding and Casagrande 1997) and in prosimian, bush babies (Lachica and Casagrande 1992) suggesting that the LGN K channels that terminate in the CO blobs and in layer 1 are not unique to macaque monkeys but are a common primate feature.
Cereb Cortex 2007 Oct
PMID:The morphology of the koniocellular axon pathway in the macaque monkey. 1721 77

Several studies have shown that neurons with similar response properties are arranged together in domains across primary visual cortex (V1). An orderly pattern of domains has been described for preferences to ocular dominance, orientation, and spatial frequency. Temporal frequency preference, another important attribute of the visual scene, also might be expected to map into different domains. Using optical imaging and a variety of quantitative methods, we examined how temporal frequency selectivity is mapped in V1 of the prosimian primate, bush baby (Otolemur garnetti). We found that unlike other attribute maps, selectivity for different temporal frequencies is arranged uniformly across V1 with no evidence of local clustering. Global tuning for temporal frequency, based on magnitude of response, showed a good match to previous tuning curves for single neurons. A peak response was found around 2.0 Hz, with smaller attenuation at lower temporal frequencies than at higher frequencies. We also examined whether the peak temporal frequency response differed between anatomical compartments defined by cytochrome oxidase (CO). No significant differences in the preference for temporal frequency were found between these CO compartments. Our findings show that key sensory attributes that are linked in perception can be organized in quite distinct ways in V1 of primates.
Cereb Cortex 2008 Aug
PMID:Functional organization of temporal frequency selectivity in primate visual cortex. 1805 99

In functional neuroimaging, neurovascular coupling is used to generate maps of hemodynamic changes that are assumed to be surrogates of regional neural activation. The aim of this study was to characterize the microvascular system of the primate cortex as a basis for understanding the constraints imposed on a region's hemodynamic response by the vascular architecture, density, as well as area- and layer-specific variations. In the macaque visual cortex, an array of anatomical techniques has been applied, including corrosion casts, immunohistochemistry, and cytochrome oxidase (COX) staining. Detailed measurements of regional vascular length density, volume fraction, and surface density revealed a similar vascularization in different visual areas. Whereas the lower cortical layers showed a positive correlation between the vascular and cell density, this relationship was very weak in the upper layers. Synapse density values taken from the literature also displayed a very moderate correlation with the vascular density. However, the vascular density was strongly correlated with the steady-state metabolic demand as measured by COX activity. This observation suggests that although the number of neurons and synapses determines an upper bound on an area's integrative capacity, its vascularization reflects the neural activity of those subpopulations that represent a "default" mode of brain steady state.
Cereb Cortex 2008 Oct
PMID:The microvascular system of the striate and extrastriate visual cortex of the macaque. 1822 35

Optical imaging was used to map patterns of visually evoked activation in the second (V2) and third (V3) visual areas of owl monkeys. Modular patterns of activation were produced in response to stimulation with oriented gratings, binocular versus monocular stimulation, and stimuli containing wide-field luminance changes. In V2, luminance-change domains tended to lie between domains selective for orientation. Regions preferentially activated by binocular stimulation co-registered with orientation-selective domains. Co-alignment of images with cytochrome oxidase (CO)-processed sections revealed functional correlates of 2 types of CO-dense regions in V2. Orientation-responsive domains and binocular domains were correlated with the locations of CO-thick stripes, and luminance-change domains were correlated with the locations of CO-thin stripes. In V3, orientation preference, luminance-change, and binocular preference domains were observed, but were more irregularly arranged than those in V2. Our data suggest that in owl monkey V2, consistent with that in macaque monkeys, modules for processing contours and binocularity exist in one type of compartment and that modules related to processing-surface features exist within a separate type of compartment.
Cereb Cortex 2009 Jun
PMID:The organization of orientation-selective, luminance-change and binocular- preference domains in the second (V2) and third (V3) visual areas of New World owl monkeys as revealed by intrinsic signal optical imaging. 1884 61

Mitochondria are known to be central to the cell's response to ischemia, because of their role in energy generation, in free radical generation, and in the regulation of apoptosis. Heat shock protein 75 (Hsp75/Grp75/mortalin/TRAP1) is a member of the HSP70 chaperone family, which is targeted to mitochondria. Overexpression of Hsp75 was achieved in rat brain by DNA transfection, and expression was observed in both astrocytes and neurons. Rats were subjected to 100 mins middle cerebral artery occlusion followed by assessment of infarct volume, neurological score, mitochondrial function, and levels of oxidative stress at 24 h reperfusion. Overexpression of Hsp75 reduced infarct area from 44.6%+/-21.1% to 25.7%+/-12.1% and improved neurological outcome significantly. This was associated with improved mitochondrial function as shown by protection of complex IV activity, marked reduction of free radical generation detected by hydroethidine fluorescence, reduction of lipid peroxidation detected by 4-hydroxy-2-nonenol immunoreactivity, and increased preservation of ATP levels. This suggests that targeting mitochondria for protection may be a useful strategy to reduce ischemic brain injury.
J Cereb Blood Flow Metab 2009 Feb
PMID:Overexpression of mitochondrial Hsp70/Hsp75 in rat brain protects mitochondria, reduces oxidative stress, and protects from focal ischemia. 1898 56

Formation of whisker-related barrels in primary somatosensory cortex (S1) requires communication between presynaptic thalamocortical afferents (TCAs) and postsynaptic cortical neurons. GAP-43 is crucially involved in targeting TCAs to postsynaptic S1 neurons but its influence on the interactions between these 2 elements has not been explored. Here, we tested the hypothesis that reduced early expression of presynaptic GAP-43 (GAP-43 heterozygous [HZ] mice) alters postsynaptic differentiation of barrel cells. We found a transient increase in cytochrome oxidase staining between P6 and P14 in HZ animals, indicative of increased metabolic activity in barrel cortex during this time. Golgi impregnation and microtubule-associated protein 2 immunohistochemistry showed anomalous dendritic patterning in GAP-43 HZ cortex at P5, with altered dendritic length and branching and abnormal retention of dendrites that extend into developing septa. This deficiency was no longer apparent at P7, suggesting partial recovery of dendritic pruning processes. Finally, we showed early defects in synaptogenesis from P4 to P5 with increased colocalization of NR1 and GluR1 staining in HZ mice. By P7, this colocalization had normalized to wild type levels. Taken together, our findings suggest abnormal postsynaptic differentiation in GAP-43 HZ cortex during early barrel development, followed by adaptive compensation and partial phenotypic rescue.
Cereb Cortex 2010 Jul
PMID:Postsynaptic deregulation in GAP-43 heterozygous mouse barrel cortex. 1991 93

Parallel visual pathways in the primate brain known as the dorsal and ventral streams receive retinal inputs mainly through the magnocellular (M) and parvocellular (P) layers of the lateral geniculate nucleus. Inputs from these layers terminate within distinct parts of layer 4C of V1 (visual area 1). Due to the complexity of M- and P-derived neural connectivity in V1 and higher visual areas, the contributions of M and P inputs to the dorsal and ventral streams remain unclear. Employing retrograde transsynaptic transport of rabies virus, we analyzed the architecture of bottom-up pathways toward ventral stream area V4 (visual area 4) and dorsal stream area MT (middle temporal area). We found that V4 receives both M and P inputs "trisynaptically" from layer 4C via layer 2/3 of V1, whereas MT receives M-dominant input "disynaptically" from layer 4C via layer 4B of V1. V4 also receives disynaptic input from the dorsal stream portion of V2 (visual area 2) (i.e., cytochrome oxidase-stained thick stripes). Moreover, both M and P inputs reach V4 trisynaptically and MT disynaptically through "short-cut" pathways that bypass layer 4C of V1. The differential patterns of multisynaptic geniculo-cortical pathways to V4 and MT imply distinct modes of information processing in the dorsal and ventral streams.
Cereb Cortex 2011 Dec
PMID:Differential architecture of multisynaptic geniculo-cortical pathways to V4 and MT. 2151 14


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