The role of the hippocampus in the semantic variant of primary progressive aphasia: A resting-state fcMRI study.

The goal of the study was to determine whether the semantic variant of primary progressive aphasia (svPPA) affects the intrinsic connectivity network anchored to left and right anterior hippocampus, but spares the posterior hippocampus. A resting-state functional connectivity MRI (rs-fcMRI) study was conducted in a group of patients with svPPA and in controls, using a seed-to-voxel approach. In comparison to controls, massively reduced connectivity was found in the anterior hippocampus, mainly the left one, for svPPA patients but not in the left or right posterior hippocampus.

Differential language network functional connectivity alterations in Alzheimer's disease and the semantic variant of primary progressive aphasia.

Patients with Alzheimer's disease (AD) and semantic variant primary progressive aphasia (svPPA) can present with similar language impairments, mainly in naming. It has been hypothesized that these deficits are associated with different brain mechanisms in each disease, but no previous study has used a network approach to explore this hypothesis. The aim of this study was to compare resting-state functional magnetic resonance imaging (rs-fMRI) language network in AD, svPPA patients, and cognitively unimpaired elderly adults (CTRL).

Test-Retest Reliability of Diffusion Measures Extracted Along White Matter Language Fiber Bundles Using HARDI-Based Tractography.

High angular resolution diffusion imaging (HARDI)-based tractography has been increasingly used in longitudinal studies on white matter macro- and micro-structural changes in the language network during language acquisition and in language impairments. However, test-retest reliability measurements are essential to ascertain that the longitudinal variations observed are not related to data processing. The aims of this study were to determine the reproducibility of the reconstruction of major white matter fiber bundles of the language network using anatomically constrained probabilistic tractography with constrained spherical deconvolution based on HARDI data, as well as to assess the test-retest reliability of diffusion measures extracted along them.

Comprehension of concrete and abstract words in semantic variant primary progressive aphasia and Alzheimer's disease: A behavioral and neuroimaging study.

The aim of this study was to investigate the comprehension of concrete, abstract and abstract emotional words in semantic variant primary progressive aphasia (svPPA), Alzheimer's disease (AD), and healthy elderly adults (HE) Three groups of participants (9 svPPA, 12 AD, 11 HE) underwent a general neuropsychological assessment, a similarity judgment task, and structural brain MRI. The three types of words were processed similarly in the group of AD participants. In contrast, patients in the svPPA group were significantly more impaired at processing concrete words than abstract words, while comprehension of abstract emotional words was in between.

The Role of the Left Anterior Temporal Lobe for Unpredictable and Complex Mappings in Word Reading.

The anterior temporal lobes (ATLs) have been consistently associated with semantic processing which, in turn, has a key role in reading aloud single words. This study aimed to investigate (1) the reading abilities in patients with the semantic variant of primary progressive aphasia (svPPA), and (2) the relationship between gray matter (GM) volume of the left ATL and word reading performance using voxel-based morphometry (VBM). Three groups of participants (svPPA, Alzheimer's Disease, AD and healthy elderly adults) performed a reading task with exception words, regular words and pseudowords, along with a structural magnetic resonance imaging scan.

Lexical decision with pseudohomophones and reading in the semantic variant of primary progressive aphasia: A double dissociation.

The co-occurrence of semantic impairment and surface dyslexia in the semantic variant of primary progressive aphasia (svPPA) has often been taken as supporting evidence for the central role of semantics in visual word processing. According to connectionist models, semantic access is needed to accurately read irregular words. They also postulate that reliance on semantics is necessary to perform the lexical decision task under certain circumstances (for example, when the stimulus list comprises pseudohomophones).

Bilingual lexical selection as a dynamic process: Evidence from Arabic-French bilinguals.

The nature of the lexical selection process in bilingual spoken word production is one of the pending questions of research on bilingualism. According to one view this competitive process is language-specific, while another holds that it is language-nonspecific (i.e.

Norms for name agreement, familiarity, subjective frequency, and imageability for 348 object names in Tunisian Arabic.

Normative databases for pictorial stimuli are widely used in research on language processing in order to control for a number of psycholinguistic variables in the selected stimuli. Such resources are lacking for Arabic and its dialectal varieties. In the present study, we aimed to provide Tunisian Arabic (TA) normative data for 348 line drawings taken from Cycowicz, Friedman, Rothstein, and Snodgrass (1997), which include Snodgrass and Vanderwart's (1980) 260 pictures.