  We show that whenever a 4-dimensional theory with N particle species emerges
as a consistent low energy description of a 3-brane embedded in an
asymptotically-flat (4+d)-dimensional space, the holographic scale of
high-dimensional gravity sets the strong coupling scale of the 4D theory. This
connection persists in the limit in which gravity can be consistently
decoupled. We demonstrate this effect for orbifold planes, as well as for the
solitonic branes and string theoretic D-branes. In all cases the emergence of a
4D strong coupling scale from bulk holography is a persistent phenomenon. The
effect turns out to be insensitive even to such extreme deformations of the
brane action that seemingly shield 4D theory from the bulk gravity effects. A
well understood example of such deformation is given by large 4D Einstein term
in the 3-brane action, which is known to suppress the strength of 5D gravity at
short distances and change the 5D Newton's law into the four-dimensional one.
Nevertheless, we observe that the scale at which the scalar polarization of an
effective 4D-graviton becomes strongly coupled is again set by the bulk
holographic scale. The effect persist in the gravity decoupling limit, when the
full theory reduces to a 4D system in which the only memory about the
high-dimensional holography is encoded in the strong coupling scale. The
observed intrinsic connection between the high-dimensional flat space
holography and 4D strong coupling suggests a possible guideline for
generalization of AdS/CFT duality to other systems.
