  The presence of an isotropic tricritical Lifshitz point for the O(N) scalar
theory is investigated in the 1/N expansion by means of the Functional
Renormalization Group equations. At leading order, the non-trivial Lifshitz
point is observed if the number of dimensions d is taken between d=4 and d=8,
and the eigenvalue spectrum of the associated eigendirections is derived. At
order 1/N, the anomalous dimension eta_N is computed and it is found to vanish
both in d=4 and d=8, while it turns out to be positive between these two
values, although strongly dependent on the choice of infrared regulator.
