Broca's Area Activity in the Lexical Semantics of Visual Causal Events

Abstract

From a cognitive linguistics perspective, is assessed the effects of causative constructions on the activity of Broca's area during the processing of visual causal and non-causal events. Lexical causatives (e.g., the orange ball moves the purple ball) describe only direct causal events whereas periphrastic causatives (e.g., the orange ball causes the purple ball to move) describe both direct and indirect causal events. Based on this difference, is used lexical and periphrastic causatives as verbal instructions that directed participants to judge billiards balls collisions depicting direct, indirect, and non-causal events. By using functional magnetic resonance imaging (fMRI) and region of interest analysis, is found that judgments of all three visual events more strongly activated Broca's area following the periphrastic instruction than following the lexical instruction, and judgments of direct events produced stronger activity in Broca's area than indirect events. Interestingly, causal judgments were segregated between pars opercularis and pars triangularis. Results are discussed within the context of the linguistic category priming hypothesis, linear ballistic accumulator models, and the hierarchical organization of the prefrontal cortex. Because this our data suggest functional segregation during causal judgments, it is proposed that 44 RLA. Revista de Lingüística Teórica y Aplicada, 54 (2), II Sem. 2016 effective connectivity between these regions is worth evaluating in a follow-up study via dynamic causal modeling of fMRI data.Keywords: Causal judgment; causal conceptualization; lexical causatives; periphrastic causatives; Broca's area. RESuMENDesde una perspectiva de la lingüística cognitiva, se evalúa los efectos de las construcciones causativas en la actividad del área de Broca durante el procesamiento de eventos visuales causales y no causales. Las estructuras léxicas causativas (e.g., la bola anaranjada mueve a la bola púrpura) describen solamente eventos causales directos mientras que las estructuras perifrásticas causativas (e.g., la bola anaranjada hace mover a la bola púrpura) describen tanto los eventos directos como los indirectos. Basados en esta diferencia, se emplea estructuras causativas léxicas y perifrásticas como instrucciones verbales que dirigían a los participantes a juzgar si colisiones del tipo "bolas de billar" simulaban eventos causales directos, causales indirectos y no causales. Mediante el uso de resonancia magnética nuclear funcional (RMNf ) y el análisis por región de interés se encontró que los juicios sobre los tres tipos de eventos activaron más la región de Broca cuando eran precedidos por la instrucción perifrástica que cuando eran precedidos por la instrucción léxica. Por otra parte, los juicios sobre los eventos directos producían mayor actividad en el área de Broca que los eventos indirectos. Se encontró interesante que los juicios causales estuvieron asociados a actividad segregada en el pars opercularis y en el pars triangularis. Los resultados son discutid...