183,622 research outputs found
Dolan, W R, NX8152
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/382100Surname: DOLAN. Given Name(s) or Initials: W R. Military Service Number or Last Known Location: NX8152. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 7273.212624
Item: [2016.0049.14393] "Dolan, W R, NX8152
Phylogenetics, systematics and biogeography of deep-sea Pennatulacea (Anthozoa: Octocorallia): evidence from molecules and morphology
No full textDespite its extreme environmental conditions, the deep sea harbours a unique andspecies-rich fauna of mostly unknown age and phylogeny. Pennatulids (Anthozoa:Octocorallia) are a group whose taxonomy and phylogenetic relationships remain poorlyknown and little studied, in spite of their abundance and ecological importance in softbottomcommunities. Phylogenetic analysis of a combination of partial ND2 and msh1sequences produced well-supported phylogenetic relationships for representative deepsea(and shallow-water) pennatulids at familial, generic and specific taxonomic levels.Generally, molecular data were congruent with current classification and previousphylogenetic reconstructions of the O. Pennatulacea based on morphology.Discrepancies were evident concerning the finer details for some families and genera: thiscan be attributable to the high frequency of homoplasy in pennatulids where reversals inevolution have led to taxa that possess apomorphic character states that are analogouswith plesiomorphic traits. Genetic analysis gave strong support that highly-derived taxaoccur in both shallow and deep water and that many may have differentiated anddispersed from the deep sea to the shallows. The Renillidae, which is considered one ofthe most primitive shallow-water families, evolved recently from deep-water ancestors.Conversely, the bathyal Anthoptilidae was the most primitive of families, and althoughmore evidence is required, pennatulids as a group may have originated in deep water.The systematics of the exclusively deep-sea genus Umbellula, which contains fortytwospecies, remains unclear despite the repeated attempts of revision. Incorporatingnew morphological and distributional data from the examination of recently collectedmaterial, together with type specimens, genetic analysis, and a critical study of theliterature, fifteen Umbellula species are here considered valid, including three new toscience. Eight species lack sclerites in the autozooids, U. magniflora, U. encrinus, U.antarctica, U. carpenteri and Umbellula sp.1 n. sp. (quadrangular axes), and U. huxleyi andU. pellucida (round axes); and seven possess autozooid sclerites, U. thomsoni and U.hemigymna (quadrangular axes), and U. monocephalus, U. aciculifera, U. durissima,Umbellula sp.2 n. sp. and Umbellula sp.3 n. sp. (round axes).Biogeographic data and genetic evidence supported the hypothesis that species ofUmbellula differentiated in the Indo-Pacific. Many radiated southwards to the Antarcticand later north into the Atlantic, E Pacific, Indian and Arctic oceans, occupying bathyaland abyssal depths. Other, older species that evolved via a separate evolutionarypathway, may have originated in the Indo-Pacific, and dispersed to the Subantarctic (U.sp.2 n. sp.) or Indian and Atlantic oceans (U. monocephalus). Further, morphologicalexamination of Umbellula showed it adapted to the oligotrophic conditions of the deepsea by reducing the number but increasing the size of the autozooids, and in doing so,enlarged the food-catchment area; abyssal species have done so even more extremely
The functional imaging of recall
No full textAn associative theory of implicit and explicit memory, G.H. Bower; encoding and retrieval processes - similarities and differences, F.I.M. Craik, M. Naveh-Benjamin, N.D. Anderson; memory imagery - a visual trace is not a mental image, C. Cornoldi, R. de Beni, F. Giusberti, M. Massironi; imaginary memories, E.F. Loftus; the rise and fall of semantic memory, J.M. Mandler; stories, selves and schemata - a review of ecological findings, U. Neisser; associative processes in false recall and false recognition, H.L. Roediger III, K.B. McDermott, K.J. Robinson; the functional imaging of recall, T. Shallice, P. Fletcher, R. Dolan; three dimensions of spatial cognition, B. Tversky. Part contents.
Dissociating valence of outcome from behavioral control in human orbital and ventral prefrontal cortices
Full text linkThe precise role of orbitofrontal cortex (OFC) in affective processing is still debated. One view suggests OFC represents stimulus reward value and supports learning and relearning of stimulus-reward associations. An alternate view implicates OFC in behavioral control after rewarding or punishing feedback. To discriminate between these possibilities, we used event-related functional magnetic resonance imaging in subjects performing a reversal task in which, on each trial, selection of the correct stimulus led to a 70% probability of receiving a monetary reward and a 30% probability of obtaining a monetary punishment. The incorrect stimulus had the reverse contingency. In one condition (choice), subjects had to choose which stimulus to select and switch their response to the other stimulus once contingencies had changed. In another condition (imperative), subjects had simply to track the currently rewarded stimulus. In some regions of OFC and medial prefrontal cortex, activity was related to valence of outcome, whereas in adjacent areas activity was associated with behavioral choice, signaling maintenance of the current response strategy on a subsequent trial. Caudolateral OFC-anterior insula was activated by punishing feedback preceding a switch in stimulus in both the choice and imperative conditions, indicating a possible role for this region in signaling a change in reward contingencies. These results suggest functional heterogeneity within the OFC, with a role for this region in representing stimulus-reward values, signaling changes in reinforcement contingencies and in behavioral control
Confidence in recognition memory for words: Dissociating right prefrontal roles in episodic retrieval
Full text linkWe used event-related functional magnetic resonance imaging (efMRI) to investigate brain regions showing differential responses as a function of confidence in an episodic word recognition task. Twelve healthy volunteers indicated whether their old-new judgments were made with high or low confidence. Hemodynamic responses associated with each judgment were modeled with an "early" and a "late" response function. As predicted by the monitoring hypothesis generated from a previous recognition study [Henson, R. N. A., Rugg, M. D., Shallice, T., Josephs, O., & Dolan, R. J. (1999a). Recollection and familiarity in recognition memory: An event-related fMRI study. Journal of Neuroscience, 19, 3962-3972], a right dorsolateral prefrontal region showed a greater response to correct low- versus correct high-confidence judgements. Several regions, including the precuneus, posterior cingulate, and left lateral parietal cortex, showed greater responses to correct old than correct new judgements. The anterior left and right prefrontal regions also showed an old-new difference, but for these regions the difference emerged relatively later in time. These results further support the proposal that different subregions of the prefrontal cortex subserve different functions during episodic retrieval. These functions are discussed in relation to a monitoring process, which operates when familiarity levels are close to response criterion and is associated with nonconfident judgements, and a recollective process, which is associated with the confident recognition of old words
Neuroimaging evidence for dissociable forms of repetition priming
Full text linkRepetition priming has been characterized neurophysiologically as a decreased response following stimulus repetition. The present study used event-related functional magnetic resonance imaging to investigate whether this repetition-related response is sensitive to stimulus familiarity. A right fusiform region exhibited an attenuated response to the repetition of familiar stimuli, both faces and symbols, but exhibited an enhanced response to the repetition of unfamiliar stimuli. Moreover, both repetition effects were modulated by lag between successive presentations. Further experiments replicated the interactions between repetition, familiarity, and lag and demonstrated the persistence of these effects over multiple repetitions. Priming-related responses are therefore not unitary but depend on the presence or absence of preexisting stimulus representations
Peter Dolan
No full textCronn, R., Dolan, P.C., Jogdeo, S., Wegrzyn, J.L., Neale, D.B., St. Clair, J.B. & Denver, D.R. (2017). Transcription through the eye of a needle: daily and annual cyclic gene expression variation in Douglas-fir needles. BMC Genomics, 18, 558.https://digitalcommons.morris.umn.edu/cosa2017/1018/thumbnail.jp
Mechanisms of top-down facilitation in perception of visual objects studied by fMRI
Full text linkPrior knowledge regarding the possible identity of an object facilitates its recognition from a degraded visual input, though the underlying mechanisms are unclear. Previous work implicated ventral visual cortex but did not disambiguate whether activity-changes in these regions are causal to or merely reflect an effect of facilitated recognition. We used functional magnetic resonance imaging to study top-down influences on processing of gradually revealed objects, by preceding each object with a name that was congruent or incongruent with the object. Congruently primed objects were recognized earlier than incongruently primed, and this was paralleled by shifts in activation profiles for ventral visual, parietal, and prefrontal cortices. Prior to recognition, defined on a trial-by-trial basis, activity in ventral visual cortex rose gradually but equivalently for congruently and incongruently primed objects. In contrast, prerecognition activity was greater with congruent priming in lateral parietal, retrosplenial, and lateral prefrontal cortices, whereas functional coupling between parietal and ventral visual (and also left lateral prefrontal and parietal) cortices was enhanced in the same context. Thus, when controlling for recognition point and stimulus information, activity in ventral visual cortex mirrors recognition success, independent of condition. Facilitation by top-down cues involves lateral parietal cortex interacting with ventral visual areas, potentially explaining why parietal lesions can lead to deficits in recognizing degraded objects even in the context of top-down knowledge
Letter re: Will Rogers
No full textLetter from George Dolan, journalist, to James R. Record, managing editor of the Fort Worth Star-Telegram, regarding a statue of Will Rogers
- …
