The Nuclear response in the isoscalar channel

The nuclear response is evaluated in the frame of the bosonic loop expansion in a purely nucleonic dynamical scheme, which seems to be reliable in handling those channels where a direct excitation of a $\Delta$-resonance is not allowed. It is shown that the response strongly depends upon the effective interaction in the spin-transverse isovector channel. New experiments at CEBAF on parity-violating electron scattering could further constrain the form of the effective interaction.