Executive functions in agenesis of the corpus callosum: Working memory and sustained attention in the BTBR inbred mouse strain.

Abstract

IntroductionAgenesis of the corpus callosum (AgCC) is characterized by the congenital partial or complete absence of the corpus callosum. Several strains of mice have been reported to carry AgCC, with the BTBR T+Itpr3tf/J (BTBR) inbred mouse strain consistently showing a complete absence of the corpus callosum, as well as a variable reduction in the size of the hippocampal commissure. While much research has focused on the social deficits of the BTBR strain, little research on its cognitive behavior has been conducted. The goal of our study was to compare two facets of executive functioning, spatial working memory, and sustained attention between the BTBR and C57BL/6J (B6) strains.MethodsSpatial working memory was measured utilizing a delayed matching‐to‐position (DMTP) task and sustained attention was measured utilizing an operant task in which mice were trained to distinguish signal and nonsignal events.ResultsBoth the BTBR and B6 mice demonstrated a predictable decline in performance on the DMTP task as the delay interval increased and predictable increase in performance on the sustained attention task as the duration of the signal event increased. Although no significant differences were found between strains on the performance of these tasks, there was a significant difference in learning the association between lever pressing and food reward. Histological investigation confirmed the complete absence of commissural fibers from the corpus callosum, but also the hippocampal commissure, counter to a previous study.ConclusionThe results suggest spatial working memory and sustained attention are unaffected by the absence of these commissural fibers alone.