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Morris Moscovitch - One of the best experts on this subject based on the ideXlab platform.
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Autobiographical memory in semantic dementia: Implications for theories of limbic-neocortical interaction in remote memory
Neuropsychologia, 2020Co-Authors: Margaret C. Mckinnon, Morris Moscovitch, Sandra E. Black, Bruce L. Miller, Brian LevineAbstract:We examined autobiographical memory performance in two patients with semantic dementia using a novel measure, the Autobiographical Interview [Levine, Svoboda, Hay, Winocur, & Moscovitch (2002). Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677–689], that is capable of dissociating episodic and personal semantic recall under varying levels of retrieval support. Earlier reports indicated that patients with semantic dementia demonstrate autobiographical episodic memory loss following a “reverse gradient” by which recent memories are preserved relative to remote memories. We found limited evidence for this pattern at conditions of low retrieval support. When structured probing was provided, patients’ autobiographical memory performance was similar to that of controls. Retesting of one patient after 1 year indicated that retrieval support was insufficient to bolster performance following progressive prefrontal volume loss, as documented with quantified structural neuroimaging. These findings are discussed in relation to theories of limbic-neocortical interaction in autobiographical memory.
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Different patterns of autobiographical memory loss in semantic dementia and medial temporal lobe amnesia: a challenge to consolidation theory.
Neurocase, 2020Co-Authors: Robyn Westmacott, Larry Leach, Morris Freedman, Morris MoscovitchAbstract:Temporally graded retrograde memory loss, with a disproportionate impairment of recent relative to remote memories, is considered a hallmark of medial temporal lobe amnesia. According to consolidation theory, the hippocampal complex, which includes the hippocampal formation, parahippocampal gyrus, the entorhinal and perirhinal cortex, plays a time-limited role in memory, needed only until consolidation in the neocortex is complete (Squire, Psychological Review 1992; 99: 195–231). Recent support for this theory comes from findings of a reverse gradient in people with semantic dementia with neocortical degeneration but a relatively preserved hippocampal complex (Hodges and Graham, Neuropsychologia 1998; 36: 803–25). Consolidation theory is challenged by evidence that remote autobiographical memory is not always spared in amnesia (Nadel and Moscovitch, Current Opinion in Neurobiology 1997; 7: 217–27) and that semantic memory becomes highly personalized in semantic dementia (Snowden et al., Memory 1995; 3: 22...
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A Neuropsychological Model of Memory and Consciousness
2020Co-Authors: Morris MoscovitchAbstract:In my contribution to the first edition of this volume, I avoided speculating about different kinds of memory. Instead, I concentrated on identifying the sufficient conditions for distinguishing between memory tests on which performance of amnesic patients is relatively intact and those on which it is impaired (Moscovitch, 1984). Those conditions are the basis of the current distinction between explicit and implicit tests of memory (Graf & Schacter, 1985). In the years since the book appeared, the theoretical and empirical literature on this topic has burgeoned as no other has done in cognitive psychology and neuropsychology. One of the main consequences of this enterprise has been a growing appreciation both of the varieties of memory and of the component cognitive processes and neurological mechanisms that underlie them (RichardsonKlavehn & Bjork, 1988; Roediger & Craik, 1989). The operational, descriptive approach I adopted in my previous chapter is still useful in classifying memory tests, but it is no longer adequate in dealing with the rich theoretical and empirical literature we now have. I therefore supplement it with (in fact, subordinate it to) theoretical speculations about the varieties of memory in normal and brain-damaged people.
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Impoverished descriptions of familiar routes in three cases of hippocampal/medial temporal lobe amnesia
Cortex, 2015Co-Authors: Katherine A. Herdman, Morris Moscovitch, Navona Calarco, Marnie Hirshhorn, R. Shayna RosenbaumAbstract:Recent research has challenged classic theories of hippocampal function in spatial memory with findings that the hippocampus may be necessary for detailed representations of environments learned long ago, but not for remembering the gist or schematic aspects that are sufficient for navigating within those environments (Rosenbaum et al., 2000; Rosenbaum, Winocur, Binns, & Moscovitch, 2012). We aimed to probe further distinctions between detailed and schematic representations of familiar environments in three cases of hippocampal/medial temporal lobe (MTL) amnesia by testing them on a route description task and mental navigation tasks that assess the identity and location of landmarks, and distances and directions between them. The amnesic cases could describe basic directions along known, imagined routes, estimate distance and direction between well-known landmarks, and produce sketch maps with accurate layouts, suggestive of intact schematic representations. However, findings that their route descriptions lack richness of detail, along with impoverished sketch maps and poor landmark recognition, substantiates previous findings that detailed representations are hippocampus-dependent.
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Autobiographical episodic memory in major depressive disorder.
Journal of Abnormal Psychology, 2014Co-Authors: Hedvig Söderlund, Morris Moscovitch, Namita Kumar, Zafiris J. Daskalakis, Alastair J. Flint, Nathan Herrmann, Brian LevineAbstract:: Autobiographical memory in major depression has been characterized as overgeneralized, with patients recalling few episodic details, prioritizing general schematic events. However, whether this effect reflects impaired episodic or semantic memory, or domain-general cognitive processes, is unknown. We used the Autobiographical Interview (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) to derive episodic and semantic contributions to autobiographical memory in patients with severe major depression. We also assessed memory for public events and famous people. Depressed patients were impaired on episodic, but not semantic, autobiographical memory from 2 weeks to 10 years before testing. They were also impaired on memory for public events, possibly because they followed the news less than controls. Patients' memory for famous names was not impaired, although this was strongly associated with non-episodic memories to a greater degree than in controls. The findings suggest a specific impairment of episodic autobiographical memory in depression that is not fully accounted for by domain-general processes involved in strategic retrieval.
Ulrich Mayr - One of the best experts on this subject based on the ideXlab platform.
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on the dissociation between clustering and switching in verbal fluency comment on troyer Moscovitch winocur alexander and stuss
Neuropsychologia, 2002Co-Authors: Ulrich MayrAbstract:Abstract Troyer, Moscovitch, Winocur, Alexander and Stuss (Neuropsychologia 36 (1998) 499) used a procedure originally introduced by Troyer, Moscovitch and Winocur (Neuropsychology 11 (1997) 138) for distinguishing two different components of verbal fluency—clustering and switching—in frontal and temporal-lobe patients. Application of this procedure yielded results that suggested a frontal-lobe switching deficit, but intact ‘clustering’. I demonstrate here that the proposed procedure may lead to incorrect conclusions because it does not allow an unambiguous dissociation between a general reduction in processing speed and a selective switching deficit. Some implications of this critique for inferences about the neurocognitive components involved in verbal fluency tasks are discussed.
Brian Levine - One of the best experts on this subject based on the ideXlab platform.
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Autobiographical memory in semantic dementia: Implications for theories of limbic-neocortical interaction in remote memory
Neuropsychologia, 2020Co-Authors: Margaret C. Mckinnon, Morris Moscovitch, Sandra E. Black, Bruce L. Miller, Brian LevineAbstract:We examined autobiographical memory performance in two patients with semantic dementia using a novel measure, the Autobiographical Interview [Levine, Svoboda, Hay, Winocur, & Moscovitch (2002). Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677–689], that is capable of dissociating episodic and personal semantic recall under varying levels of retrieval support. Earlier reports indicated that patients with semantic dementia demonstrate autobiographical episodic memory loss following a “reverse gradient” by which recent memories are preserved relative to remote memories. We found limited evidence for this pattern at conditions of low retrieval support. When structured probing was provided, patients’ autobiographical memory performance was similar to that of controls. Retesting of one patient after 1 year indicated that retrieval support was insufficient to bolster performance following progressive prefrontal volume loss, as documented with quantified structural neuroimaging. These findings are discussed in relation to theories of limbic-neocortical interaction in autobiographical memory.
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Autobiographical memory and structural brain changes in chronic phase TBI.
Cortex, 2017Co-Authors: Carrie Esopenko, Brian LevineAbstract:Abstract Traumatic brain injury (TBI) is associated with a range of neuropsychological deficits, including attention, memory, and executive functioning attributable to diffuse axonal injury (DAI) with accompanying focal frontal and temporal damage. Although the memory deficit of TBI has been well characterized with laboratory tests, comparatively little research has examined retrograde autobiographical memory (AM) at the chronic phase of TBI, with no prior studies of unselected patients drawn directly from hospital admissions for trauma. Moreover, little is known about the effects of TBI on canonical episodic and non-episodic (e.g., semantic) AM processes. In the present study, we assessed the effects of chronic-phase TBI on AM in patients with focal and DAI spanning the range of TBI severity. Patients and socioeconomic- and age-matched controls were administered the Autobiographical Interview (AI) (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) a widely used method for dissociating episodic and semantic elements of AM, along with tests of neuropsychological and functional outcome. Measures of episodic and non-episodic AM were compared with regional brain volumes derived from high-resolution structural magnetic resonance imaging (MRI). Severe TBI (but not mild or moderate TBI) was associated with reduced recall of episodic autobiographical details and increased recall of non-episodic details relative to healthy comparison participants. There were no significant associations between AM performance and neuropsychological or functional outcome measures. Within the full TBI sample, autobiographical episodic memory was associated with reduced volume distributed across temporal, parietal, and prefrontal regions considered to be part of the brain's AM network. These results suggest that TBI-related distributed volume loss affects episodic autobiographical recollection.
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Autobiographical episodic memory in major depressive disorder.
Journal of Abnormal Psychology, 2014Co-Authors: Hedvig Söderlund, Morris Moscovitch, Namita Kumar, Zafiris J. Daskalakis, Alastair J. Flint, Nathan Herrmann, Brian LevineAbstract:: Autobiographical memory in major depression has been characterized as overgeneralized, with patients recalling few episodic details, prioritizing general schematic events. However, whether this effect reflects impaired episodic or semantic memory, or domain-general cognitive processes, is unknown. We used the Autobiographical Interview (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) to derive episodic and semantic contributions to autobiographical memory in patients with severe major depression. We also assessed memory for public events and famous people. Depressed patients were impaired on episodic, but not semantic, autobiographical memory from 2 weeks to 10 years before testing. They were also impaired on memory for public events, possibly because they followed the news less than controls. Patients' memory for famous names was not impaired, although this was strongly associated with non-episodic memories to a greater degree than in controls. The findings suggest a specific impairment of episodic autobiographical memory in depression that is not fully accounted for by domain-general processes involved in strategic retrieval.
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Mental space travel: damage to posterior parietal cortex prevents egocentric navigation and reexperiencing of remote spatial memories.
Journal of Experimental Psychology: Learning Memory and Cognition, 2010Co-Authors: Elisa Ciaramelli, R. Shayna Rosenbaum, Brian Levine, Stephanie Solcz, Morris MoscovitchAbstract:The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval.
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Autobiographical Memory and Patterns of Brain Atrophy in Fronto-temporal Lobar Degeneration
Journal of Cognitive Neuroscience, 2008Co-Authors: Margaret C. Mckinnon, Morris Moscovitch, Sandra E. Black, Morris Freedman, Bruce L. Miller, Elena I. Nica, Pheth Sengdy, Natasa Kovacevic, Brian LevineAbstract:Autobiographical memory paradigms have been increasingly used to study the behavioral and neuroanatomical correlates of human remote memory. Although there are numerous functional neuroimaging studies on this topic, relatively few studies of patient samples exist, with heterogeneity of results owing to methodological variability. In this study, fronto-temporal lobar degeneration (FTLD), a form of dementia affecting regions crucial to autobiographical memory, was used as a model of autobiographical memory loss. We emphasized the separation of episodic (recollection of specific event, perceptual, and mental state information) from semantic (factual information unspecific in time and place) autobiographical memory, derived from a reliable method for scoring transcribed autobiographical protocols, the Autobiographical Interview [Levine, B., Svoboda, E., Hay, J., Winocur, G., & Moscovitch, M. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677–689, 2002]. Patients with the fronto-temporal dementia (FTD) and mixed fronto-temporal and semantic dementia (FTD/SD) variants of FTLD were impaired at reconstructing episodically rich autobiographical memories across the lifespan, with FTD/SD patients generating an excess of generic semantic autobiographical information. Patients with progressive nonfluent aphasia were mildly impaired for episodic autobiographical memory, but this impairment was eliminated with the provision of structured cueing, likely reflecting relatively intact medial-temporal lobe function, whereas the same cueing failed to bolster the FTD and FTD/SD patients' performance relative to that of matched comparison subjects. The pattern of episodic, but not semantic, autobiographical impairment was enhanced with disease progression on 1- to 2-year follow-up testing in a subset of patients, supplementing the cross-sectional evidence for specificity of episodic autobiographical impairment with longitudinal data. This behavioral pattern covaried with volume loss in a distributed left-lateralized posterior network centered on the temporal lobe, consistent with evidence from other patient and functional neuroimaging studies of autobiographical memory. Frontal lobe volumes, however, did not significantly contribute to this network, suggesting that frontal contributions to autobiographical episodic memory may be more complex than previously appreciated.
Erica Crome - One of the best experts on this subject based on the ideXlab platform.
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an empirical analysis of Moscovitch s reconceptualised model of social anxiety how is it different from fear of negative evaluation
Journal of Anxiety Disorders, 2016Co-Authors: Isilay N Kizilcik, Bree Gregory, Andrew Baillie, Erica CromeAbstract:Abstract Cognitive-behavioural models propose that excessive fear of negative evaluation is central to social anxiety. Moscovitch (2009) instead proposes that perceived deficiencies in three self attributes: fears of showing signs of anxiety, deficits in physical appearance, or deficits in social competence are at the core of social anxiety. However, these attributes are likely to overlap with fear of negative evaluation. Responses to an online survey of 286 participants with a range of social anxiety severity were analysed using hierarchical multiple regression to identify the overall unique predictive value of Moscovitch’s model. Altogether, Moscovitch’s model provided improvements in the prediction of safety behaviours, types of fears and cognitions; however only the fear of showing anxiety subscale provided unique information. This research supports further investigations into the utility of this revised model, particularly related to utility of explicitly assessing and addressing fears of showing anxiety.
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An empirical analysis of Moscovitch’s reconceptualised model of social anxiety: How is it different from fear of negative evaluation?
Journal of Anxiety Disorders, 2015Co-Authors: Isilay N Kizilcik, Bree Gregory, Andrew Baillie, Erica CromeAbstract:Abstract Cognitive-behavioural models propose that excessive fear of negative evaluation is central to social anxiety. Moscovitch (2009) instead proposes that perceived deficiencies in three self attributes: fears of showing signs of anxiety, deficits in physical appearance, or deficits in social competence are at the core of social anxiety. However, these attributes are likely to overlap with fear of negative evaluation. Responses to an online survey of 286 participants with a range of social anxiety severity were analysed using hierarchical multiple regression to identify the overall unique predictive value of Moscovitch’s model. Altogether, Moscovitch’s model provided improvements in the prediction of safety behaviours, types of fears and cognitions; however only the fear of showing anxiety subscale provided unique information. This research supports further investigations into the utility of this revised model, particularly related to utility of explicitly assessing and addressing fears of showing anxiety.
Sharon L Thompsonschill - One of the best experts on this subject based on the ideXlab platform.
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role of the left inferior frontal gyrus in covert word retrieval neural correlates of switching during verbal fluency
Neuropsychologia, 2006Co-Authors: Elizabeth A Hirshorn, Sharon L ThompsonschillAbstract:Abstract Word retrieval ability is commonly assessed with a semantic verbal fluency task, in which subjects must produce a list of exemplars of a category (e.g., animals). The order in which exemplars are produced is not random; rather, subjects tend to produce “clusters” of semantically related items (e.g., cow, pig, sheep) and occasionally “switch” to other clusters (e.g., lion, tiger, bear). Patients with frontal lobe pathology (associated with focal lesions or Parkinson's disease) exhibit reduced output on semantic fluency tasks that has been characterized as a reduction in switching, in contrast to other impaired patient groups who produce normal switches but smaller clusters (e.g., [Troyer, A. K., Moscovitch, M., Winocur, G., Leach, L., & Freedman, M. (1998). Clustering and switching on verbal fluency tests in Alzheimer's and Parkinson's disease. Journal of the International Neuropsychological Society, 4(2), 137–143]). The ability to initiate a switch between two semantic categories may require the selection of weakly activated representations over active (but already reported) representations. Previous studies have shown that increased demands on selection among competing representations are associated with activity in the left inferior frontal gyrus (LIFG) and with deficits in patients with lesions including LIFG [Thompson-Schill, S. L., Jonides, J., Marshuetz, C., Smith, E. E., D’Esposito, M., Kan, I. P., et al. (2002). Effects of frontal lobe damage on interference effects in working memory. Cognitive Affective & Behavioral Neuroscience, 2(2), 109–120; Thompson-Schill, S. L., Swick, D., Farah, M. J., D’Esposito, M., Kan, I. P., & Knight, R. T. (1998). Verb generation in patients with focal frontal lesions: A neuropsychological test of neuroimaging findings. Proceedings of the National Academy of Sciences of the United States of America, 26, 14792–14797]. In the present study, we investigated the neural correlates of switching in the verbal fluency task, and in particular, the role of the LIFG in switching between semantic sub-categories. We observed greater activation in the LIFG during switching compared to free generation (Experiment 1) and self-reported clustering (Experiment 2), which is consistent with the hypothesis that the switching mechanism is subserved by the LIFG due to high semantic selection demands.