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Hiersche, K.

Publications and source records attributed to Hiersche, K..

3 recordsLinked to original sources

Literacy acquisition and functional connectivity drive the emergence and continued development of the VWFA

The visual word form area (VWFA) is a hallmark of literacy in the human brain. Alongside reading acquisition, the functional organization of the ventral temporal cortex (VTC) undergoes substantial changes. However, it remains unclear what factors uniquely drive the emergence and continued development of the VWFA, or more broadly shaping category selectivity across the VTC. Here, we combined cross-sectional and longitudinal data from children in early childhood (3-9 years) to investigate the development of visual language selectivity. We found that after controlling for age, literacy acquisition drove increases in word selectivity of the VWFA, but not the continued development of other early-developed category selectivity. Sensitivity to spoken higher-level language information within the VWFA was also associated with reading ability. By projecting the VWFA defined at the later time point onto each childs earlier time point, we also found that the pre-VWFA showed no preferential tuning to any particular visual category. Finally, longitudinal changes within the VWFA, both increased responses to visually presented words and decreased responses to auditory control conditions, were associated with changes in functional connectivity of VWFA to high-level language regions, even after controlling for initial activity levels. Together, the current study shows a unique role for literacy acquisition and experience-dependent connectivity changes in the emergence and functional specialization of the VWFA, providing empirical evidence for the revised neuronal recycling hypothesis and connectivity hypothesis of functional brain organization.

neuroscience↗

Connectivity and function are coupled across cognitive domains throughout the brain

Decades of neuroimaging have revealed that the functional organization of the brain is roughly consistent across individuals and at rest it is resembles group-level task-evoked networks. A fundamental assumption in the field is that the functional specialization of a brain region arises from its connections to the rest of the brain, but limitations in the amount of data that can be feasibly collected in a single individual, leaves open the question: Is the association between task activation and connectivity consistent across the brain and many cognitive tasks? To answer this question, we fit ridge regressions models to activation maps from 33 cognitive domains (generated with NeuroQuery) using resting-state functional connectivity data from the Human Connectome Project as the predictor. We examine how well functional connectivity fits activation and find that all regions and all cognitive domains have a very robust relationship between brain activity and connectivity. The tightest relationship exists for higher-order, domain-general cognitive functions. These results support the claim that connectivity is a general organizational principle of brain function by comprehensively testing this relationship in a large sample of individuals for a broad range of cognitive domains and provide a reference for future studies engaging in individualized predictive models.

neuroscience↗

Demystifying the Visual Word Form Area: Precision fMRI of Visual, Linguistic, and Attentional Properties of Ventral Temporal Cortex

The functional nature of the visual word form area (VWFA), a region in left ventrotemporal cortex (VTC), remains debated after over two decades of investigation. Here we use precision fMRI to comprehensively examine the VWFAs responses to numerous visual and nonvisual stimuli. We find that the VWFA is a distinct region that while showing moderate activation to non-word visual stimuli, its response to words towers above other conditions. Interestingly, the VWFA is also the only VTC region uniquely engaged in auditory language processing, in contrast with the ubiquitous attentional effect within the VTC. However, this language selectivity is dwarfed by its visual responses. This suggests the VWFA primarily functions as a visual look-up orthographic dictionary. Searching within the entire VTC further reveals an additional language cluster in anterior fusiform preferring general visual semantics. Our detailed examination of the VWFA in direct comparison to other VTC regions clarifies the long-standing controversies about its functionality.

neuroscience↗