present early in the illness course, possibly even before illness onset during the prodromal period. While speculative, this hypothesis is consistent with the idea that the mechanisms subserving the phase synchronization of gamma oscillations with respect to an auditory stimulus are dissociable from the mechanisms governing the magnitude of these oscillations. Moreover, to the extent that the magnitude of gamma oscillations depends on the quantity or extent of underlying neural networks in the cortex, the emergence of deficient gamma oscillation magnitudes in chronic patients is consistent with accumulating longitudinal MRI evidence of progressive gray matter volume loss over the illness course of schizophrenia (e.g., Andreasen et al., 2011; DeLisi, 1999; Hulshoff Pol and Kahn, 2008; Mathalon et al., 2001).
