  We consider braneworld scenarios including the leading correction to the
Einstein-Hilbert action suggested by superstring theory, the Gauss-Bonnet term.
We obtain and study the complete set of equations governing the cosmological
dynamics. We find they have the same form as those in Randall-Sundrum scenarios
but with time-varying four-dimensional gravitational and cosmological
constants. Studying the bulk geometry we show that this variation is produced
by bulk curvature terms parameterized by the mass of a black hole. Finally, we
show there is a coupling between these curvature terms and matter that can be
relevant for early universe cosmology.
