Functional neuroimaging studies of prospective memory: What have we learnt so far?
Introduction
Prospective memory is a very new field of enquiry, but one in which there has been a startling increase of interest over the last few years. As Sellen, Louie, Harris, and Wilkins (1997) point out, a review approximately 20 years ago (Kvavilashvili, 1992) cited only twenty-four experimental studies of prospective memory. Yet there are now several entire books devoted to the topic (e.g. Brandimonte et al., 1996, Glicksohn and Myslobodsky, 2006, Kliegel et al., 2007, McDaniel and Einstein, 2007), and substantial international conferences occupied exclusively with research into prospective memory (the first International Conference on Prospective Memory was held in Hertfordshire, UK, in July, 2000). This explosion of interest has been accompanied by a change in the way that “prospective memory” has been viewed.
The earliest studies, which were largely behavioural only, tended to be concerned with the practical aspects of remembering intentions, often relating to everyday life situations, rather than experimental paradigms (e.g. Wilkins & Baddeley, 1978). Accordingly, the emphasis was very much on the study of situational and behavioural characteristics affecting delayed intentions. However as the field became more experimental, and with the help of a few key papers (e.g. Kvavilashvili, 1987) the notion grew that there might be cognitive processes or constructs unique to this form of memory (in the sense of not also being shared with memory for past events). From the viewpoint of a scientist trying to discover principles of behaviour, or of brain–behaviour relations, this would be fortuitous, making discovery simpler. However from a biological viewpoint, at the extreme at least, such an arrangement would likely be exceptionally inefficient: prospective memory is a highly complex and multi-componential behaviour so it is unlikely to have representations and brain structures dedicated entirely to it. Such a principle, carried across all cognitive functions would likely be far too costly, so it is always more likely that at both an information processing and functional level that processes and structures operate across psychological domains, or at least across our narrow definitions of subject fields. In this way it was clear to many from the outset that it would be implausible that the study of prospective memory would grow entirely independently from other fields of conceptual relevance (for review see Ellis, 1996).
And so, in large part has it transpired. However, there has been a particularly fortuitous finding for cognitive neuroscientists studying prospective memory: a consistent relation between activation in rostral PFC during prospective memory paradigms. This has given an invaluable inroad into a topic that at one time had little or no precedent within cognitive neuroscience. Moreover, as more information about this brain region from the study of other functions appears, the field is being encouraged to consider prospective behaviour more broadly, with the potential to encompass not just prospective memory, but many other forms of “prospection”.
Section snippets
Characteristics of typical prospective memory paradigms
There are a very wide variety of situations in everyday life that require prospective memory. However, for experimental purposes in cognitive neuroscience the essential features of these situations have been simplified. The typical features of prospective memory paradigms are summarised by Burgess, Scott, and Frith (2003). These are:
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There is an intention, or multiple intentions to carry out a mental or physical act. A variant might be that the intention is to withhold an act that is performed
Findings in brain regions outside rostral PFC
Finding 6 concerns activations outside rostral PFC that are also commonly found during PM tasks. A large proportion of them seem to be (bearing in mind the current temporal limits of our technology) co-activations with rostral PFC. In particular, there is a strikingly consistent finding in current functional neuroimaging studies of activation within BA 7 & 40 (precuneus; parietal lobe) in prospective memory studies. Activation within one, or both of, these regions is almost as common as for
Findings awaiting replication
Findings 7–14 (Table 1) relate either to single findings within the field, or where there is substantial apparent difference in findings amongst studies, but where each finding seems nevertheless secure. It is only on these grounds that the recommendation is made that the findings should be replicated: this is not at all a comment on the quality of the individual studies. In general, these demonstrations also might perhaps emphasise how it is that at least some regions of rostral PFC seem to
Conclusion: from prospective memory to future thinking
In recent years, investigators and theorists from various different disciplines (e.g. economics, cognitive neuroscience, psychology, anthropology) have shown an interest in an emerging field. This concerns itself with how people envisage future scenarios, and the effect that doing so has upon behaviour both in the present and the future. In general, it seems possible that the involvement of rostral PFC in prospective memory and also the many other forms of behaviour which have to do with
References (86)
- et al.
Thinking about the future versus the past in personal and non-personal contexts
Brain Research
(2008) - et al.
Constructive episodic simulation of the future and the past: Distinct subsystems of a core brain network mediate imagining and remembering
Neuropsychologia
(2009) - et al.
Remembering the past and imagining the future: Common and distinct neural substrates during event construction and elaboration
Neuropsychologia
(2007) - et al.
Episodic future thinking
Trends in Cognitive Sciences
(2001) - et al.
The role of dual-task and task-switch in prospective memory: Behavioural data and neural correlates
Neuropsychologia
(2009) - et al.
Experiencing past and future personal events: Functional neuroimaging evidence on the neural bases of mental time travel
Brain and Cognition
(2008) Evolutionary economics of mental time travel?
Trends in Cognitive Sciences
(2008)- et al.
The gateway hypothesis of rostral prefrontal cortex (area 10) function
Trends in Cognitive Sciences
(2007) - et al.
Brain regions involved in prospective memory as determined by positron emission tomography
Neuropsychologia
(2001) - et al.
The role of the rostral frontal cortex (area 10) in prospective memory: A lateral versus medial dissociation
Neuropsychologia
(2003)
The cognitive and neuroanatomical correlates of multitasking
Neuropsychologia
Task interruption in prospective memory: A frontal lobe function?
Cortex
Neural correlates of envisioning emotional events in the near and far future
Neuroimage
Motor brain regions are involved in the encoding of delayed intentions: A fMRI study
International Journal of Psychophysiology
Distinct functional connectivity associated with lateral versus medial rostral prefrontal cortex: A meta-analysis
NeuroImage
Reading hidden intentions in the human brain
Current Biology
Brain regions and their dynamics in prospective memory retrieval: A MEG study
International Journal of Psychophysiology
Thinking of the future and past: The roles of the frontal pole and the medial temporal lobes
NeuroImage
Differential involvement of regions of rostral prefrontal cortex (Brodmann area 10) in time- and event-based prospective memory
International Journal of Psychophysiology
Participation of the prefrontal cortices in prospective memory: Evidence from a PET study in humans
Neuroscience Letters
Looking to the future: Automatic regulation of attention between current performance and future plans
Neuropsychologia
Thinking about intentions
NeuroImage
Encoding the future: Successful processing of intentions engages predictive brain networks
NeuroImage
Cognitive conjunction: A new approach to brain activation experiments
NeuroImage
Anterior prefrontal cortex and the recollection of contextual information
Neuropsychologia
Differential components of prospective memory? Evidence from fMRI
Neuropsychologia
Wisconsin card sorting test performance in patients with focal frontal and posterior brain damage: Effects of lesion location and test structure on separable cognitive processes
Neuropsychologia
Differential engagement of brain regions within a ‘core’ network during scene construction
Neuropsychologia
The role of rostral prefrontal cortex in prospective memory: A voxel-based lesion study
Neuropsychologia
When the future becomes the past: Differences in brain activation patterns for episodic memory and episodic future thinking
Behavioural Brain Research
Neural activity associated with the realisation of a delayed intention
Brain Research: Cognitive Brain Research
Constructive episodic simulation: Temporal distance and detail of past and future events modulate hippocampal engagement
Hippocampus
Prospective memory: Theory and applications
Theory and methodology in executive function research
Mesulam's frontal lobe mystery re-examined
Restorative Neurology and Neuroscience
On the role of rostral prefrontal cortex (area 10) in prospective memory
Function and localization within rostral prefrontal cortex (area 10)
Philosophical Transactions of the Royal Society of London B
Rostral prefrontal brain regions (Area 10): A gateway between inner thought and the external world?
The gateway hypothesis of rostral PFC Function
The search for specific planning processes
The relationship between prospective and retrospective memory: Neuropsychological evidence
The frontopolar cortex and human cognition: Evidence for a rostrocaudal hierarchical organization within the human prefrontal cortex
Psychobiology
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