Biology subjects

Branzi, F. M.

Publications and source records attributed to Branzi, F. M..

7 recordsLinked to original sources

bioRxiv2026

Resolving the Abstract-Concrete Paradox in the Angular Gyrus: A Multimethod Investigation

Despite its well-established role in memory-guided cognition, whether and how the angular gyrus (AG) contributes to semantic processing remains unresolved. Connectomic work links the AG to abstract mentation, yet neuroimaging studies paradoxically show greater AG engagement for concrete than abstract semantics. To address this discrepancy, we conducted a multimethod investigation integrating neurostimulation, neuroimaging, and experience sampling across five studies (127 human participants; 53 males; 74 females). Using the contrast between concrete and abstract semantics as a diagnostic test-case, we show that this apparent contradiction reflects multiple interacting neurocognitive factors shaping the AGs functional repertoire. In Study 1, causal disruption of the AG disproportionately impaired abstract semantics and temporary retention of task-relevant information, demonstrating its role in abstract and memory-guided cognition. In Study 2, the apparent concreteness effect was abolished after controlling for performance speed/accuracy, indicating that AG activity is more strongly associated with low-demand mental states than semantic concreteness. In Study 3, the AG showed enhanced functional coupling with regions in the semantic network for abstract words, suggesting sustained integration with the semantic system despite reduced activation. In Study 4, experience sampling showed that concrete words are associated with experiences of mental imagery and automaticity, providing a phenomenological account of heightened AG engagement under low-demand states. Finally, Study 5 clarified how baseline choices influence the interpretation and polarity of AG activity. Together, these findings show that AG engagement is best understood along a continuum of memory-guided cognition, clarifying when and why this region supports abstract versus concrete semantics across situations. SignificanceThe contribution of the AG to semantic processing has long been debated, both regarding whether it is reliably engaged and how such engagement should be interpreted. By integrating evidence from multiple independent datasets using complementary methodologies, the present investigation moves beyond single-process accounts to identify multiple contributors that jointly define AG function. These factors align with contemporary connectomic research that situates the AG at the transmodal apex of a principal cortical gradient. Under this brain-connectomic framework, AG involvement is amplified as representations become abstract, information is buffered, operation becomes automatic, imagery is simulated, reliance on perception is reduced, shifting from perception-guided mode to memory-guided cognition. Together, these findings provide a principled framework for interpreting the elusive patterns of AG functionality.

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bioRxiv2025

Language laterality and cognitive skills: does anatomy matter?

Brain anatomy, particularly white matter microstructure, is thought to play a critical role in the relationships between cognitive function and language lateralisation. This study investigates whether white matter microstructural parameters of the arcuate fasciculus and corpus callosum is associated with cognitive performance across distinct language lateralisation groups. Neuroimaging and cognitive data from 279 healthy adults were sourced from the BIL&GIN database. Participants completed a sentence production fMRI task, diffusion MRI, and cognitive tasks assessing verbal, visuospatial, and arithmetic skills. Significant positive associations were observed in strongly atypical individuals between fractional anisotropy in the splenium and working memory (R2 = 0.96, pFDR = 0.042) and between FA in the genu and visuospatial attention (R2 = 0.92, pFDR = 0.042). ANCOVA revealed that cross-dominant individuals had significantly lower visuospatial attention scores compared to consistently lateralised individuals (pFDR = 0.02). These findings challenge the notion that atypical lateralisation is inherently maladaptive and suggest that white matter pathways may serve as an alternative mechanism for supporting cognitive function in individuals with rightward language dominance. Furthermore, the results highlight the cognitive disadvantages of crossed dominance, implicating disrupted interhemispheric communication as a potential underlying mechanism.

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bioRxiv2025

Semantic elaboration determines the time course of alpha-beta oscillations during the encoding and retrieval of narrative memories

Understanding and remembering everyday events requires us to retrieve semantic relationships between elements by activating prior knowledge, allowing us to form a deeper memory trace. However, the neural interplay between semantic and episodic systems to encode and retrieve recent memories remains unclear. The present study addresses how semantic elaboration enhances episodic memory formation through neural oscillations. We presented participants with continuous auditory verbal and non-verbal narratives to memorise. Participants rated the perceived coherence of each narrative to provide a subjective measure of semantic elaboration. We assessed participants memory of the narratives depending on semantic elaboration and modality of encoding with a subsequent retrieval test. We recorded their electroencephalogram (EEG) to establish how semantic elaboration modulated the representation of narratives information proxied by neocortical alpha-beta oscillations during the encoding and retrieval. First, we found that semantic elaboration facilitated narrative information processing by speeding perceived coherence responses during encoding. Second, the magnitude of alpha-beta desynchronisation across the semantic network progressively increased with the chronological position of the events indexing information accumulation as the narratives unfolded. Third, the coherence scores of the narratives negatively correlated with the magnitude of alpha-beta oscillation desynchronisation later during successful retrieval. Our findings provide direct behavioural and alpha-beta oscillatory evidence of how semantic elaboration influences the time course of neural operations supporting information representation and reinstatement mediated by neocortical alpha-beta oscillations.

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bioRxiv2025

The role of the right language network and the multiple-demand network in verbal semantics: Insights from an Activation Likelihood Estimation Meta-analysis of 561 Functional Neuroimaging Studies

Language processing has been traditionally associated with a network of fronto-parietal and temporal regions in the left hemisphere. Nevertheless, the right language network (frontal, temporal, and parietal regions homologous to the left language network) and the Multiple-Demand Network (MDN) are often involved in verbal semantic processing as well, however their role remain poorly understood. This is in part due to the inconsistent engagement of these latter two networks across linguistic tasks. To explore the factors driving networks recruitment of right language network and MDN during verbal semantic processing, we conducted a large-scale Activation Likelihood Estimation meta-analysis of neuroimaging studies. We examined whether the right language network is influenced by verbal stimulus type (sentences/narratives versus single words/word pairs) and whether this may be due to differences in semantic control demands and/or the presence of social content in the stimuli. Additionally, we investigated whether MDN recruitment depends on external task demands rather than semantic control demands. Our main findings revealed greater engagement of the right language network during semantic processing of sentence/narrative stimuli, with distinct regions reflecting different functions: increased semantic control demands recruit the right inferior frontal gyrus. Instead, social content processing during a semantic task engages the right Anterior Temporal Lobe, as well as the right posterior middle temporal gyrus. Finally, semantic processing engages the MDN, but only when external task (rather than semantic) demands increase.

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bioRxiv2022

The Role of the Posterior Medial Network in Language Comprehension: Dissociating Construction of Episodic versus Semantic Representations

Language comprehension involves the construction of complex mental representations, i.e., "event representations", reflecting current events or situation models. The construction of these representations requires manipulation of both semantic and episodic content and has been widely associated with the functioning of the posterior medial network, a subsystem of the default network. However, it is still unknown the extent to which activity in posterior medial network reflects construction of the variable episodic versus semantic content of event representations. In this fMRI study, we establish the unique neural correlates of (1) episodic richness and (2) semantic coherence measured during a narrative reading task. Interestingly, we observed a functional fractionation within the posterior medial network in terms of brain regions whose activity was modulated by semantic or episodic content. Specifically, the number of episodic details in the narratives modulated the activity in the left angular gyrus and the retrosplenial cortex/ventral posterior cingulate cortex. Semantic coherence, in contrast, modulated neural responses in the right anterior temporal lobe/middle temporal gyrus, but also in brain regions within the posterior medial network, such as the dorsal posterior cingulate cortex. These results provide the first demonstration of functional dissociations within the posterior medial network in terms of brain regions involved in the construction of semantic versus episodic representational content during a language comprehension task. Significance StatementThe construction of "event representations", which is crucial to understand the world around us, predict the future and make plans, requires manipulation of both semantic and episodic information. The functioning of the posterior medial network has been tightly linked to formation of event representations. However, it is unclear the extent to which activity in this network reflects construction of the variable episodic versus semantic content of event representations. The present study provides the first demonstration of functional dissociations within posterior medial network in terms of brain regions involved in construction of semantic versus episodic representational content during language comprehension. These findings represent a first step towards understanding how episodic and semantic memory systems operate during the construction of event representations.

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bioRxiv2019

Revealing the neural networks that extract conceptual gestalts from continuously evolving or changing semantic contexts

Reading a book, understanding the news reports or any other behaviour involving the processing of meaningful stimuli requires the semantic system to have two main features: being active during an extended period of time and flexibly adapting the internal representation according to the changing environment. Despite being key features of many everyday tasks, formation and updating of the semantic \"gestalt\" are still poorly understood. In this fMRI study we used naturalistic stimuli and task manipulations to identify the neural network that forms and updates conceptual gestalts during time-extended integration of meaningful stimuli. Univariate and multivariate techniques allowed at drawing a distinction between networks that are crucial for the formation of a semantic gestalt (meaning integration) and those that instead are important for linking incoming cues about the current context (e.g., time, space cues) into a schema representation. Specifically, we revealed that time-extended formation of the conceptual gestalt was reflected in the neurocomputations of the anterior temporal lobe accompanied by multi-demand areas and hippocampus, with a key role of brain structures in the right hemisphere. This \"semantic gestalt network\" was strongly recruited when an update of the current semantic representation was required during narrative processing. A distinct fronto-parietal network, instead, was recruited for context integration, independently from the meaning associations between words (semantic coherence). Finally, in contrast with accounts positing that the default-mode-network (DMN) may have a crucial role in semantic cognition, our findings revealed that DMN activity was sensitive to task difficulty, but not to semantic integration. The implications of these findings for neurocognitive models of semantic cognition and the literature on narrative processing are discussed.\n\nHighlightsO_LIfMRI revealed areas and networks for semantic integration during narrative reading\nC_LIO_LIATL has a key role in the formation of the conceptual gestalt\nC_LIO_LIIFG, pMTG and dAG reflect the update of the conceptual gestalt\nC_LIO_LILeft AG (Mid-PGp) has a key role in context integration\nC_LI

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bioRxiv2018

Functional connectivity reveals dissociable ventrolateral prefrontal mechanisms for the control of multilingual word retrieval

A fundamental cognitive operation involved in speech production is word retrieval from the mental lexicon, which in monolinguals is supported by dissociable ventro-lateral prefrontal cortex (vlPFC) mechanisms associated with proactive and reactive control. This functional magnetic resonance imaging (fMRI) study established whether in multilinguals word retrieval is supported by the same prefrontal mechanisms, and whether proactive modulation consists in suppression of the non-target lexicon. Healthy multilingual volunteers participated in a task that required them to name pictures alternatively in their dominant and less-dominant language. Two crucial variables were manipulated: the cue-target interval (CTI) to either engage (long CTI) or prevent proactive control processes (short CTI), and the cognate status of the pictures to-be-named (non-cognates versus cognates) to capture the presence of selective pre-activation of the target language. Results support the two-process account of vlPFC and indicate that multilinguals engage in proactive control to prepare the target language. This proactive modulation, enacted by anterior vlPFC, is achieved by boosting the activation of lexical representations of the target language. Control processes supported by mid-vlPFC and left inferior parietal lobe together, are similarly engaged in pre-and post-word retrieval, possibly exerted on phonological representations to reduce cross-language interference.\n\nSignificance Statement\n\nWord retrieval in monolingual speech production is enacted by left ventro-lateral prefrontal cortex (vlPFC) supporting controlled access to conceptual representations (proactive control), and left mid-vlPFC supporting post-retrieval lexical selection (reactive control). In this functional magnetic resonance imaging (fMRI) study we demonstrate that multilingual word retrieval is supported by similar prefrontal mechanisms. However, differently from monolinguals, multilingual speakers retrieve words by applying proactive control on lexical representations to reduce cross-language interference. Alternatively to what it has been proposed by one of the most influential models, here we show that this proactive modulation is achieved by boosting the activation of lexical representations of the target language.

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