Characterizing the species-specific developmental trajectory underlying our enhanced learning capacity.

Characterizing the species-specific developmental trajectory underlying our enhanced learning capacity

Cedric Boeckx1,2, Constantina Theofanopoulou2, and Saleh Alamri2

1. ICREA

2. Universitat de Barcelona, Spain

Phylogenetic studies like Hublin et al. (2015) strongly support the idea that H. sapiens follows a species-specific brain growth trajectory that departs from its closest extent and extinct relatives during the first year of life, at a time critical for language acquisition (Friedmann and Rusou 2015). This differential developmental pattern results in a selective expansion and complexification of several areas including the frontal pole, parietal lobe, and cerebellum. Here we offer evidence from results in genetics and early developmental studies that suggests that this difference stems from early postnatal changes in neurogenesis in the subventricular zone. These changes produce immature neurons displaying specific features of synaptic plasticity enhancing learning capacities, and target specific brain areas, some of which outside the classical 'language centers', but nevertheless important for language (e.g., ventromedial prefrontal cortex). When affected, these specific changes in neurogenesis entail cognitive disorders like autism. We argue that this enhancement is what lies behind the neural basis of our specific language learning instinct, which allows us to move up the vocal learning complexity scale (Petkov and Jarvis 2012), but also gives rise to higher cognitive flexibility more generally (Burghardt et al. 2012).