K Patterson

..We argue that these results cannot be explained as associated but unrelated deficits but instead are a principled consequence of a primary semantic impairment...

..What has gone wrong in his brain to produce this dramatic and selective erosion of conceptual knowledge?..

..These results, plus other features of the data such as the nature of the errors to irregular verbs, are discussed in relation to currently developing theories of the language system...

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..To account for these findings, we propose a revision to current models of long-term memory, in which sensory/perceptual information and semantic memory work in concert to support new learning...

..The results lead us to favor a model of the semantic system that is divided by attribute type but not by modality...

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..These findings demonstrate that object decision is not a single task or ability and that it is not necessarily independent of conceptual knowledge...

..Critically, in patients with atrophy in precisely these areas, the most pronounced deficit was in the retrieval of specific semantic information...

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..Both verbs and nouns are affected by the degradation of semantic memory; the fact that the impairment to noun production is manifested earlier and more catastrophically may be attributed to the relatively lower frequency of these terms...

..Recent findings indicate that the syndrome of semantic dementia can inform us about the organisation of long-term memory and the relationship between semantic memory and other cognitive systems...

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..Full-blown dementia may take many years to develop in patients with MCI but was a universal feature in this study...

..This finding supports theoretical accounts in which different temporal structures are capable of supporting acquisition of new semantic facts independently, albeit less efficiently than when both systems are available...

..The results suggest that object use is heavily dependent upon object-specific conceptual knowledge, supplemented to some degree by a combination of visual affordances and mechanical problem solving...

..These findings have implications for diagnosis and understanding of the cognitive deficits in AD and semantic dementia...

..These findings indicate that level of semantic knowledge about a word influences both baseline lexical decision performance and RP of that word. The observed hyperpriming can be parsimoniously explained by a cognitive slowing account...

..These findings are discussed with regard to the neural substrate of episodic memory and psychological models of long-term memory...

..Although such cases may mimic more focal lobar degenerative conditions, patients with atypical Alzheimer's disease have pronounced episodic memory impairments, suggesting amnesia as a critical diagnostic feature...

..This case demonstrates that the pattern of FTD may include severe anterograde amnesia as a prominent and early consequence of the disease...

..These results have implications for our understanding of the neural correlates of perceptual and semantic contributions to recognition memory...

..The results are discussed with respect to current views of long-term memory, particularly new word learning and forgetting, and to current techniques for facilitating word finding in aphasia...

..Although the temporal lobe system clearly is necessary to identify "what" an object is, we suggest that sensory inputs to a parietal "how" system can trigger the use of objects without reference to object-specific conceptual knowledge...

..The frontal and temporal presentations of FTD are clearly separable from each other and from early AD...

..e., for low-frequency exceptions) and that words with rich semantic representations (i.e., high-imageability words) are most likely to benefit from this interaction...

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..Neuropsychological observations provide an important additional source of evidence regarding models of cognitive function...

..This study aimed to characterize a large group of progressive aphasic patients from a single center (n = 38), first clinically by case note review, and then pathologically...

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..These results suggest that perceptual and conceptual processing form an interactive continuum rather than distinct stages, and that typicality effects reign throughout this continuum...

..These results provide a striking demonstration of the association between semantic dementia and surface dyslexia, a phenomenon that the authors have dubbed SD-squared...

..Unlike other frontotemporal dementia syndromes, the neuropathological findings in SD are fairly predictable: most patients have ubiquitin-positive, tau-negative neuronal inclusions...

..Despite SD patients' profoundly diminishing ability to understand the world around them, their visuospatial skills and concentration appear to be maintained or even enhanced in solving jigsaw puzzles...

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..An assessment including measures of episodic memory and visuospatial abilities as well as the semantic battery is recommended for good characterisation of the cognitive profiles associated with SD and AD...

..This study aimed to compare the clinical features of patients from these two groups...

..These findings support a primarily attribute-based neural organisation of semantic knowledge...

..These findings suggest that the retrieval of an autobiographical event requires participation from conceptual knowledge, and that this type of knowledge is bilaterally distributed in the temporal lobes...

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..These results are consistent with the brain's preferential responsiveness to how we interact with objects, rather than what they are used for...

..Data from 4 well-known semantic tasks revealed consistent patterns that find a ready explanation in the model. The relationship between the model and related theories of semantic representation is discussed...

..Familiar home context had no impact on performance. The results suggest that repeated experience with personally familiar objects helps to maintain appropriate responses to them in the face of severely degraded conceptual knowledge...

..Finally, despite good performance on tests of mechanical problem solving, the patients showed very little evidence of employing these skills in their interactions with real objects...

..These results indicate that the retrieval of perceptual semantic information activates not only a general semantic network, but also cortical areas specialized for the modality and attribute type of the knowledge retrieved...

..e., the Repeat-to-Point ratio, to aid in the diagnosis of these two language variants of frontotemporal dementia (FTD)...

..Apparent category effects arise because, at an intermediate level of specificity, animals have more visual and semantic competitors than do artifacts...

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..To characterize presenting symptomatology in patients with semantic dementia (SD) and to investigate whether left and right temporal variants of the disease have distinct behavioral and cognitive profiles...

..The interaction of typicality and lexicality can be explained by integration of information from the early form-based system and lexicosemantic processes...

..The results can be explained by the semantic deficit which disrupts the representation of a pre-verbal message, lexical retrieval and the early stages of grammatical encoding...

..Psychological Review 111, 205-235]. For partially degraded items, the residual conceptual knowledge may be insufficient to drive speech production to completion but these items might reach threshold when they are bolstered by cues...

..g. a green versus an orange carrot), performance was far poorer. The results are discussed with reference to alternative theories about the neural basis of conceptual knowledge...

..The article describes a comprehensive array of under- and overgeneralization errors by patients with SD when engaged in receptive and expressive verbal and nonverbal tasks and everyday behaviors...

..These results are consistent with the notion that the patients' relatively greater difficulty with regular past tenses reflects a phonological impairment that is sensitive to the complexity of spoken forms...

..These results indicate that each type of stored knowledge involves at least partially distinct cortical areas, and suggest that both anterior/posterior and left/right temporal regions have specialised roles...

..Results suggest greater and earlier vulnerability of person knowledge than general semantic knowledge in DAT...

..This combination of more than one deficit relevant for object use may explain why CBD patients are far more disabled by their dyspraxia in everyday life than any other patient group...

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..Implications for theories of visual object recognition are discussed...

..Although some previous research has reported significant associative priming in other tasks for patients with MTL lesions, the present results suggest that this region is critical for forming new associations of the types assessed here...

..This unique set of findings is discussed in the context of the debate as to whether syntax and semantics decline separately or in parallel in patients with Alzheimer's disease...

..These findings are discussed in the context of contemporary cognitive and computational models of semantic memory organisation...

..The phonological nature of the factors that correlated with verb-inflection performance emphasises the role of a phonological deficit in the observed pattern of irregular > regular...

..2001) and the triangle model (Plaut et al., 1996). It is argued that the triangle model provides a more straightforward account of the relationship between word comprehension and consistency effects in reading...

..The present investigation is the first to identify distinct neuronal mechanisms for semantic and phonological contributions to reading...

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..There is substantial overlap between progressive nonfluent aphasia and CBD, and the linguistic impairment can be thought of as a continuum, with mild phonologic impairment at one end and severe aphasia at the other...

..These findings are discussed in terms of theories that posit strong interactivity between phonology and semantics...

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..P.'s deficit for person knowledge and predominantly left temporal atrophy in M.A. who was impaired in general conceptual knowledge...

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..Whichever of these interpretations is preferred, this study offers the most detailed information yet available on the characteristics of surface dyslexia in Japanese...

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..Future studies are required to examine the connectivity between these areas during normal and abnormal reading...