Frontal Lobes and Memory

Casual observations of patients with focal frontal lobe lesions often reveal little if any cognitive impairment (Fuster, 1989; Hebb, 1945). At the same time, such patients display an assortment of cognitive deficits upon neuropsychological assessment (Janowsky et al., 1989c; Luria, 1980; Stuss & Benson, 1984). With respect to memory, focal frontal injury does not produce a severe amnesic disorder, such as that observed in patients with medial temporal damage, but it can cause more subtle, yet definable, memory deficits. These deficits take the form of an impairment in the control of memory (Moscovitch, 1992; Shimamura, 1995, 2000a), i.e. the prefrontal cortex appears to be crucial for the monitoring and control of memory processes, both at the time of encoding and at the time of retrieval. In this chapter, we describe patterns of memory impairment associated with focal damage to the prefrontal cortex. Specifically, we review the role of the prefrontal cortex in learning and recall, memory for contextual information, metamemory and retrieval from remote memory. We then relate these long-term memory deficits to impairments in on-line processing associated with working memory and attention. Finally, we put these deficits in the context of a more global view of prefrontal function.