Biomedical subjects

Rita Capasso

Publications and source records attributed to Rita Capasso.

5 recordsLinked to original sources

PubMed2005

Patterns of comprehension performance in agrammatic Broca's aphasia: a test of the Trace Deletion Hypothesis.

We tested the core prediction of the Trace Deletion Hypothesis (TDH) of agrammatic Broca's aphasia, which contends that such patients' comprehension performance is normal for active reversible sentences but at chance level for passive reversible sentences. We analyzed the comprehension performance of 38 Italian Broca's aphasics with verified damage to Broca's area, who completed sentence-to-picture matching tasks using active and passive reversible sentences as stimuli. The results failed to confirm the predictions made by TDH: only a small minority (15%) performed at chance on passive sentences and better than chance on active sentences. Furthermore, the distribution of the 38 subjects' performance on passive sentences differed from that predicted by the TDH since many more subjects performed at better-than-chance levels than expected. We discuss the implication of these results for claims about the distribution of language processing mechanisms in the brain.

Adult↗

PubMed2005

Hyperproduction of fibrin and inefficacy of antithrombin III and alpha2 macroglobulin in the presence of bacterial porins.

Bacterial porins enhance the thrombin activity upon chromogen substrate chromozym. Should porin-dependent enhancement of thrombin activity take place also upon fibrinogen in vivo, this might greatly increase the fibrin production which, in turn, might lead to blood vessel obstruction. In this study, we demonstrate fibrin hyperproduction in a simplified coagulative system, consisting of fibrinogen and thrombin-pure molecules, in the presence of bacterial porins. In particular, bacterial porins, in the presence of thrombin, significantly increased the fibrin production compared with thrombin alone. Also, fibrin hyperproduction took place even in the presence of the thrombin inhibitors antithrombin III (AT III) or alpha2 macroglobulin (alpha2M). However, the thrombin-fibrinogen reaction in the presence of AT III or alpha2M did not generate fibrin, unless porins were present. In conclusion, porins not only enhance thrombin activity but also inhibit the antithrombin activity exerted by AT III or alpha2M. We hypothesize that, because of porins activity, fibrin is largely generated due to thrombin hyperactivation. Moreover, further fibrin is produced by thrombin, which is not blocked by two serpins for the presence of porins. These results might be relevant as to the occurrence of disseminated intravascular coagulation in sepsis by gram-negative bacteria, which are known to produce porins.

Antithrombin III↗

PubMed2004

The relationships between morphological and phonological errors in aphasic speech: data from a word repetition task.

Current theories of single-word processing predict that in some cases brain damage should selectively impair morphological processes, resulting in the selective occurrence of morphological errors. However, such a selective pattern of errors has never been documented, and the available case studies report the systematic association of morphological and phonological (segmental) errors in the same subject. The number of relevant case reports is very small, however. To better understand the relationship between morphological and phonological processes, we analyzed the repetition performance of 26 subjects who produced morphological errors in a screening battery for aphasia. Although the results confirm that subjects who make morphological errors also invariably make phonological errors, the probabilities of the two types of errors are not (quantitatively) correlated. Furthermore, the relationship between morphological and phonological errors was asymmetrical: although all subjects who produced morphological errors also produced phonological errors, some aphasics who produced phonological errors did not also produce morphological errors. The one-way relationship between morphological and phonological errors could result either from the anatomical proximity of the structures involved in morphological and phonological processes, or from the functional inseparability of the two processes. The fact that phonological errors can occur either in isolation or in association with morphological errors could be attributed to the functional heterogeneity of phonological errors, and to the separability of the neural substrates involved in processing various aspects of phonological information.

Adult↗

PubMed2004

The categorical distinction of vowel and consonant representations: evidence from dysgraphia.

Subject GSI presents with a graphemic buffer deficit following a massive left fronto-parietal lesion. His errors involved essentially only consonants (98.2%). However, he always spelled correctly the first consonant in a string, and produced steadily increasing numbers of errors on the following consonants, while always spelling all the vowels in the target correctly. The pattern of performance observed in this subject provides strong evidence for the separate (categorical) representation of consonants and vowels, and suggests that working memory interacts with independent consonant and vowel representations in spelling.

Adult↗

PubMed2002

The neural correlates of grammatical gender: an fMRI investigation.

In an fMRI experiment, subjects saw a written noun and made three distinct decisions in separate sessions: Is its grammatical gender masculine or feminine (grammatical feature task)? Is it an animal or an artifact (semantic task)? Does it contain a /tch/ or a /k/ sound (phonological task)? Relative to the other experimental conditions, the grammatical feature task activated areas of the left middle and inferior frontal gyrus and of the left middle and inferior temporal gyrus. These activations fit in well with neuropsychological studies that document the correlation between left frontal lesions and damage to morphological processes in agrammatism, and the correlation between left temporal lesions and failure to access lexical representations in anomia. Taken together, these data suggest that grammatical gender is processed in a left frontotemporal network. In addition, the observation that the grammatical feature task and the phonology task activated neighboring but distinct regions of the left frontal lobe provides a plausible neuroanatomical basis for the systematic occurrence of phonological errors in aphasic subjects with morphological deficits.

Adult↗