Fig. 1.

Fiber selection strategy–segregating the motorMFB into sub-bundles. a Indicates an unconstrained selection of fibers attached to the lateral VTA seed (r < 3 mm) initially described in Coenen et al. 2018. The lateral VTA seed (red) is located ventral from the red nucleus (magenta) and medial from the substantia nigra (yellow). In addition to the well known pre-frontal projections, numerous streamlines reach sensorimotor-related cortical areas. b Left: directional color-coded fiber density of the selection indicated in a. A clear bimodality is visible dividing the selection into a frontal/emotional part (slMFB, green) and a sensorimotor part (motorMFB, blue). Middle: a rather liberal seed (blue sphere; r < 15 mm) is set into the posterior limb of the internal capsule (PLIC) to capture the motorMFB. Right: the motorMFB is obviously composed of three distinct sub-bundles that can be defined by their origin: pre-frontal cortex (PFC), mammillary body (MB) and brainstem/cerebellum (BC). c Subdivision of the mtrMFB into three well-defined bundles selected by different seeds: an ALIC seed (magenta, r < 8 mm) targeting the PFC bundle; an MB seed (cyan, r < 3 mm) targeting the MB bundle; an Pons seed (orange; r < 10 mm) targeting the BC bundle. The red sphere indicates the latVTA seed (− 6, − 12, 8; r < 3 mm)