The receptor mGluR5 is a metabotropic glutamate receptor with messenger RNA abundantly present throughout cortex, hippocampus, and caudate/putamen that is also coupled to phosphatidyl inositide hydrolysis and calcium mobilization. In this study, the distribution of mGluR5 was examined in rat brain by immunocytochemistry. The antibody utilized is highly specific and does not cross react with the most closely related other metabotropic glutamate receptor, as determined by Western blot analysis of nonneuronal cells transfected with metabotropic receptor coding sequences. The receptor mGluR5 is widely expressed with the highest density in olfactory bulb, caudate/putamen, lateral septum, cortex, and hippocampus, as confirmed with both immunocytochemistry and Western blot analysis. Electron microscopic studies in hippocampus and cortex indicate that the labeling is mostly on membranes of dendritic spines and shafts. Light and electron microscopic evidence indicates that some mGluR5 immunoreactivity is located in presynaptic axon terminals, suggesting that mGluR5 may function as a presynaptic receptor.

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Two new techniques for analyzing retinotopic mapsarrow diagrams and visual field sign maps-are demonstrated with a large electrophysiological mapping data set from owl monkey extrastriate visual cortex. An arrow diagram (vectors indicating receptive field centers placed at cortical coordinates) provides a more compact and understandable representation of retinotopy than does a standard receptive field chart (accompanied by a penetration map) or a double contour map (e.g., isoeccentricity and isopolar angle as a function of cortical x, y-coordinates). None of these three representational techniques, however, make separate areas easily visible, especially in data sets containing numerous areas with partial, distorted representations of the visual hemrfield. Therefore, we computed visual field sign maps (non-mirror-image vs mirror-image visual field representation) from the angle between the direction of the cortical gradient in receptive field eccentricity and the cortical gradient in receptive field angle for each small region of the cortex. Visual field sign is a local measure invariant to cortical map orientation and distortion but also to choice of receptive field coordinate system. To estimate the gradients, we first interpolated the eccentricity and polar angle data onto regular grids using a distance-weighted smoothing algorithm. The visual field sign technique provides a more objective method for using retinotopy to outline multiple visual areas. In order to relate these arrow and visual field sign maps accurately to architectonic features visualized in the stained, flattened cortex, we also developed a deformable template algorithm for warping the photograph-derived penetration map using the final observed location of a set of marking lesions.

Fever in SAH is associated with vasospasm and poor outcome independently of hemorrhage severity or presence of infection.

Dense retinotopy data sets were obtained by microelectrode visual receptive field mapping in dorsal and lateral visual cortex of anesthetized owl monkeys. The cortex was then physically flatmounted and stained for myelin or cytochrome oxidase. Retinotopic mapping data were digitized, interpolated to a uniform grid, analyzed using the visual field sign technique—which locally distinguishes mirror image from nonmirror image visual field representations—and correlated with the myelin or cytochrome oxidase patterns. The region between V2 (nonmirror) and MT (nonmirror) contains three areas—DLp (mirror), DLi (nonmirror), and DLa/MTc (mirror). DM (mirror) was thin anteroposteriorly, and its reduced upper field bent somewhat anteriorly away from V2. DI (nonmirror) directly adjoined V2 (nonmirror) and contained only an upper field representation that also adjoined upper field DM (mirror). Retinotopy was used to define area VPP (nonmirror), which adjoins DM anteriorly, area FSTd (mirror), which adjoins MT ventrolaterally, and TP (mirror), which adjoins MT and DLa/MTc dorsoanteriorly. There was additional retinotopic and architectonic evidence for five more subdivisions of dorsal and lateral extrastriate cortex—TA (nonmirror), MSTd (mirror), MSTv (nonmirror), FSTv (nonmirror), and PP (mirror). Our data appear quite similar to data from marmosets, though our field sign-based areal subdivisions are slightly different. The region immediately anterior to the superiorly located central lower visual field V2 varied substantially between individuals, but always contained upper fields immediately touching lower visual field V2. This region appears to vary even more between species. Though we provide a summary diagram, given within- and between-species variation, it should be regarded as a guide to parsing complex retinotopy rather than a literal representation of any individual, or as the only way to agglomerate the complex mosaic of partial upper and lower field, mirror- and nonmirror-image patches into areas.