Effects of cue focality on the neural mechanisms of prospective memory: A meta-analysis of neuroimaging studies

Abstract

Remembering to execute pre-defined intentions at the appropriate time in the future is typically referred to as Prospective Memory (PM). Studies of PM showed that distinct cognitive processes underlie the execution of delayed intentions depending on whether the cue associated with such intentions is focal to ongoing activity processing or not (i.e., cue focality). The present activation likelihood estimation (ALE) meta-analysis revealed several differences in brain activity as a function of focality of the PM cue. The retrieval of intention is supported mainly by left anterior prefrontal cortex (Brodmann Area, BA 10) in nonfocal tasks, and by cerebellum and ventral parietal regions in focal tasks. Furthermore, the precuneus showed increased activation during the maintenance phase of intentions compared to the retrieval phase in nonfocal tasks, whereas the inferior parietal lobule showed increased activation during the retrieval of intention compared to maintenance phase in the focal tasks. Finally, the retrieval of intention relies more on the activity in anterior cingulate cortex for nonfocal tasks, and on posterior cingulate cortex for focal tasks. Such focality-related pattern of activations suggests that prospective remembering is mediated mainly by top-down and stimulus-independent processes in nonfocal tasks, whereas by more automatic, bottom-up, processes in focal tasks.

Figure 1. Foci of activation in the maintenance phase (in red) and retrieval phase (in yellow), for both nonfocal tasks and focal tasks.

(a) Nonfocal tasks, z = {271, 241, 226, 218, 192, 169, 153, 130, 108}); (b) Focal tasks, z = {270, 255, 246, 209, 184, 166, 136, 119, 99}.

Figure 2. Foci of activation from the direct comparison between the maintenance and retrieval phase for nonfocal and focal tasks.

(a) Foci of activation from the direct comparison between the maintenance and retrieval phase presented in the axial plane (z = {126, 117, 108, 63}). The foci of activation for the contrast maintenance >retrieval phase when a nonfocal cue is provided are reported in red. The opposite comparison (retrieving >maintenance) when a nonfocal cue is provided did not reveal any significant result. The foci of activation for the contrast retrieval >maintenance phase when a focal cue is provided are reported in green. The opposite comparison (maintenance >retrieval) when a focal cue is provided did not reveal significant results. (b) Maintenance >Retrieval with nonfocal cues results were projected onto a surface rendering in order to visually appreciate the activation in the precuneus (BA 7); (c) Retrieval >maintenance with focal cues results were projected onto a surface rendering in order to visually appreciate the activation in inferior parietal lobule (BA 40).

Figure 3. Foci of activation of the direct comparison between nonfocal and focal PM tasks (z = {237, 223, 199, 171, 140, 97, 76}).

The foci of activation referring to the contrast nonfocal tasks >focal tasks are reported in pink and revealed that nonfocal tasks are associated with increased activity in lateral aPFC regions (BA 10). The foci of activation referring to the contrast focal tasks >nonfocal tasks are reported in light blue and showed that focal tasks are associated with increased activity in the anterior cerebellum, in the ventral parietal regions (BA 40) and in the BA 9.