  Modifications to the Friedmann equation in brane cosmology can have important
implications for early universe phenomena such as inflation and the generation
of the baryon asymmetry. We study a simple scenario of chaotic brane inflation
where, in a minimal supersymmetric seesaw model, the scalar superpartner of a
heavy singlet Majorana neutrino drives inflation and, simultaneously, generates
the required lepton asymmetry through its direct out-of-equilibrium decays
after the inflationary era. For a gravitino mass in the range 100 GeV - 1 TeV,
we find that successful nucleosynthesis and leptogenesis in this framework
require that the 5D Planck mass is in the range M5 ~ 10^10 - 10^13 GeV and the
reheating temperature Trh ~ 10^6 - 10^8 GeV.
