The contribution of single synapses to sensory representation in vivo     

Arenz A  Silver RA  Schaefer AT  Margrie TW 《Science (New York, N.Y.)》2008,321(5891):977-980

The extent to which synaptic activity can signal a sensory stimulus limits the information available to a neuron. We determined the contribution of individual synapses to sensory representation by recording excitatory postsynaptic currents (EPSCs) in cerebellar granule cells during a time-varying, quantifiable vestibular stimulus. Vestibular-sensitive synapses faithfully reported direction and velocity, rather than position or acceleration of whole-body motion, via bidirectional modulation of EPSC frequency. The lack of short-term synaptic dynamics ensured a highly linear relationship between velocity and charge transfer, and as few as 100 synapses provided resolution approaching psychophysical limits. This indicates that highly accurate stimulus representation can be achieved by small networks and even within single neurons.  相似文献   

Anterior cingulate conflict monitoring and adjustments in control     

Kerns JG  Cohen JD  MacDonald AW  Cho RY  Stenger VA  Carter CS 《Science (New York, N.Y.)》2004,303(5660):1023-1026

Conflict monitoring by the anterior cingulate cortex (ACC) has been posited to signal a need for greater cognitive control, producing neural and behavioral adjustments. However, the very occurrence of behavioral adjustments after conflict has been questioned, along with suggestions that there is no direct evidence of ACC conflict-related activity predicting subsequent neural or behavioral adjustments in control. Using the Stroop color-naming task and controlling for repetition effects, we demonstrate that ACC conflict-related activity predicts both greater prefrontal cortex activity and adjustments in behavior, supporting a role of ACC conflict monitoring in the engagement of cognitive control.  相似文献   

Chronic infection with Trichostrongylus vitrinus in sheep. Pathological changes in the small intestine     

R L Coop  K W Angus  A R Sykes 《Research in veterinary science》1979,26(3):363-371

Eight four-month-old sheep were infected daily for 90 days with 2500 Trichostrongylus vitrinus larvae. Infections were patent by week 3; mean faecal egg counts reached a peak of 645 epg at week 5, then subsequently declined. Mean worm burden at slaughter was 6100 (range 60--25,080). Two sheep had visible lesions in the small intestine at slaughter. In both sheep, numerous shallow red depressed areas extended for 5 to 7 metres distal to the pylorus while, in one, more extensive irregular depressed areas occupied the first 1.5 metres. Microtopographical examination and scanning electron microscopy showed that these affected areas were devoid of villi and contained numerous worms embedded in the mucosa. Histological examination revealed many similarities with the lesions caused by T colubriformis. Subtotal villous atrophy and crypt elongation were present in the intestines from five of the remaining six sheep, and in these the mucosa contained numerous mononuclear cells and intraepithelial globule leucocytes.  相似文献   

Intestinal infection and host response to oral administration of Mycobacterium johnei in sheep     

N.J.L. Gilmour  K.W. Angus  B. Mitchell 《Veterinary microbiology》1977,2(3):223-235

Sheep were experimentally infected orally with Mycobacterium johnei and their immune response assessed by measurement of delayed-type skin hypersensitivity, viable unit counts of M. johnei in the tissues, and by pathology, histochemistry and serial biopsies of selected sheep. In those killed shortly after infection, the rapid development of a “strong” degree of skin hypersensitivity was associated with low levels of intestinal infection. However, the failure to mount a “strong” degree of skin hypersensitivity did not preclude eventual recovery from the infection. Electron microscopy of macrophages within lesions in sheep with “strong” skin hypersensitivity showed mainly degenerating bacilli, in contrast to those from sheep with “weak” skin hypersensitivity where the macrophages in similar lesions often contained numerous intact bacilli. The finding of cells rich in β-galactosidase in the lesions bore no relationship to the extent of infection.  相似文献   

Spontaneous renal disease resembling hyperoxaluria in young lambs.     

K A Linklater  K W Angus 《The Veterinary record》1979,104(19):429-431

Five out of 60 purebred Suffolk lambs died when four to six weeks old with a nephrosis characterised by heavy deposits of crystals resembling calcium oxalate in the tubules. The source of oxalate was not clearly identified but may have resulted from oxalate-forming mould contamination of concentrates fed to both ewes and lambs.  相似文献   

Optimizing early detection of avian influenza H5N1 in backyard and free-range poultry production systems in Thailand     

Goutard FL  Paul M  Tavornpanich S  Houisse I  Chanachai K  Thanapongtharm W  Cameron A  Stärk KD  Roger F 《Preventive veterinary medicine》2012,105(3):223-234

For infectious diseases such as highly pathogenic avian influenza caused by the H5N1 virus (A/H5N1 HP), early warning system is essential. Evaluating the sensitivity of surveillance is a necessary step in ensuring an efficient and sustainable system. Stochastic scenario tree modeling was used here to assess the sensitivity of the A/H5N1 HP surveillance system in backyard and free-grazing duck farms in Thailand. The whole surveillance system for disease detection was modeled with all components and the sensitivity of each component and of the overall system was estimated. Scenarios were tested according to selection of high-risk areas, inclusion of components and sampling procedure, were tested. Nationwide passive surveillance (SSC1) and risk-based clinical X-ray (SSC2) showed a similar sensitivity level, with a median sensitivity ratio of 0.96 (95% CI 0.40-15.00). They both provide higher sensitivity than the X-ray laboratory component (SSC3). With the current surveillance design, the sensitivity of detection of the overall surveillance system when the three components are implemented, was equal to 100% for a farm level prevalence of 0.05% and 82% (95% CI 71-89%) for a level of infection of 3 farms. Findings from this study illustrate the usefulness of scenario-tree modeling to document freedom from diseases in developing countries.  相似文献   

Evaluation of azithromycin in systemic and toothpaste forms for the treatment of ciclosporin‐associated gingival overgrowth in dogs     

Andrew Rosenberg  Wayne Rosenkrantz  Craig Griffin  John Angus  Deborah Keys 《Veterinary dermatology》2013,24(3):337-e75

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Migration pathways,speed and mortality of Atlantic salmon (Salmo salar) smolts in a Scottish river and the near‐shore coastal marine environment          下载免费PDF全文

Angus J. Lothian  Matthew Newton  James Barry  Marcus Walters  Richard C. Miller  Colin E. Adams 《Ecology of Freshwater Fish》2018,27(2):549-558

Long‐distance migration of Atlantic salmon (Salmo salar) is known to result in high levels of mortality. For a species experiencing global population decline, it is thus vital to better understand migration behaviour, both in the river and marine stages. Atlantic salmon smolts (n = 50) were tracked using acoustic telemetry in the River Deveron, Scotland, and adjacent coastal area. Higher rates of mortality were observed in the river (0.77% per km) than the early marine stage of migration (0.0% per km). Mortality likely resulted from predation. Higher swim speeds were recorded in the early marine stage compared with the river (marine = 7.37 ± 28.20 km/day; river = 5.03 ± 1.73 km/day [mean ± SD]), a potential predator avoidance behaviour. The majority of smolts leaving the river did so in darkness and on a flooding tide. Overall river and marine migration success were linked to nights of lower lunar brightness. Marine migration speed decreased with increasing environmental noise levels, a finding with implications for fisheries management. The migration pathway in the early marine environment did not follow obvious geographical features, such as the coastline. Thus, we suggest that early marine environment pathways are more influenced by complex water currents. These findings highlight factors that influence smolt migration survival and behaviour, areas on which future research should focus.  相似文献   

Direct high-resolution genotyping of Toxoplasma gondii in arctic foxes (Vulpes lagopus) in the remote arctic Svalbard archipelago reveals widespread clonal Type II lineage     

Prestrud KW  Asbakk K  Mørk T  Fuglei E  Tryland M  Su C 《Veterinary parasitology》2008,158(1-2):121-128

Characterization of Toxoplasma gondii genotypes in hosts living in remote, isolated regions is important for elucidating the population structure and transmission mode of this parasite. Herein, we report the results of direct genotyping of T. gondii in brain tissue of arctic foxes (Vulpes lagopus) from the remote, virtually cat-free, high arctic islands of Svalbard. DNA extracts from brains of 167 seropositive arctic foxes (including four cases of fatal toxoplasmosis) and 11 seronegative arctic foxes were genotyped at 10 loci (SAG1, SAG2, SAG3, BTUB, GRA6, L358, c22-8, c29-2, PK1, and Apico) using the polymerase chain reaction-restriction fragment length polymorphism method. Of the 167 samples from seropositive foxes (including toxoplasmosis cases), 31 were genotyped at all 10 loci and 24 were genotyped at four to nine loci. To ensure confidence in T. gondii strain genotyping, samples for which less than four loci were genotyped were not considered positive. None of the 11 samples from seronegative foxes was positive for the 10 markers. Of the 55 samples that genotyped positively, 46 were of the Type II strain, 7 were of the Type III strain, and 2 were of atypical T. gondii strains. Five representative samples of the three genotypes were sequenced at loci SAG2, SAG3, GRA6, PK1, and UPRT-1. The DNA sequences confirmed the genotyping results. This study shows that the archetype Type II T. gondii strain, which is most widely distributed in North America and Europe, also predominates in arctic foxes on the Svalbard archipelago. This suggests that the T. gondii at this location originate from continental Europe and that transmission may be mediated by migrating birds. This study highlights the significance of long-distance transport of T. gondii and demonstrates that high-resolution genotyping protocols are useful for direct genetic studies of T. gondii when isolation of live parasites is infeasible.  相似文献   

Optimized immunocytochemistry using leukocyte and tissue markers on Romanowsky‐stained slides from dogs and cats     

Rose E. Raskin  Julie Vickers  Jennifer G. Ward  Angus Toland  Andrew G. Torrance 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2019,48(Z1):88-97

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