White matter integrity of premotor–motor connections is associated with motor output in chronic stroke patients

•Cortico-cortical functional interactions in the motor network are relevant for residual motor output after subcortical stroke.•Microstructural integrity of the underlying white matter tracts might play a significant role in preserved motor functions.•Diffusion-tensor imaging (DTI) was used in stroke patients to reconstruct individual intrahemispheric connections between M1 and three secondary motor areas (PMd, PMv, SMA).•The extent to which the tract related microstructural integrity correlates with residual motor function was determined.•Microstructural integrity of intrahemispheric corticocortical tracts can be determined in stroke patients.•Data support the view that the microstructural integrity of the tract connecting ipsilesional M1 and PMd is significantly associated with recovered motor output in stroke patients.

Corticocortical functional interactions between the primary motor cortex (M1) and secondary motor areas, such as the dorsal (PMd) and ventral (PMv) premotor cortices and the supplementary motor area (SMA) are relevant for residual motor output after subcortical stroke. We hypothesized that the microstructural integrity of the underlying white matter tracts also plays a role in preserved motor output. Using diffusion-tensor imaging we aimed at (i) reconstructing individual probable intrahemispheric connections between M1 and the three secondary areas (PMd, PMv, SMA) and (ii) examining the extent to which the tract-related microstructural integrity correlates with residual motor output. The microstructural integrity of the tract connecting ipsilesional M1 and PMd was significantly associated with motor output (R = 0.78, P = 0.02). The present results support the view that ipsilesional secondary motor areas such as the PMd might support M1 via corticocortical connections to generate motor output after stroke.