Language impairments in ASD resulting from a failed domestication of the human brain

Abstract

Autism spectrum disorders (ASD) are pervasive neurodevelopmental disorders entailing social and cognitive deficits, including marked problems with language. Numerous genes have been associated with ASD, but it is unclear how language deficits arise from gene mutation or dysregulation. It is also unclear why ASD shows such high prevalence within human populations. Interestingly, the emergence of a modern faculty of language has been hypothesized to be linked to changes in the human brain/skull, but also to the process of self-domestication of the human species. It is our intention to show that people with ASD exhibit less marked domesticated traits at the morphological, physiological, and behavioral levels. We also discuss many ASD candidates represented among the genes known to be involved in the "domestication syndrome" (the constellation of traits exhibited by domesticated mammals, which seemingly results from the hypofunction of the neural crest) and among the set of genes involved in language function closely connected to them. Moreover, many of these genes show altered expression profiles in the brain of autists. In addition, some candidates for domestication and language-readiness show the same expression profile in people with ASD and chimps in different brain areas involved in language processing. Similarities regarding the brain oscillatory behavior of these areas can be expected too. We conclude that ASD may represent an abnormal ontogenetic itinerary for the human faculty of language resulting in part from changes in genes important for the "domestication syndrome" and, ultimately, from the normal functioning of the neural crest.

Germline 16p11.2 Microdeletion Predisposes to Neuroblastoma

“…68 This possibility is supported by a recent study which suggests that altered neural crest activity explains some of these features in the context of ASD. 69 Additionally, several 16p11.2 genes were implicated in neural crest-related phenotypes in a zebrafish loss-of-function screen. 70 Future research on the role of the 16p11.2 region in neural crest development could uncover novel biology and shed light on the clinical manifestations of the 16p11.2 CNV.…”

Human Self‐Domestication and the Evolution of Pragmatics

“…In fact, most, if not all, cognitive disorders entailing abnormal patterns of brain development and organization, as well as abnormal patterns of social functions, also exhibit problems with figurative language and language use in general (see Benítez‐Burraco, 2017b, for discussion). Importantly for our view here, they also tend to show abnormal management of aggression and, more generally, altered features of self‐domestication (e.g., Benítez‐Burraco, Lattanzi, & Murphy, 2016, 2017). This is why we wish to consider these disorders as useful proxies of (specific stages of) modern pragmatics evolution under the effects of human self‐domestication.…”

The evolution of human music in light of increased prosocial behavior: a new model

“…Also, low levels of reactive aggression affect the manifestation of physical and behavioral traits. Thus, such traits are found attenuated in autism spectrum disorder (ASD) which features high levels of reactive aggression [603]. Conditions like Williams Syndrome (WS) [604], in contrast, are characterized by friendly, prosocial behavior.…”