Figure 5

Summary of results. (A) The ventral posterior lateral thalamus (used as a seed in our dFC analyses) functionally interacts with the basal ganglia and sensorimotor regions within the cerebello-thalamo-cortical network (CTCN), with areas from the parieto-medial temporal pathway (PMTP), and with high-level cognitive networks (HCNs). (B) These functional interactions vary over time across three dFC states: in particular, state 1 (S₁) showcases strong positive-valued dFC to the whole PMTP, state 2 (S₂) is characterized by strong anticorrelations with the parahippocampus within the PMTP and the sensorimotor cerebellum, and state 3 (S₃) displays strong positive-valued dFC to the salience network. The width of the arrows is qualitatively proportional to the intensity of dFC. (C) Brain structure, here quantified by surface-based morphometry (SBM), is the substrate over which brain function (studied through dFC analysis) occurs. The latter itself drives behavior (in the present case, tremor quantified via the Tremor Score on Treated Hand [TSTH]). When essential tremor (ET) declares itself (with variable onset age), each patient has characteristic morphometric and functional activity profiles, without any tremor. As the disease unfolds, SBM features become gradually more distinct from those of healthy controls (HCs, denoted in green on the left), while dFC renormalizes. At the time of thalamotomy, there is an anticorrelation between dFC and SBM similarity to HCs. The patients who, before intervention, express S₃ with greater spatial stability and exhibit an S₃/S₁ balance more geared towards the former state, are the ones whose tremor is reduced the most 1 year after thalamotomy. Increased stability in S₃ expression will associate with greater clinical improvement less strongly if a familial ET history is present, while the S₃/S₁ occurrence ratio impact is modulated by the MR signature. 1 year after thalamotomy, the anticorrelation between dFC and SBM similarity to HCs has vanished.