  Light-front Hamiltonian dynamics is used to relate low-energy constituent
quark models to deep inelastic unpolarized structure functions of the nucleon.
The approach incorporates the correct Pauli principle prescription consistently
and it allows a transparent investigation of the effects due to the
spin-dependent SU(6)-breaking terms in the quark model Hamiltonian. Both
Goldstone-boson-exchange interaction and hyperfine-potential models are
discussed in a unified scheme and a detailed comparison, between the
two(apparently) different potential prescriptions, is presented.
