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I primi mesi di vita del bambino sono caratterizzati da radicali cambiamenti evolutivi che pongono le basi per lo sviluppo successivo. A livello cerebrale, nel corso dei primi mesi di vita risposte non specifiche e subottimali si specializzano e, man mano che il bambino cresce, questo processo di specializzazione getta le basi per lo sviluppo dei network cerebrali osservati negli adulti. In tale contesto gruppi di aree cerebrali si specializzano progressivamente per l’elaborazione di stimoli sociali, andando a formare quel che viene definito con il termine social brain. L’emergere del cervello sociale rappresenta un importante spartiacque tra le traiettorie di sviluppo tipiche e quelle atipiche, specialmente in disturbi fortemente caratterizzati da deficit di natura sociale, quali il disturbo dello spettro autistico (ASD; Grossman & Johnson, 2007). Lo scopo di questa tesi è quindi di caratterizzare i network cerebrali che supportano l’elaborazione di stimoli sociali nella prima infanzia e di indagare tali network all’interno di traiettorie di sviluppo atipiche, quali sono quelle osservate in bambini con maggiore probabilità di sviluppare ASD (HL-ASD). Nel Capitolo1 abbiamo indagato lo sviluppo dei network cerebrali coinvolti nell’elaborazione di semplici stimoli uditivi attraverso tecniche di ricostruzione di sorgente. Nel Capitolo 2 ci siamo focalizzati sull’elaborazione della salienza sociale delle voci in bambini a basso rischio (LR) e in bambini HL-ASD tramite tracking corticale. Nel Capitolo 3 ci siamo focalizzati sull’elaborazione di volti emozionali attraverso tecniche di decoding. Dato che volti e voci sono spesso associati, nel Capitolo 4, attraverso tecniche di ricostruzione di sorgente e di connettività time-varying, abbiamo indagato come avviene nel cervello l’integrazione di vocalizzazioni emozionali multimodali. Nonostante i dati presentati siano a tratti preliminari a causa della pandemia di Covid-19, i nostri risultati rivelano la presenza di capi, The first months of life are characterized by striking developmental changes. As the infant grows, through processes of interactive specialization between the environment and the brain, unspecific and suboptimal neural responses specialize and lay the basis for the development of the brain networks observed in adults. Within this context, particular sets of brain areas specialize progressively for the processing of social stimuli, becoming what is known as the social brain. This feature highlights the central role that social processing has across the first year of life, when social cues represent the primary mean through which preverbal infants interact with and absorb information from their surroundings. Hence, the emergence of the social brain may represent a turning point separating typical from atypical development, especially in disorders whose core features include disruptions in social processing, such as autism spectrum disorder (ASD; Grossman & Johnson, 2007). The aim of this thesis is to define brain networks involved in social processing across developmental stages and to investigate the departures from typical development seen in infants at higher likelihood of developing ASD (HL-ASD). To this end, in Chapter 1 we first isolated the developmental axis of brain networks involved in low-level auditory processing through source reconstruction techniques. In Chapter 2 we manipulated social saliency in voice processing in both low risk (LR) and HL-ASD infants, investigating the encoding of voices in the brain through cortical tracking. Following the same line of thought, in Chapter 3 we focused on the early processing of emotional faces in the brain via decoding techniques. As faces and voice mostly co-occur in everyday life, through source reconstruction and time-varying connectivity measures, we then investigated how the integration of multimodal emotional vocalization happens in the brain of adults and of HL-ASD infants in Chapter 4. While some of the dat

Le espressioni facciali svolgono un ruolo importante nelle interazioni sociali, comunicando informazioni sullo stato d’animo e le intenzioni di chi le esprime. La maggioranza della letteratura sulla percezione delle emozioni ha preso in esame i volti emotivi isolandoli dal contesto, assumendo che essi siano di per sé sufficienti a veicolare, in maniera non ambigua ed indipendente dal contesto, le manifestazioni emotive (Calder et al., 1996; Smith et al., 2005) . Tuttavia, nella vita reale è assai raro osservare espressioni emotive isolate da un contesto e molti studi recenti che coinvolgono partecipanti adulti indicano che il contesto nel quale le espressioni emotive sono inserite svolge un ruolo essenziale nella loro percezione (Aviezer et al., 2017; Wieser et al., 2014). In particolare, negli adulti, è stato mostrato come varie forme di contesti emotivi e sociali (ad esempio, emozioni espresse tramite gestualità corporee e scene visive, fattori sociali intrinseci o precedenti esperienze sociali) modulano il riconoscimento, la valutazione e l’elaborazione neurale delle espressioni facciali (Aviezer et al., 2017; Iidaka et al., 2010; Jack et al., 2012; Pickett et al., 2004; Righart & De Gelder, 2006). Alcuni studi suggeriscono che anche nei primi anni di vita i fattori contestuali svolgano un ruolo nella percezione delle emozioni (citazioni). Tuttavia, la ricerca in questo ambito è estremamente scarsa e prende in esame una gamma di contesti fortemente limitata e selettiva. Questa tesi di dottorato ha quindi l’obiettivo di fornire un quadro più completo sull’influenza del contesto nell’elaborazione delle espressioni facciali nel corso dello sviluppo, esaminando gli effetti di diversi contesti sulla percezione, e sul riconoscimento delle espressioni facciali nei bambini in età infantile prescolare e scolare. La prima parte di questa tesi prende in esame i segnali emotivi contestuali, verificando come la presenza di altre emozioni nel contesto possa modulare la, Facial expressions, by conveying information on individuals’ internal state and intentions, play an important role in social interactions. The idea that faces alone convey all the necessary information about the expresser’s emotional state in an unambiguous manner and independently of contextual factors was prevalent in the past decades (Calder et al., 1996; Smith et al., 2005) and drove the majority of literature on emotion perception to examine faces in isolation. Nonetheless, facial expressions are very rarely encountered in isolation in real life, and many recent adult studies indicate that the context in which they occur plays an essential part in their perception (for a review, see Aviezer et al., 2017; Wieser et al., 2014). Specifically, various forms of emotional and social context (e.g., emotional bodies or visual scenes, intrinsic social factors or past social experiences) were shown to have a significant influence on adults’ recognition, evaluation, and neural processing of facial expressions (Aviezer et al., 2017; Iidaka et al., 2010; Jack et al., 2012; Pickett et al., 2004; Righart & De Gelder, 2006). However, research investigating the influence of context on the processing of emotional faces in developmental populations is extremely scarce, and although it suggests that contextual effects are also present in infancy and childhood, only a small subset of contextual cues have been examined so far. Therefore, this doctoral dissertation aimed at providing a more comprehensive view of the influence of context on the processing of facial emotions at different developmental stages, by examining the effects of different contextual cues on the perception, neural processing and recognition of facial expressions in infants and children. The first part of this thesis focused on contextual emotional signals. Results indicated that the surrounding facial emotional context (Chapter 1) as well as emotional kinematics cues (Chapter 2) influenced 12-month-olds’ attenti

ULBabyLab, info:eu-repo/semantics/published

The present study investigated whether, as in adults, 7-month-old infants’ sensorimotor brain areas are recruited in response to the observation of emotional facial expressions. Activity of the sensorimotor cortex, as indexed by µ rhythm suppression, was recorded using electroencephalography (EEG) while infants observed neutral, angry, and happy facial expressions either in a static (N = 19) or dynamic (N = 19) condition. Graph theory analysis was used to investigate to which extent neural activity was functionally localized in specific cortical areas. Happy facial expressions elicited greater sensorimotor activation compared to angry faces in the dynamic experimental condition, while no difference was found between the three expressions in the static condition. Results also revealed that happy but not angry nor neutral expressions elicited a significant right-lateralized activation in the dynamic condition. Furthermore, dynamic emotional faces generated more efficient processing as they elicited higher global efficiency and lower networks’ diameter compared to static faces. Overall, current results suggest that, contrarily to neutral and angry faces, happy expressions elicit sensorimotor activity at 7 months and dynamic emotional faces are more efficiently processed by functional brain networks. Finally, current data provide evidence of the existence of a right-lateralized activity for the processing of happy facial expressions.

Statistical learning refers to the ability to extract the statistical relations embedded in a sequence, and it plays a crucial role in the development of communicative and social skills that are impacted in the Autism Spectrum Disorder (ASD). Here, we investigated the relationship between infants’ SL ability and autistic traits in their parents. Using a visual habituation task, we tested infant offspring of adults (non-diagnosed) who show high (HAT infants) versus low (LAT infants) autistic traits. Results demonstrated that LAT infants learned the statistical structure embedded in a visual sequence, while HAT infants failed. Moreover, infants’ SL ability was related to autistic traits in their parents, further suggesting that early dysfunctions in SL might contribute to variabilities in ASD symptoms.

info:eu-repo/semantics/published

Rule learning (RL) refers to infants’ ability to extract high‐order, repetition‐based rules from a sequence of elements and to generalize them to new items. RL has been demonstrated in both the auditory and the visual modality, but no studies have investigated infants’ transfer of learning across these two modalities, a process that is fundamental for the development of many complex cognitive skills. Using a visual habituation procedure within a cross‐modal RL task, we tested 7‐month‐old infants’ transfer of learning both from speech to vision (auditory‐visual—AV—condition) and from vision to speech (visual‐auditory—VA—condition). Results showed a transfer of learning in the AV condition, but only for those infants who were able to efficiently extract the rule during the learning (habituation) phase. In contrast, in the VA condition infants provided no evidence of RL. Overall, this study indicates that 7‐month‐old infants can transfers high‐order rules across modalities with an advantage for transferring from speech to vision, and that this ability is constrained by infants’ individual differences in the way they process the to‐be‐learned rules.

Tracking adjacent (AD) and non-adjacent (NAD) dependencies in a sequence of elements is critical for the development of many complex abilities, such as language acquisition and social interaction. While learning of AD in infancy is a domain-general ability that is functioning across different domains, infants’ processing of NAD has been reported only for speech sequences. Here, we tested 9- to 12- and 13- to 15-month-olds’ ability to extract AxB grammars in visual sequences of unfamiliar elements. Infants were habituated to a series of 3-visual arrays following an AxB grammar in which the first element (A) predicted the third element (B), while intervening X elements changed continuously. Following habituation, infants were tested with 3-item arrays in which initial and final positions were switched (novel) or kept consistent with the habituation phase (familiar). Older infants successfully recognized the familiar AxB grammar at test, whereas the younger group showed some sensitivity to extract to NAD, albeit in a less robust form. This finding provides the first evidence that the ability to track NAD is a domain-general ability that is present also in the visual domain and that the sensitivity to such dependencies is related to developmental changes, as demonstrated in the auditory domain.

Infants’ social environment is rich of complex sequences of events and actions. This study investigates whether 12-month-old infants are able to learn statistical regularities from a sequence of human gestures and whether this ability is affected by a social vs non-social context. Using a visual familiarization task, infants were familiarized to a continuous sequence of eight videos in which two women imitated each other performing arm gestures. The sequence of videos in which the two women performed imitative gestures was organized into 4 different gesture units. Videos within a gesture unit had a highly predictable transitional probability, while such transition was less predictable between gesture units. The social context was manipulated varying the mutual gaze of the actors and their body orientation. At test, infants were able to discriminate between the high- and low-predictable gesture units in the social, but not in the non-social condition. Results demonstrate that infants are capable to detect statistical regularities from a sequence of human gestures performed by two different individuals. Moreover, our findings indicate that salient social cues can modulate infants’ ability to extract statistical information from a sequence of gestures.

Uno dei problemi fondamentali nello studio dei disturbi del neurosviluppo è quello di individuare abilità cognitive di tipo generale che potrebbero sottostare a complessi fenotipi clinici. Uno dei possibili candidati che potrebbe contribuire a spiegare la sovrapposizione e la variabilità di sintomi che caratterizzano il disturbo specifico del linguaggio (DSL), dislessia evolutiva (DE), e il disturbo dello spettro autistico (ASD) è l’abilità di apprendimento implicito (Ullman, 2004). L’apprendimento implicito è una complessa ed eterogena abilità, composta da diversi tipi di meccanismi di apprendimento, e nel presente elaborato di tesi saranno indagati il meccanismo di statistical e rule learning in relazione ai disturbi del linguaggio e della comunicazione. Il meccanismo di SL permette di estrarre contingenze di tipo statistico tra elementi di una sequenza (Saffran et al., 1996), mentre, il RL permette di estrarre regole, high-order, da sequenze di stimoli e di generalizzarle tali regole a nuovi elementi (Marcus et al., 1999). Questi meccanismi sembrano coinvolti in diversi aspetti dello sviluppo linguistico, i.e. abilità fonologiche e di tipo grammaticale, ed è stato recentemente proposto che questi meccanismi potrebbero svolgere un ruolo fondamentale nello sviluppo della teoria della mente e di abilità di tipo comunicativo. Diversi studi hanno indagato se l’abilità di SL fosse importante per lo sviluppo di abilità di tipo comunicativi e linguistico in SLI, DE e ASD, mentre, a nostra conoscenza, non ci sono studi che hanno indagato il ruolo del meccanismo di RL nello sviluppo di abilità di linguaggio. Tenendo in considerazione queste evidenze, riteniamo sia importante indagare se e come differenti tipi di meccanismi di apprendimento siano legati allo sviluppo tipico e atipico di abilità di linguaggio e della comunicazione. Pertanto, lo scopo del presente lavoro di tesi era quello di indagare il funzionamento del meccanismo di SL e, in particolare, di R, One of the central issues in the study of neurodevelopmental disorders is the investigation of domain-general cognitive abilities that could underlying complex clinical phenotypes. On this vein, it has been recently proposed that impairments in domain-general implicit learning mechanisms might underlie language and communication disorders, such as specific language impairment (SLI), developmental dyslexia (DD) and autism spectrum disorders (ASD). The present thesis had the general aim to investigate the functioning of visual implicit learning in the development of SLI, DD and ASD. Specifically, we decided to focus on visual statistical (SL) and rule learning (RL) abilities. SL allows to extract the statistical relationships embedded in a sequence of elements (Saffran et al., 1996), while RL allows to extract high-order rules from a sequence of elements and to generalize these rules to novel stimuli (Marcus et al., 1999). As these mechanisms are thought to be a prerequisite for language acquisition and the development of social understanding, they could serve as possible precursors or mediators of deficits in language and social skills that defined SLI, DD and ASD. Here, I suggest the importance of investigating whether and how different types of learning mechanisms are related to different typical and atypical outcomes in language and communication development. To this end, we used four different approaches: 1) the study of typically developing infants; 2) the study of diagnosed children; 3) the study of infants at low risk to develop language and communication disorders by virtue of having a parent with sub-threshold high traits; 4) the study of infants with a family risk to develop these disorders by virtue of having a first degree relative with a certified diagnosis. The thesis includes four empirical studies in which we used these four different approaches. The first study provides evidence that visual RL at 7 months of age predicts grammatical outcome at 2 year

A wealth of studies show that human adults map ordered information onto a directional spatial continuum. We asked whether mapping ordinal information into a directional space constitutes an early predisposition, already functional prior to the acquisition of symbolic knowledge and language. While it is known that preverbal infants represent numerical order along a left-to-right spatial continuum, no studies have investigated yet whether infants, like adults, organize any kind of ordinal information onto a directional space. We investigated whether 7-month-olds' ability to learn high-order rule-like patterns from visual sequences of geometric shapes was affected by the spatial orientation of the sequences (left-to-right vs. right-to-left). Results showed that infants readily learn rule-like patterns when visual sequences were presented from left to right, but not when presented from right to left. This result provides evidence that spatial orientation critically determines preverbal infants' ability to perceive and learn ordered information in visual sequences, opening to the idea that a left-to-right spatially organized mental representation of ordered dimensions might be rooted in biologically-determined constraints on human brain development.