Biology subjects

Plaut, D.

Publications and source records attributed to Plaut, D..

3 recordsLinked to original sources

bioRxiv2024

Cross-sectional and longitudinal changes in category-selectivity in visual cortex following pediatric cortical resection

The topographic organization of category-selective responses in human ventral occipitotemporal cortex (VOTC) and its relationship to regions subserving language functions is remarkably uniform across individuals. This arrangement is thought to result from the clustering of neurons responding to similar inputs, constrained by intrinsic architecture and tuned by experience. We examined the malleability of this organization in individuals with unilateral resection of VOTC during childhood for the management of drug-resistant epilepsy. In cross-sectional and longitudinal functional imaging studies, we compared the topography and neural representations of 17 category-selective regions in individuals with a VOTC resection, a control patient with resection outside VOTC, and typically developing matched controls. We demonstrated both adherence to and deviation from the standard topography and uncovered fine-grained competitive dynamics between word- and face-selectivity over time in the single, preserved VOTC. The findings elucidate the nature and extent of cortical plasticity and highlight the potential for remodeling of extrastriate architecture and function. TeaserAfter pediatric cortical resection, deviations from the constraints of standard topography in visual cortex reflect plasticity.

neuroscience↗

bioRxiv2023

Beyond the Visual Word Form Area: Characterizing a hierarchical, distributed and bilateral network for visual word processing

Although the left hemisphere (LH) Visual Word Form Area (VWFA) is considered the pre-eminent cortical region engaged in visual text processing, other regions in both hemispheres have also been implicated. To examine the entire circuit, using functional MRI data, we defined ten regions of interest (ROI) in each hemisphere that, based on functional connectivity measures, naturally grouped into early vision, high-level vision, and language clusters. We analysed univariate and multivariate responses to words, inverted words, and consonant strings for ROIs and clusters, and demonstrated modulation by text condition bihemispherically, albeit more strongly and in a larger number of regions in the LH. Graph theory analysis revealed that the high-level vision cluster and, specifically, the VWFA was equivalently connected with both early visual and language clusters in both hemispheres, reflecting its role as a mediator in the circuit. Our findings reveal bihemispheric, stimulus-mediated ROI response flexibility but circuit-level connectivity stability, reflecting the complex contribution of a distributed system for word processing.

neuroscience↗

bioRxiv2021

A connectivity-constrained computational account of topographic organization in high-level visual cortex

Inferotemporal cortex (IT) in humans and other primates is topo-graphically organized, containing multiple hierarchically-organized areas selective for particular domains, such as faces and scenes. This organization is commonly viewed in terms of evolved domain-specific visual mechanisms. Here, we develop an alternative, domain-general and developmental account of IT cortical organization. The account is instantiated as an Interactive Topographic Network (ITN), a form of computational model in which a hierarchy of model IT areas, subject to connectivity-based constraints, learns high-level visual representations optimized for multiple domains. We find that minimizing a wiring cost on spatially organized feedforward and lateral connections within IT, combined with constraining the feedforward processing to be strictly excitatory, results in a hierarchical, topographic organization. This organization replicates a number of key properties of primate IT cortex, including the presence of domain-selective spatial clusters preferentially involved in the representation of faces, objects, and scenes, columnar responses across separate excitatory and inhibitory units, and generic spatial organization whereby the response correlation of pairs of units falls off with their distance. We thus argue that domain-selectivity is an emergent property of a visual system optimized to maximize behavioral performance while minimizing wiring costs. Significance StatementWe introduce the Interactive Topographic Network, a framework for modeling high-level vision, to demonstrate in computational simulations that the spatial clustering of domains in late stages of the primate visual system may arise from the demands of visual recognition under the constraints of minimal wiring costs and excitatory between-area neuronal communication. The learned organization of the model is highly specialized but not fully modular, capturing many of the properties of organization in primates. Our work is significant for cognitive neuroscience, by providing a domain-general developmental account of topo-graphic functional specialization, and for computational neuroscience, by demonstrating how well-known biological details can be successfully incorporated into neural network models in order to account for critical empirical findings.

neuroscience↗