February 4, 2026

@michaelokun

Parkinson’s as a Somato-Cognitive Action Network Disorder? A New Brain Circuit Model Emerges. Somato-cognitive refers to how the body and brain work together by integrating movement, motivation and internal body states in order to guide action. Ren, Zhang Dosenbach, Liu and colleagues describe in a new paper that just dropped in Nature how Parkinson’s disease may be better understood, not just as a movement disorder, but as a disorder of the Somato-Cognitive Action Network (SCAN). The team leveraged a massive multimodal dataset across six interventions to show how SCAN hyperconnectivity might explain both motor and non-motor symptoms and could guide future neuromodulation treatments. Key Points: – The SCAN links motor, cognitive, autonomic and emotional systems, and is more tightly connected to PD circuits than traditional motor-only areas. – Folks w/ Parkinson’s showed hyperconnectivity between the SCAN and key subcortical structures (e.g., substantia nigra, STN, GPi), a pattern not seen in other movement disorders. – Successful therapies like DBS, TMS, focused ultrasound, and levodopa reduced the SCAN to subcortex hyperconnectivity. My take: This paper opens the door to rethinking Parkinson’s as a disorder of action readiness and integration, not just movement execution. This is a big step forward for brain network science in Parkinson's. Here are 5 points that resonated w/ me: 1- Parkinson’s may be better framed as a whole-body network disorder rooted in the SCAN, not just a hand or foot movement issue. 2- Brain imaging showed that the subthalamic nucleus and other DBS targets are functionally linked to the SCAN, not just to movement effectors. 3- Reducing SCAN hyperconnectivity through neuromodulation or dopamine led to better motor outcomes. 4- Targeting cortical SCAN regions w/ repetitive transcranial magnetic stimulation (rTMS) doubled the benefit as compared to traditional motor cortex stimulation. 5- Future neuromodulation strategies have the potential to personalize therapy by matching treatment to SCAN hubs, rather than single motor targets. https://www.nature.com/articles/s41586-025-10059-1 #michaelokun #fixelinstitute #parkinson