Neural correlates of remembering false memories in young and older adults: A brief review of fmri studies

Transcription

1 J Phys Fitness Sports Med, 3(2): (2014) DOI: /jpfsm JPFSM: Review Article Neural correlates of remembering false memories in young and older adults: A brief review of fmri studies Takashi Tsukiura Department of Cognitive and Behavioral Sciences, Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-Nihonmatsu-cho, Sakyo-ku, Kyoto , Japan Received: February 19, 2014 / Accepted: February 27, 2014 Abstract Episodic memory is often impaired by the effect of aging. There are two main forms of age-related decline in episodic memory: increased forgetting of experienced events and remembering of events that have not been experienced. Neural correlates of the former types of memory disturbance have been investigated carefully in several previous fmri studies, but evidence with regard to the latter remains scarce. This review article summarizes previous fmri findings associated with false memory retrieval and effect of aging on it, and proposes frameworks for understanding the underlying mechanisms. Previous fmri studies of false memories in young adults have shown significant activation related to false remembering in the lateral prefrontal cortex (PFC), medial PFC including the anterior cingulate cortex (ACC), and superior/inferior parietal cortices. The findings suggest that incompatible interaction between these regions could contribute to the retrieval of false memories related to failure of the process of monitoring retrieved memories. An age-related decrease in activation associated with false remembering has been identified in the lateral PFC, ACC and visual cortices such as the precuneus or occipital lobe. Decreasing activation in these regions in older adults indicates that the age-related increase of false remembering could be caused by decreased interaction between the monitoring and remembering systems in older adults compared to young adults. Future fmri research into false memories should include further investigation of how the processing of false memories is correlated with other cognitive functions such as lying or confabulation. Keywords : fmri, retrieval, false memory, aging Introduction Correspondence: tsukiura.takashi.6c@kyoto-u.ac.jp Retrieval-related errors in episodic memory are often encountered in our daily lives, and the increasing problem of age-related memory decline is widely recognized in our society. Distortions of human episodic memory have been categorized into two main forms: forgetting previously experienced events and remembering events that have not occurred 1). The former type of memory distortion is known as forgetting true memories (misses). The neural mechanisms underlying the effect of aging on forgetting memories have been investigated by functional neuroimaging techniques such as functional magnetic resonance imaging (fmri) 2-4). However, there is little available evidence concerning the underlying mechanisms associated with the latter form of age-related memory distortion, which is manifested as an increase in false memories of events (false alarms) in older adults. The purpose of this review article is to summarize previous fmri studies investigating the neural correlates of false memory retrieval in healthy young and older adults, and to propose a brainbased framework for understanding the age-related increase in the retrieval of false memories. Neural correlates of false remembering in young adults Several review studies have reported neural correlates associated with the processing of false memories 5-7). Table 1 summarizes the brain activation that has been identified in previous fmri studies of the neural correlates associated with the retrieval of false memories 8-23). The studies cited in the table were selected from a search of the PubMed database ( on the basis of the following criteria: the studies involved only healthy young adults, reported activation related to false remembering, analyzed activation patterns in whole brain (i.e. were not limited to regions-of-interest (ROIs) only), did not include examination of individual differences in activation between genetic types, and were published after One region of the brain that is associated with the retrieval of false memories is the lateral prefrontal cortex (PFC) including the superior, middle, and inferior frontal gyri. Significant activation in these regions has been

2 156 JPFSM: Tsukiura T consistently found in previous fmri studies 8,11-13,15-18,21,23). For example, one fmri study 17) investigated retrievalrelated activation of false memories by employing the Deese-Roediger-McDermott (DRM) paradigm, in which participants are required to learn word lists related to a critical lure word that is not presented, and when tested are likely to show a higher rate of false recognition for the lure words 24,25). Results demonstrated that the left inferior frontal gyrus showed greater activation during the recollection of false memories than of true memories. The possible roles of the lateral PFC in the retrieval of false memories could be explained by the framework of the source monitoring process 6,7). When a specific event is remembered, the source-related information of the event should be monitored appropriately 26). The process of monitoring memory sources during retrieval could be used to judge whether remembered events had been previously experienced (veridical memories) or had not occurred (illusory memories). The importance of the medial PFC including the anterior cingulate cortices (ACC) in the retrieval of false memories has been identified in previous studies 9-13,15,17,18,20,21,23). A possible interpretation of ACC activation related to false remembering is that this region could contribute to the processing of efforts or conflict monitoring during retrieval 20,27,28). This concept is supported by previous findings in which response times in the retrieval of false memories were longer than those in the retrieval of correct memories 20), and in which ACC activation related to conflict monitoring was found during the conscious detection of errors 29). ACC activation in the retrieval of false memories could reflect the effort expended in the process of detecting the erroneous situation in differentiation between veridical and illusory memories. Several previous studies have shown increasing activation in the inferior parietal cortices during the retrieval of false memories 10,16,17,21), whereas other studies have reported significant activation in the superior parietal cortices 8,10,16). Although involvement of these regions in the retrieval of episodic memories has been identified 30,31), the hypothesis of dual attentional processes could explain the process of dissociation between the inferior and superior parietal cortices during the retrieval of false memories 32,33). According to this hypothesis, a ventral part of the parietal region is associated with bottom-up attention as a relatively automatic process, and a dorsal part of this region is involved in top-down attention as a relatively controlled process. Taken together with a neuropsychological finding for patients with parietal lobe lesion 34), activation in the inferior parietal region during episodic memory retrieval could be modulated by the subjective feeling of recollection of both true and false memories 34). On the other hand, given that false remembering involves episodic details by recombining several different components of previously encountered episodes, activation in the superior parietal region could be modulated by the controlled or strategic retrieval process, which is more relevant in the retrieval of false memories than of true memories 10). Although a few studies have found greater activation in the medial temporal lobe (MTL) region including the hippocampus and parahippocampal gyrus during the retrieval of false memories 8,10,22), many studies have failed to show MTL activation selectively associated with false remembering. The absence of MTL activation related to false remembering suggests that the MTL region could contribute equally to the retrieval of true and false memories. For example, one block-designed fmri study reported that retrieval-related activation in the hippocampus was greater for both true and false items than for new items, but that there was no difference in activation for true and false items 9). In another example of an event-related fmri study, significant activation in the anterior parahippocampal gyri was identified in the remembering of both true and false memories 10). Thus, during the retrieval of false memories, the MTL regions could contribute to the processing of objective as well as subjective aspects of recollection by interacting with the inferior parietal regions 34,35). However, given that one fmri study showed dissociable roles within MTL between the processing of subjective and objective oldness 36), further investigation is required to clarify MTL roles in the retrieval of false memories. In summary, activation in multiple brain regions during the retrieval of false memories has been identified in previous fmri studies. First, significant activation in the lateral PFC region, which is associated with the source monitoring process, has consistently been found in the retrieval of false memories. Second, the medial PFC region including the ACC, which is involved in the conflict monitoring process, showed significant activation related to the retrieval of false memories. Third, activation in the inferior and superior parietal regions has been identified in the retrieval of false memories. Parietal activation reflects possible involvement of the inferior parietal region in the subjective feeling of recollection, and possible modulation of the superior parietal region by the controlled or strategic retrieval process. In addition, the absence of MTL activation during the retrieval of false memories suggests that the MTL region could contribute equally to the retrieval of true and false memories. Based on these findings, false retrieval could underlie the failure of monitoring whether retrieved memories are true or false on the basis of subjective feeling, and it could be involved in the incompatible interactions between activation in the PFCsuperior parietal regions and the inferior parietal-mtl regions. Age-related differences of activation in false remembering Table 2 summarizes the brain regions reflecting the effects of healthy aging on activation during the retrieval of false memories 37-40). The studies cited in this table were

3 JPFSM: fmri studies of false remembering 157 Table 1. Summary of previous studies associated with the retrieval of false memories in young participants. Study Stimuli Lateral FL Medial FL Lateral TL Medial TL Lateral PL Medial PL OL Others SFG MFG IFG PCG MedFG OFC ACC STG MTG ITG FG/LG Hip PHG SPL IPL PreC POS Ins Caud Cer Dennis et al. (2012) 10) Picture Guerin et al. (2012) 12) Picture Gutchess et al. (2012) 13) Picture Iidaka et al. (2012) 16) Face Stark et al. (2010) 22) Word Abe et al. (2008) 8) Word Marchewka et al. (2008) 18) Picture Garoff-Eaton et al. (2007) 11) Word Hofer et al. (2007) 15) Face Kim & Cabeza (2007) 17) Word Moritz et al. (2006) 19) Word Heun et al. (2004) 14) Word Slotnick & Schacter (2004) 21) Picture Okado & Stark (2003) 20) Picture Cabeza et al. (2001) 9) Word von Zerssen et al. (2001) 23) Word FL: Frontal lobe, TL: Temporal lobe, PL: Parietal lobe, OL: Occipital lobe, SFG: Superior frontal gyrus, MFG: Middle frontal gyrus, IFG: Inferior frontal gyrus, PCG: Precentral gyrus, MedFG: Medial frontal gyrus, OFC: Orbitofrontal cortex, ACC: Anterior cingulate cortex, STG: Superior temporal gyrus, MTG: Middle temporal gyrus, ITG: Inferior temporal gyrus, FG/LG: Fusiform gyrus/lingual gyrus, Hip: Hippocampus, PHG: Parahippocampal gyrus, SPL: Superior parietal lobule, IPL: Inferior parietal lobule, PreC: Precuneus, POS: Parietooccipital sulcus, Ins: Insula, Caud: Caudate nucleus, Cer: Cerebellum, : Left, : Right, : Bilateral. Table 2. Summary of previous studies showing an age-related decrease in activation during the retrieval of false memories. Study Stimuli Lateral FL Medial FL Lateral TL Medial TL Lateral PL Medial PL OL Others SFG MFG IFG PCG MedFG OFC ACC STG MTG ITG FG/LG Hip PHG SPL IPL PreC PCC Ins Caud Cer Dennis et al. (2013) 37) Picture Royet et al. (2011) 40) Odor Duarte et al. (2010) 39) Picture Dennis et al. (2008) 38) Word FL: Frontal lobe, TL: Temporal lobe, PL: Parietal lobe, OL: Occipital lobe, SFG: Superior frontal gyrus, MFG: Middle frontal gyrus, IFG: Inferior frontal gyrus, PCG: Precentral gyrus, MedFG: Medial frontal gyrus, OFC: Orbitofrontal cortex, ACC: Anterior cingulate cortex, STG: Superior temporal gyrus, MTG: Middle temporal gyrus, ITG: Inferior temporal gyrus, FG/LG: Fusiform gyrus/lingual gyrus, Hip: Hippocampus, PHG: Parahippocampal gyrus, SPL: Superior parietal lobule, IPL: Inferior parietal lobule, PreC: Precuneus, PCC: Posterior cingulate cortex, Ins: Insula, Caud: Caudate nucleus, Cer: Cerebellum, : Left, : Right, : Bilateral.

4 158 JPFSM: Tsukiura T selected on the basis of criteria similar to those in Table 1, but investigated activation related to false remembering in healthy young and older adults, and found an age-related decrease in activation. One of the critical regions showing an age-related decrease in activation associated with the retrieval of false memories is the lateral PFC region including the middle and inferior frontal gyri 37,38). For example, one fmri study of healthy young and older adults demonstrated that, compared to young adults, older adults showed significantly higher rates of false recollection, and lower activation in the lateral PFC regions including the inferior frontal and precentral gyri during the recollection of false memories 37). The findings of an age-related decrease in lateral PFC activation related to false remembering have been supported by several neuropsychological studies, in which older adults with lower scores of frontal lobe function in neuropsychological tests were likely to show higher rates of false remembering than those with higher scores of frontal lobe function 1,41,42). Given that the involvement of the lateral PFC regions in the source monitoring process during the retrieval of false memories has been highlighted in previous studies 6,7), higher rates of false memories and decreasing activation of the lateral PFC regions related to false remembering in older adults could reflect an age-related decline in source monitoring abilities. Activation in the medial PFC including the ACC region during the retrieval of false memories is decreased by the effects of aging 37,38). For example, in an fmri experiment investigating aging effects on recollection-related activations, ACC activation related to false recollection was significantly greater in young adults than in older adults, and significant ACC activation was also found during the recollection of true memories in older adults 37). Functional neuroimaging findings imply that ACC roles in false remembering could be interpreted by the concept of conflict monitoring 20,43,44) ; and an age-related decline in conflict monitoring has been found in several electroencephalogram (EEG) studies 45,46). Taken together, findings of lower ACC activation in older adults than in young adults when false memories were remembered could reflect age-related impairment in the monitoring and detection of conflicts or differences between veridical and illusory memories. An age-related decrease in activation in the precuneus 37-39) or occipital lobe 37,40) is another important finding in previous fmri studies related to false remembering. The aging effect on such activation could be explained by the sensory reactivation hypothesis, in which the retrieval of true memories involves more sensory/perceptual details than that of false memories 47-50). Previous neuroimaging findings have consistently supported the sensory reactivation hypothesis by showing greater activation in sensory/perceptual-related regions during the retrieval of true memories than of false memories 5-7). For example, one fmri study demonstrated that the retrieval of true memories formed with visual components caused greater reactivation in vision-related regions including the early visual cortex, cuneus, and lingual gyrus, than that of false memories 22). Thus, the finding of an age-related decrease in activation in the visual cortices supports the concept that older adults could experience difficulty in the efficient use of perceptual details, which are important in the retrieval of true memories 37,51). In summary, previous fmri studies have shown a reduction in activation in several regions associated with the retrieval of false memories as an effect of healthy aging. First, activation in the lateral PFC region during the retrieval of false memories was significantly greater in young adults than in older adults (Fig. 1A). These different activation patterns suggest that, compared to young adults, older adults could be impaired in the process of monitoring source-related information as memory details. Second, the ACC region showed an age-related decrease in activation in false remembering (Fig. 1B). The aging effect on ACC activation could reflect a decline in the retrieval-related process of monitoring conflicts between true and false memories in older adults, compared to young adults. Third, an age-related decrease in activation in the visual cortices including the precuneus and occipital lobe (Fig. 1B) indicates that the efficient use of perceptual details of memory, which supports the retrieval of true memories, could be disturbed in older adults compared to young adults. Taken together with the findings that hippocampal activation, involved in the successful retrieval of memory details, was reduced by the effects of healthy aging 2), an age-related increase in false remembering could be caused by reduced interaction between the two systems of monitoring (lateral PFC and ACC) and remembering memory details (visual cortex and hippocampus) in older adults compared to young adults. Conclusion This review summarizes brain activation identified in previous fmri studies investigating the retrieval of false memories, and proposes possible neural mechanisms underlying false remembering and the effects that aging has on it. Findings from fmri studies in young adults have indicated that three main regions - including the lateral PFC, medial PFC (ACC), and lateral parietal cortex - show significant activation during the retrieval of false memories, and that incompatible interaction between activation in the PFC-superior parietal regions and in the inferior parietal-mtl regions could contribute to false retrieval related to failure in the process of monitoring whether retrieved memories are true or false based on subjective feeling. In addition, when brain activation related to false remembering is compared between young and older adults, an age-related decrease in activation in the lateral PFC, ACC, and visual cortex such as the pre-

5 JPFSM: fmri studies of false remembering 159 Fig. 1 Regions showing an age-related decrease in activation during the retrieval of false memories. (A) Lateral PFC activation plotted from previous fmri studies. All activation with different x-axis coordinates is expediently plotted on the same sagittal slice (x=-40). (B) Medial PFC and medial parietal-occipital activation plotted from previous fmri studies. All activation with different x-axis coordinates is expediently plotted on the same sagittal slice (x=-8). cuneus or occipital lobe has been identified in previous fmri studies. The decreasing activation of these regions in older adults indicates that an age-related increase in false remembering could be caused by reduced interaction between the two systems of monitoring (lateral PFC and ACC) and remembering memory details (visual cortex and hippocampus) in older adults compared to young adults. In future neuroimaging studies of false memories, steps should be taken to clarify further our understanding of the neural and psychological mechanisms of false memories in basic and clinical research. In the domain of basic research, one such step would be to study the relationship between the processing of false memory and lying. As mentioned in this review, the retrieval of false memories as a form of memory distortion is defined as the objectively incorrect, but subjectively correct retrieval of events that never occurred; whereas lying depends on the intentional manipulation of the retrieval of events that have not been experienced. One fmri study found greater activation in the lateral PFC regions during lying than during the retrieval of false memories, suggesting that this region could be involved in the intentional manipulation of retrieval, or in the cognitive control process 8). However, there is little available evidence related to the detection of differences in activation between incidental (false memory) and intentional (lying) errors of memory retrieval. Another step that should be taken in the domain of clinical research is to examine how the processing of false memories is correlated with the symptom of confabulation. Confabulation is defined as the making of false statements without a conscious effort to deceive in association with neurological disease 52,53). It is often observed in patients with basal forebrain and frontal lobe lesions after the rupture of aneurysms in the anterior communicating artery (ACoA) 54). The results of several neuropsychological studies of brain-damaged patients have implied that the processing of false memory is correlated with confabulation 55,56). For example, one neuropsychological study demonstrated that confabulating ACoA patients were likely to have more false alarms in the retrieval of autobiographical events than non-confabulating ACoA patients or normal controls 56). However, another neuropsychological study reported no difference in scores of false recall or false recognition assessed by the DRM paradigm 24,25) between confabulating ACoA patients and age-matched normal controls 55). Further investigations in neuropsychological and neuroimaging studies are required to provide a plausible explanation of this discrepancy. Acknowledgments This work was supported by the Funding Program for Next Generation World-Leading Researchers (LZ001) from the Cabinet Office, Government of Japan. References 1) McCabe DP, Roediger HL 3rd, McDaniel MA and Balota DA Aging reduces veridical remembering but increases false remembering: neuropsychological test correlates of remember-know judgments. Neuropsychologia 47: ) Cabeza R Prefrontal and medial temporal lobe contributions to relational memory in young and older adults. In Zimmer D, Mecklinger A, Lindenberger U, (Eds.), Binding in human memory: A neurocognitive approach. pp New York: Oxford University Press. 3) Dennis NA and Peterson KM Neural correlates me-

6 160 JPFSM: Tsukiura T diating age differences in episodic memories: evidence from BOLD contrasts and connectivity analyses. Psychologia 55: ) Sperling R Functional MRI studies of associative encoding in normal aging, mild cognitive impairment, and Alzheimer s disease. Ann NY Acad Sci 1097: ) Abe N Neuroimaging studies of false memory: a selective review. Psychologia 55: ) Schacter DL and Slotnick SD The cognitive neuroscience of memory distortion. Neuron 44: ) Straube B An overview of the neuro-cognitive processes involved in the encoding, consolidation, and retrieval of true and false memories. Behav Brain Funct 8: 35. 8) Abe N, Okuda J, Suzuki M, Sasaki H, Matsuda T, Mori E, Tsukada M and Fujii T Neural correlates of true memory, false memory, and deception. Cereb Cortex 18: ) Cabeza R, Rao SM, Wagner AD, Mayer AR and Schacter DL Can medial temporal lobe regions distinguish true from false? An event-related functional MRI study of veridical and illusory recognition memory. Proc Natl Acad Sci USA 98: ) Dennis NA, Bowman CR and Vandekar SN True and phantom recollection: an fmri investigation of similar and distinct neural correlates and connectivity. Neuroimage 59: ) Garoff-Eaton RJ, Kensinger EA and Schacter DL The neural correlates of conceptual and perceptual false recognition. Learn Mem 14: ) Guerin SA, Robbins CA, Gilmore AW and Schacter DL Interactions between visual attention and episodic retrieval: dissociable contributions of parietal regions during gist-based false recognition. Neuron 75: ) Gutchess AH and Schacter DL The neural correlates of gist-based true and false recognition. Neuroimage 59: ) Heun R, Jessen F, Klose U, Erb M, Granath DO and Grodd W Response-related fmri of veridical and false recognition of words. Eur Psychiatry 19: ) Hofer A, Siedentopf CM, Ischebeck A, Rettenbacher MA, Verius M, Golaszewski SM, Felber S and Fleischhacker WW Neural substrates for episodic encoding and recognition of unfamiliar faces. Brain Cogn 63: ) Iidaka T, Harada T, Kawaguchi J and Sadato N Neuroanatomical substrates involved in true and false memories for face. Neuroimage 62: ) Kim H and Cabeza R Trusting our memories: dissociating the neural correlates of confidence in veridical versus illusory memories. J Neurosci 27: ) Marchewka A, Brechmann A, Nowicka A, Jednorog K, Scheich H and Grabowska A False recognition of emotional stimuli is lateralised in the brain: an fmri study. Neurobiol Learn Mem 90: ) Moritz S, Glascher J, Sommer T, Buchel C and Braus DF Neural correlates of memory confidence. Neuroimage 33: ) Okado Y and Stark C Neural processing associated with true and false memory retrieval. Cogn Affect Behav Neurosci 3: ) Slotnick SD and Schacter DL A sensory signature that distinguishes true from false memories. Nat Neurosci 7: ) Stark CE, Okado Y and Loftus EF Imaging the reconstruction of true and false memories using sensory reactivation and the misinformation paradigms. Learn Mem 17: ) von Zerssen GC, Mecklinger A, Opitz B and von Cramon DY Conscious recollection and illusory recognition: an event-related fmri study. Eur J Neurosci 13: ) Deese J On the prediction of occurrence of particular verbal intrusions in immediate recall. J Exp Psychol 58: ) Roediger HL 3rd and McDermott KB Creating false memories: remembering words not presented in lists. J Exp Psychol Learn Mem Cogn 21: ) Johnson MK, Hashtroudi S and Lindsay DS Source monitoring. Psychol Bull 114: ) Botvinick MM, Braver TS, Barch DM, Carter CS and Cohen JD Conflict monitoring and cognitive control. Psychol Rev 108: ) Botvinick MM, Cohen JD and Carter CS Conflict monitoring and anterior cingulate cortex: an update. Trends Cogn Sci 8: ) Orr C and Hester R Error-related anterior cingulate cortex activity and the prediction of conscious error awareness. Front Hum Neurosci 6: ) Cabeza R and Nyberg L Imaging cognition II: an empirical review of 275 PET and fmri studies. J Cogn Neurosci 12: ) Wagner AD, Shannon BJ, Kahn I and Buckner RL Parietal lobe contributions to episodic memory retrieval. Trends Cogn Sci 9: ) Cabeza R Role of parietal regions in episodic memory retrieval: the dual attentional processes hypothesis. Neuropsychologia 46: ) Cabeza R, Ciaramelli E, Olson IR and Moscovitch M The parietal cortex and episodic memory: an attentional account. Nat Rev Neurosci 9: ) Drowos DB, Berryhill M, Andre JM and Olson IR True memory, false memory, and subjective recollection deficits after focal parietal lobe lesions. Neuropsychology 24: ) Tsukiura T, Shigemune Y, Nouchi R, Kambara T and Kawashima R Age-related differences in prefrontal, parietal, and hippocampal activations during correct rejections of faces. Jpn Psychol Res 56: ) Daselaar SM, Fleck MS, Prince SE and Cabeza R The medial temporal lobe distinguishes old from new independently of consciousness. J Neurosci 26: ) Dennis NA, Bowman CR and Peterson KM Age-related differences in the neural correlates mediating false recollection. Neurobiol Aging 35: ) Dennis NA, Kim H and Cabeza R Age-related differences in brain activity during true and false memory retrieval. J Cogn Neurosci 20: ) Duarte A, Graham KS and Henson RN Age-related changes in neural activity associated with familiarity, recollection and false recognition. Neurobiol Aging 31: ) Royet JP, Morin-Audebrand L, Cerf-Ducastel B, Haase L, Issanchou S, Murphy C, Fonlupt P, Sulmont-Rosse C and Plailly J True and false recognition memories of odors

7 JPFSM: fmri studies of false remembering 161 induce distinct neural signatures. Front Hum Neurosci 5: ) Meade ML, Geraci LD and Roediger HL 3rd Neuropsychological status in older adults influences susceptibility to false memories. Am J Psychol 125: ) Roediger HL 3rd and Geraci L Aging and the misinformation effect: a neuropsychological analysis. J Exp Psychol Learn Mem Cogn 33: ) Browndyke JN, Paskavitz J, Sweet LH, Cohen RA, Tucker KA, Welsh-Bohmer KA, Burke JR and Schmechel DE Neuroanatomical correlates of malingered memory impairment: event-related fmri of deception on a recognition memory task. Brain Inj 22: ) Buchweitz A, Mason RA, Tomitch LM and Just MA Brain activation for reading and listening comprehension: an fmri study of modality effects and individual differences in language comprehension. Psychol Neurosci 2: ) Hammerer D, Li SC, Muller V and Lindenberger U An electrophysiological study of response conflict processing across the lifespan: assessing the roles of conflict monitoring, cue utilization, response anticipation, and response suppression. Neuropsychologia 48: ) Lucci G, Berchicci M, Spinelli D, Taddei F and Di Russo F The effects of aging on conflict detection. PLoS One 8: e ) Johnson MK, Foley MA, Suengas AG and Raye CL Phenomenal characteristics of memories for perceived and imagined autobiographical events. J Exp Psychol Gen 117: ) Mather M, Henkel LA and Johnson MK Evaluating characteristics of false memories: remember/know judgments and memory characteristics questionnaire compared. Mem Cognit 25: ) Norman KA and Schacter DL False recognition in younger and older adults: exploring the characteristics of illusory memories. Mem Cognit 25: ) Schooler JW, Gerhard D and Loftus EF Qualities of the unreal. J Exp Psychol Learn Mem Cogn 12: ) Koutstaal W, Reddy C, Jackson EM, Prince S, Cendan DL and Schacter DL False recognition of abstract versus common objects in older and younger adults: testing the semantic categorization account. J Exp Psychol Learn Mem Cogn 29: ) Berlyne N Confabulation. Br J Psychiatry 120: ) Mendez MF and Fras IA The false memory syndrome: experimental studies and comparison to confabulations. Med Hypotheses 76: ) DeLuca J and Diamond BJ Aneurysm of the anterior communicating artery: a review of neuroanatomical and neuropsychological sequelae. J Clin Exp Neuropsychol 17: ) Borsutzky S, Fujiwara E, Brand M and Markowitsch HJ Susceptibility to false memories in patients with ACoA aneurysm. Neuropsychologia 48: ) Gilboa A, Alain C, Stuss DT, Melo B, Miller S and Moscovitch M Mechanisms of spontaneous confabulations: a strategic retrieval account. Brain 129: