OHBM 2022 | 143 | Talk | Stuart Oldham | A conserved developmental axis of thalamocortical connect…

Title: A conserved developmental axis of thalamocortical connectivity in humans.
Session: Talk
Speaker: Stuart Oldham
The thalamus has wide-spread connectivity with the cortex, facilitating transmission of sensory inputs to cortical regions and intra-cortical communication. To understand how whole brain dynamics are shaped, it is crucial to understand thalamocortical organisation. Recent work in mice found thalamic nuclei form a hierarchy arranged along a medial-lateral axis of gene expression, and position along this axis was associated with differences in cortical projections. However, it is unknown if this same axis is present in humans. By combining streamlines tractography data from thalamic seeds to cortical targets for 76 health adults, and 2233 thalamic gene expression maps of the thalamus, we performed a joint decomposition. The resulting components reflect axes of variation in gene expression and cortical connectivity across thalamic seeds. The primary principal component defined a medial-lateral thalamic gradient (30.3% variance explained) and was significant enriched for genes previously identified as defining the mouse medial-lateral axis. The cortical projections of this thalamic gradient mapped onto a rostral-caudal cortical axis and were positively correlated with cortical intrinsic timescales. Our results suggest a dominant medial-lateral gradient is conserved across species. This gradient may reflect thalamic variation in integrative capacity, and sequential development across both the thalamus and cortex.