Figure 8.

Hypothesized high-gamma power (60–100 Hz) neural response to cognitive demand in healthy children and children treated for brain tumors with CRT. We propose that children treated with CRT have reduced total high-gamma power (60–100 Hz) and that relative high-gamma increases compared with healthy control children in the lower load task may reflect compensatory mechanisms for lower levels of absolute gamma power. The observation that further gamma potentiation did not occur in patients during the higher load task, relative to the lower load task, suggests that high-gamma power has an asymptote in this population, which makes further potentiation in response to a more difficult task impossible. The lack of total high-gamma power in our patients may reflect the limited capacity of their brains to fire in synchrony at the fastest oscillations.