Figure 2.

In the study by Ramsden and colleagues [72], 33 neurologically normal adolescents had structural and functional brain scans, along with an IQ measurement (Wechsler Adult Intelligence Scale III and WISC III), at two different times (Time 1: 12–16  years old; Time 2: 15–20  years old). Results showed that changes in Verbal IQ, observed between the two time points, were positively correlated with changes in grey matter density (and volume) in a region of the left motor cortex, which is activated by the articulation of speech (a). In striking contrast, changes in Non-Verbal IQ, observed between the two time points, were positively correlated with grey matter density in the anterior cerebellum, which is associated with motor movements of the hand (b). Adapted and reprinted with permission from Macmillan Publishers Ltd: Nature [72] © (2011).