Declining object recognition performance in Semantic Dementia - a case for stored visual object representations

The role of the semantic system in recognising objects is a matter of debate. Connectionist theories argue that it is impossible for a participant to determine that an object is familiar to them without recourse to a semantic hub; localist theories state that accessing a stored representation of the visual features of the object is sufficient for recognition. We examine this issue through the longitudinal study of two cases of Semantic Dementia, a neurodegenerative disorder characterised by a progressive degradation of the semantic system. The cases in this paper do not conform to the "common" pattern of object recognition performance in Semantic Dementia described by Rogers et al (2004b), and show no systematic relationship between severity of semantic impairment and success in object decision. We argue that this data is inconsistent with the connectionist position but can be easily reconciled with localist theories that propose stored structural descriptions of objects outside of the semantic system

Intranasal Inhalation of Oxytocin Improves Face Processing in Developmental Prosopagnosia

Developmental prosopagnosia (DP) is characterised by a severe, lifelong impairment in face recognition. Little work has attempted to improve face processing in these individuals, but intriguingly, recent evidence suggests oxytocin can improve face processing in both healthy participants and individuals with autism. This study examined whether oxytocin could also improve face processing in individuals with DP. Ten adults with the condition and 10 matched controls were tested using a randomized placebo-controlled double-blind within-subject experimental design (AB-BA). Each participant took part in two testing sessions where they inhaled 24IU of oxytocin or placebo spray and completed two face processing tests: one assessing face memory and the other face perception. Results showed main effects of both participant group and treatment condition in both face processing tests, but the two did not interact. Specifically, the performance of DP participants was significantly lower than control performance under both oxytocin and placebo conditions, but oxytocin improved processing to a similar extent in both groups

Naming acronyms : the influence of reading context in skilled reading and surface dyslexia

Background: Within dual route models of reading, words with regular spelling to sound correspondences can be read successfully using lexical or non-lexical reading processes. Research has indicated that which of these pathways is used is influenced by the other items that form the presentation context. We extend these findings using acronym stimuli as targets, presenting them in contexts designed to cue reading through grapheme phoneme conversion or letter naming. Method: In experiment 1, undergraduate participants (n = 30) read aloud stimuli presented onscreen. Response times and accuracy for target acronyms ambiguous in their print to pronunciation conversion (e.g. HIV versus NASA) were compared between two contexts. In one condition the majority of items were unambiguous acronyms (e.g. BBC). In the second condition, the non-target items were regular words (e.g. CAT). Experiment 2 administered the same reading task to a single case of semantic dementia. Results: A significant interaction between presentation context and acronym pronunciation was observed, such that responses were faster and more accurate to items that were pronounced in the same way as the majority of other stimuli in the list. Similar, though more dramatic, context effects were observed in a case of semantic dementia. Conclusions: We argue that context effects are pervasive in reading research and that presentation context should be considered when interpreting future findings, particularly in cases of aphasia and dyslexia.</p

Two new Australian fungus-feeding thrips in two new Plectrothripini genera (Thysanoptera, Phlaeothripinae)

Two new genera are erected of plectrothripine Phlaeothripidae from northern Australia, each based on a single species. One has a long stout projection ventrally on the second antennal segment, the other has a unique arrangement of the dorsal facets of the compound eyes. In both of them the thoracic ventral sclerites are extensively eroded. The tribe Plectrothripini is one of the few apparently discrete lineages within the large and complex subfamily Phlaeothripinae (Dang et al. 2014). The species in this Tribe are all fungus-feeders on dead branches, and the group is found in the tropics worldwide. Okajima (1981) provided an extensive, illustrated account of the Plectrothripini, recognising 10 genera and almost 50 species, to which Tyagi et al. (2016) added one further species. Six of these genera remain monotypic, with two genera each comprising five or six species, and Plectrothrips itself with about 30 species. This asymmetry of taxon distribution, with a high proportion of monotypic genera, is due to the presence of certain characters in unusual autapomorphic states. Phylogenetic relationships within the tribe are further confused here through the diagnosis of two new monotypic genera for species from the tropical north of Australia. One of these new species has a bizarre projection ventrally on the second antennal segment (Fig. 5), whilst the other has the structure of the compound eyes unique amongst Phlaeothripidae (Figs 7, 8). Membership of the Tribe Plectrothripini is fairly clear, with the species sharing most of the following character states as indicated by Okajima (1981): antennae 8-segmented, segment II with the campaniform sensillum on the basal half, III–IV with a variable number of short, stout sense cones, VIII elongate with narrow base. Head with posterior ocelli close to compound eyes. Pronotum commonly with sclerotised plate eroded and reduced; prosternal basantra absent; fore tarsal tooth large; apex of hind tibiae commonly with stout setae. Pelta wide at base, tergite II eroded laterally; sternites often with reticulate glandular areas

Genera of fungivorous Phlaeothripinae (Thysanoptera) from dead branches and leaf-litter in Australia

An illustrated key is provided for the identification of 39 genera of Thysanoptera-Phlaeothripinae with species that live in association with dead branches and leaf-litter in Australia and are considered to be fungus-feeding. Seven of these gen-era are not previously recorded from this continent, including un-named species of Deplorothrips, Malacothrips, Mystro-thrips, Preeriella and Tylothrips, together with Azaleothrips lepidus Okajima and Terthrothrips ananthakrishnani Kudo. A brief generic diagnosis is provided for each genus, together with comments on systematic problems and numbers of species. Copyright © 2013 Magnolia Press

The Man Who Mistook His Neuropsychologist For a Popstar: When Configural Processing Fails in Acquired Prosopagnosia

We report the case of an individual with acquired prosopagnosia who experiences extreme difficulties in recognizing familiar faces in everyday life despite excellent object recognition skills. Formal testing indicates that he is also severely impaired at remembering pre-experimentally unfamiliar faces and that he takes an extremely long time to identify famous faces and to match unfamiliar faces. Nevertheless, he performs as accurately and quickly as controls at identifying inverted familiar and unfamiliar faces and can recognize famous faces from their external features. He also performs as accurately as controls at recognizing famous faces when fracturing conceals the configural information in the face. He shows evidence of impaired global processing but normal local processing of Navon figures. This case appears to reflect the clearest example yet of an acquired prosopagnosic patient whose familiar face recognition deficit is caused by a severe configural processing deficit in the absence of any problems in featural processing. These preserved featural skills together with apparently intact visual imagery for faces allow him to identify a surprisingly large number of famous faces when unlimited time is available. The theoretical implications of this pattern of performance for understanding the nature of acquired prosopagnosia are discussed.DY, Avery Braun, Jacob Waite, and Nadine Wanke, Bruno Rossion, Thomas Busigny and the grant awarded by AJ by the Experimental Psychology Society (EPS

The Influence of Psycholinguistic Variables on Articulatory Errors in Naming in Progressive Motor Speech Degeneration

We describe an analysis of speech errors on a naming task in a man with progressive speech degeneration. Early assessment indicated naming impairments with no significant phonological or semantic impairment. To examine naming and the factors that influence speech errors, we selected 210 words varying in lexical and phonetic variables and conducted logistic regression analysis on speech error types. No significant naming errors were found. The only significant predictor of articulation errors was phonemic length and the only error type predicted was phone omissions. Results suggest that the sound omissions in naming are caused by motor speech impairment unrelated to lexical factors

Disfluency in dialogue:an intentional signal from the speaker?

Disfluency is a characteristic feature of spontaneous human speech, commonly seen as a consequence of problems with production. However, the question remains open as to why speakers are disfluent: Is it a mechanical by-product of planning difficulty, or do speakers use disfluency in dialogue to manage listeners' expectations? To address this question, we present two experiments investigating the production of disfluency in monologue and dialogue situations. Dialogue affected the linguistic choices made by participants, who aligned on referring expressions by choosing less frequent names for ambiguous images where those names had previously been mentioned. However, participants were no more disfluent in dialogue than in monologue situations, and the distribution of types of disfluency used remained constant. Our evidence rules out at least a straightforward interpretation of the view that disfluencies are an intentional signal in dialogue. © 2012 Psychonomic Society, Inc

How to get by with half a loop - An investigation of visual and auditory codes in a case of impaired phonological short-term memory (pSTM).

In the field of cognitive neuropsychology of phonological short-term memory (pSTM), a key debate surrounds the issue of how impairment on tasks deemed to tap this system imply a dissociable phonological input and output buffer system, with the implication that impairments can be fractionated across disruption to separate functional components (Nickels, Howard & Best, 1997). This study presents CT, a conduction aphasic who showed no impairment on basic auditory discrimination tasks, but had very poor nonword repetition. Clear-cut examples of such cases are very rare (see Jacquemot, Dupoux & Bachoud-Levi, 2007), and we interpret the case with reference to a pSTM model that includes input and output buffers. The dissociation between performance on auditory phonological tasks and visual phonological tasks we interpret as consistent with disruption to the link from input buffer to output buffer without concurrent damage to connections from output to input. Previous research has also shown that patients with impairments of pSTM can make visual confusions with orthographically presented items in tasks seeking to tap this mechanism (Warrington & Shallice, 1972), which might stem from having an incomplete pSTM loop. In light of this we examined whether CT's ability on tests of ISR was affected by visual orthographic similarity among list items, and this is indeed what we observed. On balance then, CT's overall profile is considered best interpreted with respect to a dual buffer pSTM model (e.g., Vallar & Papagno, 2002). [Abstract copyright: Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.