Motor Cortex Plasticity Links Depression Severity to Acupuncture Response

A two-phase study published in BMC Medicine identifies altered neuroplasticity in the primary motor cortex, known as M1, as a neurophysiological marker associated with the severity of depressive symptoms. The research, led by Sheng Li and colleagues, combines a cross-sectional assessment with a randomized controlled trial to evaluate how M1 plasticity relates to clinical outcomes in patients with depression. The study suggests that the degree of impairment in motor cortex plasticity may serve as an index of cortical dysfunction linked to depression, while also highlighting the potential of adjunctive acupuncture to enhance treatment efficacy in moderate cases.

The study was designed in two distinct phases to address the poorly characterized relationship between neuroplasticity deficits and clinical severity. Phase I employed a cross-sectional design involving 134 participants to assess M1 plasticity across different levels of depressive severity. Phase II consisted of a randomized controlled trial with 60 patients suffering from moderate depression. These patients were assigned to one of three treatment groups: sertraline plus verum acupuncture, sertraline plus sham acupuncture, or sertraline alone. The trial lasted for six weeks, during which clinical outcomes and plasticity changes were evaluated.

In the cross-sectional phase, patients with depression exhibited significantly blunted long-term potentiation-like and long-term depression-like plasticity compared to healthy controls. The statistical analysis, adjusted for multiple comparisons, showed highly significant differences with P values less than 0.001. Furthermore, the impairment in plasticity was more pronounced in groups with higher depressive symptom severity, indicating a correlation between the extent of neurophysiological deficit and the clinical presentation of the disorder.

In the randomized controlled trial phase, the combination of sertraline and verum acupuncture resulted in a greater percentage reduction in Hamilton Depression Rating Scale scores compared to both sertraline with sham acupuncture and sertraline alone. The differences in clinical improvement were statistically significant, with P values less than 0.01. Additionally, the group receiving verum acupuncture reported reduced antidepressant-related side effects.

A key finding from the trial was the positive correlation between treatment-induced improvements in long-term potentiation-like plasticity and the reduction in depressive symptoms. Specifically, the change in motor evoked potentials associated with the longer stimulation protocol was positively correlated with the percentage reduction in depression scores, with a Spearman’s correlation coefficient of 0.423 and a P value of 0.006. In contrast, the changes associated with the shorter stimulation protocol were not significantly associated with clinical improvement.

The authors conclude that altered M1 neuroplasticity is associated with depressive symptom severity and may serve as a useful neurophysiological index for depression-related cortical dysfunction. The study provides evidence that adjunctive acupuncture enhances therapeutic efficacy in moderate depression, a clinical benefit that is associated with changes in long-term potentiation-like plasticity.

The study was registered in the Chinese Clinical Trial Registry, with registration dates in February and October 2020. The research was published in BMC Medicine, an open-access journal, and is available for citation with a permanent DOI. The authors note that this version is shared early to provide faster access to peer-reviewed research and is subject to further edits before the final version of record is released.

While the study provides significant insights into the relationship between motor cortex plasticity and depression, it is important to consider the scope of the research. The cross-sectional phase establishes associations rather than causal links, and the randomized controlled trial focuses specifically on patients with moderate depression. However, the generalizability of these findings to other forms of depression or other treatment modalities requires further investigation.

Subject of Research: Neurophysiological indices of depression severity and treatment response

Article Title: M1 neuroplasticity as a neurophysiological index of depressive symptom severity and treatment associated neural changes: a two-phase cross-sectional and randomized controlled trial

Article References: Li, S., Yuan, J., Huang, J., Zhou, P., Yan, L., Zhang, Y., Xu, N., Fu, W., & Liu, J. (2026). M1 neuroplasticity as a neurophysiological index of depressive symptom severity and treatment associated neural changes: a two-phase cross-sectional and randomized controlled trial. BMC Medicine. https://doi.org/10.1186/s12916-026-05392-9

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05392-9

Keywords: depression, neuroplasticity, motor cortex, acupuncture, sertraline, randomized controlled trial, paired associative stimulation, BMC Medicine, neurophysiological, index, depressive, symptom