Representation of Attended Versus Remembered Locations in Prefrontal Cortex

Abstract

A great deal of research on the prefrontal cortex (PF), especially in nonhuman primates, has focused on the theory that it functions predominantly in the maintenance of short-term memories, and neurophysiologists have often interpreted PF's delay-period activity in the context of this theory. Neuroimaging results, however, suggest that PF's function extends beyond the maintenance of memories to include aspects of attention, such as the monitoring and selection of information. To explore alternative interpretations of PF's delay-period activity, we investigated the discharge rates of single PF neurons as monkeys attended to a stimulus marking one location while remembering a different, unmarked location. Both locations served as potential targets of a saccadic eye movement. Although the task made intensive demands on short-term memory, the largest proportion of PF neurons represented attended locations, not remembered ones. The present findings show that short-term memory functions cannot account for all, or even most, delay-period activity in the part of PF explored. Instead, PF's delay-period activity probably contributes more to the process of attentional selection.

Comparison of the Effects of Bilateral Orbital Prefrontal Cortex Lesions and Amygdala Lesions on Emotional Responses in Rhesus Monkeys

“…There is no working memory requirement. Thus, the present results, like the findings from several ablation (Bussey et al, 2001;Rushworth et al, 1997) and physiological (Lebedev et al, 2004;Passingham and Sakai, 2004) studies, argue against the idea that the primary function of the prefrontal cortex is the mediation of working memory. Instead, the deficit after PFo lesions must be in another domain.…”

Quantitative Investigation of Connections of the Prefrontal Cortex in the Human and Macaque using Probabilistic Diffusion Tractography

“…Lesion and single-cell data (Lebedev et al, 2004;Rushworth et al, 2004) suggest the same is true in the macaque, in which the UF has been shown to mediate these functions (Gutnikov et al, 1997).…”

Modulation of Dorsolateral Prefrontal Delay Activity during Self-Organized Behavior

“…In fact, an executive function (including working memory) can be thought of as a special case of attentional phenomena (Barkley, 2001) and, conversely, attention can be seen as "a varying reflection, in behavior, of the operation of a single underlying mechanism of cognitive control" (Miller and Cohen, 2001). Various dimensions of attentional control and selection have been put forward as the main functions of the PFC (Rowe and Passingham, 2001;Lebedev et al, 2004).…”