A replica-symmetric mean-field theory approach is presented to the multi-neuron interaction model introduced by de Almeida and Iglesias (1990 Phys. Lett. 146A 239). Fixed-point equations are derived for the relevant order parameters of the model, extended to include biased patterns, without truncating the interaction. The capacity-bias and the temperature-capacity phase diagrams are discussed. Compared with the truncated version of the model, it is found that the capacity at zero temperature is infinite and that the retrieval states satisfy the de Almeida-Thouless stability condition.