  It is shown that the addition of a topological invariant (Gauss-Bonnet term)
to the anti-de Sitter (AdS) gravity action in four dimensions recovers the
standard regularization given by holographic renormalization procedure. This
crucial step makes possible the inclusion of an odd parity invariant
(Pontryagin term) whose coupling is fixed by demanding an asymptotic (anti)
self-dual condition on the Weyl tensor. This argument allows to find the dual
point of the theory where the holographic stress tensor is related to the
boundary Cotton tensor as $T_{j}^{i}=\pm (\ell ^{2}/8\pi G)C_{j}^{i}$, which
has been observed in recent literature in solitonic solutions and hydrodynamic
models.
  A general procedure to generate the counterterm series for AdS gravity in any
even dimension from the corresponding Euler term is also briefly discussed.
