Reacción a "Researchers study the role of a new brain network in Parkinson's disease"

This work is based on a very extensive database and robust neuroimaging and neuromodulation methods. The authors integrate data from nearly 900 individuals, combining resting-state functional magnetic resonance imaging (fMRI), direct electrophysiological recordings (ECoG), levodopa response tests, and various forms of neuromodulation (deep brain stimulation, transcranial magnetic stimulation (TMS), and focal ultrasound). This combination of techniques is particularly appropriate for investigating Parkinson's disease, as it is a disease that affects several brain circuits rather than a single region. Resting-state fMRI is a widely validated tool for studying altered functional networks in Parkinson's disease, and ECoG recordings during surgery provide direct validation, with high temporal resolution, of imaging findings. Furthermore, the use of clinical changes—improvement in symptoms—as a reference reinforces that the neurobiological measures analysed have real functional relevance.

Its main contribution, however, is not methodological but conceptual: it proposes that Parkinson's disease, which was already known to produce motor and non-motor symptoms, involves the alteration of a broader brain network, the so-called “somatocognitive action network”, which integrates movement, cognition and bodily functions. This idea fits well with previous clinical observations, such as the early presence of non-motor symptoms and the influence of cognitive factors on movement, but is now supported by direct experimental evidence.

It is important, however, to avoid exaggerated interpretations. Although the results suggest new targets for optimising therapies such as deep brain stimulation or TMS, many of the interventions tested, especially those involving transcranial magnetic stimulation and focal ultrasound, are based on small samples and studies conducted in one or a few centres, which limits their generalisability. The authors themselves acknowledge that, for example, the TMS trial is a pilot study and that its results need to be confirmed in larger multicentre trials, which is common in the early stages of clinical research. Secondly, although fMRI is a validated technique for studying brain networks in Parkinson's disease, it does not measure direct neuronal activity, but rather functional correlations. The study mitigates this limitation by combining fMRI with ECoG and clinical response to treatment, but even so, it cannot establish a definitive causal relationship between SCAN network hyperconnectivity and all Parkinson's symptoms. Furthermore, the study focuses mainly on motor and axial symptoms; the real impact on non-motor symptoms (cognition, mood, dysautonomia) remains largely unexplored.

This means that a change in standard clinical practice in Spain is not yet anticipated, but it does open up a promising avenue for better personalising treatments in the future. Furthermore, Parkinson's is a highly heterogeneous disease, and it is not yet clear whether this alteration of the SCAN network behaves the same in all clinical subtypes or at different stages of the disease. The key message for patients is that this is a step forward in understanding Parkinson's and how therapies could be refined, not an immediate cure or a technique ready for widespread use.