High-field functional magnetic resonance imaging generates in vivo retinotopic maps, but quantifying them remains challenging. Here, we present a pipeline based on conformal geometry and Teichmüller theory for the quantitative characterization of human retinotopic maps. We describe steps for cortical surface parameterization and surface-spline-based smoothing. We then detail Beltrami coefficient-based mapping, which provides a quantitative and re-constructible description of the retinotopic maps. This framework has been successfully used to analyze the Human Connectome Project's V1 retinotopic maps. For complete details on the use and execution of this protocol, please refer to Ta et al. (2022)..
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http://dx.doi.org/10.1016/j.xpro.2023.102246 | DOI Listing |
Computational theories posit that attention is guided by a combination of spatial maps for individual features that can be dynamically weighted according to task goals. Consistent with this framework, when a stimulus contains several features, attending to one or another feature results in stronger fMRI responses in regions preferring the attended feature. We hypothesized that multivariate activation patterns across feature-responsive cortical regions form spatial 'feature dimension maps', which combine to guide attentional priority.
View Article and Find Full Text PDFbioRxiv
January 2025
Department of Psychology, Dartmouth College.
Adaptive behavior in complex environments requires integrating visual perception with memory of our spatial environment. Recent work has implicated three brain areas in posterior cerebral cortex - the place memory areas (PMAs) that are anterior to the three visual scene perception areas (SPAs) - in this function. However, PMAs' relationship to the broader cortical hierarchy remains unclear due to limited group-level characterization.
View Article and Find Full Text PDFBrain
January 2025
Faculty of Social and Behavioural Sciences, University of Amsterdam, 1001 NK, Amsterdam, The Netherlands.
Mid-level visual processing represents a crucial stage between basic sensory input and higher-level object recognition. The conventional model posits that fundamental visual qualities like color and motion are processed in specialized, retinotopic brain regions (e.g.
View Article and Find Full Text PDFJ Neurosci
January 2025
Instituto de Neurociencias de Alicante (Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH), Campus San Juan, Alicante 03550, Spain
Eph/ephrin signaling is crucial for organizing retinotopic maps in vertebrates. Unlike other EphAs, which are expressed in the embryonic ventral retina, EphA4 is found in the retinal ganglion cell (RGC) layer at perinatal stages, and its role in mammalian visual system development remains unclear. Using classic in vitro stripe assays, we demonstrate that, while RGC axons are repelled by ephrinB2, they grow on ephrinB1 stripes through EphA4-mediated adhesion.
View Article and Find Full Text PDFProc IEEE Int Symp Biomed Imaging
May 2024
School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, AZ, USA.
Retinotopic mapping aims to uncover the relationship between visual stimuli on the retina and neural responses on the visual cortical surface. This study advances retinotopic mapping by applying diffeomorphic registration to the 3T NYU retinotopy dataset, encompassing analyze-PRF and mrVista data. Diffeomorphic Registration for Retinotopic Maps (DRRM) quantifies the diffeomorphic condition, ensuring accurate alignment of retinotopic maps without topological violations.
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