RESUMEN
Current models of word production assume the existence of functionally distinct lexical-syntactic and word-form representations. However, there are competing hypotheses about whether prior access to syntactic properties of words is obligatory during lexical retrieval. In this paper we report preliminary evidence from the single case study of a Welsh-speaking patient with a lexical access deficit. We examined the patient's ability to access word forms and to retrieve information about the grammatical gender of Welsh nouns. The data show no correlation between the retrieval of word-form and grammatical gender information. This pattern of performance is inconsistent with hypotheses postulating obligatory syntactic mediation in lexical production.
Asunto(s)
Afasia/diagnóstico , Lingüística , Anciano , Afasia/etiología , Femenino , Humanos , Lenguaje , Pruebas Neuropsicológicas , Lóbulo Parietal/irrigación sanguínea , Lóbulo Parietal/diagnóstico por imagen , Lóbulo Parietal/fisiopatología , Índice de Severidad de la Enfermedad , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/fisiopatología , Hemorragia Subaracnoidea/complicaciones , Hemorragia Subaracnoidea/diagnóstico por imagen , Hemorragia Subaracnoidea/fisiopatología , Lóbulo Temporal/irrigación sanguínea , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/fisiopatología , Tomografía Computarizada por Rayos X , VocabularioRESUMEN
When orienting attention, inhibition mechanisms prevent the return of attention to previously examined stimuli. This inhibition of the return of attention (IOR) has been shown to be associated additively with location- and object-based representations. That is, when static objects are attended, IOR is associated with both the object and the location cued, and hence IOR is larger than when only spatial location is attended. Recently McAuliffe, Pratt, and O'Donnell (2001) failed to observe such additive effects except under a narrow set of conditions (at short cue-target intervals and using mixed blocks in which object- and pure location-based effects were probed in the same display). The present study shows that additive IOR effects are observed under conditions that violate all of these boundary conditions. The results also show that IOR is modulated by internal structural properties of objects. These findings are cosistent with the hypothesis that IOR operates over functionally independent object- and location-based frames of reference.
Asunto(s)
Inhibición Psicológica , Atención , Humanos , Distribución Aleatoria , Tiempo de Reacción , Percepción VisualRESUMEN
Two main hypotheses have been proposed regarding the role of phonology in written word production. According to the phonological mediation hypothesis, the retrieval of the lexical phonological representation of a word is an obligatory prerequisite to the retrieval of its spelling. Therefore, deficits to the phonological lexicon should affect both spoken and written picture naming. In contrast, the orthographic autonomy hypothesis posits that the lexical orthographic representations of words can be accessed without any necessary phonological mediation. In support of this view, cases of preserved written naming despite impaired lexical phonology have been reported following brain damage. In this report, we replicate this basic pattern of performance in case YP, a 60-year-old woman with a pattern of frontotemporal dementia. As her disease progressed, YP's ability to write down the names of pictures remained very good despite a severe decline in oral naming. Further testing indicated that this deficit was not primarily due to an articulatory or post-lexical phonological deficit. YP's case provides strong additional support for the orthographic autonomy hypothesis. The significance of this case with respect to the characterization of dementia syndromes is discussed.
Asunto(s)
Agrafia/complicaciones , Agrafia/fisiopatología , Demencia/complicaciones , Demencia/fisiopatología , Lóbulo Frontal/fisiopatología , Trastornos del Habla/complicaciones , Trastornos del Habla/fisiopatología , Lóbulo Temporal/fisiopatología , Agrafia/patología , Demencia/patología , Femenino , Lóbulo Frontal/patología , Humanos , Persona de Mediana Edad , Fonética , Trastornos del Habla/patología , Lóbulo Temporal/patologíaRESUMEN
The drawing from memory task is frequently used in cognitive neuropsychology to investigate visual processing impairments. However, in surprising contrast to most other neuropsychological tests, the analyses of results on this task are most often based solely on qualitative judgements about the normality of a patient's performance. In most case reports, these judgements are not made with reference to normative data and are not made by individuals who are impartial with respect to the study (that is, using a blind rating procedure). There are several grounds for arguing that such analyses are inadequate. First, seemingly abnormal drawings made by a patient may well be within the range of performance shown by control subjects. Second, judgments that are not based on a blind rating procedure are likely to be influenced by knowledge about the patient's performance on other tasks. We describe an alternative assessment procedure that addresses both of these concerns.
Asunto(s)
Encéfalo/fisiología , Memoria , Desempeño Psicomotor/fisiología , Anciano , Humanos , Masculino , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
How does the visual system recognise stimuli presented at different orientations? According to the multiple-views hypothesis, misoriented objects are matched to one of several orientation-specific representations of the same objects stored in long-term memory. Much of the evidence for this hypothesis comes from the observation of group mean orientation effects in recognition memory tasks showing that the time taken to identify objects increases as a function of the angular distance between the orientation of the stimulus and its nearest familiar orientation The aim in this paper is to examine the validity of this interpretation of group mean orientation effects. In particular, it is argued that analyses based on group performance averages that appear consistent with the multiple-views hypothesis may, under certain circumstances, obscure a different theoretically relevant underlying pattern of results. This problem is examined by using hypothetical data and through the detailed analysis of the results from an experiment based on a recognition memory task used in several previous studies. Although a pattern of results that is consistent with the multiple-views hypothesis was observed in both the group mean performance and the underlying data, it is argued that the potential limitations of analyses based solely on group performance averages must be considered in future studies that use orientation effects to make inferences about the kinds of shape representations that mediate visual recognition.