Evidence for genetic regulation of the human parieto‐occipital 10‐Hz rhythmic activity

Abstract

Several functional and morphological brain measures are partly under genetic control. The identification of direct links between neuroimaging signals and corresponding genetic factors can reveal cellular-level mechanisms behind the measured macroscopic signals and contribute to the use of imaging signals as probes of genetic function. To uncover possible genetic determinants of the most prominent brain signal oscillation, the parieto-occipital 10-Hz alpha rhythm, we measured spontaneous brain activity with magnetoencephalography in 210 healthy siblings while the subjects were resting, with eyes closed and open. The reactivity of the alpha rhythm was quantified from the difference spectra between the two conditions. We focused on three measures: peak frequency, peak amplitude and the width of the main spectral peak. In accordance with earlier electroencephalography studies, spectral peak amplitude was highly heritable (h 2 > 0.75). Variance component-based analysis of 28 000 single-nucleotide polymorphism markers revealed linkage for both the width and the amplitude of the spectral peak. The strongest linkage was detected for the width of the spectral peak over the left parieto-occipital cortex on chromosome 10 (LOD = 2.814, nominal P < 0.03). This genomic region contains several functionally plausible genes, including GRID1 and ATAD1 that regulate glutamate receptor channels mediating synaptic transmission, NRG3 with functions in brain development and HRT7 involved in the serotonergic system and circadian rhythm. Our data suggest that the alpha oscillation is in part genetically regulated, and that it may be possible to identify its regulators by genetic analyses on a realistically modest number of samples.

Schizophrenia and Human Self-Domestication: An Evolutionary Linguistics Approach

“…The locus of GRID1 has been associated with the parieto-occipital 10-Hz rhythmic activity [Salmela et al, 2016]. This α rhythm, which synchronizes distant cortical regions, is involved in lexical decision making and contributes to the embedding of γ rhythms generated crosscortically in order to yield intermodular set formation during language processing [see Murphy, 2015, for details].…”

Discovering heritable modes of MEG spectral power

“…We further discovered that the MEG spatiospectral composition of any individual participant can be reliably identified based on only a few seconds of data, and mostly independently of the experimental conditions or time interval within the measurement, suggesting that it may be considered as representing an individual “cortical fingerprint.” Furthermore, application of BRRR on gene data resulted in MEG spatiospectral components which largely agreed with the components identified on the basis of familial structure alone, with a significant genetic link to SDK1 in chromosome 7, as well as suggestive links to several other genes expressed in the brain. Previous analysis of this data collection regarding genetic background of the 10‐Hz parieto‐occipital rhythm pointed to chromosome 10 with several plausible genes (Salmela et al, ). The SDK1 gene has been implicated previously in neuronal connectivity in the retina (Yamagata & Sanes, ), but a survey of its expression pattern in the human brain in the FANTOM5 database revealed high expression in the human brain, including fetal occipital and parietal lobes, adult hippocampus, substantia nigra, parietal cortex and spinal cord, suggesting wide‐spread functions in neural processing.…”

“…Autosomal genotypes of the studied individuals were obtained as described earlier by Renvall et al () and Salmela et al (). In short, genomic DNA extracted from blood samples was genotyped on Affymetrix 250K StyI SNP arrays (Affymetrix, Santa Clara, CA) according to manufacturer's instructions.…”

“…So far, genetic connections to brain imaging have mainly been sought by associating single‐nucleotide polymorphisms (SNPs) of predefined candidate genes with neuroimaging measurements, especially in clinical populations (Egan et al, ; Meyer‐Lindenberg, ) but increasingly also in healthy participants (Darki et al, ; Mueller, Makeig, Stemmler, Hennig, & Wacker, ; Smolka et al, ). Recently, unrestricted genome‐wide linkage and association analyses have successfully been applied to neuroimaging phenotypes, but so far mainly to fairly simple and prevalent imaging measures, such as the different cortical rhythms (Malone et al, ; Porjesz et al, ; Salmela et al, ; Smit et al, ), and auditory evoked responses (Renvall et al, ).…”

“…An especially prominent feature among human cortical functions is the brain's background activity that covers a wide range of frequencies, including delta (1 − 4 Hz), alpha (≈10 Hz), beta (≈20 Hz), and gamma (≈30 − 200 Hz) bands, featuring both salient rhythmicity and more arrhythmic patterns. The spectral power at delta, alpha, and beta bands has been shown to be highly heritable (Hodgkinson et al, ; Salmela et al, ; Smit, Posthuma, Boomsma, & Geus, ; Smit, Wright, Hansell, Geffen, & Martin, ; Van Baal, De Geus, & Boomsma, ; Van Beijsterveldt, Molenaar, De Geus, & Boomsma, ; Vogel, ; Young, Lader, & Fenton, ), but still relatively little is known about the underlying genome‐level correlates. The most salient of these intrinsic oscillations are the parieto‐occipital 10 Hz alpha rhythm and the rolandic somatomotor mu rhythm with distinct 10 and 20 Hz components (for a review, see, e.g., Hari & Salmelin, ).…”