2,867 research outputs found
We-them\u27 inhumanity
I am saddened by your editorial endorsement of quiet complacency by suggesting that the Gay community would have been better off respecting the individualist dictum of You do your thing and I\u27ll do mine
Laminar and columnar organization of ascending excitatory projections to layer 2/3 pyramidal neurons in rat barrel cortex
Excitatory synaptic projections to layer 2/3 (L2/3) pyramidal neurons in brain slices from the rat barrel cortex were measured using quantitative laser-scanning photostimulation (LSPS) mapping. In the barrel cortex, cytoarchitectonic "barrels" and "septa" in L4 define a stereotypical array of landmarks, allowing alignment and averaging of LSPS maps from multiple cells in different slices. We distinguished inputs to L2 and L3 neurons above barrels and septa. Average input maps revealed that barrel-related ascending projections (L4-->2/3barrel) interdigitated with a novel septum-related projection (L5A-->2septum). We also explored the functional organization of these projections by comparing the input maps of multiple cells in individual slices. L2/3 cells sharing the same barrel-related column showed strong correlations in their input maps, independent of their precise locations within the column; otherwise, correlations fell rapidly as a function of intersomatic separation. Our data indicate that barrel-related and septum-related columns are associated with distinct functional circuits. These projections are likely to mediate parallel processing of somatosensory signals within the barrel cortex, with L4-->2/3barrel and L5A-->2septum representing the intracortical continuations of, respectively, the subcortical lemniscal and paralemniscal systems conveying somatosensory information to the barrel cortex
Guide and Index to the Microfilm Edition of the Charles E. Bessey Papers (1865-1915)
Contents
Introduction and Acknowledgments................... 7
Evaluation of the Bessey Papers....................... 10
Results of Research from the Bessey Papers.................... 12
Biographical Sketch of Charles E. Bessey................... 13
Editorial Comment................... 16
Roll Description.................... 18
Index...................... 2
Survey of Vegetated Areas and Muskox Populations in East-Central Ellesmere Island
The results of 1981-84 summer helicopter surveys and ground reconnaissance of east-central Ellesmere Island are presented. This was the first systematic ecological survey to be conducted in this region of the Canadian High Arctic. Central Ellesmere Island is dominated by two large ice fields separated by the deglaciated Sverdrup Pass (79 degrees N). Muskox migrate freely through the 70 km long corridor between the Fosheim Peninsula and some lowlands on the east coast, but large areas of suitable habitat were found unused on the central east coast. Muskox densities in Sverdrup Pass were comparable with those at other arctic sites, as were their reproduction rates (proportion of calves). Vegetated areas (>5 percent cover) constituted only 5 percent of the total surveyed land area and were largely restricted to coastal lowlands and the Sverdrup Pass valley.Key words: Ellesmere Island, Sverdup Pass, high arctic vegetation, polar oases, muskox, muskox habitatMots clés: île d'Ellesmere, Col Sverdrup, végétation dans le Grand Nord, oasis polaires, boeuf musqué, habitat du boeuf musqué
Circuit and plasticity defects in the developing somatosensory cortex of FMR1 knock-out mice
Silencing of the Fmr1 gene causes fragile X syndrome. Although defects in synaptic plasticity in the cerebral cortex have been linked to cognitive impairments in Fmr1 knock-out (ko) mice, the specific cortical circuits affected in the syndrome are unknown. Here, we investigated the development of excitatory projections in the barrel cortex of Fmr1 ko mice. In 2-week-old Fmr1 ko mice, a major ascending projection connecting layer 4 (L4) to L3 (L4-->L3), was defective in multiple and independent ways: its strength was reduced, caused by a lower connection probability; the axonal arbors of L4 cells were spatially diffuse in L2/3; the L4-->L3 projection did not show experience-dependent plasticity. By 3 weeks, the strength of the L4-->L3 projection was similar to that of wild type. Our data indicate that Fmr1 shapes sensory cortical circuits during a developmental critical period
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