Figure 1. Monaural Sound Localization in PET Experiments Performed in the Three Groups of Subjects

(A) CBF (cerebral blood flow) increases. Activations of the right striate and extrastriate cortices (normally visual areas) are observed in EBSP but not in the two other groups for the contrast of MSL minus its control task. Upper image series, sagittal slices; lower image series, coronal slices. X and Y coordinates refer to standardized stereotaxic space.

PET scans, Positron Emission Tomography, reveal relative amount of CBF to areas.

(B) Behavioral data. Behavioral results in MSL (monaural sound location) task (with SE bars). The dashed lines represent the ideal performance, whereas the solid lines indicate the best linear fit to the observed localization performance. Negative angles on the abscissa correspond to the obstructed ear, while positive angles correspond to the unobstructed ear. Note the better performance of the EBSP (early blind superior performance) group compared to the EBNP (early blind normal performance) and SIG (sighted controls).

From: Gougoux F, Zatorre RJ, Lassonde M, Voss P, Lepore F (2005) A Functional Neuroimaging Study of Sound Localization: Visual Cortex Activity Predicts Performance in Early-Blind Individuals. PLoS Biol 3(2): e27.