Beta activity is a widely distributed resting brain rhythm in invasive cortical recordings.

(A) Exemplar sEEG electrodes with dominant beta (teal; 20 Hz) or dominant alpha (purple; 9 Hz) rhythms, alongside the respective raw signal and parametrised power spectrum. (B) 1005/1772 channels showed higher maximum peak power in beta (13 – 30 Hz) than theta (4 – 8 Hz), alpha (8 – 12 Hz) and gamma (30 – 100 Hz). 397/1772 were alpha dominant (theta and gamma not shown). (C) Beta dominant channels were distributed across the entire cortex, from occipital to frontal regions, with highest density in sensorimotor areas like precentral gyrus, frontal middle gyrus, frontal inferior gyrus and supplementary motor area. Alpha channels were largely concentrated posteriorly in temporoparietal and occipital areas based on the automatic anatomical labelling atlas11. Neither alpha nor beta activity showed systematic hemispheric differences (p>0.05).

Spread of invasive electrophysiological channels.

Given the low number of channels exhibiting resting state gamma activity, we excluded those from the present table.

MRI connectomics reveal shared cortico-subcortical beta networks.

Individual network fingerprints (A) seeded from representative beta (top) and alpha (bottom) dominant electrodes highlight the methodological approach and showcase the distinct connectivity patterns that arise in dependence of the connected brain regions (for raw signal traces from these locations see Figure 1). Aggregated functional (B) and structural (C) connectivity maps across all beta (top) and alpha (bottom) dominant electrodes were subjected to mass univariate t-tests comparing beta vs. alpha networks with Statistical Parametric Mapping software and visualised as T-maps with significant clusters identified using family-wise error correction (shown opaque). Channel locations from beta dominant channels were associated with more robust functional and structural connectivity to frontal cortex and the basal ganglia, when compared to alpha channel locations, which were more connected to the occipital cortex.

The connectomic beta network correlates with molecular markers of dopamine signalling.

Dopamine uptake significantly correlates with beta functional connectivity (A) A methods schematic explaining how correlations were calculated in Figure 3. Each point on the scatterplot represents a parcellation from the compound brain atlas. For every parcel Xi, a correlation is calculated for that parcel in the PET scan and in the beta network (B) in cortex (rho=0.22, P=0.0001) and basal ganglia (rho=0.5, P=0.0001) but not cerebellum (P>0.05), and beta structural connectivity (C) in cortex (rho=0.4, P=0.0001) and basal ganglia (rho=0.33, P=0.001) but not cerebellum (P>0.05). GABA was used as a control molecule which revealed no significant correlations with beta functional connectivity (D) in cortex, basal ganglia or cerebellum (P>0.05). Beta structural connectivity (E) revealed weaker positive correlation with GABA in cortex (rho=0.17, P=0.0003), a negative correlation in the basal ganglia (rho=-0.55, P=0.0001) and no correlation in cerebellum (P>0.05).