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Pascale Piolino

Publications and source records attributed to Pascale Piolino.

17 recordsLinked to original sources
PubMed2007

Hippocampal activation for autobiographical memories over the entire lifetime in healthy aged subjects: an fMRI study.

We used functional magnetic resonance imaging to determine the cerebral structures required during the recollection of episodic autobiographical memories according to 5 time periods covering the whole lifespan to test the 2 concurring models of memory consolidation, which propose either a temporary (standard model) or a permanent (multiple-trace model) role of the hippocampus in episodic memory retrieval. The experimental paradigm was specially designed to engage subjects (67.17 +/- 5.22 years old) in the retrieval of episodic autobiographical memories, whatever the time period, from personally relevant cues selected by questioning a family member. Moreover, the nature of the memories was checked at debriefing by means of behavioral measures to control the degree of episodicity. Behavioral data showed that recollected memories were characterized by specificity and details whatever their remoteness. Main neuroimaging data (Statistical Parametric Mapping 99) revealed the activation of a network including the left superior frontal gyri, bilateral precuneus/posterior cingulate and lingual gyri, left angular gyrus, and left hippocampus, although the subtraction analyses detected subtle differences between certain time periods. Small volume correction centered on the hippocampus detected left hippocampal activation for all time periods and additional right hippocampal activation for the intermediate periods. Further confirmation was provided by using a 3-way analysis of variance on blood oxygen level-dependent values, which revealed hippocampal activation whatever the time interval. The present data challenge the standard model of memory consolidation and support the multiple-trace model, instead. The comparison with previous literature stresses the idea that a bilateral involvement of the hippocampus characterizes rich episodic autobiographical memory recollection.

Aged↗
PubMed2007

The semantic and episodic subcomponents of famous person knowledge: dissociation in healthy subjects.

Fifty-two subjects between ages 40 and 79 years were administered a questionnaire assessing their ability to recall semantic information about famous people from 4 different decades and to recollect its episodic source of acquisition together with autonoetic consciousness via the remember-know paradigm. In addition, they underwent a battery of standardized neuropsychological tests to assess episodic and semantic memory and executive functions. The analyses of age reveal differences for the episodic source score but no differences between age groups for the semantic scores within each decade. Regardless of the age of people, the analyses also show that semantic memory subcomponents of the famous person test are highly associated with each other as well as with the source component. The recall of semantic information on the famous person test relies on participants' semantic abilities, whereas the recall of its episodic source depends on their executive functions. The present findings confirm the existence of an episodic-semantic distinction in knowledge about famous people. They provide further evidence that personal source and semantic information are at once distinct and highly interactive within the framework of remote memory.

Adult↗
PubMed2006

Anatomical and functional alterations in semantic dementia: a voxel-based MRI and PET study.

Rare studies have used magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) to assess atrophy, and only two positron emission tomography (PET) studies used SPM to examine functional changes in semantic dementia (SD). Our aim was to highlight both morphological and functional abnormalities in a same group of 10 SD patients, in the entire brain, using a "state of the art" methodology (optimized VBM procedure, PET data corrected for partial volume effects and voxel-based analyses). We also used an extensive neuropsychological battery. We showed that main alterations concerned the left temporal lobe, in accordance with the striking impairment of semantic memory in SD patients, as well as the hippocampal region, which may partly explain their moderate episodic memory deficits. Hypometabolism was more extensive than grey matter loss in both temporal lobes, and specifically concerned the orbitofrontal areas, consistent with the moderate impairment of executive functions and behavioural changes. While PET is more sensitive than MRI, there is striking concordance between morphological and functional abnormalities, which contrasts with the discordance observed in Alzheimer's disease and might be a typical feature of SD.

Adaptation, Physiological↗
PubMed2006

Autonoetic consciousness in Alzheimer's disease: neuropsychological and PET findings using an episodic learning and recognition task.

OBJECTIVE: This study aims to map in patients with mild Alzheimer's disease (AD) the correlations between resting-state brain glucose utilization measured by FDG-PET and scores reflecting autonoetic consciousness in an episodic learning and recognition task. METHODS: Autonoetic consciousness, that gives a subject the conscious feeling to mentally travelling back in time to relive an event, was assessed using the Remember/Know (R/K) paradigm. RESULTS: AD patients provided less R responses (reflecting autonoetic consciousness) and more K ones (indicating the involvement of noetic consciousness) than healthy controls. Correct recognitions associated with a R response correlated with the metabolism of frontal areas bilaterally whereas those associated with a K response mainly correlated with the metabolism of left parahippocampal gyrus and lateral temporal cortex. CONCLUSIONS: These data show that recollection is impaired in AD and recognition is more based on a feeling of familiarity than in controls. In addition, the findings of our correlative approach indicate that the impairment of episodic memory is mainly subserved by the dysfunction of frontal areas and of the hippocampal region.

Aged↗
PubMed2006

Retrieval mechanisms for autobiographical memories: insights from the frontal variant of frontotemporal dementia.

Very few studies have investigated autobiographical memory in the frontal variant of frontotemporal dementia (fv-FTD). The aim of this study was therefore to unravel the mechanisms of autobiographical memory disruption in general and in the anterograde and retrograde components of amnesia in particular, in patients suffering from fv-FTD. An autobiographical memory task assessing overall (AM) and strictly episodic memories (EM) from five lifetime periods covering the entire lifespan revealed the absence of a temporal gradient for both scores, suggesting the existence of a retrieval deficit. An analysis of the correlation between these two scores and a general cognitive assessment of executive function, working, episodic (i.e. new learning ability) and semantic memory, and behavioural changes highlighted the considerable involvement of executive function, semantic memory and, to a lesser degree, episodic memory and behavioural changes. Moreover, step-wise regression analyses performed on the EM score revealed that the executive function was a better predictor of the retrograde component than of the anterograde component, which was linked principally to new episodic learning ability. All these results confirm the impact of executive dysfunction on autobiographical deficits in fv-FTD, and suggest that the mechanisms at the root of autobiographical memory disruption may also involve difficulties in new episodic learning and semantic storage, though this may be due to the fact that we studied an advanced form of fv-FTD.

Aged↗
PubMed2006

Autobiographical memory, autonoetic consciousness, and self-perspective in aging.

In this study, the authors examined the effects of aging on autobiographical memory in 180 participants by means of a new method designed to assess across 5 lifetime periods the nature of memories-that is, specificity and spontaneity--and the phenomenal experience of remembering--that is, self-perspective and autonoetic consciousness--via the field/observer and remember/know paradigms respectively. Age-related differences were found for the specificity and spontaneity of memories and the phenomenal experience of remembering. There was an increase in observer and know responses with age, but a decrease in field and remember responses and in the ability to justify them by recalling sensory-perceptive, affective, or spatiotemporal specific details. This pattern confirms the existence of a semantic-episodic dissociation in autobiographical memory in aging. Moreover, the data support the view that older participants can subjectively "travel back in time" to relive personal events in the most distant past better than those in the recent past.

Adult↗
PubMed2006

[False memories: an interface between normal memory and pathology].

One of the most unexpected aspects of our memory is the existence of false memories. This phenomenon concerns the recall or recognition of events that never took place. Since a few years, the study of false memories became a field of research particularly active in psychology and neuropsychology. The objective of this review is to examine the various studies undertaken on false memories, while being interested more specifically by the influence of age and Alzheimer's disease on their production. We discuss then the mechanisms of production of false memories reviewing the assumptions related to the organization of semantic memory and to executive functions.

Aged↗
PubMed2005

Episodic autobiographical memory in depression: Specificity, autonoetic consciousness, and self-perspective.

Autobiographical memory (AM) and the self are closely linked. AM retrieval in depression is characterized by a lack of specificity, suggesting an impairment of episodic AM. Autonoetic consciousness and self-perspective, which are critical to episodic AM, have never been addressed in depression. Twenty-one depressed inpatients and 21 matched controls were given an episodic AM task designed to assess positive and negative memories regarding specificity, autonoetic consciousness (remember/know procedure), and self-perspective (field/observer procedure). For specificity, "remember", and "field" responses, ANOVAs revealed a main group effect and a group x valence interaction. Between groups, patients showed lower scores than controls for positive memories. Within groups, patients showed greater scores for negative memories, and controls showed greater scores for positive memories. There is a global episodic AM impairment of positive memories in depression regarding specificity, autonoetic consciousness, and self-perspective. Our results suggest new cognitive interventions to improve the self-relevance of positive memories in depression.

Adult↗
PubMed2005

Conscious recollection in autobiographical memory: an investigation in schizophrenia.

Whether or not conscious recollection in autobiographical memory is affected in schizophrenia is unknown. The aim of this study was to address this issue using an experiential approach. An autobiographical memory enquiry was used in combination with the Remember/Know procedure. Twenty-two patients with schizophrenia and 22 normal subjects were asked to recall specific autobiographical memories from four lifetime periods and to indicate the subjective states of awareness associated with the recall of what happened, when and where. They gave Remember, Know or Guess responses according to whether they recalled these aspects of the event on the basis of conscious recollection, simply knowing, or guessing. Results showed that the frequency and consistency of Remember responses was significantly lower in patients than in comparison subjects. In contrast, the frequency of Know responses was not significantly different, whereas the frequency of patients' Guess responses was significantly enhanced. It is concluded that the frequency and consistency of conscious recollection in autobiographical memory is reduced in patients with schizophrenia.

Adolescent↗
PubMed2004

'In the course of time': a PET study of the cerebral substrates of autobiographical amnesia in Alzheimer's disease.

Neuroimaging studies in healthy subjects have yielded controversial results about the neural substrates of autobiographical memory. Moreover, the neural networks responsible for autobiographical amnesia remain poorly understood. Since autobiographical memory is frequently altered in Alzheimer's disease (AD), we used this degenerative disorder as a model and applied a correlative approach between resting cerebral glucose utilization (CMRGlc) and temporally graded memory scores to identify the cerebral structures whose synaptic dysfunction subserves the impairment in autobiographical memory. To this end, we studied a group of 17 AD patients with mild to moderate dementia in whom autobiographical memory was assessed using a specially designed task from three broad time periods [the previous 5 years (period A); middle age (period B); and teenage and childhood (period C)], and measures of resting CMRGlc were obtained with PET. The patients performed less well than a control group for all three time periods and showed the expected temporal gradient, with the most remote period being best preserved (Ribot's gradient). Qualitative analysis showed that remote memories concerned generic (i.e. semantic) rather than specific (i.e. episodic) events. We found a significant positive correlation between autobiographical scores and the metabolism of the right hippocampus (extending to the lingual gyrus), restricted to period A. In addition, period A scores were significantly correlated with the right middle and inferior frontal gyri and the right middle temporal gyrus. Period B scores correlated chiefly with the prefrontal cortex bilaterally (bilateral superior, bilateral middle and right inferior gyri). Metabolic correlations with period C scores were restricted to the left middle frontal gyrus. These findings show striking differences in metabolic correlations with the autobiographical time period, in agreement with prevalent theories of normal functioning of human memory. Thus, in accordance with theories of long-term memory consolidation, we find the expected implication of the hippocampal region in the recall of recent memories, and a disengagement of this structure when the retention interval is beyond 5 years. Moreover, according to the hemispheric encoding/retrieval asymmetry model based on activation studies in healthy subjects, the fact that recent memories preferentially involved the right prefrontal cortex whereas remote memories involved the left prefrontal cortex supports the notion of semanticization of memories with time interval, such that preserved remote memories in AD have a predominantly semantic character.

Aged↗
PubMed2004

Re-experiencing old memories via hippocampus: a PET study of autobiographical memory.

The time-scale of medial temporal lobe (MTL) involvement in storage and retrieval of episodic memory is keenly debated. To test competitive theories of long-term memory consolidation, the present work aimed at characterizing which cerebral regions are involved during retrieval of recent and remote strictly episodic autobiographical memory. Using positron emission tomography (PET), we examined mental retrieval of recent (0-1 year) and remote (5-10 years) autobiographical memories, controlling for the nature of the autobiographical memories (i.e., specificity, state of consciousness, vividness of mental visual imagery, emotion) retrieved during scanning by behavioral measures assessed at debriefing for each event recalled. Cognitive results showed that specificity and emotion did not change with time interval although both autonoetic consciousness and mental image quality were significantly higher for recent memories, suggesting an underlying shift in the phenomenal experience of remembering with the passage of time. The SPM analysis revealed common activations during the recollection of recent and remote memories that involved a widespread but mainly left-sided cerebral network, consistent with previous studies. Subtraction analysis demonstrated that the retrieval of recent (relative to remote) autobiographical memories principally activated the left dorsolateral prefrontal cortex whereas the retrieval of remote (relative to recent) autobiographical memories activated the inferior parietal cortex bilaterally. ROIs analysis revealed more hippocampal activity for remote memories than for recent ones and a preferentially right-sided involvement of the hippocampal responses whatever the remoteness of autobiographical memories. New insights based on higher hippocampal response to the remoteness of episodic autobiographical memories challenge the standard model and are less discrepant with the multiple trace theory.

Adult↗
PubMed2003

Autobiographical memory and autonoetic consciousness: triple dissociation in neurodegenerative diseases.

Few studies have investigated autobiographical amnesia in neurodegenerative diseases and yet these pathologies are particularly relevant when addressing the issue of theories of long-term memory consolidation. According to the standard model, the medial temporal lobe (MTL) is involved in the storage and retrieval of episodic and semantic memories during a limited period of years. An alternative model, the multiple trace theory (MTT), suggests that the capacity of the MTL to recollect episodic memories is of a more permanent nature. In order to test these models, we studied three groups of patients with a neurodegenerative disease predominantly affecting different cerebral structures namely the MTL (13 patients in the early stages of Alzheimer's disease) and the neocortex involving either the anterior temporal lobe (10 patients with semantic dementia) or the frontal lobe (15 patients with the frontal variant of frontotemporal dementia, fv-FTD). We compared these groups of patients with control subjects using an original and reliable autobiographical memory task designed specially to assess strictly episodic memory over the entire lifespan. This task, developed on the basis of the most up-to-date definition of episodic memory, takes into account the ability to mentally travel back in time and re-experience the source of acquisition (remembering, i.e. autonoetic consciousness) via the remember/know paradigm. All three groups of patients produced strongly contrasting profiles of autobiographical amnesia (regardless of the nature of the memories), which also differed markedly from that of the control group: temporally graded memory loss in Alzheimer's disease, showing that remote memories are better preserved than recent ones; memory loss with a reversed gradient in semantic dementia; and memory loss without any clear gradient in fv-FTD. Most strictly episodic memories (i.e. unique, specific in time and space, and detailed) were impaired, whatever the time interval considered in the three groups, though the memory loss was ungraded in Alzheimer's disease and fv-FTD, and temporally graded in semantic dementia, sparing the most recent period. A deficit of autonoetic consciousness emerged in Alzheimer's disease and fv-FTD, but not in semantic dementia, though beyond the most recent 12-month period, the latter group could not justify their subjective sense of remembering to the same extent as the controls, in terms of the actual contextual information retrieved-phenomenological, spatial or temporal details. Our results demonstrate that autobiographical amnesia varies according to the nature of the memories under consideration and the locus of cerebral dysfunction. They are discussed in the light of the two competing models of long-term memory consolidation and recent conceptions of autobiographical recollection: new insights based on current concepts of episodic memories challenge the standard model and tend to support the MTT instead.

Aged↗
PubMed2003

The hyperpriming phenomenon in normal aging: a consequence of cognitive slowing?

Increased semantic priming effects (hyperpriming) are sometimes observed in Alzheimer's disease (AD) and in normal aging. Whereas the processes underlying this phenomenon are now well understood in AD, the interpretation is much more woolly in normal aging. To explore semantic priming, the authors used a lexical decision task in which the influence of attention and cognitive slowing was controlled. To explore the semantic organization, the words had coordinate (tiger-lion) or attribute relations (zebra-stripes). Priming scores of 21 older and 20 young participants were equivalent in the 2 conditions. These results reflect the integrity of semantic memory with normal aging and call into question some investigations showing hyperpriming for older participants; this may instead be an artifact of a general slowing effect.

Adult↗
PubMed2003

[Autobiographical memory in aging].

Episodic memory deficits are characteristic of old subjects. However, few results concern studies of autobiographical memory, one of the most essential part of human memory. Usually remote, but not recent, memory is regarded as preserved in aging. This phenomenom is well known as the Ribot's law. We briefly present the recent models of autobiographical memory and we detail the different aspects of aging on the two components, either episodic or semantic, of autobiographical memory. The data are reviewed with respect to the different kinds of autobiographical memory assessments : cue-words technique, autobiographical verbal fluency and interview. In addition, we present the results from novel autobiographical memory tasks specially designed to be more valid and reliable than the previous neuropsychological tools by assessing the contribution of episodic and semantic memory systems to autobiographical performance viaexperimental paradigms (remember/know). This review shows that the Ribot's law is not confirmed in aging by contrast with Alzheimer's disease. Indeed, in older subjects, the performances on episodic autobiographical memory tests diminish with time interval, with a clear recency effect. Moreover, the episodic, but not the semantic, component of autobiographical memory is significantly altered in aging.

Aged↗
PubMed2003

[Explicit and implicit memory for emotional stimuli in depressed elderly and Alzheimer's disease].

It is well known that emotional events are better recalled than neutral events. It indicates that memory is affected by the emotional content of stimuli. Since psychiatric and neurodegenerative diseases produce qualitatively and quantitively different memory and emotional disorders, a better understanding of their relations should improve our knowledge about memory and emotion interaction. We present here a review of recent studies that examined the effects of emotions on episodic (explicit) memory and on perceptual and conceptual priming (implicit memory) in depression and in Alzheimer's disease. Several studies of memory in depressed patients reported a tendency toward recall of negatively toned material indicating the existence of a bias toward processing of mood-congruent information. On the other hand, an enhancement of memory performance is observed in Alzheimer's disease when positive and negative stimuli are used.

Affect↗
PubMed2002

Episodic and semantic remote autobiographical memory in ageing.

Many laboratory studies have demonstrated an age effect on episodic memory which is in contrast with the preservation of semantic memory. The aim of this study was the assessment of age effects on autobiographical memory according to the length of the retention interval, taking into account the episodic and semantic components. A total of 52 subjects, aged between 40 and 79, were divided into four age groups. They were tested with a sophisticated autobiographical questionnaire consisting of two tasks, one involving the recall of semantic information and another the recall of episodic events. Results revealed that episodic recall deteriorated more with age and retention interval than semantic recall. These data, gathered using an ecological test, confirm age differences demonstrated by laboratory tests on the episodic-semantic distinction. Furthermore, the profile of results obtained for the recall of specific detailed events, and analysed according to age of encoding, confirms the distribution of episodic memories across the lifespan, as modelled by Rubin, Wetzler, and Nebes (1986) with the cue-word technique.

Adult↗