Mapping the basal temporal language network: a SEEG functional connectivity study

Abstract

The Basal Temporal Language Area (BTLA) is recognized in epilepsy surgery setting when cortical electrical stimulation (CES) of the ventral temporal cortex (VTC) trigger anomia or paraphasia during naming tasks. Despite acknowledging a ventral language stream, current cognitive language models fail to properly integrate this entity. In this SEEG study we used cortico-cortical evoked potentials in nine epileptic patients to assess and compare the effective connectivity of 73 sites in the left VTC of which 26 were deemed eloquent for naming after CES (BTLA). Eloquent sites connectivity supports the existence of a basal temporal language network (BTLN) structured around posterior projectors while the fusiform gyrus behaved as an integrator. BTLN was strongly connected to the amygdala and hippocampus unlike the non-eloquent sites, except for the anterior fusiform gyrus (FG). These observations support the FG as a multimodal functional hub and add to our understanding of ventral temporal language processing.