Brain’s synergistic signaling may link obesity to weaker working memory

Higher body mass index is associated with poorer working memory performance, and a new analysis of brain imaging data points to a possible contributor: reduced efficiency of synergistic information processing across large-scale brain networks. The study, published in Behavioral and Brain Functions, used resting-state functional MRI data from the Human Connectome Project to examine how obesity-related differences in metabolic state might relate to the way key brain regions share and combine information.

The researchers applied an information-theoretic framework to resting-state scans, quantifying two distinct kinds of connectivity among brain regions known to support working memory: synergistic connectivity, where regions jointly carry information that neither provides alone, and redundant connectivity, where regions carry overlapping information. They then tested whether network-level and edge-level measures of these connectivity features were associated with body mass index and with working memory performance, and whether they moderated the relationship between the two. Exploratory indirect-effect analyses were also included.

Statistically, higher BMI was associated with poorer working memory performance, with an estimated effect of β = −0.149 (95% CI −0.256 to −0.041). Higher BMI was also associated with reduced efficiency of synergistic information processing within large-scale brain networks, with β = −0.134 (95% CI −0.241 to −0.026). In other words, the same individual-level pattern appeared twice: greater adiposity coincided with both weaker working memory and less efficient synergistic integration across network-level connectivity measures.

At the level of individual connections between brain areas, the analysis identified a specific edge whose behavior differed from the overall pattern. Reduced synergistic connectivity between the anterior insula and the dorsomedial prefrontal cortex was associated with a weaker negative relationship between BMI and working memory (p = 0.032, Cohen’s d = 0.308). This moderation result suggests that the strength of the BMI–working memory association may depend, in part, on how strongly these two regions transmit synergistic information to each other, rather than on a uniform relationship across the whole connectome.

A further finding was that different connectivity measures revealed different patterns of association with BMI and working memory performance. Synergistic and redundant connectivity are mathematically distinct components of information sharing, and the results indicate they do not behave identically when related to metabolic state and cognition. The authors argue this supports treating synergistic information processing as a potential marker of network-level information organization, rather than relying solely on conventional measures of functional correlation.

The study’s conclusions are framed carefully in associational terms. Because the data are cross-sectional resting-state scans, the findings indicate that BMI is associated with working memory through different patterns of network-level information processing, including reduced efficiency of synergistic integration and connectivity patterns that influence the BMI–working memory relationship. They do not establish that obesity causes changes in information transmission, nor that altered transmission causes cognitive differences. The authors position the framework as a way of investigating links between metabolic status and cognitive function, with synergistic information processing highlighted as a promising target for future work.

Subject of Research: Associations between obesity, cortical synergistic information transmission, and working memory performance

Article Title: Cortical synergistic information transmission is associated with obesity-related differences in working memory through different interaction patterns

Article References: Xu, Z., Wei, B., Zhou, H., Zhou, Y., Chen, Z., & Yi, C. (2026). Cortical synergistic information transmission is associated with obesity-related differences in working memory through different interaction patterns. Behavioral and Brain Functions. https://doi.org/10.1186/s12993-026-00367-5

Image Credits: AI Generated

DOI: 10.1186/s12993-026-00367-5

Keywords: obesity, body mass index, working memory, resting-state fMRI, synergistic information, brain networks, anterior insula, dorsomedial prefrontal cortex, information theory, Human Connectome Project, cognitive function, Cortical