  We present an ab-initio study of the isoscalar monopole excitations of 4He
using different realistic nuclear interactions, including modern effective
field theory potentials. In particular we concentrate on the transition form
factor $F_{\cal M}$ to the narrow $0^+$ resonance close to threshold. F_M
exhibits a strong potential model dependence, and can serve as a kind of prism
to distinguish among different nuclear force models. Comparing to the
measurements obtained from inelastic electron scattering off 4He, one finds
that the state-of-the-art theoretical transition form factors are at variance
with experimental data, especially in the case of effective field theory
potentials. We discuss some possible reasons for such discrepancy, which still
remains a puzzle.
