Neural mechanisms underlying socioemotional behavior in typical and atypical populations

This doctoral thesis outlines the review and experimental studies conducted during my Ph.D. that aimed to clarify the neurocognitive processes underlying socioemotional behavior in neurotypical and Autism Spectrum Disorders (ASD) individuals, a clinical population with impairments in the socioemotional core. The thesis is divided into four chapters. Chapter 1 is concerning the involvement of the hypothalamus in socioemotional behavior. Indeed, despite the large number of studies on the relationship between hypothalamic neuropeptides and social behavior in ASD, only a few studies investigated the association between the hypothalamus and socioemotional response in ASD. Results from this review highlighted anatomical hypothalamic atrophy and functional hypothalamic hypoactivation during face processing and social interaction tasks. The above results from the review highlighted the need to have an appropriate paradigm to investigate hypothalamic involvement in socioemotional behavior. For this reason, in Chapter 2, I performed a systematic review of the neuroimaging studies that used a classical conditioning paradigm to study socioemotional behavior. Results raised the presence of a gap in the literature: indeed, it has been shown that (1) no study used a purely social unconditioned stimulus; (2) the literature mainly focused on conditioning to aversive stimuli, whereas no study focused on conditioning to positive stimuli. Building on this evidence, an EEG study, described in Chapter 3, aimed to investigate whether classical conditioning also underlies the acquisition of socioemotional preference using a novel conditioning paradigm employing more ecological positive and neutral social stimuli. Results show that even with a short period of classical conditioning an increase in valence and attractiveness of positive conditioned stimuli, which was previously neutral may be performed. Then, explorative analysis of the event-related potentials (i.e., the Late Positive Potential, LPP) highlights differences about the LPP elicited by the positive conditioned stimuli concerning neutral conditioned stimuli. Finally, as a side project, Chapter 4 illustrates an investigation that aimed to explore differences in sleep between ASD and neurotypical populations and describe their relationship with the impaired socioemotional characteristics.