Fig. 5: Relationships between white matter tract anatomy and volitional gestural communication as indexed by the initiation of a behavioral request (IBR) task.
From: Individual variation in the chimpanzee arcuate fasciculus predicts vocal and gestural communication
A Box-and-whisker plot of individual FA values for each tract in BA (red) and AA (blue) chimpanzees. Chimpanzees that performed above average (AA, blue) had significantly higher mean bihemispheric FA within the arcuate fasciculus (AF) than chimpanzees that performed below average (BA, red). Significant main effect of IBR performance on mean AF FA value F(1, 42) = 4.239, p = 0.046, ηp2 = 0.092. B Box-and-whisker plot of individual AQ FA values for each tract in BA (red) and AA (blue) chimpanzees. Chimpanzees that performed above average had significantly greater leftward asymmetries for FA values than those that performed below average. Significant effect of IBR performance on asymmetry quotient for superior longitudinal fasciculus (SLF) FA: F(1, 53) = 9.611, p = 0.003, ηp2 = 0.153. C Box-and-whisker plot of individual AQ volume values for each tract in BA (red) and AA (blue) chimpanzees. Chimpanzees that performed above average had significantly more leftwardly-asymmetric SLF volume values than those that performed below average. Significant effects of IBR performance on asymmetry quotient for SLF volume: F(2, 52) = 8.824, p = 0.004, ηp2 = 0.143. For all Figures, each circle within the bar graph represents an individual subject data point and the highest and lowest horizontal lines (boundaries) of the whiskers represent the maximum and minimum values. The upper and lower lines within the box represent the 25th and 75th percentiles while the central horizontal line indicates the median. Negative AQ values indicate leftward asymmetry. AG− indicates individuals that do not produce attention-getting sounds; AG+ indicates individuals that do. For all analyses, * indicates p < 0.05. CST corticospinal tract, VP ventral pathway.
