Deciphering structural asymmetry of the habenula in the human brain

Abstract

Functional laterality of the habenula has been suggested in both animal models and the humans. Understanding this evolutionarily conserved brain feature is of fundamental importance and has been attracting attention due to its potential role in human cognition and a variety of neuropsychiatric disorders such as depression and schizophrenia. Deciphering structural asymmetry of the human habenula remains to be challenging. Here, we present a large-scale meta-analysis of the left-right differences in the habenular volume in the human brain with 52 datasets (N = 1,427), and also assessed the potential moderating effects of the sampling variability and other methodological factors. Results showed significant heterogeneity in the left-right differences across the datasets, which seems to be mainly due to different MRI scanners and segmentation approaches used. While little evidence was found for the volume asymmetry across all the datasets, the most pronounced and significant leftward asymmetry was found in the datasets from 3 T scanners and when using manual segmentation approaches. We did not find significant disorder-related differences relative to healthy controls in either the left-right asymmetry or the unilateral volume. This study not only provides useful data for future studies of brain imaging and methodological developments related to precision habenula measurements, but also helps to understand potential roles of habenular laterality in health and disorders.