Evidence for the involvement of orbitofrontal cortex in memory functions: an interference effect.

Although it is frequently stated that the frontal lobes play a significant role in memory function, research proof has been ambiguous at best. This problem was addressed by administering a variety of memory tests to 16 schizophrenic patients who had undergone prefrontal leucotomy approximately 25 years earlier. The 16 were divided into three groups on the basis of recovery after surgery. Two comparison groups were established to control for psychiatric symptomatology, years of institutionalization, age, and years of education. The results demonstrate that large bilateral orbitofrontal lesions may not result in amnesia; in fact, the nonoperated schizophrenic control group performed the most poorly. Proactive interference was demonstrated, however, resulting in significant impairment for all patients with prefrontal lobe damage despite normal scores on commonly used memory tests. Ability to maintain consistent and directed attention and to overcome interference is proposed as a role of the frontal lobes in memory function.