Editors' ChoiceNeuroscience

Twin Peaks

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Science Translational Medicine  21 Mar 2012:
Vol. 4, Issue 126, pp. 126ec48
DOI: 10.1126/scitranslmed.3004010

Rhythms of the brain create the music of our lives. The gamma-band rhythm is defined by high-frequency waveforms (30 to 100 Hz) that are important for perception, consciousness, and memory. The properties of most other brain rhythms are known to be heritable. However, this has not been explored for the highly variable gamma waves, which are thought to be more dependent on external stimuli and task conditions than on endogenous triggers. Now, van Pelt and colleagues demonstrate that the peak frequency of gamma activity is correlated in twin subjects.

The investigators studied monozygotic and dizygotic pairs of human subjects using magnetoencephalography, a neuroimaging technique based on the magnetic fields of electrical brain activity. Twins and unrelated subject pairs were shown a circular sine wave grating, which is known to induce strong gamma-band synchronization in the occipital cortex (where primary visual processing takes place). The results were striking. The correlation between peak gamma frequencies was highest in monozygotic twins, less in dizygotic twins, and lowest in unrelated pairs; other properties of the gamma waveform (strength and frequency width) were also found to be heritable.

The study of van Pelt and colleagues suggests that gamma-mediated cognition is under tight genetic control, which advances the field by pointing to a molecular mechanism underlying gamma wave regulation. The findings are of particular translational importance when considering thought disorders such as schizophrenia, which has been posited to be a “disconnection syndrome” that leads to disrupted coordination of high-frequency brain rhythms such as gamma. As such, deeper investigation into gamma’s genetic and regulatory machinery may yield insight into the pathogenesis or symptomatology of schizophrenia. One limitation of the current study is that it focused on visual-evoked gamma only, as opposed to past studies of schizophrenia that assessed auditory-evoked gamma. Nonetheless, van Pelt and colleagues reveal an important genetic component of a brain rhythm that is involved in both normal and pathological states of consciousness.

S. van Pelt et al., Magnetoencephalography in twins reveals a strong genetic determination of the peak frequency of visually induced gamma-band synchronization. J. Neurosci. 32, 3388–3392 (2012). [Abstract]

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