Biology subjects

Billot, A.

Publications and source records attributed to Billot, A..

3 recordsLinked to original sources

bioRxiv2026

Large-Scale Network Embedding Predicts Opposing Functions of Adjacent Regions Within Human Prefrontal Cortex

Prefrontal regions are hypothesized to be organized hierarchically in support of cognitive control. Using precision functional MRI in three independent cohorts of intensively scanned participants (N=37), we consistently identified a lateral prefrontal cortex (LPFC) region linked to a canonical control network separate from a nearby rostral LPFC region linked to the action-mode network. Despite their spatial juxtaposition, the two regions were differentially coupled to the caudate and ventral putamen, suggesting they are components of segregated networks. Working memory demands activated the canonical LPFC control region but not the adjacent region. Contrasting go and no-go trials during target detection revealed a robust functional double dissociation during goal-directed behavior. The canonical LPFC control region activated when responses were withheld, while the putamen-coupled LPFC region increased activity during executed responses. These findings demonstrate that adjacent LPFC regions participate in opposing functions predicted by their embedding within distinct parallel large-scale networks.

neuroscience↗

bioRxiv2026

Multiple Nested Distributed Language Networks in the Human Brain

Brain regions specialized for language have been extensively described, yet their arrangement into one or multiple networks remains debated. Using precision functional mapping across three independent cohorts of intensively scanned individuals (22 individuals scanned over 216 separate MRI sessions), we dissociated two nested left-lateralized perisylvian networks: an intermediate language network (intLANG) and an anatomically distinct association language network (aLANG). intLANG is anchored to precentral speech areas and the Sylvian parietal-temporal area (Spt), whereas aLANG surrounds intLANG and extends into higher-order prefrontal and temporal association cortices. The two networks can be fully recapitulated by functional connectivity from adjacent cerebellar regions, indicating that they are segregated, brain-wide networks. Task-based analyses further reveal that intLANG and aLANG are functionally distinct: intLANG responds robustly during rhyme judgments and nonword reading that emphasize phonology, whereas aLANG is preferentially recruited during meaning-based sentence processing. These findings indicate that human language engages nested distributed networks each specialized for distinct components of language processing: a lower-order network biased toward phonology, and a surrounding association network that subserves higher-order syntax and semantics. This nested organization is similar to other brain systems suggesting a shared hierarchical motif that may give rise to specialized cognitive functions across the human brain.

neuroscience↗

bioRxiv2024

The language network ages well: Preserved selectivity, lateralization, and within-network functional synchronization in older brains

Healthy aging is associated with structural and functional brain changes. However, cognitive abilities vary in how they change with age: whereas executive functions, like working memory, show age-related decline, aspects of linguistic processing remain relatively preserved. The heterogeneity of the cognitive-behavioral landscape in aging predicts differences among brain networks in whether and how they should change with age. To evaluate this prediction, we used individual-subject fMRI analyses (precision fMRI) to examine the language-selective network and--for control purposes--the Multiple Demand (MD) network, which supports executive functions, in older adults (n=64) relative to young controls (n=483). In line with past claims, relative to young adults, the MD network of older adults shows weaker, less spatially extensive, and more topographically variable activations during an executive function task and reduced within-network functional connectivity. However, in stark contrast to the MD network, we find remarkable preservation of the language network in older adults. Their language network responds during language comprehension as strongly and selectively as in younger adults, and shows a similar degree of left-hemispheric lateralization and within-network functional connectivity. Our findings suggest that the language network remains young-like--at least on standard measures of function and connectivity--and align with behavioral preservation of language comprehension in healthy aging.

neuroscience↗