Anisotropic structures in the inelastic scattering cross-section of x-rays from single crystal Li and of fast electrons from single crystal Na are found to arise from zone boundary collective states (ZBCS), whose properties depend crucially on the symmetry and on the strength of the crystal potential. These ZBCSs are important in discussing various many-body effects. For Na the ⟨110⟩-ZBCS is consistent with a NFE band structure. This contrasts with the reduced bandwidth observed in photoemission and believed to be caused by many-body effects beyond the RPA. In Li a ⟨200⟩-ZBCS falls into a (q, ω) regime beyond the plasmon where structures have been associated with short-range correlations.