3,743 research outputs found
A matter of hand: Causal links between hand dominance, structural organization of fronto-parietal attention networks, and variability in behavioural responses to transcranial magnetic stimulation
Get PDFConsiderable evidence suggests that, on a group level, human visuospatial attention is asymmetrically organized, with a right-hemispheric dominance. The asymmetrical organization of the superior longitudinal fasciculus (SLF) has been shown to account for the right-hemispheric dominance in visual attention. However, such account is by no means universal, and large individual differences in asymmetrical performance on visuospatial tasks have been reported. Furthermore, the variability in the SLF lateralization has been shown to correlate with behavioural asymmetries. Continuous theta burst stimulation (cTBS) enables to temporarily interfere with cortical activity. cTBS applied over the posterior parietal cortex (PPC) has been previously used to systematically study attentional asymmetries. Interestingly, large individual differences in the effectiveness of stimulation have been reported. In accordance with earlier both animal and human studies, one possible cause underlying these striking individual differences might lie in the structural organization of frontoparietal pathways subserving visuospatial attention. Thus, the current study employed diffusion tractography to examine the relationship between the variability in the structural organization of the SLF and the individual differences in attentional shifts induced by a modified cTBS (cTBSmod; triplets of pulses at 30 Hz, repeated at 6 Hz) applied over the IPS, as measured by a line bisection task. Consistent with previous studies, on a group level, cTBSmod applied over the right intraparietal sulcus (IPS) triggered a rightward bisection bias shift, and there were no significant effects of cTBSmod applied over the left IPS. However, further analyses demonstrated that both handedness and structural variability (as assessed based on hindrance modulated orientational anisotropy) within the middle and the ventral branches of the SLF predicted individual differences in the cTBSmod-induced attentional shifts. Our study thus suggests that the effects of cTBSmod over the IPS may depend on intra-hemispheric interactions between cortical loci controlling visual attention. To conclude, our findings provide converging evidence for the notion put forward previously that inter-individual variability in the structural organization of intra-hemispheric frontoparietal connections has important implications for the functional models of human visual attention. Moreover, we hypothesize that this may also be relevant for the understanding of attentional disorders and their rehabilitation
Bilateral parietal dysfunctions and disconnections in simultanagnosia and Bálint syndrome
No full textIn 1909 Rezsö Bálint published an extraordinary case study of a man with complex visuospatial deficits resulting from bilateral parietal lesions. Despite some controversies over the nature of reported symptoms, in 1954 Hecaen and Ajuriaguerra conceived the term "Bálint syndrome," not only to honor Bálint's influential work but to firmly conceptualize this striking neurologic disorder. Nowadays it is largely agreed that, while Bálint syndrome may result from multiple etiologies, it is principally diagnosed based on the presence of three symptoms: simultanagnosia, optic ataxia, and ocular apraxia. One of the most striking characteristics of Bálint syndrome, perfectly capturing the nature of this remarkable disorder, is that affected patients cannot perceive more than one object at a time or comprehend multiobject visual scenes due to a lack of ability to detect several objects concurrently and to grasp the spatial relationships between them. This chapter gives an overview of the cognitive mechanisms and neuroanatomy underlying Bálint syndrome, which provides key insights into our understanding of the role of parietal cortex in human attention, visual perception, and visuomotor control. This chapter also pays homage to Glyn Humphreys (1954-2016), who pioneered contributions to the knowledge about complexity of visual and spatial deficits associated with Bálint syndrome.</p
Hemispatial neglect: An evaluation of novel assessment methods and rehabilitation
Get PDFHemispatial neglect, is a major cause of post-stroke disability and poor functional recovery. Hence, identifying sensitive methods to assess and rehabilitate neglect is important.
Chapters 3 and 4 focused on development of novel assessment techniques for representational neglect. The âShopping Mallâ and âClock Cueingâ tasks improved upon previous tests and were useful in identifying dissociations in representational neglect based on type of stimuli (topological, non-topological) and time of assessment (pre-stroke, post-stroke) in chronic stroke patients.
Chapters 5 and 6 investigated the efficacy of offline inhibitory repetitive Transcranial Magnetic Stimulation (rTMS) in producing short (<1 month) and long term (>6 months) changes in visual neglect behaviour. Overall, the findings from these chapters were limited due to lack of sufficient power. After controlling for the effect of baseline performance, the Intervention groupâs Activities of Daily Living scores significantly improved in the short-term post rTMS, as compared to the Control group. The fMRI task attempted to recruit attention-based top down modulation of sensory activity. It revealed relative hypoactivation of the right occipital lobe in the four left neglect patients tested, both pre and post rTMS, when compared to elderly controls.
Chapter 7 explored cognitive predictors of spatial and object neglect in the sub-acute stage after controlling for demographic and stroke related factors, using multivariate blocked logistic regressions. Cognitive performance indicative of spatial attention and selective attention to local features predicted both spatial and object neglect. In addition, coding of spatial relations between features also predicted spatial neglect. Suggestions for combining neglect rehabilitation techniques to target these cognitive processes are discussed.
Overall, this thesis provides novel methods to improve representational neglect assessment and highlights the importance of ancillary cognitive domains in contributing to both representational and visual neglect. The rTMS research provides study design-related insights to incorporate in future studies with larger patient samples.</p
Collective Improvisation: The Practice and Vision of Ingemar Lindh
Get PDFIngemar Lindh's research on the principles of collective improvisation and performance conceived as process announce an important development in the 20th-century tradition of the actor's work. After early studies with Étienne Decroux and working collaborations with Jerzy Grotowski, Eugenio Barba, and Yves Lebreton, Lindh founded the first laboratory theatre in Sweden in 1971, the Institutet för Scenkonst. His practice of collective improvisation is viewed in light of postdramatic concerns such as its resistance to fixed scores, directorial montage, and choreography as an organizing principle
Spatial and non-spatial aspects of visual attention: Interactive cognitive mechanisms and neural underpinnings
Get PDFFrom electrophilic to stereospecific SN2 alpha-functionalization reactions of acyclic carboxylic acid derivatives
No full textAuthor Magdalena Piringer, BScMasterarbeit Universität Linz 202
Conversion and Artistic Creation of Magdalena V.
No full textThis Bachelor thesis Conversion and Artistic Creation of Magdalena V. deals with the change of artistic expression of the Czech graphic artist Magdalena V., in a close connection to her religious conversion to the Catholic faith. The first part summarizes the theoretical knowledge of the psychology of religion. It introduces basic definitions and concepts of religion in relation to a religious conversion. In the second part, the author deals with the psychological analysis of Magdalena V.'s typical work through her life, which is supported by numerous photographs. Using the approach of rožnovská school, the author attempts to interpret this artwork on a hypothetical level, focusing on the M.V.'s life and artistic paralel before and after her conversion. The author draws on Magdalena V.'s testimonies about her life which bring light on the intention and context in her art. Related to the author's identification with Magdalena V.'s work, which later became apparent, this paper evolved further into identifying these moments and thus the potential risks inherent in author's own therapeutic work
From electrophilic to stereospecific SN2 alpha-functionalization reactions of acyclic carboxylic acid derivatives
No full textAuthor Magdalena Piringer, BScMasterarbeit Universität Linz 202
The Development of Sculpture in the Quito School
No full textMagdalena Gallegos de Donoso, Ecuadorian anthropologist and art historian, author of over fifty exhibition catalogues, Director of the Central Bank of Ecuador Museums
First person – Magdalena Woloszynska
No full textABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Magdalena Woloszynska is the first author on ‘The Elongator complex regulates hypocotyl growth in darkness and during photomorphogenesis’, published in Journal of Cell Science. While completing this work, Magdalena was a postdoctoral fellow in the Chromatin and Growth Control group at the VIB-UGent Center for Plant Systems Biology at Ghent University, Belgium. Her research interests include plant molecular biology, epigenetics, transcriptomics, plant physiology and plant mitochondria.</jats:p
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