Examining Neural Competition In The Visual Word Form Area (VWFA) Using Complex Scenes

Abstract

The ventral visual stream is crucial for visual processing and contains cortical regions that respond selectively for different visual categories. However, a cortical region that responds selectively for one category (e.g., faces) may also respond for another category (e.g., words), indicating that the two categories may compete for shared neural resources in the same cortical region. However, it remains unclear how neural competition impacts brain activation when people view categories embedded in complex scenes that present multiple categories simultaneously. This fMRI study employed standard category localizers with isolated category instances to identify cortical regions that demonstrated category-selectivity and employed complex scenes with multiple categories to investigate how brain activation in those category-selective regions is affected by the simultaneous presence of competing categories. Specifically, this study investigated how brain activity in the visual word form area (VWFA) is affected by the simultaneous presence of competing categories (faces, places, and numbers) embedded in complex scenes. This study also investigated competition effects with complex scenes in other category-selective areas, including the fusiform face area (FFA) and parahippocampal place area (PPA). While the FFA and PPA demonstrated reduced activation when competing categories were present, the VWFA demonstrated increased activation. Findings suggest that neural competition effects may be useful to explain brain responses to complex scenes in the FFA and PPA, but not the VWFA, indicating that neural competition may not be a universal property of category selective processing in the ventral visual stream.