Movie S7.

Directional memory, illustrated with a Neurospora crassa hypha loaded with the marker dye FM4-64 (pseudo-coloured red). The hypha initially encounters a wall at a steep angle and temporarily redirects its growth direction according to the constraining geometry. During the ‘nestling’ phase, the Spitzenkörper shifts from the apex centre toward the wall, and the apex shape becomes skewed also toward the wall. Upon reaching the corner, the hypha immediately recovers its initial growth direction. Frame rate = 17.9 s per frame; total real-time sequence duration = 20 min 44 s.