Blog Archives

The role of the left anterior temporal lobe in language processing revisited: Evidence from an individual with ATL resection

Various hypotheses about the role of the anterior temporal lobe (ATL) in language processing have been proposed. One hypothesis is that it binds the semantic/conceptual properties of words, functioning as a hub for linking modality-specific conceptual properties of objects. This hypothesis predicts that damage to ATL would give rise to impaired conceptual knowledge of all categories. A related school of hypotheses assumes that the left ATL is critical for lexical retrieval, with different sub-regions potentially important for different categories of items. We examined these hypotheses by studying a case of surgical resection of left ATL due to a low-grade glioma (LGG). Thorough language assessments performed four months after the operation revealed the following profile: the patient showed intact conceptual knowledge for all categories of items tested using both accuracy and response latency measures; he suffered from name retrieval deficits for proper names (people and place names) and artifacts (including tools), but showed no name retrieval difficulties for animate things. This pattern of results challenges both target hypotheses about the role of ATL in language processing tested here.

from Cortex

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When one can write SALTO as noun but not as verb: A grammatical category-specific, modality-specific deficit

We report the naming performance of a Spanish patient (AQF) suffering from Primary Progressive Aphasia (PPA). AQF’s performance revealed a grammatical category-specific deficit, with poorer performance in verb than in noun naming. Furthermore, this dissociation was only present in written naming. Importantly, the patient’s dissociation between nouns and verbs was present also when we studied her performance with homonymous words. We argue that this dissociation is not due to a range of semantic factors but is a true grammatical category-specific deficit located at the lexical level of orthographic processing. Thus, we bring in new evidence in favour of grammatical category representation at a post-semantic level where output modalities are represented separately.

from Brain and Language

The impact of dementia, age and sex on category fluency: Greater deficits in women with Alzheimer’s disease

from Cortex

A category specific effect in naming tasks has been reported in patients with Alzheimer’s dementia. Nonetheless, naming tasks are frequently affected by methodological problems, e.g., ceiling effects for controls and “nuisance variables” that may confound results. Semantic fluency tasks could help to address some of these methodological difficulties, because they are not prone to producing ceiling effects and are less influenced by nuisance variables. One hundred and thirty-three participants (61 patients with probable AD; and 72 controls: 36 young and 36 elderly) were evaluated with semantic fluency tasks in 14 semantic categories. Category fluency was affected both by dementia and by age: while in nonliving-thing categories there were differences among the three groups, in living thing categories larger lexical categories produced bigger differences among groups. Sex differences in fluency emerged, but these were moderated both by age and by pathology. In particular, fluency was smaller in female than male Alzheimer patients for almost every subcategory.