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Liampas I, Kyriakoulopoulou P, Akrioti A, Stamati P, Germeni A, Batzikosta P, Tsiamaki E, Veltsista D, Kefalopoulou Z, Siokas V, Chroni E, Dardiotis E. Cognitive deficits and course of recovery in transient global amnesia: a systematic review. J Neurol 2024:10.1007/s00415-024-12563-2. [PMID: 39090229 DOI: 10.1007/s00415-024-12563-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 07/02/2024] [Accepted: 07/04/2024] [Indexed: 08/04/2024]
Abstract
OBJECTIVE Published evidence suggests that cognitive impairment during a TGA (transient global amnesia) spell may not be confined to episodic memory. We undertook a systematic review to determine the pattern of cognitive deficits during a TGA episode. As a secondary objective, we aimed to delineate the course of cognitive recovery. METHODS MEDLINE, EMBASE, CENTRAL, and Google scholar were systematically searched up to October 2023. Observational controlled studies including 10 or more TGA patients (Hodges and Warlow criteria) were retrieved. Data from case-control, cross-sectional, and cohort studies were reviewed and qualitatively synthesized. RESULTS Literature search yielded 1302 articles. After the screening of titles and abstracts, 115 full texts were retrieved and 17 of them were included in the present systematic review. During the acute phase, spatiotemporal disorientation, dense anterograde and variable retrograde amnesia, semantic memory retrieval difficulties, and working memory deficits comprised the neuropsychological profile of patients with TGA. Visuospatial abilities, attention and psychomotor speed, semantic memory, confrontation naming, and other measures of executive function (apart from semantic fluency and working memory) were consistently found normal. In the course of recovery, after the resolution of repetitive questioning, the restoration of spatiotemporal orientation follows, working memory and semantic memory retrieval ensue, while episodic memory impairment persists for longer. Meticulous evaluations may reveal subtle residual memory (especially recognition) deficits even after 24 h. CONCLUSIONS Μemory impairment, spatiotemporal disorientation, and working memory deficits constitute the pattern of cognitive impairment during a TGA spell. Residual memory deficits may persist even after 24 h.
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Affiliation(s)
- Ioannis Liampas
- Department of Neurology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo Hill, 41100, Larissa, Greece.
| | - Panayiota Kyriakoulopoulou
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Anna Akrioti
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Polyxeni Stamati
- Department of Neurology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo Hill, 41100, Larissa, Greece
| | - Alexandra Germeni
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Paraskevi Batzikosta
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Eirini Tsiamaki
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Dimitra Veltsista
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Zinovia Kefalopoulou
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Vasileios Siokas
- Department of Neurology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo Hill, 41100, Larissa, Greece
| | - Elisabeth Chroni
- Department of Neurology, University Hospital of Patras, School of Medicine, University of Patras, 26504, Patras, Rio, Greece
| | - Efthimios Dardiotis
- Department of Neurology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo Hill, 41100, Larissa, Greece
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Matijevic S, Hoscheidt S, Ryan L. Semantic details in autobiographical memory narratives increase with age among younger adults. Memory 2024:1-11. [PMID: 38870423 DOI: 10.1080/09658211.2024.2365302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 05/30/2024] [Indexed: 06/15/2024]
Abstract
It is well documented that older adults, compared to younger adults, produce fewer episodic details and more semantic details when recalling autobiographical memories. However, group comparisons have provided limited insight into the trajectories of detail generation across the lifespan. Utilising an open source dataset [Clark, I. A., & Maguire, E. A. (2023). Release of cognitive and multimodal MRI data including real-world tasks and hippocampal subfield segmentations. Scientific Data, 10(1), 1-29. https://doi.org/10.1038/s41597-022-01899-x], we examined how episodic and semantic detail generation varied with age among 194 younger adults, ages 20-41. We tested whether age differences were mediated by hippocampal subfield volumes and MTL resting-state functional connectivity. Results indicated that semantic details increased with age, while episodic details remained stable. We observed age differences in hippocampal subfield volumes and MTL connectivity, but these measures did not mediate age effects on semantic detail. Based on these and prior findings [Matijevic, S., Andrews-Hanna, J. R., Wank, A. A., Ryan, L., & Grilli, M. D. (2022). Individual differences in the relationship between episodic detail generation and resting state functional connectivity vary with age. Neuropsychologia, 166, 108138. https://doi.org/10.1016/j.neuropsychologia.2021.108138], we suggest a model of diverging episodic and semantic detail generation trajectories across the adult lifespan.
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Affiliation(s)
| | | | - Lee Ryan
- Department of Psychology, University of Arizona, Tucson, USA
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Marier A, Dadar M, Bouhali F, Montembeault M. Irregular word reading as a marker of cognitive and semantic decline in Alzheimer's disease rather than an estimate of premorbid intellectual abilities. RESEARCH SQUARE 2023:rs.3.rs-3381469. [PMID: 37841870 PMCID: PMC10571618 DOI: 10.21203/rs.3.rs-3381469/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Background Irregular word reading has been used to estimate premorbid intelligence in Alzheimer's disease (AD) dementia. However, reading models highlight the core influence of semantic abilities on irregular word reading, which shows early decline in AD. The general aim of this study is to determine whether irregular word reading is a valid estimate of premorbid intelligence, or a marker of cognitive and semantic decline in AD. Method 681 healthy controls (HC), 104 subjective cognitive decline, 290 early and 589 late mild cognitive impairment (EMCI, LMCI) and 348 AD participants from the Alzheimer's Disease Neuroimaging Initiative were included. Irregular word reading was assessed with the American National Adult Reading Test (AmNART). Multiple linear regressions were conducted predicting AmNART score using diagnostic category, general cognitive impairment and semantic tests. A generalized logistic mixed-effects model predicted correct reading using extracted psycholinguistic characteristics of each AmNART words. Deformation-based morphometry was used to assess the relationship between AmNART scores and voxel-wise brain volumes, as well as with the volume of a region of interest placed in the left anterior temporal lobe (ATL). Results EMCI, LMCI and AD patients made significantly more errors in reading irregular words compared to HC, and AD patients made more errors than all other groups. Across the AD continuum, as well as within each diagnostic group, irregular word reading was significantly correlated to measures of general cognitive impairment / dementia severity. Neuropsychological tests of lexicosemantics were moderately correlated to irregular word reading whilst executive functioning and episodic memory were respectively weakly and not correlated. Age of acquisition, a primarily semantic variable, had a strong effect on irregular word reading accuracy whilst none of the phonological variables significantly contributed. Neuroimaging analyses pointed to bilateral hippocampal and left ATL volume loss as the main contributors to decreased irregular word reading performances. Conclusions Irregular word reading performances decline throughout the AD continuum, and therefore, premorbid intelligence estimates based on the AmNART should not be considered accurate in MCI or AD. Results are consistent with the theory of irregular word reading impairments as an indicator of disease severity and semantic decline.
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Affiliation(s)
- Anna Marier
- Department of Psychology, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, QC, Canada, H3C 3J7
| | - Mahsa Dadar
- Douglas Research Centre & Department of Psychiatry, McGill University, 6875 Boulevard LaSalle, Montréal, QC, Canada, H4H 1R3
| | | | - Maxime Montembeault
- Douglas Research Centre & Department of Psychiatry, McGill University, 6875 Boulevard LaSalle, Montréal, QC, Canada, H4H 1R3
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Lin MC, Chih YC. Application of the Semantic Fluency Test in the Screening of Mandarin-Chinese-Speaking Older Adults with Mild Dementia of the Alzheimer Type. Behav Sci (Basel) 2023; 13:635. [PMID: 37622775 PMCID: PMC10451810 DOI: 10.3390/bs13080635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/21/2023] [Accepted: 07/27/2023] [Indexed: 08/26/2023] Open
Abstract
Semantic fluency tests have been widely used as a screening test for dementia of Alzheimer type. However, few studies have explored the application of semantic fluency tests in Mandarin Chinese speakers. This study aimed to explore the feasibility of using different semantic fluency test categories to distinguish between older adults without cognitive impairments and those with dementia of Alzheimer type in Taiwan. A total of 58 healthy older adults and 54 individuals with dementia of Alzheimer type were recruited. Semantic categories of "animals", "fruits", "vegetables", "birds", "means of transportations" and "musical instruments" were administered to participants. The scores from two groups of participants for each category were analyzed. Significant differences in the test scores of each category between two groups of participants were found. The results also revealed that the variables related to whether the participant had dementia, gender, age, and years of schooling significantly influenced the semantic fluency scores for each category. Among all the demographic characteristic of participants, the diagnosis of dementia was the most determining factor. Furthermore, this study proposed optimal cutoff points and calculated the AUC for various test durations (i.e., 30 s, 45 s and 60 s) and semantic categories in the semantic fluency test, which may serve as a reference that would help clinical personnel distinguish between older adults without cognitive impairments and those with dementia of Alzheimer type in Taiwan.
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Affiliation(s)
| | - Yu-Chun Chih
- Department of Speech Language Pathology and Audiology, Chung Shan Medical University, Taichung 402, Taiwan;
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Banks B, Connell L. Category production norms for 117 concrete and abstract categories. Behav Res Methods 2023; 55:1292-1313. [PMID: 35650380 PMCID: PMC10126059 DOI: 10.3758/s13428-021-01787-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2021] [Indexed: 11/08/2022]
Abstract
We present a database of category production (aka semantic fluency) norms collected in the UK for 117 categories (67 concrete and 50 abstract). Participants verbally named as many category members as possible within 60 seconds, resulting in a large variety of over 2000 generated member concepts. The norms feature common measures of category production (production frequency, mean ordinal rank, first-rank frequency), as well as response times for all first-named category members, and typicality ratings collected from a separate participant sample. We provide two versions of the dataset: a referential version that groups together responses that relate to the same referent (e.g., hippo, hippopotamus) and a full version that retains all original responses to enable future lexical analysis. Correlational analyses with previous norms from the USA and UK demonstrate both consistencies and differences in English-language norms over time and between geographical regions. Further exploration of the norms reveals a number of structural and psycholinguistic differences between abstract and concrete categories. The data and analyses will be of use in the fields of cognitive psychology, neuropsychology, psycholinguistics, and cognitive modelling, and to any researchers interested in semantic category structure. All data, including original participant recordings, are available at https://osf.io/jgcu6/ .
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Affiliation(s)
- Briony Banks
- Department of Psychology, Fylde College, Lancaster University, Bailrigg, Lancaster, LA1 4YF, UK.
| | - Louise Connell
- Department of Psychology, Fylde College, Lancaster University, Bailrigg, Lancaster, LA1 4YF, UK.
- Department of Psychology, Maynooth University, Maynooth, Co. Kildare, Ireland.
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Roysommuti S, Wyss JM. Brain-Derived Neurotrophic Factor Potentiates Entorhinal-Dentate but not Hippocampus CA1 Pathway in Adult Male Rats: A Mechanism of Taurine-Modulated BDNF on Learning and Memory. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1370:369-379. [PMID: 35882811 PMCID: PMC9467516 DOI: 10.1007/978-3-030-93337-1_35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Taurine plays an important role in neural growth and function from early to adult life, particularly in learning and memory via BDNF action. This study tested the hypothesis that BDNF differentially potentiates entorhinal-hippocampal synaptic transmission in vivo in adult rats. In anesthetized male Sprague-Dawley rats, a stainless steel recording electrode with an attached microinjector was placed into CA1 and the dentate gyrus to record fEPSP, and a paired stainless steel electrode was inserted into entorhinal cortex for continuous paired-pulse stimulation of that brain region. In the dentate gyrus, microinjection of BDNF resulted in a gradual increase in the peak slope of the fEPSP. Following the infusion, the peak fEPSP began to rise in about 8 min, reached a maximum of 120 ± 2% (from baseline) by about 20 min, and remained near peak elevation (~115%) for more than 30 min. In contrast, the same dose of BDNF when injected into CA1 had no consistent effect on fEPSP slopes in the CA1. Further, an equimolar cytochrome C (horse heart) infusion had no significant effect on fEPSP slopes in either the dentate gyrus or CA1. The potentiation effect of BDNF in the dentate gyrus is consistent with a significant increase in power spectral density of dentate gyrus field potentials at 70-200 Hz, but not at frequencies below 70 Hz. In addition, the CA1 power spectral density was not affected by BDNF (compared to cytochrome C). These data indicate that in vivo BDNF potentiates entorhinal-hippocampal synaptic transmission in dentate gyrus, but not in CA1.
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Affiliation(s)
- Sanya Roysommuti
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
| | - James Michael Wyss
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Autobiographical Memory Fluency Reductions in Cognitively Unimpaired Middle-Aged and Older Adults at Increased Risk for Alzheimer's Disease Dementia. J Int Neuropsychol Soc 2021; 27:905-915. [PMID: 33509324 PMCID: PMC8319219 DOI: 10.1017/s1355617720001319] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Recent research has revealed that cognitively unimpaired older adults who are at higher risk for developing Alzheimer's disease (AD) dementia often exhibit subtle cognitive alterations in their neuropsychological profiles. Emerging evidence suggests that autobiographical memory, which is memory for personal events and knowledge, may be sensitive to early AD-related cognitive alterations. In the present study, we investigated whether the rapid generation of autobiographical memory category exemplars, a retrieval process that taxes the neural network that is vulnerable to early AD, is compromised in cognitively unimpaired middle-aged and older carriers of the e4 allele of the apolipoprotein E gene (APOE4), which increases risk for AD dementia. METHODS In addition to standard neuropsychological tests, we administered a fluency task that requires generating exemplars for two types of autobiographical memory, namely episodic memories and personal semantics, to a group of cognitively unimpaired middle-aged and older adults (n = 45) enriched with APOE4 carriers (n = 20). RESULTS While no APOE4 deficits were found on standard neuropsychological tests, episodic and personal semantic exemplar generation was reduced in the APOE4 group. DISCUSSION Autobiographical memory aberrations associated with a higher risk for AD are evident in fluency and affect both episodic memory and personal semantics.
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Elbich DB, Webb CE, Dennis NA. The influence of item familiarization on neural discriminability during associative memory encoding and retrieval. Brain Cogn 2021; 152:105760. [PMID: 34126588 DOI: 10.1016/j.bandc.2021.105760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 04/13/2021] [Accepted: 05/27/2021] [Indexed: 10/21/2022]
Abstract
Associative memory requires one to encode and form memory representations not just for individual items, but for the association or link between those items. Past work has suggested that associative memory is facilitated when individual items are familiar rather than simultaneously learning the items and their associative link. The current study employed multivoxel pattern analyses (MVPA) to investigate whether item familiarization prior to associative encoding affects the distinctiveness of neural patterns, and whether that distinctiveness is also present during associative retrieval. Our results suggest that prior exposure to item stimuli impacts the representations of their shared association compared to stimuli that are novel at the time of associative encoding throughout most of the associative memory network. While this distinction was also present at retrieval, the overall extent of the difference was diminished. Overall the results suggest that stimulus familiarity influences the representation of associative pairings during memory encoding and retrieval, and the pair-specific representation is maintained across memory phases irrespective of this distinction.
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Affiliation(s)
- Daniel B Elbich
- Department of Neurology, The Pennsylvania State University, Hershey, PA, United States; Department of Psychology, The Pennsylvania State University, University Park, PA, United States
| | - Christina E Webb
- Department of Psychology, The Pennsylvania State University, University Park, PA, United States; Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, United States
| | - Nancy A Dennis
- Department of Psychology, The Pennsylvania State University, University Park, PA, United States.
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Sandikci V, Ebert A, Hoyer C, Platten M, Szabo K. Impaired semantic memory during acute transient global amnesia. J Neuropsychol 2021; 16:149-160. [PMID: 34021536 DOI: 10.1111/jnp.12251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/15/2021] [Indexed: 11/27/2022]
Abstract
As a clinical model of hippocampal dysfunction, transient global amnesia (TGA) causes reversible memory disturbance. While episodic memory deficits in TGA patients have been extensively described, data regarding semantic memory involvement are sparse and contradictory. We report impaired semantic fluency performance in 16 patients with hippocampal lesions on MRI during acute TGA compared to their performance one day later and to that of 20 healthy subjects. Our findings support the involvement of the hippocampus in semantic retrieval.
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Affiliation(s)
- Vesile Sandikci
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), Heidelberg University, Mannheim, Germany
| | - Anne Ebert
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), Heidelberg University, Mannheim, Germany
| | - Carolin Hoyer
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), Heidelberg University, Mannheim, Germany
| | - Michael Platten
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), Heidelberg University, Mannheim, Germany
| | - Kristina Szabo
- Department of Neurology, Medical Faculty Mannheim and Mannheim Center for Translational Neurosciences (MCTN), Heidelberg University, Mannheim, Germany
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10
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Lee DJ, Drummond NM, Saha U, De Vloo P, Dallapiazza RF, Gramer R, Al-Ozzi TM, Lam J, Loh A, Elias GJB, Boutet A, Germann J, Hodaie M, Fasano A, Munhoz RP, Hutchison W, Cohn M, Chen R, Kalia SK, Lozano AM. Acute low frequency dorsal subthalamic nucleus stimulation improves verbal fluency in Parkinson's disease. Brain Stimul 2021; 14:754-760. [PMID: 33940243 DOI: 10.1016/j.brs.2021.04.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 04/12/2021] [Accepted: 04/26/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Parkinson's disease (PD) is a common neurodegenerative disorder that results in movement-related dysfunction and has variable cognitive impairment. Deep brain stimulation (DBS) of the dorsal subthalamic nucleus (STN) has been shown to be effective in improving motor symptoms; however, cognitive impairment is often unchanged, and in some cases, worsened particularly on tasks of verbal fluency. Traditional DBS strategies use high frequency gamma stimulation for motor symptoms (∼130 Hz), but there is evidence that low frequency theta oscillations (5-12 Hz) are important in cognition. METHODS We tested the effects of stimulation frequency and location on verbal fluency among patients who underwent STN DBS implantation with externalized leads. During baseline cognitive testing, STN field potentials were recorded and the individual patients' peak theta frequency power was identified during each cognitive task. Patients repeated cognitive testing at five different stimulation settings: no stimulation, dorsal contact gamma (130 Hz), ventral contact gamma, dorsal theta (peak baseline theta) and ventral theta (peak baseline theta) frequency stimulation. RESULTS Acute left dorsal peak theta frequency STN stimulation improves overall verbal fluency compared to no stimulation and to either dorsal or ventral gamma stimulation. Stratifying by type of verbal fluency probes, verbal fluency in episodic categories was improved with dorsal theta stimulation compared to all other conditions, while there were no differences between stimulation conditions in non-episodic probe conditions. CONCLUSION Here, we provide evidence that dorsal STN theta stimulation may improve verbal fluency, suggesting a potential possibility of integrating theta stimulation into current DBS paradigms to improve cognitive outcomes.
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Affiliation(s)
- Darrin J Lee
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada; Department of Neurological Surgery, University of Southern California, 1200 North State Street, Suite 3300, Los Angeles, CA, 90033, USA; USC Neurorestoration Center, Keck School of Medicine of USC, 1333 San Pablo Street, McKibben Hall B51, Los Angeles, CA, 90033, USA.
| | - Neil M Drummond
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada
| | - Utpal Saha
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; USC Neurorestoration Center, Keck School of Medicine of USC, 1333 San Pablo Street, McKibben Hall B51, Los Angeles, CA, 90033, USA
| | - Philippe De Vloo
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada; Department of Neurosurgery, University Hospitals Leuven - KU Leuven, Herestraat 49, 3000, Leuven, Vlaams-Brabant, Belgium
| | - Robert F Dallapiazza
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
| | - Robert Gramer
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
| | - Tameem M Al-Ozzi
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
| | - Jordan Lam
- Department of Neurological Surgery, University of Southern California, 1200 North State Street, Suite 3300, Los Angeles, CA, 90033, USA; USC Neurorestoration Center, Keck School of Medicine of USC, 1333 San Pablo Street, McKibben Hall B51, Los Angeles, CA, 90033, USA
| | - Aaron Loh
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada
| | - Gavin J B Elias
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada
| | - Alexandre Boutet
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Joint Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
| | - Jurgen Germann
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada
| | - Mojgan Hodaie
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
| | - Alfonso Fasano
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Canada; Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada
| | - Renato P Munhoz
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Canada; Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada
| | - William Hutchison
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
| | - Melanie Cohn
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Department of Psychology, University of Toronto, Toronto, Canada
| | - Robert Chen
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Canada; Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada
| | - Suneil K Kalia
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
| | - Andres M Lozano
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada
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Varying demands for cognitive control reveals shared neural processes supporting semantic and episodic memory retrieval. Nat Commun 2021; 12:2134. [PMID: 33837220 PMCID: PMC8035200 DOI: 10.1038/s41467-021-22443-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 03/09/2021] [Indexed: 12/21/2022] Open
Abstract
The categorisation of long-term memory into semantic and episodic systems has been an influential catalyst for research on human memory organisation. However, the impact of variable cognitive control demands on this classical distinction remains to be elucidated. Across two independent experiments, here we directly compare neural processes for the controlled versus automatic retrieval of semantic and episodic memory. In a multi-session functional magnetic resonance imaging experiment, we first identify a common cluster of cortical activity centred on the left inferior frontal gyrus and anterior insular cortex for the retrieval of both weakly-associated semantic and weakly-encoded episodic memory traces. In an independent large-scale individual difference study, we further reveal a common neural circuitry in which reduced functional interaction between the identified cluster and ventromedial prefrontal cortex, a default mode network hub, is linked to better performance across both memory types. Our results provide evidence for shared neural processes supporting the controlled retrieval of information from functionally distinct long-term memory systems. Making sense of the world around us often requires flexible access to information from both semantic and episodic memory systems. Here, the authors show that controlled retrieval from functionally distinct long-term memory stores is supported by shared neural processes in the human brain.
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12
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Hilverman C, Duff MC. Evidence of impaired naming in patients with hippocampal amnesia. Hippocampus 2021; 31:612-626. [PMID: 33822428 DOI: 10.1002/hipo.23325] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 01/27/2021] [Accepted: 02/06/2021] [Indexed: 11/07/2022]
Abstract
Object naming involves accessing meaning and retrieving the associated word form from remote semantic memory. Historically, previously acquired semantic knowledge (i.e., remote semantic memory) was thought to be independent of the hippocampus via neocortical consolidation. This view is based on evidence demonstrating a dissociation in behavior in patients with hippocampal amnesia: amnesic patients are impaired in acquiring new vocabulary yet can name and define previously acquired words. More recently, the view that remote semantic memory is hippocampus-independent has been challenged by the documentation of disruptions in aspects of remote semantic memory in patients with hippocampal amnesia, particularly in language use and depth of semantic knowledge. Based on these findings, we hypothesized that the hippocampus plays a long-term role in remote semantic memory. We tested amnesic patients and demographically matched healthy comparison participants in an extensive naming task using photographic images of objects normalized for familiarity, object agreement, and visual complexity. Amnesic patients were less likely to correctly name objects than healthy comparison participants. Further, amnesic patients' performance worsened for words that were less familiar, more visually complex, and had less object agreement. These findings suggest that the hippocampus may play a long-term role in semantic memory processes, rather than a time-limited role in the initial acquisition of semantic information, and that hippocampal damage can disrupt object naming.
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Affiliation(s)
| | - Melissa C Duff
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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13
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Cognitive effects of theta frequency bilateral subthalamic nucleus stimulation in Parkinson's disease: A pilot study. Brain Stimul 2021; 14:230-240. [PMID: 33418095 DOI: 10.1016/j.brs.2020.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 11/12/2020] [Accepted: 12/28/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND There is significant evidence for cognitive decline following deep brain stimulation (DBS). Current stimulation paradigms utilize gamma frequency stimulation for optimal motor benefits; however, little has been done to optimize stimulation parameters for cognition. Recent evidence implicates subthalamic nucleus (STN) theta oscillations in executive function, and theta oscillations are well-known to relate to episodic memory, suggesting that theta frequency stimulation could potentially improve cognition in Parkinson's disease (PD). OBJECTIVE To evaluate the acute effects of theta frequency bilateral STN stimulation on executive function in PD versus gamma frequency and off, as well as investigate the differential effects on episodic versus nonepisodic verbal fluency. METHODS Twelve patients (all males, mean age 60.8) with bilateral STN DBS for PD underwent a double-blinded, randomized cognitive testing during stimulation at (1) 130-135 Hz (gamma), (2) 10 Hz (theta) and (3) off. Executive functions and processing speed were evaluated using verbal fluency tasks (letter, episodic category, nonepisodic category, and category switching), color-word interference task, and random number generation task. Performance at each stimulation frequency was compared within subjects. RESULTS Theta frequency significantly improved episodic category fluency compared to gamma, but not compared to off. There were no significant differences between stimulation frequencies in other tests. CONCLUSION In this pilot trial, our results corroborate the role of theta oscillations in episodic retrieval, although it is unclear whether this reflects direct modulation of the medial temporal lobe and whether similar effects can be found with more canonical memory paradigms. Further work is necessary to corroborate our findings and investigate the possibility of interleaving theta and gamma frequency stimulation for concomitant motor and cognitive effects.
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14
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Zhang M, Varga D, Wang X, Krieger-Redwood K, Gouws A, Smallwood J, Jefferies E. Knowing what you need to know in advance: The neural processes underpinning flexible semantic retrieval of thematic and taxonomic relations. Neuroimage 2021; 224:117405. [PMID: 32992002 PMCID: PMC7779371 DOI: 10.1016/j.neuroimage.2020.117405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/22/2020] [Accepted: 09/22/2020] [Indexed: 11/26/2022] Open
Abstract
Semantic retrieval is flexible, allowing us to focus on subsets of features and associations that are relevant to the current task or context: for example, we use taxonomic relations to locate items in the supermarket (carrots are a vegetable), but thematic associations to decide which tools we need when cooking (carrot goes with peeler). We used fMRI to investigate the neural basis of this form of semantic flexibility; in particular, we asked how retrieval unfolds differently when participants have advanced knowledge of the type of link to retrieve between concepts (taxonomic or thematic). Participants performed a semantic relatedness judgement task: on half the trials, they were cued to search for a taxonomic or thematic link, while on the remaining trials, they judged relatedness without knowing which type of semantic relationship would be relevant. Left inferior frontal gyrus showed greater activation when participants knew the trial type in advance. An overlapping region showed a stronger response when the semantic relationship between the items was weaker, suggesting this structure supports both top-down and bottom-up forms of semantic control. Multivariate pattern analysis further revealed that the neural response in left inferior frontal gyrus reflects goal information related to different conceptual relationships. Top-down control specifically modulated the response in visual cortex: when the goal was unknown, there was greater deactivation to the first word, and greater activation to the second word. We conclude that top-down control of semantic retrieval is primarily achieved through the gating of task-relevant 'spoke' regions.
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Affiliation(s)
- Meichao Zhang
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD.
| | - Dominika Varga
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | - Xiuyi Wang
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | | | - Andre Gouws
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | - Jonathan Smallwood
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | - Elizabeth Jefferies
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD.
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15
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Duff MC, Covington NV, Hilverman C, Cohen NJ. Semantic Memory and the Hippocampus: Revisiting, Reaffirming, and Extending the Reach of Their Critical Relationship. Front Hum Neurosci 2020; 13:471. [PMID: 32038203 PMCID: PMC6993580 DOI: 10.3389/fnhum.2019.00471] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/23/2019] [Indexed: 11/22/2022] Open
Abstract
Since Tulving proposed a distinction in memory between semantic and episodic memory, considerable effort has been directed towards understanding their similar and unique features. Of particular interest has been the extent to which semantic and episodic memory have a shared dependence on the hippocampus. In contrast to the definitive evidence for the link between hippocampus and episodic memory, the role of the hippocampus in semantic memory has been a topic of considerable debate. This debate stems, in part, from highly variable reports of new semantic memory learning in amnesia ranging from profound impairment to full preservation, and various degrees of deficit and ability in between. More recently, a number of significant advances in experimental methods have occurred, alongside new provocative data on the role of the hippocampus in semantic memory, making this an ideal moment to revisit this debate, to re-evaluate data, methods, and theories, and to synthesize new findings. In line with these advances, this review has two primary goals. First, we provide a historical lens with which to reevaluate and contextualize the literature on semantic memory and the hippocampus. The second goal of this review is to provide a synthesis of new findings on the role of the hippocampus and semantic memory. With the perspective of time and this critical review, we arrive at the interpretation that the hippocampus does indeed make necessary contributions to semantic memory. We argue that semantic memory, like episodic memory, is a highly flexible, (re)constructive, relational and multimodal system, and that there is value in developing methods and materials that fully capture this depth and richness to facilitate comparisons to episodic memory. Such efforts will be critical in addressing questions regarding the cognitive and neural (inter)dependencies among forms of memory, and the role that these forms of memory play in support of cognition more broadly. Such efforts also promise to advance our understanding of how words, concepts, and meaning, as well as episodes and events, are instantiated and maintained in memory and will yield new insights into our two most quintessentially human abilities: memory and language.
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Affiliation(s)
- Melissa C Duff
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Natalie V Covington
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Caitlin Hilverman
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Neal J Cohen
- Department of Psychology, Beckman Institute, University of Illinois, Champaign, IL, United States
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16
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Renoult L, Irish M, Moscovitch M, Rugg MD. From Knowing to Remembering: The Semantic–Episodic Distinction. Trends Cogn Sci 2019; 23:1041-1057. [DOI: 10.1016/j.tics.2019.09.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/09/2019] [Accepted: 09/29/2019] [Indexed: 01/02/2023]
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17
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Cutler RA, Duff MC, Polyn SM. Searching for Semantic Knowledge: A Vector Space Semantic Analysis of the Feature Generation Task. Front Hum Neurosci 2019; 13:341. [PMID: 31680903 PMCID: PMC6797818 DOI: 10.3389/fnhum.2019.00341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/17/2019] [Indexed: 12/15/2022] Open
Abstract
A recent neuropsychological study found that amnesic patients with hippocampal damage (HP) and severe declarative memory impairment produce markedly fewer responses than healthy comparison (CO) participants in a semantic feature generation task (Klooster and Duff, 2015), consistent with the idea that hippocampal damage is associated with semantic cognitive deficits. Participants were presented with a target word and asked to produce as many features of that word as possible (e.g., for target word "book," "read words on a page"). Here, we use the response sequences collected by Klooster and Duff (2015) to develop a vector space model of semantic search. We use this model to characterize the dynamics of semantic feature generation and consider the role of the hippocampus in this search process. Both HP and CO groups tended to initiate the search process with features close in semantic space to the target word, with a gradual decline in similarity to the target word over the first several responses. Adjacent features in the response sequence showed stronger similarity to each other than to non-adjacent features, suggesting that the search process follows a local trajectory in semantic space. Overall, HP patients generated features that were closer in semantic space to the representation of the target word, as compared to the features generated by the CO group, which ranged more widely in semantic space. These results are consistent with a model in which a compound retrieval cue (containing a representation of the target word and a representation of the previous response) is used to probe semantic memory. The model suggests that the HP group's search process is restricted from ranging as far in semantic space from the target word, relative to the CO group. These results place strong constraints on the structure of models of semantic memory search, and on the role of hippocampus in probing semantic memory.
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Affiliation(s)
- Rebecca A. Cutler
- Department of Psychology, Vanderbilt University, Nashville, TN, United States
| | - Melissa C. Duff
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Sean M. Polyn
- Department of Psychology, Vanderbilt University, Nashville, TN, United States
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18
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Yang H, Laforge G, Stojanoski B, Nichols ES, McRae K, Köhler S. Late positive complex in event-related potentials tracks memory signals when they are decision relevant. Sci Rep 2019; 9:9469. [PMID: 31263156 PMCID: PMC6603184 DOI: 10.1038/s41598-019-45880-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 05/16/2019] [Indexed: 11/09/2022] Open
Abstract
The Late Positive Complex (LPC) is an Event-Related Potential (ERP) consistently observed in recognition-memory paradigms. In the present study, we investigated whether the LPC tracks the strength of multiple types of memory signals, and whether it does so in a decision dependent manner. For this purpose, we employed judgements of cumulative lifetime exposure to object concepts, and judgements of cumulative recent exposure (i.e., frequency judgements) in a study-test paradigm. A comparison of ERP signatures in relation to degree of prior exposure across the two memory tasks and the study phase revealed that the LPC tracks both types of memory signals, but only when they are relevant to the decision at hand. Another ERP component previously implicated in recognition memory, the FN400, showed a distinct pattern of activity across conditions that differed from the LPC; it tracked only recent exposure in a decision-dependent manner. Another similar ERP component typically linked to conceptual processing in past work, the N400, was sensitive to degree of recent and lifetime exposure, but it did not track them in a decision dependent manner. Finally, source localization analyses pointed to a potential source of the LPC in left ventral lateral parietal cortex, which also showed the decision-dependent effect. The current findings highlight the role of decision making in ERP markers of prior exposure in tasks other than those typically used in studies of recognition memory, and provides an initial link between the LPC and the previously suggested role of ventral lateral parietal cortex in memory judgements.
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Affiliation(s)
- Haopei Yang
- Brain and Mind Institute, Graduate Program in Neuroscience, London, N6A 3K7, Canada.
| | - Geoffrey Laforge
- Department of Psychology, Brain and Mind Institute, London, N6A 3K7, Canada
| | - Bobby Stojanoski
- Department of Psychology, Brain and Mind Institute, London, N6A 3K7, Canada
| | - Emily S Nichols
- Brain and Mind Institute, Department of Physics, London, N6A 3K7, Canada
| | - Ken McRae
- Department of Psychology, Brain and Mind Institute, London, N6A 3K7, Canada
| | - Stefan Köhler
- Department of Psychology, Brain and Mind Institute, London, N6A 3K7, Canada. .,Rotman Research Institute, Baycrest Centre, Toronto, M6A 2X8, Canada.
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19
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Affiliation(s)
- Felipe De Brigard
- Department of Philosophy, Department of Psychology and Neuroscience, Center for Cognitive Neuroscience, Duke Institute for Brain Sciences, Duke University, Durham, NC, USA
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20
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Weidemann CT, Kragel JE, Lega BC, Worrell GA, Sperling MR, Sharan AD, Jobst BC, Khadjevand F, Davis KA, Wanda PA, Kadel A, Rizzuto DS, Kahana MJ. Neural activity reveals interactions between episodic and semantic memory systems during retrieval. J Exp Psychol Gen 2019; 148:1-12. [PMID: 30596439 DOI: 10.1037/xge0000480] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Whereas numerous findings support a distinction between episodic and semantic memory, it is now widely acknowledged that these two forms of memory interact during both encoding and retrieval. The precise nature of this interaction, however, remains poorly understood. To examine the role of semantic organization during episodic encoding and retrieval, we recorded intracranial encephalographic signals as 69 neurosurgical patients studied and subsequently recalled categorized and unrelated word lists. Applying multivariate classifiers to neural recordings, we were able to reliably predict encoding success, retrieval success, and temporal and categorical clustering during recall. By assessing how these classifiers generalized across list types, we identified specific retrieval processes that predicted recall of categorized lists and distinguished between recall transitions within and between category clusters. These results particularly implicate retrieval (rather than encoding) processes in the categorical organization of episodic memories. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
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Affiliation(s)
| | | | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern
| | | | | | | | | | | | - Kathryn A Davis
- Department of Neurology, Hospital of the University of Pennsylvania
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania
| | - Allison Kadel
- Department of Psychology, University of Pennsylvania
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21
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Elibol-Pekaslan N, Sahin-Acar B. The use of episodic and semantic memory systems in classroom context regarding time delay and college experience level. APPLIED COGNITIVE PSYCHOLOGY 2018. [DOI: 10.1002/acp.3447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Basak Sahin-Acar
- Department of Psychology; Middle East Technical University; Ankara Turkey
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22
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Bartha-Doering L, Novak A, Kollndorfer K, Kasprian G, Schuler AL, Berl MM, Fischmeister FPS, Gaillard WD, Alexopoulos J, Prayer D, Seidl R. When two are better than one: Bilateral mesial temporal lobe contributions associated with better vocabulary skills in children and adolescents. BRAIN AND LANGUAGE 2018; 184:1-10. [PMID: 29913315 PMCID: PMC6192511 DOI: 10.1016/j.bandl.2018.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/14/2018] [Accepted: 06/10/2018] [Indexed: 05/30/2023]
Abstract
This study considered the involvement of the mesial temporal lobe (MTL) in language and verbal memory functions in healthy children and adolescents. We investigated 30 healthy, right-handed children and adolescents, aged 7-16, with a fMRI language paradigm and a comprehensive cognitive test battery. We found significant MTL activations during language fMRI in all participants; 63% of them had left lateralized MTL activations, 20% exhibited right MTL lateralization, and 17% showed bilateral MTL involvement during the fMRI language paradigm. Group analyses demonstrated a strong negative correlation between the lateralization of MTL activations and language functions. Specifically, children with less lateralized MTL activation showed significantly better vocabulary skills. These findings suggest that the mesial temporal lobes of both hemispheres play an important role in language functioning, even in right-handers. Our results furthermore show that bilateral mesial temporal lobe involvement is advantageous for vocabulary skills in healthy, right-handed children and adolescents.
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Affiliation(s)
- Lisa Bartha-Doering
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Astrid Novak
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Kathrin Kollndorfer
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria; Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Gregor Kasprian
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Anna-Lisa Schuler
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Madison M Berl
- Center for Neuroscience and Behavioral Health, Children's National Health System (CNHS), George Washington University School of Medicine, 111 Michigan Avenue, NW, WA, DC 20010, United States.
| | | | - William D Gaillard
- Center for Neuroscience and Behavioral Health, Children's National Health System (CNHS), George Washington University School of Medicine, 111 Michigan Avenue, NW, WA, DC 20010, United States.
| | - Johanna Alexopoulos
- Department of Psychoanalysis and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Daniela Prayer
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Rainer Seidl
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
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23
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Fang J, Rüther N, Bellebaum C, Wiskott L, Cheng S. The Interaction between Semantic Representation and Episodic Memory. Neural Comput 2018; 30:293-332. [DOI: 10.1162/neco_a_01044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The experimental evidence on the interrelation between episodic memory and semantic memory is inconclusive. Are they independent systems, different aspects of a single system, or separate but strongly interacting systems? Here, we propose a computational role for the interaction between the semantic and episodic systems that might help resolve this debate. We hypothesize that episodic memories are represented as sequences of activation patterns. These patterns are the output of a semantic representational network that compresses the high-dimensional sensory input. We show quantitatively that the accuracy of episodic memory crucially depends on the quality of the semantic representation. We compare two types of semantic representations: appropriate representations, which means that the representation is used to store input sequences that are of the same type as those that it was trained on, and inappropriate representations, which means that stored inputs differ from the training data. Retrieval accuracy is higher for appropriate representations because the encoded sequences are less divergent than those encoded with inappropriate representations. Consistent with our model prediction, we found that human subjects remember some aspects of episodes significantly more accurately if they had previously been familiarized with the objects occurring in the episode, as compared to episodes involving unfamiliar objects. We thus conclude that the interaction with the semantic system plays an important role for episodic memory.
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Affiliation(s)
- Jing Fang
- Mercator Research Group “Structure of Memory,” Institute for Neural Computation, and Faculty of Psychology, Ruhr University Bochum, Bochum 44801, Germany
| | - Naima Rüther
- Faculty of Psychology, Ruhr University Bochum, Bochum 44801, Germany
| | - Christian Bellebaum
- Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany
| | - Laurenz Wiskott
- Institute for Neural Computation, Ruhr University Bochum, Bochum 44801, Germany
| | - Sen Cheng
- Mercator Research Group “Structure of Memory” and Institute for Neural Computation, Ruhr University Bochum, Bochum 44801, Germany
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24
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Stickel A, Kawa K, Walther K, Glisky E, Richholt R, Huentelman M, Ryan L. Age-Modulated Associations between KIBRA, Brain Volume, and Verbal Memory among Healthy Older Adults. Front Aging Neurosci 2018; 9:431. [PMID: 29375362 PMCID: PMC5767716 DOI: 10.3389/fnagi.2017.00431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 12/15/2017] [Indexed: 12/15/2022] Open
Abstract
The resource modulation hypothesis suggests that the influence of genes on cognitive functioning increases with age. The KIBRA single nucleotide polymorphism rs17070145, associated with episodic memory and working memory, has been suggested to follow such a pattern, but few studies have tested this assertion directly. The present study investigated the relationship between KIBRA alleles (T carriers vs. CC homozygotes), cognitive performance, and brain volumes in three groups of cognitively healthy adults-middle aged (ages 52-64, n = 38), young old (ages 65-72, n = 45), and older old (ages 73-92, n = 62)-who were carefully matched on potentially confounding variables including apolipoprotein ε4 status and hypertension. Consistent with our prediction, T carriers maintained verbal memory performance with increasing age while CC homozygotes declined. Voxel-based morphometric analysis of magnetic resonance images showed an advantage for T carriers in frontal white matter volume that increased with age. Focusing on the older old group, this advantage for T carriers was also evident in left lingual gyrus gray matter and several additional frontal white matter regions. Contrary to expectations, neither KIBRA nor the interaction between KIBRA and age predicted hippocampal volumes. None of the brain regions investigated showed a CC homozygote advantage. Taken together, these data suggest that KIBRA results in decreased verbal memory performance and lower brain volumes in CC homozygotes compared to T carriers, particularly among the oldest old, consistent with the resource modulation hypothesis.
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Affiliation(s)
- Ariana Stickel
- Cognition and Neuroimaging Laboratory, Department of Psychology, University of Arizona, Tucson, AZ, United States
| | - Kevin Kawa
- Cognition and Neuroimaging Laboratory, Department of Psychology, University of Arizona, Tucson, AZ, United States
| | - Katrin Walther
- Epilepsy Center Erlangen, Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | - Elizabeth Glisky
- Aging and Cognition Laboratory, Department of Psychology, University of Arizona, Tucson, AZ, United States
| | - Ryan Richholt
- Neurogenomics Division, The Translational Genomics Research Institute, Phoenix, AZ, United States
| | - Matt Huentelman
- Neurogenomics Division, The Translational Genomics Research Institute, Phoenix, AZ, United States
| | - Lee Ryan
- Cognition and Neuroimaging Laboratory, Department of Psychology, University of Arizona, Tucson, AZ, United States
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25
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Verbal and Figural Fluency in Temporal Lobe Epilepsy: Does Hippocampal Sclerosis Affect Performance? Cogn Behav Neurol 2017. [PMID: 28632521 DOI: 10.1097/wnn.0000000000000123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES Clinicians commonly use verbal and nonverbal measures to test fluency in patients with epilepsy, either during routine cognitive assessment or as part of pre- and postsurgical evaluation. We hypothesized that patients with mesial temporal lobe epilepsy (TLE) with hippocampal sclerosis would perform worse than patients with lateral TLE in both verbal and design fluency. METHODS We assessed semantic, phonemic, and nonverbal fluency in 49 patients with TLE: 31 with lateral TLE and 18 with mesial TLE plus hippocampal sclerosis. We also gave non-fluency cognitive measures: psychomotor speed, attentional set shifting, selective attention, abstract reasoning, verbal and visual episodic memory, and incidental memory. RESULTS Patients with mesial TLE performed significantly worse on figural fluency than patients with lateral TLE. Even though group differences on verbal fluency measures were not significant, the patients with mesial TLE had a pattern of poorer performance. The patients with mesial TLE scored significantly worse on measures of selective attention, verbal episodic memory, and incidental memory. CONCLUSIONS Our study underlines differences in cognitive function between patients with mesial and lateral TLE, particularly in figural fluency. Although we cannot directly assess the role of the hippocampus in cognitive aspects of creative and divergent thinking related to figural fluency, the cognitive discrepancies between these two TLE groups could be ascribed to the mesial TLE hippocampal pathology shown in our study and addressed in the literature on hippocampal involvement in divergent thinking. Our findings could benefit cognitive rehabilitation programs tailored to the needs of patients with TLE.
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26
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Pelletier A, Bernard C, Dilharreguy B, Helmer C, Le Goff M, Chanraud S, Dartigues JF, Allard M, Amieva H, Catheline G. Patterns of brain atrophy associated with episodic memory and semantic fluency decline in aging. Aging (Albany NY) 2017; 9:741-752. [PMID: 28278492 PMCID: PMC5391228 DOI: 10.18632/aging.101186] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 02/21/2017] [Indexed: 12/31/2022]
Abstract
The cerebral substratum of age-related cognitive decline was evaluated in an elderly-cohort followed for 12 years (n=306). Participants, free of dementia, received neuropsychological assessments every two years and an MRI exam at baseline and four years later. Cognitive decline was evaluated on two broadly used tests to detect dementia: the Free and Cued Selective Reminding Test (FCSRT), a verbal episodic memory task, and the Isaacs Set Test (IST), a semantic fluency task. Using voxel-based approach, the relationship between cognitive decline with 1/ baseline grey matter volumes and 2/ grey matter volume loss between the two scans was explored. Baseline volumes analysis revealed that FCSRT and IST declines were both associated with lower volumes of the medial temporal region. Volumes loss analysis confirmed that both declines are related to medial temporal lobe atrophy and revealed that FCSRT decline was specifically associated with atrophy of the posterior cingulate cortex whereas IST decline was specifically related to temporal pole atrophy. These results suggest that cognitive decline across aging is firstly related to structural modifications of the medial temporal lobe, followed by an atrophy in the posterior midline structures for episodic memory and an atrophy of the temporal pole for semantic fluency.
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Affiliation(s)
- Amandine Pelletier
- University Bordeaux, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France.,INSERM, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France
| | - Charlotte Bernard
- University Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France.,CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France
| | - Bixente Dilharreguy
- University Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France.,CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France
| | - Catherine Helmer
- University Bordeaux, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France.,INSERM, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France
| | - Melanie Le Goff
- University Bordeaux, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France.,INSERM, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France
| | - Sandra Chanraud
- University Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France.,CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France.,EPHE, PSL Research University, F-33000 Bordeaux, France
| | - Jean-François Dartigues
- University Bordeaux, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France.,INSERM, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France
| | - Michèle Allard
- University Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France.,CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France.,EPHE, PSL Research University, F-33000 Bordeaux, France.,CHU de Bordeaux, F-33000 Bordeaux, France
| | - Hélène Amieva
- University Bordeaux, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France.,INSERM, ISPED, Centre INSERM U1219, F-33000 Bordeaux, France
| | - Gwénaëlle Catheline
- University Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France.,CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France.,EPHE, PSL Research University, F-33000 Bordeaux, France
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27
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Abstract
An important theory holds that semantic knowledge can develop independently of episodic memory. One strong source of evidence supporting this independence comes from the observation that individuals with early hippocampal damage leading to developmental amnesia generally perform normally on standard tests of semantic memory, despite their profound impairment in episodic memory. However, one aspect of semantic memory that has not been explored is conceptual structure. We built on the theoretically important distinction between intrinsic features of object concepts (e.g., shape, colour, parts) and extrinsic features (e.g., how something is used, where it is typically located). The accrual of extrinsic feature knowledge that is important for concepts such as chair or spoon may depend on binding mechanisms in the hippocampus. We tested HC, an individual with developmental amnesia due to a well-characterized lesion of the hippocampus, on her ability to generate semantic features for object concepts. HC generated fewer extrinsic features than controls, but a similar number of intrinsic features than controls. We also tested her on typicality ratings. Her typicality ratings were abnormal for nonliving things (which more strongly depend on extrinsic features), but normal for living things (which more strongly depend on intrinsic features). In contrast, NB, who has MTL but not hippocampal damage due to surgery, showed no impairments in either task. These results suggest that episodic and semantic memory are not entirely independent, and that the hippocampus is important for learning some aspects of conceptual knowledge.
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Nikolai T, Bezdicek O, Markova H, Stepankova H, Michalec J, Kopecek M, Dokoupilova M, Hort J, Vyhnalek M. Semantic verbal fluency impairment is detectable in patients with subjective cognitive decline. APPLIED NEUROPSYCHOLOGY-ADULT 2017; 25:448-457. [PMID: 28548549 DOI: 10.1080/23279095.2017.1326047] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Patients with subjective cognitive decline (SCD) are at higher risk for conversion to dementia due to Alzheimer's disease (AD). Semantic verbal fluency (SVF) seems to be impaired in the early stages of AD. The goal of the present study was to identify the discriminative potential of verbal fluency (VF) in patients with SCD to show if very early signs of cognitive decline may be detected in SCD. We examined 93 normal controls (NC) and 61 participants with SCD. Each participant was administered a comprehensive neuropsychological battery. All participants underwent tests of VF: phonemic verbal fluency (PVF), letters K and P and SVF (animals and vegetables categories). In addition to the total score, two 30-second intervals, and clustering and switching indices in SVF were evaluated. SCD generated fewer words in the total score and 30- to 60-second interval in vegetables category and they performed more switches in animals category. There was no significant difference between the SCD and the NC groups in all other VF measures. Quantitative measures of SVF (a decreased number of vegetables) as well as qualitative measures were detected in SCD group and could be considered as an early neuropsychological marker of subtle cognitive impairment.
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Affiliation(s)
- Tomas Nikolai
- a Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine and General University Hospital in Prague , Charles University , Prague , Czech Republic.,b International Clinical Research Center , St. Anne's University Hospital Brno , Brno , Czech Republic.,d Memory Disorders Clinic, Department of Neurology, 2nd Faculty of Medicine , Charles University and Motol University Hospital , Prague , Czech Republic
| | - Ondrej Bezdicek
- a Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine and General University Hospital in Prague , Charles University , Prague , Czech Republic.,c National Institute of Mental Health , Klecany , Czech Republic
| | - Hana Markova
- b International Clinical Research Center , St. Anne's University Hospital Brno , Brno , Czech Republic.,d Memory Disorders Clinic, Department of Neurology, 2nd Faculty of Medicine , Charles University and Motol University Hospital , Prague , Czech Republic
| | - Hana Stepankova
- c National Institute of Mental Health , Klecany , Czech Republic
| | - Jiri Michalec
- e Department of Psychiatry, First Faculty of Medicine , Charles University, and General University Hospital , Prague , Czech Republic
| | - Miloslav Kopecek
- c National Institute of Mental Health , Klecany , Czech Republic
| | - Monika Dokoupilova
- a Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine and General University Hospital in Prague , Charles University , Prague , Czech Republic.,d Memory Disorders Clinic, Department of Neurology, 2nd Faculty of Medicine , Charles University and Motol University Hospital , Prague , Czech Republic
| | - Jakub Hort
- b International Clinical Research Center , St. Anne's University Hospital Brno , Brno , Czech Republic.,d Memory Disorders Clinic, Department of Neurology, 2nd Faculty of Medicine , Charles University and Motol University Hospital , Prague , Czech Republic
| | - Martin Vyhnalek
- b International Clinical Research Center , St. Anne's University Hospital Brno , Brno , Czech Republic.,d Memory Disorders Clinic, Department of Neurology, 2nd Faculty of Medicine , Charles University and Motol University Hospital , Prague , Czech Republic
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29
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Sormaz M, Jefferies E, Bernhardt BC, Karapanagiotidis T, Mollo G, Bernasconi N, Bernasconi A, Hartley T, Smallwood J. Knowing what from where: Hippocampal connectivity with temporoparietal cortex at rest is linked to individual differences in semantic and topographic memory. Neuroimage 2017; 152:400-410. [DOI: 10.1016/j.neuroimage.2017.02.071] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 02/10/2017] [Accepted: 02/24/2017] [Indexed: 01/20/2023] Open
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30
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Mollo G, Karapanagiotidis T, Bernhardt BC, Murphy CE, Smallwood J, Jefferies E. An individual differences analysis of the neurocognitive architecture of the semantic system at rest. Brain Cogn 2016; 109:112-123. [PMID: 27662589 PMCID: PMC5090046 DOI: 10.1016/j.bandc.2016.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 02/08/2023]
Abstract
Efficient semantic cognition depends on accessing and selecting conceptual knowledge relevant to the current task or context. This study explored the neurocognitive architecture that supports this function by examining how individual variation in functional brain organisation predicts comprehension and semantic generation. Participants underwent resting state functional magnetic resonance imaging (fMRI) and, on separate days, performed written synonym judgement, and letter and category fluency tasks. We found that better synonym judgement for high frequency items was linked to greater functional coupling between posterior fusiform and anterior superior temporal cortex (aSTG), which might index orthographic-to-semantic access. However, stronger coupling between aSTG and ventromedial prefrontal cortex was associated with poor performance on the same trials, potentially reflecting greater difficulty in focussing retrieval on relevant features for high frequency items that appear in a greater range of contexts. Fluency performance was instead linked to variations in the functional coupling of the inferior frontal gyrus (IFG); anterior IFG was more coupled to regions of primary visual cortex for individuals who were good at category fluency, while poor letter fluency was predicted by stronger coupling between posterior IFG and retrosplenial cortex. These results show that individual differences in functional connectivity at rest predict semantic performance and are consistent with a component process account of semantic cognition in which representational information is shaped by control processes to fit the current requirements, in both comprehension and fluency tasks.
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Affiliation(s)
- Giovanna Mollo
- Department of Psychology and York Neuroimaging Centre, University of York, Heslington, York, United Kingdom.
| | - Theodoros Karapanagiotidis
- Department of Psychology and York Neuroimaging Centre, University of York, Heslington, York, United Kingdom
| | - Boris C Bernhardt
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Charlotte E Murphy
- Department of Psychology and York Neuroimaging Centre, University of York, Heslington, York, United Kingdom
| | - Jonathan Smallwood
- Department of Psychology and York Neuroimaging Centre, University of York, Heslington, York, United Kingdom
| | - Elizabeth Jefferies
- Department of Psychology and York Neuroimaging Centre, University of York, Heslington, York, United Kingdom
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31
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Dissociating patterns of anterior and posterior hippocampal activity and connectivity during distinct forms of category fluency. Neuropsychologia 2016; 90:148-58. [DOI: 10.1016/j.neuropsychologia.2016.06.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 05/25/2016] [Accepted: 06/22/2016] [Indexed: 01/13/2023]
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32
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Shapira-Lichter I, Klovatch I, Nathan D, Oren N, Hendler T. Task-specific Aspects of Goal-directed Word Generation Identified via Simultaneous EEG–fMRI. J Cogn Neurosci 2016; 28:1406-18. [DOI: 10.1162/jocn_a_00976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
Generating words according to a given rule relies on retrieval-related search and postretrieval control processes. Using fMRI, we recently characterized neural patterns of word generation in response to episodic, semantic, and phonemic cues by comparing free recall of wordlists, category fluency, and letter fluency [Shapira-Lichter, I., Oren, N., Jacob, Y., Gruberger, M., & Hendler, T. Portraying the unique contribution of the default mode network to internally driven mnemonic processes. Proceedings of the National Academy of Sciences, U.S.A., 110, 4950–4955, 2013]. Distinct selectivity for each condition was evident, representing discrete aspects of word generation-related memory retrieval. For example, the precuneus, implicated in processing spatiotemporal information, emerged as a key contributor to the episodic condition, which uniquely requires this information. Gamma band is known to play a central role in memory, and increased gamma power has been observed before word generation. Yet, gamma modulation in response to task demands has not been investigated. To capture the task-specific modulation of gamma power, we analyzed the EEG data recorded simultaneously with the aforementioned fMRI, focusing on the activity locked to and immediately preceding word articulation. Transient increases in gamma power were identified in a parietal electrode immediately before episodic and semantic word generation, however, within a different time frame relative to articulation. Gamma increases were followed by an alpha-theta decrease in the episodic condition, a gamma decrease in the semantic condition. This pattern indicates a task-specific modulation of the gamma signal corresponding to the specific demands of each word generation task. The gamma power and fMRI signal from the precuneus were correlated during the episodic condition, implying the existence of a common cognitive construct uniquely required for this task, possibly the reactivation or processing of spatiotemporal information.
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Affiliation(s)
| | | | | | - Noga Oren
- 1Tel-Aviv Sourasky Medical Center
- 2Tel-Aviv University
| | - Talma Hendler
- 1Tel-Aviv Sourasky Medical Center
- 2Tel-Aviv University
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33
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Bowles B, Duke D, Rosenbaum RS, McRae K, Köhler S. Impaired assessment of cumulative lifetime familiarity for object concepts after left anterior temporal-lobe resection that includes perirhinal cortex but spares the hippocampus. Neuropsychologia 2016; 90:170-9. [DOI: 10.1016/j.neuropsychologia.2016.06.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 05/16/2016] [Accepted: 06/28/2016] [Indexed: 01/01/2023]
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34
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Bonnici HM, Richter FR, Yazar Y, Simons JS. Multimodal Feature Integration in the Angular Gyrus during Episodic and Semantic Retrieval. J Neurosci 2016; 36:5462-71. [PMID: 27194327 PMCID: PMC4871983 DOI: 10.1523/jneurosci.4310-15.2016] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/09/2016] [Accepted: 03/29/2016] [Indexed: 01/26/2023] Open
Abstract
UNLABELLED Much evidence from distinct lines of investigation indicates the involvement of angular gyrus (AnG) in the retrieval of both episodic and semantic information, but the region's precise function and whether that function differs across episodic and semantic retrieval have yet to be determined. We used univariate and multivariate fMRI analysis methods to examine the role of AnG in multimodal feature integration during episodic and semantic retrieval. Human participants completed episodic and semantic memory tasks involving unimodal (auditory or visual) and multimodal (audio-visual) stimuli. Univariate analyses revealed the recruitment of functionally distinct AnG subregions during the retrieval of episodic and semantic information. Consistent with a role in multimodal feature integration during episodic retrieval, significantly greater AnG activity was observed during retrieval of integrated multimodal episodic memories compared with unimodal episodic memories. Multivariate classification analyses revealed that individual multimodal episodic memories could be differentiated in AnG, with classification accuracy tracking the vividness of participants' reported recollections, whereas distinct unimodal memories were represented in sensory association areas only. In contrast to episodic retrieval, AnG was engaged to a statistically equivalent degree during retrieval of unimodal and multimodal semantic memories, suggesting a distinct role for AnG during semantic retrieval. Modality-specific sensory association areas exhibited corresponding activity during both episodic and semantic retrieval, which mirrored the functional specialization of these regions during perception. The results offer new insights into the integrative processes subserved by AnG and its contribution to our subjective experience of remembering. SIGNIFICANCE STATEMENT Using univariate and multivariate fMRI analyses, we provide evidence that functionally distinct subregions of angular gyrus (AnG) contribute to the retrieval of episodic and semantic memories. Our multivariate pattern classifier could distinguish episodic memory representations in AnG according to whether they were multimodal (audio-visual) or unimodal (auditory or visual) in nature, whereas statistically equivalent AnG activity was observed during retrieval of unimodal and multimodal semantic memories. Classification accuracy during episodic retrieval scaled with the trial-by-trial vividness with which participants experienced their recollections. Therefore, the findings offer new insights into the integrative processes subserved by AnG and how its function may contribute to our subjective experience of remembering.
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Affiliation(s)
- Heidi M Bonnici
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Franziska R Richter
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Yasemin Yazar
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Jon S Simons
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
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35
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Li M, Liu J, Tsien JZ. Theory of Connectivity: Nature and Nurture of Cell Assemblies and Cognitive Computation. Front Neural Circuits 2016; 10:34. [PMID: 27199674 PMCID: PMC4850152 DOI: 10.3389/fncir.2016.00034] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/11/2016] [Indexed: 11/25/2022] Open
Abstract
Richard Semon and Donald Hebb are among the firsts to put forth the notion of cell assembly—a group of coherently or sequentially-activated neurons—to represent percept, memory, or concept. Despite the rekindled interest in this century-old idea, the concept of cell assembly still remains ill-defined and its operational principle is poorly understood. What is the size of a cell assembly? How should a cell assembly be organized? What is the computational logic underlying Hebbian cell assemblies? How might Nature vs. Nurture interact at the level of a cell assembly? In contrast to the widely assumed randomness within the mature but naïve cell assembly, the Theory of Connectivity postulates that the brain consists of the developmentally pre-programmed cell assemblies known as the functional connectivity motif (FCM). Principal cells within such FCM is organized by the power-of-two-based mathematical principle that guides the construction of specific-to-general combinatorial connectivity patterns in neuronal circuits, giving rise to a full range of specific features, various relational patterns, and generalized knowledge. This pre-configured canonical computation is predicted to be evolutionarily conserved across many circuits, ranging from these encoding memory engrams and imagination to decision-making and motor control. Although the power-of-two-based wiring and computational logic places a mathematical boundary on an individual’s cognitive capacity, the fullest intellectual potential can be brought about by optimized nature and nurture. This theory may also open up a new avenue to examining how genetic mutations and various drugs might impair or improve the computational logic of brain circuits.
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Affiliation(s)
- Meng Li
- Brain and Behavior Discovery Institute and Department of Neurology, Medical College of Georgia at Augusta UniversityAugusta, GA, USA; The Brain Decoding Center, Banna Biomedical Research Institute, Yunnan Academy of Science and TechnologyYunnan, China
| | - Jun Liu
- Brain and Behavior Discovery Institute and Department of Neurology, Medical College of Georgia at Augusta University Augusta, GA, USA
| | - Joe Z Tsien
- Brain and Behavior Discovery Institute and Department of Neurology, Medical College of Georgia at Augusta University Augusta, GA, USA
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36
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Neuroplastic Response After Radiation Therapy for Pediatric Brain Tumors: A Pilot Study. Int J Radiat Oncol Biol Phys 2016; 95:991-998. [PMID: 27302514 DOI: 10.1016/j.ijrobp.2016.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 12/03/2015] [Accepted: 01/07/2016] [Indexed: 11/23/2022]
Abstract
PURPOSE Clinically effective measurement of cognitive toxicity from photon radiation therapy (XRT) should be accurate, sensitive, and specific. This pilot study tested translational findings on phasic changes in children's memory systems that are sensitive and insensitive to toxic XRT effects to identify a possible neuroplastic effect. METHODS AND MATERIALS Memory processes were prospectively tested before XRT and at 3 later time points up to 2 years in 35 children with mixed primary brain tumors who had not experienced recurrence. Memory processes were verbal-semantic, visual-semantic, and visual-perceptual, including accuracy, speed to recall, encoding, retrieval, and recognition. The mixed-effects model included time (to estimate slope), covariates (age, tumor locus, XRT field, and medications) as fixed effects, and individual random intercepts. A sensitivity analysis examined the influence of XRT dose to the hippocampi on memory. RESULTS Retrieval from long-term verbal-semantic memory declined 2 months after completing XRT, as seen in adults, and was lowest at 1 year, which was delayed in comparison with adults. Double dissociation from visual-perceptual memory at baseline and 2 months was found, consistent with adults. Recovery was demonstrated 2 years after XRT. Patterns were unchanged when dose to hippocampus was included in the model. CONCLUSIONS Verbal and semantic long-term retrieval is specifically sensitive to XRT-related cognitive dysfunction, without effect on visual-perceptual memory. Children reached nadir in XRT-sensitive memory 1 year after XRT and recovered by 2 years, which is later than that observed in adults. The protracted period of post-XRT injury may represent the maturation of the human hippocampus and white matter into late adolescence.
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37
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Default network activation during episodic and semantic memory retrieval: A selective meta-analytic comparison. Neuropsychologia 2016; 80:35-46. [DOI: 10.1016/j.neuropsychologia.2015.11.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 11/07/2015] [Accepted: 11/09/2015] [Indexed: 11/21/2022]
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38
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Harrison TM, Burggren AC, Small GW, Bookheimer SY. Altered memory-related functional connectivity of the anterior and posterior hippocampus in older adults at increased genetic risk for Alzheimer's disease. Hum Brain Mapp 2015; 37:366-80. [PMID: 26503161 DOI: 10.1002/hbm.23036] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 12/24/2022] Open
Abstract
The hippocampal complex is affected early in Alzheimer's disease (AD). Increasingly, altered functional connectivity of the hippocampus is recognized as an important feature of preclinical AD. Carriers of the APOEɛ4 allele are at an increased risk for AD, which could lead to altered hippocampal connectivity even in healthy older adults. To test this hypothesis, we used a paired-associates memory task to examine differences in task-dependent functional connectivity of the anterior and posterior hippocampus in nondemented APOEɛ4 carriers (n = 34, 18F) and noncarriers (n = 46, 31F). We examined anterior and posterior portions of the hippocampus separately to test the theory that APOEɛ4-mediated differences would be more pronounced in the anterior region, which is affected earlier in the AD course. This study is the first to use a psychophysiological interaction approach to query the context-dependent connectivity of subregions of the hippocampus during a memory task in adults at increased genetic risk for AD. During encoding, APOEɛ4 carriers had lower functional connectivity change compared to baseline between the anterior hippocampus and right precuneus, anterior insula and cingulate cortex. During retrieval, bilateral supramarginal gyrus and right precuneus showed lower functional connectivity change with anterior hippocampus in carriers. Also during retrieval, carriers showed lower connectivity change in the posterior hippocampus with auditory cortex. In each case, APOEɛ4 carriers showed strong negative connectivity changes compared to noncarriers where positive connectivity change was measured. These differences may represent prodromal functional changes mediated in part by APOEɛ4 and are consistent with the anterior-to-posterior theory of AD progression in the hippocampus.
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Affiliation(s)
- Theresa M Harrison
- Neuroscience Interdepartmental Graduate Program, UCLA, Los Angeles, California.,Department of Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, California
| | - Alison C Burggren
- Department of Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, California
| | - Gary W Small
- Department of Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, California.,Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, California
| | - Susan Y Bookheimer
- Department of Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, California.,Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, California.,Center for Cognitive Neuroscience, UCLA, Los Angeles, California
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39
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Remote semantic memory is impoverished in hippocampal amnesia. Neuropsychologia 2015; 79:42-52. [PMID: 26474741 DOI: 10.1016/j.neuropsychologia.2015.10.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/09/2015] [Accepted: 10/10/2015] [Indexed: 01/24/2023]
Abstract
The necessity of the hippocampus for acquiring new semantic concepts is a topic of considerable debate. However, it is generally accepted that any role the hippocampus plays in semantic memory is time limited and that previously acquired information becomes independent of the hippocampus over time. This view, along with intact naming and word-definition matching performance in amnesia, has led to the notion that remote semantic memory is intact in patients with hippocampal amnesia. Motivated by perspectives of word learning as a protracted process where additional features and senses of a word are added over time, and by recent discoveries about the time course of hippocampal contributions to on-line relational processing, reconsolidation, and the flexible integration of information, we revisit the notion that remote semantic memory is intact in amnesia. Using measures of semantic richness and vocabulary depth from psycholinguistics and first and second language-learning studies, we examined how much information is associated with previously acquired, highly familiar words in a group of patients with bilateral hippocampal damage and amnesia. Relative to healthy demographically matched comparison participants and a group of brain-damaged comparison participants, the patients with hippocampal amnesia performed significantly worse on both productive and receptive measures of vocabulary depth and semantic richness. These findings suggest that remote semantic memory is impoverished in patients with hippocampal amnesia and that the hippocampus may play a role in the maintenance and updating of semantic memory beyond its initial acquisition.
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40
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Autobiographical Memory Disturbances in Depression: A Novel Therapeutic Target? Neural Plast 2015; 2015:759139. [PMID: 26380121 PMCID: PMC4561987 DOI: 10.1155/2015/759139] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 04/30/2015] [Indexed: 11/23/2022] Open
Abstract
Major depressive disorder (MDD) is characterized by a dysfunctional processing of autobiographical memories. We review the following core domains of deficit: systematic biases favoring materials of negative emotional valence; diminished access and response to positive memories; a recollection of overgeneral memories in detriment of specific autobiographical memories; and the role of ruminative processes and avoidance when dealing with autobiographical memories. Furthermore, we review evidence from functional neuroimaging studies of neural circuits activated by the recollection of autobiographical memories in both healthy and depressive individuals. Disruptions in autobiographical memories predispose and portend onset and maintenance of depression. Thus, we discuss emerging therapeutics that target memory difficulties in those with depression. We review strategies for this clinical domain, including memory specificity training, method-of-loci, memory rescripting, and real-time fMRI neurofeedback training of amygdala activity in depression. We propose that the manipulation of the reconsolidation of autobiographical memories in depression might represent a novel yet largely unexplored, domain-specific, therapeutic opportunity for depression treatment.
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Persson J, Söderlund H. Hippocampal hemispheric and long-axis differentiation of stimulus content during episodic memory encoding and retrieval: An activation likelihood estimation meta-analysis. Hippocampus 2015; 25:1614-31. [DOI: 10.1002/hipo.22482] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 06/18/2015] [Accepted: 06/22/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Jonas Persson
- Department of Psychology; Uppsala University; Uppsala Sweden
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Lamb YN, Thompson CS, McKay NS, Waldie KE, Kirk IJ. The brain-derived neurotrophic factor (BDNF) val66met polymorphism differentially affects performance on subscales of the Wechsler Memory Scale - Third Edition (WMS-III). Front Psychol 2015; 6:1212. [PMID: 26347681 PMCID: PMC4538220 DOI: 10.3389/fpsyg.2015.01212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/30/2015] [Indexed: 01/02/2023] Open
Abstract
Single nucleotide polymorphisms in the brain-derived neurotrophic factor (BDNF) gene and the catechol-O-methyltransferase (COMT) gene influence brain structure and function, as well as cognitive abilities. They are most influential in the hippocampus and prefrontal cortex (PFC), respectively. Recall and recognition are forms of memory proposed to have different neural substrates, with recall having a greater dependence on the PFC and hippocampus. This study aimed to determine whether the BDNF val66met or COMT val158met polymorphisms differentially affect recall and recognition, and whether these polymorphisms interact. A sample of 100 healthy adults was assessed on recall and familiarity-based recognition using the Faces and Family Pictures subscales of the Wechsler Memory Scale – Third Edition (WMS-III). COMT genotype did not affect performance on either task. The BDNF polymorphism (i.e., met carriers relative to val homozygotes) was associated with poorer recall ability, while not influencing recognition. Combining subscale scores in memory tests such as the WMS might obscure gene effects. Our results demonstrate the importance of distinguishing between recall and familiarity-based recognition in neurogenetics research.
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Affiliation(s)
- Yvette N Lamb
- School of Psychology, Faculty of Science, The University of Auckland, Auckland New Zealand
| | - Christopher S Thompson
- School of Psychology, Faculty of Science, The University of Auckland, Auckland New Zealand
| | - Nicole S McKay
- School of Psychology, Faculty of Science, The University of Auckland, Auckland New Zealand
| | - Karen E Waldie
- School of Psychology, Faculty of Science, The University of Auckland, Auckland New Zealand
| | - Ian J Kirk
- School of Psychology, Faculty of Science, The University of Auckland, Auckland New Zealand
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43
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Semantic Processing Impairment in Patients with Temporal Lobe Epilepsy. EPILEPSY RESEARCH AND TREATMENT 2015; 2015:746745. [PMID: 26257956 PMCID: PMC4519536 DOI: 10.1155/2015/746745] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/02/2015] [Indexed: 11/17/2022]
Abstract
The impairment in episodic memory system is the best-known cognitive deficit in patients with temporal lobe epilepsy (TLE). Recent studies have shown evidence of semantic disorders, but they have been less studied than episodic memory. The semantic dysfunction in TLE has various cognitive manifestations, such as the presence of language disorders characterized by defects in naming, verbal fluency, or remote semantic information retrieval, which affects the ability of patients to interact with their surroundings. This paper is a review of recent research about the consequences of TLE on semantic processing, considering neuropsychological, electrophysiological, and neuroimaging findings, as well as the functional role of the hippocampus in semantic processing. The evidence from these studies shows disturbance of semantic memory in patients with TLE and supports the theory of declarative memory of the hippocampus. Functional neuroimaging studies show an inefficient compensatory functional reorganization of semantic networks and electrophysiological studies show a lack of N400 effect that could indicate that the deficit in semantic processing in patients with TLE could be due to a failure in the mechanisms of automatic access to lexicon.
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44
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Catheline G, Amieva H, Dilharreguy B, Bernard C, Duperron MG, Helmer C, Dartigues JF, Allard M. Semantic retrieval over time in the aging brain: Structural evidence of hippocampal contribution. Hippocampus 2015; 25:1008-16. [PMID: 25614980 DOI: 10.1002/hipo.22423] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2015] [Indexed: 01/15/2023]
Abstract
This study investigates relationship between regional cerebral volumes and performances over time of a categorical fluency task, in a sample of older adults (n = 316). Using voxel-wise technique, the relationship between local grey matter volume and Isaacs Set Test (IST) scores at its early (first 15 sec) and late (last 15 sec) phase production was analyzed with a linear regression model adjusting for age, sex, educational level, ApoEɛ4 allele, handedness and Grey Matter atrophy. Lower early IST scores were associated with smaller volumes in bilateral inferior frontal gyri and in right thalamus, whereas lower late IST scores were associated to smaller left inferior parietal gyrus and left anterior hippocampus. An analysis based on automatic segmentation of hippocampus confirmed the latest relationship which cannot be attributed to the correlation of each variable with global cognitive impairment because it remained when MMSE was accounted for. We observed a switch from frontal to temporo-parietal regions as words retrieval become more difficult over time. Automatic speech production of the early phase of the category fluency task is dependent on executive networks integrity whereas controlled speech production of the late phase is dependent on memory networks integrity, including left hippocampus. These results are concordant with recent imaging studies expanding the implication of hippocampus to semantic memory performances and they underlie the need to consider verbal fluency task over time.
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Affiliation(s)
- Gwénaëlle Catheline
- Univ. Bordeaux, INCIA, UMR 5287, Talence, France.,CNRS, INCIA, UMR 5287, Talence, France.,EPHE, Paris, France
| | - Hélène Amieva
- ISPED, Université de Bordeaux, Bordeaux, France.,Centre de Recherche Inserm U897, Bordeaux, France
| | - Bixente Dilharreguy
- Univ. Bordeaux, INCIA, UMR 5287, Talence, France.,CNRS, INCIA, UMR 5287, Talence, France
| | | | | | - Catherine Helmer
- ISPED, Université de Bordeaux, Bordeaux, France.,Centre de Recherche Inserm U897, Bordeaux, France
| | - Jean-François Dartigues
- ISPED, Université de Bordeaux, Bordeaux, France.,Centre de Recherche Inserm U897, Bordeaux, France
| | - Michèle Allard
- Univ. Bordeaux, INCIA, UMR 5287, Talence, France.,CNRS, INCIA, UMR 5287, Talence, France.,EPHE, Paris, France.,Chu de Bordeaux, France
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45
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Lau JKL, Humphreys GW, Douis H, Balani A, Bickerton WL, Rotshtein P. The relation of object naming and other visual speech production tasks: a large scale voxel-based morphometric study. Neuroimage Clin 2015; 7:463-75. [PMID: 25685713 PMCID: PMC4325087 DOI: 10.1016/j.nicl.2015.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 01/21/2015] [Accepted: 01/23/2015] [Indexed: 01/09/2023]
Abstract
We report a lesion-symptom mapping analysis of visual speech production deficits in a large group (280) of stroke patients at the sub-acute stage (<120 days post-stroke). Performance on object naming was evaluated alongside three other tests of visual speech production, namely sentence production to a picture, sentence reading and nonword reading. A principal component analysis was performed on all these tests' scores and revealed a 'shared' component that loaded across all the visual speech production tasks and a 'unique' component that isolated object naming from the other three tasks. Regions for the shared component were observed in the left fronto-temporal cortices, fusiform gyrus and bilateral visual cortices. Lesions in these regions linked to both poor object naming and impairment in general visual-speech production. On the other hand, the unique naming component was potentially associated with the bilateral anterior temporal poles, hippocampus and cerebellar areas. This is in line with the models proposing that object naming relies on a left-lateralised language dominant system that interacts with a bilateral anterior temporal network. Neuropsychological deficits in object naming can reflect both the increased demands specific to the task and the more general difficulties in language processing.
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Affiliation(s)
| | - Glyn W. Humphreys
- School of Psychology, University of Birmingham, Birmingham, UK
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Hassan Douis
- School of Psychology, University of Birmingham, Birmingham, UK
- Department of Radiology, Royal Orthopaedic Hospital, Birmingham, UK
| | - Alex Balani
- School of Psychology, University of Birmingham, Birmingham, UK
- Department of Psychology, Edge Hill University, Lancashire, UK
| | | | - Pia Rotshtein
- School of Psychology, University of Birmingham, Birmingham, UK
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46
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Distinct functional connectivity of the hippocampus during semantic and phonemic fluency. Neuropsychologia 2015; 69:39-49. [PMID: 25619848 DOI: 10.1016/j.neuropsychologia.2015.01.031] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/21/2014] [Accepted: 01/21/2015] [Indexed: 01/12/2023]
Abstract
Verbal fluency tasks are typically used in neuropsychological practice for assessment of language function in a variety of neurological disorders. Recently, it has been shown that the hippocampus, a region thought to be exclusive to the domain of memory, is also involved in tests of semantic fluency. The present study further explores hippocampal contribution to verbal fluency using functional Magnetic Resonance Imaging (fMRI) and examining mean activity and inter-regional functional connectivity with known task-related brain regions. Given the clear lateralization of brain areas involved in language, lateralization of hippocampal involvement in semantic and phonemic word fluency was also investigated. Different hippocampal recruitment during semantic and phonemic fluency was found: greater change in activity was seen during semantic fluency, as compared with phonemic fluency. This pattern was obtained in the right and the left hippocampus, with no lateralization effects. Functional connectivity analyses corroborate the notion of selective contribution of the hippocampus to semantic fluency. During the semantic fluency task, connectivity levels between the hippocampi and components of the semantic network did not differ from connectivity levels within the semantic network. In contrast, during the phonemic fluency task, the hippocampi were less correlated with components of the phonemic network, as compared to the within phonemic network connectivity. Importantly, hippocampal connectivity with the semantic network was task-dependent and restricted to periods of semantic fluency performance. Altogether, results suggest that the right and the left hippocampus are integral components of the brain network that selectively supports verbal semantic fluency, but not phonemic fluency.
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Renoult L, Davidson PSR, Schmitz E, Park L, Campbell K, Moscovitch M, Levine B. Autobiographically Significant Concepts: More Episodic than Semantic in Nature? An Electrophysiological Investigation of Overlapping Types of Memory. J Cogn Neurosci 2015; 27:57-72. [DOI: 10.1162/jocn_a_00689] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Abstract
A common assertion is that semantic memory emerges from episodic memory, shedding the distinctive contexts associated with episodes over time and/or repeated instances. Some semantic concepts, however, may retain their episodic origins or acquire episodic information during life experiences. The current study examined this hypothesis by investigating the ERP correlates of autobiographically significant (AS) concepts, that is, semantic concepts that are associated with vivid episodic memories. We inferred the contribution of semantic and episodic memory to AS concepts using the amplitudes of the N400 and late positive component, respectively. We compared famous names that easily brought to mind episodic memories (high AS names) against equally famous names that did not bring such recollections to mind (low AS names) on a semantic task (fame judgment) and an episodic task (recognition memory). Compared with low AS names, high AS names were associated with increased amplitude of the late positive component in both tasks. Moreover, in the recognition task, this effect of AS was highly correlated with recognition confidence. In contrast, the N400 component did not differentiate the high versus low AS names but, instead, was related to the amount of general knowledge participants had regarding each name. These results suggest that semantic concepts high in AS, such as famous names, have an episodic component and are associated with similar brain processes to those that are engaged by episodic memory. Studying AS concepts may provide unique insights into how episodic and semantic memory interact.
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Affiliation(s)
| | | | | | - Lillian Park
- 3State University of New York College at Old Westbury
| | | | | | - Brian Levine
- 4Rotman Research Institute, Baycrest, Toronto, Ontario, Canada
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48
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Increased neural activity during overt and continuous semantic verbal fluency in major depression: mainly a failure to deactivate. Eur Arch Psychiatry Clin Neurosci 2014; 264:631-45. [PMID: 24557502 DOI: 10.1007/s00406-014-0491-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 02/07/2014] [Indexed: 12/15/2022]
Abstract
Major depression is associated with impairments in semantic verbal fluency (VF). However, the neural correlates underlying dysfunctional cognitive processing in depressed subjects during the production of semantic category members still remain unclear. In the current study, an overt and continuous semantic VF paradigm was used to examine these mechanisms in a representative sample of 33 patients diagnosed with a current episode of unipolar depression and 33 statistically matched healthy controls. Subjects articulated words in response to semantic category cues while brain activity was measured with functional magnetic resonance imaging (fMRI). Compared to controls, patients showed poorer task performance. On the neural level, a group by condition interaction analysis, corrected for task performance, revealed a reduced task-related deactivation in patients in the right parahippocampal gyrus, the right fusiform gyrus, and the right supplementary motor area. An additional and an increased task-related activation in patients were observed in the right precentral gyrus and the left cerebellum, respectively. These results indicate that a failure to suppress potentially interfering activity from inferior temporal regions involved in default-mode network functions and visual imagery, accompanied by an enhanced recruitment of areas implicated in speech initiation and higher-order language processes, may underlie dysfunctional cognitive processing during semantic VF in depression. The finding that patients with depression demonstrated both decreased performance and aberrant brain activation during the current semantic VF task demonstrates that this paradigm is a sensitive tool for assessing brain dysfunctions in clinical populations.
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49
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Verfaellie M, Bousquet K, Keane MM. Medial temporal and neocortical contributions to remote memory for semantic narratives: evidence from amnesia. Neuropsychologia 2014; 61:105-12. [PMID: 24953960 PMCID: PMC4122606 DOI: 10.1016/j.neuropsychologia.2014.06.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 06/11/2014] [Accepted: 06/12/2014] [Indexed: 12/28/2022]
Abstract
Studies of remote memory for semantic facts and concepts suggest that hippocampal lesions lead to a temporally graded impairment that extends no more than ten years prior to the onset of amnesia. Such findings have led to the notion that once consolidated, semantic memories are represented neocortically and are no longer dependent on the hippocampus. Here, we examined the fate of well-established semantic narratives following medial temporal lobe (MTL) lesions. Seven amnesic patients, five with lesions restricted to the MTL and two with lesions extending into lateral temporal cortex (MTL+), were asked to recount fairy tales and bible stories that they rated as familiar. Narratives were scored for number and type of details, number of main thematic elements, and order in which the main thematic elements were recounted. In comparison to controls, patients with MTL lesions produced fewer details, but the number and order of main thematic elements generated was intact. By contrast, patients with MTL+ lesions showed a pervasive impairment, affecting not only the generation of details, but also the generation and ordering of main steps. These findings challenge the notion that, once consolidated, semantic memories are no longer dependent on the hippocampus for retrieval. Possible hippocampal contributions to the retrieval of detailed semantic narratives are discussed.
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Affiliation(s)
- Mieke Verfaellie
- Memory Disorders Research Center, VA Boston Healthcare System and Boston University School of Medicine, 150 S Huntington Avenue, Boston, MA 02130, USA.
| | - Kathryn Bousquet
- Memory Disorders Research Center, VA Boston Healthcare System and Boston University School of Medicine, 150 S Huntington Avenue, Boston, MA 02130, USA
| | - Margaret M Keane
- Department of Psychology, Wellesley College, Wellesley, MA 02481, USA; Memory Disorders Research Center, VA Boston Healthcare System and Boston University School of Medicine, 150 S Huntington Avenue, Boston, MA 02130, USA
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50
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Memory reconsolidation, emotional arousal, and the process of change in psychotherapy: New insights from brain science. Behav Brain Sci 2014; 38:e1. [PMID: 24827452 DOI: 10.1017/s0140525x14000041] [Citation(s) in RCA: 212] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Since Freud, clinicians have understood that disturbing memories contribute to psychopathology and that new emotional experiences contribute to therapeutic change. Yet, controversy remains about what is truly essential to bring about psychotherapeutic change. Mounting evidence from empirical studies suggests that emotional arousal is a key ingredient in therapeutic change in many modalities. In addition, memory seems to play an important role but there is a lack of consensus on the role of understanding what happened in the past in bringing about therapeutic change. The core idea of this paper is that therapeutic change in a variety of modalities, including behavioral therapy, cognitive-behavioral therapy, emotion-focused therapy, and psychodynamic psychotherapy, results from the updating of prior emotional memories through a process of reconsolidation that incorporates new emotional experiences. We present an integrated memory model with three interactive components - autobiographical (event) memories, semantic structures, and emotional responses - supported by emerging evidence from cognitive neuroscience on implicit and explicit emotion, implicit and explicit memory, emotion-memory interactions, memory reconsolidation, and the relationship between autobiographical and semantic memory. We propose that the essential ingredients of therapeutic change include: (1) reactivating old memories; (2) engaging in new emotional experiences that are incorporated into these reactivated memories via the process of reconsolidation; and (3) reinforcing the integrated memory structure by practicing a new way of behaving and experiencing the world in a variety of contexts. The implications of this new, neurobiologically grounded synthesis for research, clinical practice, and teaching are discussed.
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