Figure 2.

(A) Left: visually induced gamma-band activity in MEG data in a monozygotic (MZ) and a dyzygotic (DZ) twin pair. Time-frequency representations (TFRs) of activity in the gamma-band range relative to prestimulus baseline levels in two twins of a MZ pair, averaged across 74 parieto-occipital MEG sensors. Time 0s denotes stimulus onset. Right: correlation between gamma-peak frequencies in MZ twins [A] and DZ twins [B]. Each data point represents the peak frequency of one twin vs. that of his or her co-twin (random axis assignment). Slope values are estimated by random permutations of x and y values. The data suggest a heritability of the gamma-band frequency of 91%. Adapted from van Pelt et al. (2012). (B) Evoked oscillatory activity in schizophrenia patients and their unaffected co-twins. EEG time-frequency analyses of evoked gamma-band power during an auditory oddball task for responses to the standard stimuli at electrode Cz in healthy twins, MZ twins concordant with schizophrenia, MZ twins discordant with schizophrenia, and unaffected co-twin members. Impaired evoked gamma-band power was significantly associated with schizophrenia and unaffected co-twins exhibited significantly reduced 30–60 Hz power as well-compared with controls, highlighting the genetic contribution toward impairments in high-frequency oscillations in the disorder. Adapted from Hall et al. (2011) by permission of Oxford University Press.