Biology subjects

Molinaro, N.

Publications and source records attributed to Molinaro, N..

22 records · Page 2Linked to original sources

bioRxiv2020

Linguistic input drives brain network configuration during language comprehension.

Assessing the synchrony and interplay between distributed neural regions is critical to understanding how language is processed. Here, we investigated possible neuro-functional links between form and meaning during sentence comprehension combining a classical whole-brain approach, which characterizes patterns of brain activation resulting from our experimental manipulation, and a novel multivariate network-based approach, which uses graph-theory measures to unravel the architectural configuration of the language system. Capitalizing on the Spanish gender agreement system, we experimentally manipulated formal and conceptual factors: whether the noun-adjective grammatical gender relationship was congruent or not and whether the noun gender type was semantically informative or strictly formal. Left inferior and middle frontal gyri, as well as left MTG/STG emerged as critical areas for the computation of grammatical relations. We demonstrate how the interface between formal and conceptual features depends on the synergic articulation of brain areas divided in three subnetworks that extend beyond the classical left-lateralized perisylvian language circuit. Critically, we isolated a subregion of the left angular gyrus showing a significant interaction between gender congruency and gender type. The functional interplay between the angular gyrus and left perisylvian language-specific circuit proves crucial for constructing coherent and meaningful messages. Importantly, using graph theory we show that this complex system is functionally malleable: the role each node plays within the network changes depending on the available linguistic cues. Significance StatementNeural networks can be described as graphs comprising distributed and interconnected nodes. These nodes share functional properties but also differ in terms of functional specialization and the number of interconnections mediating the efficient transfer of information. Previous work has shown functional connectivity differences based on graph-theory properties between typical and atypical samples. However, here we have used concepts from graph theory to characterize connectivity during language processing using task-related fMRI. This approach allowed us to demonstrate how linguistic input drives brain network configuration during language comprehension. This is the first evidence of functional flexibility in language networks: the communicative capacity of each hub changes depending on whether the linguistic input grants access to meaning or is purely formal.

neuroscience↗

bioRxiv2019

Neocortical activity tracks syllable and phrasal structure of self-produced speech

To gain novel insights into how the human brain processes self-produced auditory information during reading aloud, we investigated the coupling between neuromagnetic activity and the temporal envelope of the heard speech sounds (i.e., speech brain tracking) in a group of adults who 1) read a text aloud, 2) listened to a recording of their own speech (i.e., playback), and 3) listened to another speech recording. Coherence analyses revealed that, during reading aloud, the readers brain tracked the slow temporal fluctuations of the speech output. Specifically, auditory cortices tracked phrasal structure (<1 Hz) but to a lesser extent than during the two speech listening conditions. Also, the tracking of syllable structure (4-8 Hz) occurred at parietal opercula during reading aloud and at auditory cortices during listening. Directionality analyses based on renormalized partial directed coherence revealed that speech brain tracking at <1 Hz and 4-8 Hz is dominated by speech-to-brain directional coupling during both reading aloud and listening, meaning that speech brain tracking mainly entails auditory feedback processing. Nevertheless, brain-to-speech directional coupling at 4- 8 Hz was enhanced during reading aloud compared with listening, likely reflecting speech monitoring before production. Altogether, these data bring novel insights into how auditory verbal information is tracked by the human brain during perception and self-generation of connected speech.\n\nHighlightsO_LIThe brain tracks phrasal and syllabic rhythmicity of self-produced (read) speech.\nC_LIO_LITracking of phrasal structures is attenuated during reading compared with listening.\nC_LIO_LISpeech rhythmicity mainly drives brain activity during reading and listening.\nC_LIO_LIBrain activity drives syllabic rhythmicity more during reading than listening.\nC_LI

neuroscience↗

bioRxiv2018

Hearing through lip-reading: the brain synthesizes features of absent speech

Lip-reading is crucial to understand speech in challenging conditions. Neuroimaging investigations have revealed that lip-reading activates auditory cortices in individuals covertly repeating absent--but known--speech. However, in real-life, one usually has no detailed information about the content of upcoming speech. Here we show that during silent lip-reading of unknown speech, activity in auditory cortices entrains more to absent speech than to seen lip movements at frequencies below 1 Hz. This entrainment to absent speech was characterized by a speech-to-brain delay of 50-100 ms as when actually listening to speech. We also observed entrainment to lip movements at the same low frequency in the right angular gyrus, an area involved in processing biological motion. These findings demonstrate that the brain can synthesize high-level features of absent unknown speech sounds from lip-reading that can facilitate the processing of the auditory input. Such a synthesis process may help explain well-documented bottom-up perceptual effects.

neuroscience↗

bioRxiv2018

Native experience modulates neural timing: plasticity in language prediction hierarchies

We investigated how native language experience shapes prediction mechanisms. Two groups of bilinguals (either Spanish or Basque natives) performed a word matching task (WMT) and a picture matching task (PMT). They indicated whether the stimuli they perceived matched with the noun they heard. Spanish noun endings were either diagnostic of the gender (transparent), or ambiguous (opaque). ERPs were time-locked to the gender-marked determiner preceding the predicted noun. In the WMT both groups showed a negative (~340 ms) effect. Basque natives displayed an earlier effect (~150 ms) for determiners preceding transparent nouns. In the PMT both groups showed an early effect (~160 ms) for determiners preceding opaque nouns. Transparent nouns' determiners elicited prediction at ~330 ms in Spanish natives, but at ~460 ms in Basque natives. It is concluded that bilinguals rely on the features of the L1 for predicting in the L2: native experience moulds prediction. Linguistic prediction is hierarchical, with different operation levels communicating at an interface stage.

neuroscience↗