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R A McCarthy

Publications and source records attributed to R A McCarthy.

44 records · Page 3Linked to original sources
PubMed1983

Analysis of sequential letter matching tasks utilising lateralised tachistoscopic presentation.

Four experiments are reported in which sequential matches were demanded for double letter stimuli, the first stimulus pair was presented in central vision and the second in the left or right field. The responses were analysed according to the type of classification required (physical or nominal identify, or different). The results indicated that there were alterations in laterality patterns between retention intervals of 50 msec. and 990 msec. despite evidence for a prolonged and stable form of visual memory. These findings were incompatible with a model of the letter matching task which maps "name" codes to the left hemisphere and "visual" codes to the right.

Dominance, Cerebral↗
PubMed1968

Streptokinase therapy in acute major pulmonary embolism: effectiveness and problems.

Eighteen patients with major pulmonary embolism were treated with streptokinase infused by a catheter or given intravenously. Fourteen showed clinical improvement and 12 out of 16 patients investigated showed definite angiographic improvement after 24 to 48 hours of treatment with streptokinase. The angiographic improvement following streptokinase contrasted with the lack of this in three patients after 24 hours of heparin treatment.Resolution following streptokinase therapy was most noticeable in patients treated shortly after a single embolic episode, and was least marked in those with recurrent embolism complicated by associated cardiac or pulmonary disease. Of the four patients who failed to improve, two died and two had pulmonary embolectomy and survived.The results suggest that streptokinase therapy is practicable provided that adequate laboratory control is available, and that it hastens early resolution in acute major pulmonary embolism.

Acute Disease↗
PubMedDate not supplied

Probing sensory and associative semantics for animals and objects in normal subjects.

Neuropsychological studies of patients with "category-specific" semantic memory disorders have fuelled a debate concerning the organisation of knowledge. In particular it has been suggested that the reported double dissociation between knowledge of animals and living things on the one hand, and objects on the other, reflects a more fundamental division of semantic representation into functional-associative and sensory-visual domains. The present study attempted to investigate whether there were systematic differences along these dimensions in normal subjects using a sentence-verification technique. It was found that response times were significantly longer for verification of statements concerning the sensory attributes of objects than for statements about their associative attributes. In the case of animals, there were no differences in response latency to associative or sensory statements. In the light of this previously unreported fractionation within verbal semantics, the possible consequences for models of semantic memory are discussed.

Adult↗
PubMedDate not supplied

Naming without knowing and appearance without associations: evidence for constructive processes in semantic memory?

This study describes a patient (SE) with temporal lobe injury resulting from Herpes Simplex Encephalitis, who displayed a previously unreported impairment in which his knowledge of associative and functional attributes of animals was disproportionately impaired by comparison with his knowledge of their sensory attributes (including their visual properties and characteristic sounds). His knowledge of man-made objects was preserved. A striking aspect of the present case was that the patient remained able to name many animals from their pictures, despite making gross errors in generating associative information about these same animals. This suggests that a semantic representation incorporating stored sensory knowledge may be sufficient for naming (at least for biological categories) and associative information may be unnecessary. Semantic knowledge may normally incorporate more information than is necessary for identification. SE's errors were found to be confabulatory and reconstructive in nature and it is argued that this aspect of his performance challenges passive conceptions of semantic memory couched in terms of a catalogue of stored representations. It is proposed that the patient's disorder affects a dynamic, constructive, and inferential component of his knowledge base, and that this component is sensitive to semantic category.

Anomia↗