Functional connectivity in chronic stroke compared with normal aging changes
The retrieval of low frequency words is usually slower than that of high frequency words. Neuroimaging research on the role of word frequency in linguistic tasks suggests candidate brain areas for the neural substrates of this effect. The only previous fMRI study of word frequency in Russian (Malutina et al., 2012) used an action naming task and obtained data that were highly inconsistent with results for other languages, findings which were mainly obtained using noun-retrieval tasks. In order to verify whether the reasons for such inconsistency were methodological or cross-linguistic, we examined the fMRI correlates of word frequency in Russian using a covert object naming task. We found that the retrieval of low frequency and high frequency nouns activated the same general pattern of brain areas typical for object naming tasks in many languages. Several brain regions were more activated in the low frequency but not the high frequency condition, including the areas and structures usually associated with linguistic processing (the inferior frontal gyrus bilaterally, the left thalamus, the left insula), visual perception (the fusiform gyrus, the inferior occipital gyrus, the middle occipital gyrus bilaterally) and cognitive and motor control (the supplementary motor area and the right cingulate gyrus). The right cingulate gyrus was the only area that responded only to the low frequency stimuli but not the high frequency items, when compared to the baseline. At the same time, we found no brain areas that responded more to high versus low word frequency. These results are generally consistent with previous fMRI studies in English, German and Chinese and therefore suggest that the inconsistency between the previous research in Russian and other languages was due to the possible interaction of the part of speech (verb or noun) and word frequency in brain mechanisms for word retrieval, rather than cross-linguistic differences.
The study of cerebral organization of usage of verbs and nouns was carried out by means of functional magnetic resonance imaging. The influence of strategy of word actualization (verbs and nouns extraction on paradigmatic and syntagmatic connections) and the level of automation of these processes on the pattern of cerebral cortex activation was shown.
Key characteristics of non-fluent (Broca, motor) aphasia are, among others, verb finding difficulties and effortful speech output. These characteristics are related to different levels of speech production (lexical retrieval and motor execution). This study was aimed at identifying normative brain activation related to verb production in healthy individuals, as well as patterns of its reorganization depending on the locus of the linguistic deficit in patients with non-fluent aphasia.
Investigations of the neural correlates of face recognition have typically used old/new paradigms where subjects learn to recognize new faces or identify famous faces. Familiar faces, however, include one's own face, partner's and parents' faces. Using event-related fMRI, we examined the neural correlates of these personally familiar faces. Ten participants were presented with photographs of own, partner, parents, famous and unfamiliar faces and responded to a distinct target. Whole brain, two regions of interest (fusiform gyrus and cingulate gyrus), and multiple linear regression analyses were conducted. Compared with baseline, all familiar faces activated the fusiform gyrus; own faces also activated occipital regions and the precuneus; partner faces activated similar areas, but in addition, the parahippocampal gyrus, middle superior temporal gyri and middle frontal gyrus. Compared with unfamiliar faces, only personally familiar faces activated the cingulate gyrus and the extent of activation varied with face category. Partner faces also activated the insula, amygdala and thalamus. Regions of interest analyses and laterality indices showed anatomical distinctions of processing the personally familiar faces within the fusiform and cingulate gyri. Famous faces were right lateralized whereas personally familiar faces, particularly partner and own faces, elicited bilateral activations. Regression analyses show experiential predictors modulated with neural activity related to own and partner faces. Thus, personally familiar faces activated the core visual areas and extended frontal regions, related to semantic and person knowledge and the extent and areas of activation varied with face type.
The distractive effects on attentional task performance in different paradigms are analyzed in this paper. I demonstrate how distractors may negatively affect (interference effect), positively (redundancy effect) or neutrally (null effect). Distractor effects described in literature are classified in accordance with their hypothetical source. The general rule of the theory is also introduced. It contains the formal prediction of the particular distractor effect, based on entropy and redundancy measures from the mathematical theory of communication (Shannon, 1948). Single- vs dual-process frameworks are considered for hypothetical mechanisms which underpin the distractor effects. Distractor profiles (DPs) are also introduced for the formalization and simple visualization of experimental data concerning the distractor effects. Typical shapes of DPs and their interpretations are discussed with examples from three frequently cited experiments. Finally, the paper introduces hierarchical hypothesis that states the level-fashion modulating interrelations between distractor effects of different classes.
This article describes the expierence of studying factors influencing the social well-being of educational migrants as mesured by means of a psychological well-being scale (A. Perrudet-Badoux, G.A. Mendelsohn, J.Chiche, 1988) previously adapted for Russian by M.V. Sokolova. A statistical analysis of the scale's reliability is performed. Trends in dynamics of subjective well-being are indentified on the basis the correlations analysis between the condbtbions of adaptation and its success rate, and potential mechanisms for developing subjective well-being among student migrants living in student hostels are described. Particular attention is paid to commuting as a factor of adaptation.