Do light nuclei exhibit "collective" motions?

The Lorentz integral transform ( LIT) method has allowed to perform ab initio calculations of the response function of He-4,He-6, and Li-6,Li-7 to the isoscalar monopole and isovector dipole operators in a wide range of energies. In this work we discuss some of these results and focus in particular on the He-4 case, where one has a 0(+) resonance close to the 3+1 thresholds. In fact, in inelastic electron scattering off He-4 one finds a pronounced resonant structure in the isoscalar monopole strength. The knowledge of this strength as a function of energy makes possible calculations of the corresponding non-energy weighted and energy-weighted sum rules. Comparing the sum rules with their contribution from the resonance region hints to the degree of collectivity of the resonant structure.