ABSTRACT
Since the frontal region is also involved in non-verbal memory, regarding its relation to the medial temporal lobe it may be suggested that the critical cascade driving human memory formation occurs only when frontal activity provides information to medial temporal lobe structures. Therefore, both regions would be critical to the conception of a memory, and lack of participation of either brain region would disrupt memory formation. Activity within frontal cortex would fail to instil a memory if the medial temporal lobes are damaged. Consistent with this hypothesis, patients with amnesia due to medial temporal lobe damage can show normal frontal activity patterns associated with encoding, yet these patients fail to form new memories (Buckner & Koutstaal, 1998; Gabrieli et al., 1998). Correspondingly, normal
The exact neural structures and mechanisms underlying human memory remain uncertain. None of the current theories seems to encompass the full range or complexity of memory processes, which include memory for sights and sounds, for feelings, and for belief systems that integrate information on a larger number of concepts. However, current research has been very helpful in clarifying some of the aspects of the memory processes and functions. The classic dichotomy between STM and LTM emphasised the relative resistance of memories stored over long durations as compared with newly acquired memories that are held briefly and lost if not reinforced. Although this distinction is certainly valid on a functional basis, it may be less valid on a topographical basis, since the two types of memory share much of the same cerebral substrate (Fuster, 1995). What seems to have become obvious from the results of current research on neural basis of memory is that, although seminal in their time, the pioneering work of Brodmann and others will be substituted by the convergence of results of different disciplines (neuroanatomical as well as functional
subjects with intact medial temporal lobes fail to form memories when frontal activity is absent. Thus the interaction of frontal and medial temporal regions, rather than the isolated contribution of either region, seems to be crucial for the effective formation of memories that contribute to consciousness of past events.
