The correlation between the principal tensor elements of diffusion in MFI-type zeolites such as silicalite-1 and ZSM-5 may be substantially affected by memory effects. Extensive MD simulations of the molecular diffusion of methane in zeolite silicalite-1 are analyzed on the basis of the concept of memory-dependent molecular propagation. The obtained results are in good agreement with analytical approaches to memory effects presented in the literature.