Myelin implications in executive control in adolescence and adulthood – Myelex

During brain development, the myelination process by oligodendrocytes is critical to shape action potential fidelity and neuronal network synchronization. Although myelin is critical for the proper function of neuronal circuits and behaviour, little is known on how myelination shapes complex cognitive processes during development. We hypothesize that myelination is a crucial developmental component for the construction of neuronal network activities leading to complex cognitive processes such as executive control. Specifically, we will perform a cross-species and multi-level analysis to assess the role of myelination on cognitive control in adolescence and adulthood. First, by combining in vivo electrophysiology with behaviour in two mouse models displaying global or specific myelin defects, we will study the impact of myelin impairments on cortical oscillations and cognitive control using an intra-/extradimensional (ID/ED) task. Then, we will examine human cognitive control using a comparable ID/ED task analysed with behaviour, in vivo brain imaging and electrophysiology (anatomo-functional connectivity from EEG, diffusion and functional MRI) in adolescent and adult subjects. This will allow us to determine whether increasing myelination from adolescence to adulthood leads to an increased anatomical connectivity, and hence to an increased functional connectivity/integration that in turn enhances cognitive control at a behavioral level. Finally, we will integrate our data in a computational model of learning and cognitive control in both humans and rodents to assess specific and subtle common behaviors that may be influenced by myelination. In summary, we will use a multi-level approach to assess the impact of myelination from the cellular to the behavioural level on executive control.