Biology subjects

Gastaldon, S.

Publications and source records attributed to Gastaldon, S..

8 recordsLinked to original sources

bioRxiv2026

Challenging the right-hemisphere assumption in post-stroke pragmatics: largely comparable impairment profiles across lesion sides

Traditional views assume that pragmatic deficits after stroke, which compromise the interpretation of communicative intentions and non-literal meanings, follow damage to the right hemisphere (RHD), with left-hemisphere damage (LHD) primarily linked to aphasia and structural language impairment. To examine hemispheric contributions to post-stroke pragmatic profiles, we assessed 99 stroke patients (40 LHD, including 14 with aphasia of minimal-to-moderate severity; 59 RHD) and 60 healthy controls with the Assessment of Pragmatic Abilities and Cognitive Substrates (APACS). While stroke patients overall performed worse than controls, LHD and RHD profiles were largely comparable across three converging analyses: (1) permutation tests revealed no hemispheric differences except on the two tasks requiring expressive components (Interview and Figurative Language 2), which in turn lowered the composites (APACS Production and Total); (2) equivalence testing established equivalence for most measures, with only these same tasks and composites remaining inconclusive; and (3) unsupervised clustering did not group patients by lesion side. Theory of Mind was robustly associated with pragmatic performance in both groups, whereas structural language abilities related specifically to LHD performance and general cognition only to RHD. Excluding aphasic LHD patients strengthened the evidence for comparable profiles, indicating that aphasic LHD patients largely drove the residual differences. In conclusion, primary pragmatic impairment, especially in the receptive domain, emerged comparably after LHD and RHD, with the only residual LHD disadvantage limited to tasks demanding open verbal output. These findings challenge the assumption of right-hemispheric specialization for pragmatics, stressing the need for pragmatic assessment in all post-stroke patients.

neuroscience↗

bioRxiv2026

Chronic acoustic degradation via cochlear implants alters predictive processing of audiovisual speech

This study provides the first neurophysiological evidence of how cochlear implant (CI) input affects predictive processing during audiovisual language comprehension in deaf individuals. Using EEG, we compared 18 CI users with 18 normal-hearing (NH) controls during sentence comprehension where final word predictability was determined by high or low semantic constraint (HC vs. LC) of the preceding sentence frame. Between sentence frame and final word, a 800 ms silent gap was introduced. Mouth visibility was manipulated during sentence frames (visible or digitally occluded; V+ vs. V-), while the final words were always presented with the mouth visible. In NH participants, lower-beta power (12-15 Hz) in left frontal and central sensors decreased for HC vs. LC contexts during the pre-target silent gap, but only when the mouths was visible, suggesting active prediction generation. In CI users, this lower beta power decrease was absent. After final word presentation, both groups showed N400 predictability effects, indicating preserved prediction evaluation. However, CI users exhibited extended N400 effects in the V+ condition, suggesting additional processing demands. Across all participants, pre-target beta modulations correlated with language production abilities, supporting prediction-by-production frameworks. Within CI users, poorer audiometric thresholds correlated with larger N400 constraint effects, possibly indicating greater reliance on contextual prediction to compensate for degraded sensory input. These findings demonstrate that CI-mediated perception alters the neural mechanisms of prediction generation. The link between production skills and predictive mechanisms suggests that strengthening expressive language abilities may enhance predictive processing in CI users.

neuroscience↗

bioRxiv2025

In the words of others: ERP evidence of speaker-specific phonological prediction

Prediction models usually assume that highly constraining contexts allow the pre-activation of phonological information. However, the evidence for phonological prediction is mixed and controversial. In this study, we implement a paradigm that capitalizes on the phonological errors produced by non-native speakers to investigate whether speaker-specific phonological predictions are made based on speaker identity (native-vs-foreign). EEG data was recorded from 42 healthy native Italian speakers. Participants were asked to read sentence fragments after which a final word was spoken by either a native- or a foreign-accented speaker. The spoken final word could be predictable or not, depending on the sentence context. The identity of the speaker (native-vs-foreign) may or may not be cued by an image of the face of the speaker. Our main analysis indicated that cueing the speaker identity was associated with a larger N400 predictability effect, possibly reflecting an easier processing of predictable words due to phonological preactivation. As visual inspection of the waveforms revealed a more complex pattern than initially anticipated, we used temporal EFA (Exploratory Factor Analysis) to identify and disentangle the ERP components underlying the effect observed. In the native-accent condition, predictable words elicited a posterior positivity relative to unpredictable words, possibly reflecting a P3b response, which was more pronounced when the speaker identity was cued. In the foreign-accent condition, cueing the speaker identity was associated with a smaller N1 and a larger P3a response. These results suggest that phonological prediction for native- and foreign-accented speakers likely involve different cognitive processes.

neuroscience↗

bioRxiv2024

Cortical tracking of speech is reduced in adults who stutter when listening for speaking

PurposeInvestigate cortical tracking of speech (CTS) in adults who stutter (AWS) compared to typically fluent adults (TFA) to test the involvement of the speech-motor network in tracking auditory information. MethodParticipants EEG was recorded while they either had to simply listen to sentences (listening only) or complete them by naming a picture (listening-for-speaking), thus manipulating the upcoming involvement of speech production. We analyzed speech-brain coherence and brain connectivity during listening. ResultsDuring the listening-for-speaking task, AWS exhibited reduced CTS in the 3-5 Hz range (theta), corresponding to the syllabic rhythm. The effect was localized in left inferior parietal and right pre-/supplementary motor regions. Connectivity analyses revealed that TFA had stronger information transfer in the theta range in both tasks in fronto-temporo-parietal regions. When considering the whole sample of participants, increased connectivity from the right superior temporal cortex to the left sensorimotor cortex was correlated with faster naming times in the listening-for-speaking task. ConclusionsAtypical speech-motor functioning in stuttering also impacts speech perception, especially in situations requiring articulatory alertness. The involvement of frontal and (pre-) motor regions in CTS in typically fluent adults is highlighted. Speech perception in individuals with speech-motor deficits should be further investigated, especially when smooth transitioning between listening and speaking is required, such as in real-life conversational settings.

neuroscience↗

bioRxiv2023

The role of the Frontal Aslant tract in bilingual language control

In the present study, we investigated the microstructural properties of the right and left Frontal Aslant tract (FAT) in relation to bilingualism and language modality by comparing a group of unimodal bilinguals (i.e., bilinguals proficient in two spoken languages) and a group of bimodal bilinguals (i.e., bilinguals proficient in a spoken and a signed language). We found that the microstructural properties of the left FAT were related to the performance in semantic fluency in the second language (L2), either signed or spoken. Additionally, only for bimodal bilinguals, the microstructural properties of the right FAT were related to picture naming performance in the first spoken language (L1). No significant effects on performance were found in a language comprehension task. Overall, the results suggest that the FAT plays a significant role in language production in bilinguals. The left FAT appears to be involved primarily during the use of spoken or signed L2, while the right FAT appears to be involved in handling the competition of the signed L2 language while speaking L1.

neuroscience↗

bioRxiv2021

When inefficient speech-motor control affects speech comprehension: atypical electrophysiological correlates of language prediction in stuttering

It is well attested that people predict forthcoming information during language comprehension. The literature presents different proposals on how this ability could be implemented. Here, we tested the hypothesis according to which language production mechanisms have a role in such predictive processing. To this aim, we studied two electroencephalographic correlates of predictability during speech comprehension - pretarget alpha-beta (8-30 Hz) power decrease and the post-target N400 event-related potential (ERP) effect, - in a population with impaired speech-motor control, i.e., adults who stutter (AWS), compared to typically fluent adults (TFA). Participants listened to sentences that could either constrain towards a target word or not, allowing or not to make predictions. We analyzed time-frequency modulations in a silent interval preceding the target and ERPs at the presentation of the target. Results showed that, compared to TFA, AWS display: i) a widespread and bilateral reduced power decrease in posterior temporal and parietal regions, and a power increase in anterior regions, especially in the left hemisphere (high vs. low constraining) and ii) a reduced N400 effect (non-predictable vs. predictable). The results suggest a reduced efficiency in generating predictions in AWS with respect to TFA. Additionally, the magnitude of the N400 effect in AWS is correlated with alpha power change in the right pre-motor and supplementary motor cortex, a key node in the dysfunctional network in stuttering. Overall, the results support the idea that processes and neural structures prominently devoted to speech planning and execution support prediction during language comprehension. Significance StatementThe study contributes to the developing enterprise of investigating language production and comprehension not as separate systems, but as sets of processes which may be partly shared. We showed that a population with impaired speech-motor control, i.e., adults who stutter, are characterized by atypical electrophysiological patterns associated with prediction in speech comprehension. The results highlight that an underlying atypical function of neural structures supporting speech production also affects processes deployed during auditory comprehension. The implications are twofold: on the theoretical side, the study supports the need for a more integrated view of language comprehension and production as human capabilities, while on the applied and clinical side, these results might open new venues for efficient treatments of developmental stuttering.

neuroscience↗

bioRxiv2020

Commonalities in alpha and beta neural desynchronizations during prediction in language comprehension and production

The present study investigates whether predictions during language comprehension are generated by engaging the production system. We recorded EEG from participants performing both a comprehension and a production task in two separate blocks. Participants listened to high and low constraint incomplete sentences and were asked either to name a picture to complete it (production) or to simply listen to the final word (comprehension). We found that in a silent gap before the final stimulus, predictable stimuli elicited alpha (8-10 Hz) and beta (13-30 Hz) desynchronization in both tasks. Source estimation highlighted not only the involvement of the left-lateralized language network, but also of temporo-parietal areas in the right hemisphere. Furthermore, correlations between the desynchronizations in comprehension and production showed spatiotemporal commonalities in language-relevant areas in the left hemisphere, especially in the temporal, lateral inferior and dorsal frontal, and inferior parietal corteces. As proposed by prediction-by-production models, our results show that comprehenders engage the production system while predicting upcoming words.

neuroscience↗

bioRxiv2017

Comparative Genomic Evidence For Self-Domestication In Homo sapiens

This study identifies and analyzes statistically significant overlaps between selective sweep screens in anatomically modern humans and several domesticated species. The results obtained suggest that (paleo-) genomic data can be exploited to complement the fossil record and support the idea of self-domestication in Homo sapiens, a process that likely intensified as our species populated its niche. Our analysis lends support to attempts to capture the \"domestication syndrome\" in terms of alterations to certain signaling pathways and cell lineages, such as the neural crest.

genomics↗