Metacognitive ability correlates with hippocampal and prefrontal microstructure

Description: The ability to introspectively evaluate our experiences and form accurate metacognitive beliefs is essential for learning and decision-making. Previous research suggests individuals vary significantly in this ability, and that this variation predicts brain volume and function, particularly in the rostro-lateral prefrontal cortex (RLPFC). However, the neurobiological mechanisms underlying these effects are unclear, as qualitative, macroscopic measures such as brain volume can be related to a variety of microstructural features. Here we used a newly developed, high-resolution (800µm isotropic) multi-parameter mapping technique in 48 healthy individuals to delineate quantitative markers of in vivo histological features underlying metacognitive ability. Specifically, we examined neuroimaging markers of local grey matter myelination, macromolecular and iron content. Extending previous volumetric findings, we found that metacognitive ability was positively related to the myelo-architectural integrity of RLPFC grey matter. Interestingly, perceptual metacognition predicted decreased macromolecule content coupled with increased iron in the hippocampus and precuneus, areas previously only implicated in meta-memory tasks. These results highlight the power of quantitative mapping to reveal novel neurobiological correlates of behaviour, providing valuable new biomarkers for future experimental and clinical metacognition research. They may further suggest that metacognition depends upon the integrity and stress-resilience of a memory-related brain network.

Related article: http://doi.org/10.1016/j.neuroimage.2017.02.008