Fig. 3.

Mean change in oxyHb concentration in frontal and prefrontal brain regions in response to speech. The bar graphs illustrate differences in concentration changes found at frontal and prefrontal sites for speech collapsed across modalities ((1), left panel), and at frontal ((2), middle panel) and prefrontal sites ((3), right panel) depending on modality with AV = audiovisual speech (solid bars), A = auditory speech (striped bars), and V = visual speech (dotted bars); error bars indicate +/- 1 SE, asterisks indicate a significance level of ** p ≤  .01, * p ≤  .02, ⁺ p = .05.