According to a prominent account of inflectional encoding (Pinker, 1999; Pinker & Ullman, 2002), regular forms are encoded by a rule-governed combination of stems and affixes, whereas irregular forms are retrieved from memory while inhibiting rule application. Importantly , this dual system account proposes that both rule application for regulars and inhibition for irregulars is subserved by the basal ganglia, as suggested by past tense productions deficits observed in Parkinson’s disease patients. In this dissertation, my first goal was to examine if inhibition is indeed a crucial process in verb inflection; my second goal was to explore the role of the basal ganglia in language production by looking at the literature on dysfunction of the basal ganglia; and my third goal was to investigate whether the production of the past tense of regulars and irregulars is subserved by distinct brain regions, if there was any basal ganglia involvement in this processes, and if any inhibitory regions were associated with irregular production. My main findings are that regulars and irregulars seem to be produced by different processes in different brain regions, but that there does not seem to be any inhibition nor basal ganglia involved in them.
João Pedro Santos Ferreira was born on December 11th of 1988, in Cascais, Portugal. In 2011, he started his Bachelors in Psychology at Faculdade de Psicologia in the Universidade de Lisboa. In 2014 he enrolled in the Master’s Program in Cognitive Science at Universidade de Lisboa, where he explored the intersection between Memory and Language by studying how we can learn new words. In 2017 he started his PhD at the Donders Center for Cognition at Radboud Universiteit in Nijmegen, Nederlands. Here he explored the role of the basal ganglia and inhibition on past tense production, in a series of behavioral and fMRI experiments with healthy adults and patients with Parkinson’s disease, and also through a systematic review and meta-analysis on basal ganglia diseases and language production. On December 2022 he started a position as Technical Onboarding Specialist at Samotics in Leiden, Nederlands.