Quynh Nguyen

Title:
Distinct causal roles of DLPFC and M1 in long-term motor expertise

Abstract:
Despite the importance of motor skill expertise in human behavior, our understanding of the neural mechanisms underlying long-term motor learning remains limited. While there is growing interest in using neuroimaging techniques such as functional magnetic resonance imaging to examine the development of skilled motor performance, the current literature faces several limitations. The present study aims to address such shortcomings by combining non-invasive brain stimulation with a fine-grained neuroimaging analysis of spatially distributed patterns of brain activity after six weeks of training on a motor sequencing task. Our pilot results show that over the course of training, participants markedly speed up sequence execution. While disruption of both the dorsolateral prefrontal and the primary motor cortex produce deficits at all levels of expertise, we find evidence of a double dissociation as a function of expertise. We also validate the utility of Representational Similarity Analysis in detecting the spatial patterns of brain activity associated with different motor sequences. This allows us to test hypotheses about how the strength of sequence encoding varies across the brain over the development of motor expertise.

Natasha Vernooij

Title:
Incongruent cambios de código: Code switching when grammars do not align

Abstract:
A code switch is when a speaker switches from one language to another, and these switches can either be congruent or incongruent. For congruent code switches, the syntax of the two languages is the same. For incongruent code switches, the syntax of the two languages is different. When the syntaxes for a phrase are equivalent in two languages, then the bilingual stores a single, language independent, grammatical ‘unit’ for that phrase in their mental grammar (Hartsuiker and Pickering, 2008; Kootstra, van Hell, & Dijkstra, 2012). Similarly, bilinguals make language independent predictions about an upcoming syntactic category for congruent code switches (de los Santos, Boland, & Lewis, 2019). However, few studies have investigated how bilinguals code switch when their two grammars do not align. The current experiments investigate congruent and incongruent code switches to determine what factors facilitate incongruent code switching and if any existing code switching hypothesis can account for incongruent code switches.