Biology subjects

Fuentes-Jimenez, M.

Publications and source records attributed to Fuentes-Jimenez, M..

3 recordsLinked to original sources

bioRxiv2025

Visual Word Form Area demonstrates individual and task-agnostic consistency but inter-individual variability

Ventral Occipital Temporal Cortex (VOTC) contains a mosaic of categorically-selective functional regions that respond to visual stimuli. Within left VOTC lies the Visual Word Form Area (VWFA) - a text-selective region that develops as individuals learn to read. While there is consistency in the general location of text-selective responses - within the posterior occipitotemporal sulcus (OTS) - there is substantial variability across individuals in the size and precise anatomical location. Moreover, debate continues regarding whether VWFA a) encodes the visual features of text, versus b) is driven by the task of reading. Using functional magnetic resonance imaging, we scanned adults and children as they completed two tasks while viewing text, pseudo fonts, faces, objects, limbs: (1) a fixation task where participants ignored stimuli while making psychophysical judgements on a fixation dot, and (2) a one-back task, where they attend to stimuli to detect repeats. We found a consistent VWFA location could be identified on each individuals cortical surface using either task. At the same time, the one-back task evoked a larger territory of text-selective response (leading to a larger ROI) than the fixation task. However, when averaged in template space, text-selective cortex could not be identified due to variability in the relative locations of text-, face-, object-, and limb-selective cortex. Thus, despite task-agnostic consistency in individual VWFA, text-selective responses are masked when averaged in template space due to variability in the exact configuration of category-selective regions. Furthermore, these effects were present in both children and adults.

neuroscience↗

bioRxiv2025

Small or absent Visual Word Form Area is a trait of dyslexia

Understanding the balance between plastic and persistent traits in the dyslexic brain is critical for developing effective interventions. This longitudinal intervention study examines the Visual Word Form Area in dyslexic and typical readers, exploring how this key component of the brains reading circuitry changes with learning. We find that children with dyslexia show significant differences in Visual Word Form Area presence, size, and tuning properties compared to typical readers. While reading intervention improves reading skills and increases Visual Word Form Area size, disparities persist a year later, suggesting that Visual Word Form Area abnormalities are enduring traits of dyslexia. Our results reveal long-term neural and behavioral changes, while also elucidating stable differences in the functional architecture of the dyslexic brain. This work provides comprehensive insights into the potential and limitations of short-term learning-induced plasticity in human visual cortex.

neuroscience↗

bioRxiv2024

Anatomically distinct regions in the inferior frontal cortex are modulated by task and reading skill

Inferior frontal cortex (IFC) is a critical region for reading and language. This part of the cortex is highly heterogeneous in its structural and functional organization and shows high variability across individuals. Despite decades of research, the relationship between specific IFC regions and reading skill remains unclear. To shed light on the function of IFC in reading, we aim to (1) characterize the functional landscape of text-selective responses in the IFC, while accounting for interindividual variability; and (2) examine how text-selective regions in the IFC relate to reading proficiency. To this end, children with a wide range of reading ability (N=66; age 7-14 years, 34 female, 32 male) completed functional MRI scans while performing two tasks on text and non-text visual stimuli. Importantly, both tasks do not explicitly require reading, and can be performed on all visual stimuli. This design allows us to tease apart stimulus-driven responses from task-driven responses and examine where in the IFC task and stimulus interact. We were able to identify three anatomically-distinct, text-selective clusters of activation in the IFC, in the inferior frontal sulcus (IFS), and dorsal and ventral precentral gyrus (PrG). These three regions showed a strong task effect that was highly specific to text. Furthermore, text-selectivity in the IFS and dorsal PrG was associated with reading proficiency, such that better readers showed higher selectivity to text. These findings suggest that text-selective regions in the IFC are sensitive to both stimulus and task, and highlight the importance of this region for proficient reading. Significance statementThe inferior frontal cortex (IFC) is a critical region for language processing, yet despite decades of research, its relationship with reading skill remains unclear. In a group of children with a wide range of reading skills, we were able to identify three anatomically distinct text-selective clusters of activation in the IFC. These regions showed a strong task effect that was highly selective to text. Text-selectivity was positively correlated with reading proficiency, such that better readers showed higher selectivity to text, even in tasks that did not require reading. These findings suggest that multiple text-selective regions within IFC are sensitive to both stimulus and task, and highlight the critical role of IFC for reading proficiency.

neuroscience↗