Time-lapse movie of a cortical and a thalamic axon in vitro.
As the growth cones
encounter each other, they collapse, restart their growth and collapse again.
This is why afferent thalamic and efferent cortical axons are
segregated within
the white matter as illustrated in picture 19 (page 3) in "Science in Pictures".
(see Bagnard et al., 2001)