51
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Choice-predictive activity in parietal cortex during source memory decisions. Neuroimage 2019; 189:589-600. [DOI: 10.1016/j.neuroimage.2019.01.071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/16/2019] [Accepted: 01/28/2019] [Indexed: 10/27/2022] Open
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52
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Affiliation(s)
| | - Eeva Kallio
- Education, University of Jyväskylä, Jyväskylä, Finland
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53
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More Is Less: Increased Processing of Unwanted Memories Facilitates Forgetting. J Neurosci 2019; 39:3551-3560. [PMID: 30858162 DOI: 10.1523/jneurosci.2033-18.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 02/08/2019] [Accepted: 02/13/2019] [Indexed: 02/03/2023] Open
Abstract
The intention to forget can produce long-lasting effects. This ability has been linked to suppression of both rehearsal and retrieval of unwanted memories, processes mediated by the prefrontal cortex and hippocampus. Here, we describe an alternative account in which the intention to forget is associated with increased engagement with the unwanted information. We used pattern classifiers to decode human functional magnetic resonance imaging data from a task in which male and female participants viewed a series of pictures and were instructed to remember or forget each one. Pictures followed by a forget instruction elicited higher levels of processing in the ventral temporal cortex compared with those followed by a remember instruction. This boost in processing led to more forgetting, particularly for items that showed moderate (vs weak or strong) activation. This result is consistent with the nonmonotonic plasticity hypothesis, which predicts weakening and forgetting of memories that are moderately activated.SIGNIFICANCE STATEMENT The human brain cannot remember everything. Forgetting has a critical role in curating memories and discarding unwanted information. Intentional forgetting has traditionally been linked to passive processes, such as the withdrawal of sustained attention or a stoppage of memory rehearsal. It has also been linked to active suppression of memory processes during encoding and retrieval. Using functional magnetic resonance imaging and machine-learning methods, we show new evidence that intentional forgetting involves an enhancement of memory processing in the sensory cortex to achieve desired forgetting of recent visual experiences. This enhancement temporarily boosts the activation of the memory representation and renders it vulnerable to disruption via homeostatic regulation. Contrary to intuition, deliberate forgetting may involve more rather than less attention to unwanted information.
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54
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Human Verbal Memory Encoding Is Hierarchically Distributed in a Continuous Processing Stream. eNeuro 2019; 6:eN-NWR-0214-18. [PMID: 30847390 PMCID: PMC6402539 DOI: 10.1523/eneuro.0214-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 11/28/2018] [Accepted: 12/10/2018] [Indexed: 12/16/2022] Open
Abstract
Processing of memory is supported by coordinated activity in a network of sensory, association, and motor brain regions. It remains a major challenge to determine where memory is encoded for later retrieval. Here, we used direct intracranial brain recordings from epilepsy patients performing free recall tasks to determine the temporal pattern and anatomical distribution of verbal memory encoding across the entire human cortex. High γ frequency activity (65–115 Hz) showed consistent power responses during encoding of subsequently recalled and forgotten words on a subset of electrodes localized in 16 distinct cortical areas activated in the tasks. More of the high γ power during word encoding, and less power before and after the word presentation, was characteristic of successful recall and observed across multiple brain regions. Latencies of the induced power changes and this subsequent memory effect (SME) between the recalled and forgotten words followed an anatomical sequence from visual to prefrontal cortical areas. Finally, the magnitude of the memory effect was unexpectedly found to be the largest in selected brain regions both at the top and at the bottom of the processing stream. These included the language processing areas of the prefrontal cortex and the early visual areas at the junction of the occipital and temporal lobes. Our results provide evidence for distributed encoding of verbal memory organized along a hierarchical posterior-to-anterior processing stream.
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55
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Thakral PP, Wang TH, Rugg MD. Effects of age on across-participant variability of cortical reinstatement effects. Neuroimage 2019; 191:162-175. [PMID: 30731244 DOI: 10.1016/j.neuroimage.2019.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/03/2019] [Accepted: 02/04/2019] [Indexed: 10/27/2022] Open
Abstract
Using functional magnetic resonance imaging data, we assessed whether across-participant variability of content-selective retrieval-related neural activity differs with age. We addressed this question by employing across-participant multi-voxel pattern analysis (MVPA), predicting that increasing age would be associated with reduced variability of retrieval-related cortical reinstatement across participants. During study, 24 young and 24 older participants viewed objects and concrete words. Test items comprised studied words, names of studied objects, and unstudied words. Participants judged whether the items were recollected, familiar, or new by making 'Remember', 'Know' and 'New' responses, respectively. MVPA was conducted on each region belonging to the 'core recollection network', dorsolateral prefrontal cortex, and a previously identified content-selective voxel set. A leave-one-participant-out classification approach was employed whereby a classifier was trained on a subset of participants and tested on the data from a yoked pair of held-out participants. Classifiers were trained on the study phase data to discriminate the study trials as a function of content (picture or word). The classifiers were then applied to the test phase data to discriminate studied test words according to their study condition. In all of the examined regions, classifier performance demonstrated little or no sensitivity to age and, for the test data, was robustly above chance. Thus, there was little evidence to support the hypothesis that across-participant variability of retrieval-related cortical reinstatement differs with age. The findings extend prior evidence by demonstrating that content-selective cortical reinstatement is sufficiently invariant to support across-participant multi-voxel classification across the healthy adult lifespan.
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Affiliation(s)
| | - Tracy H Wang
- Department of Psychology, University of Texas at Austin, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas at Dallas, USA
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56
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Characterizing the Impact of Distracting Input on Visual Working Memory Representations. J Neurosci 2018; 38:10589-10591. [PMID: 30541768 DOI: 10.1523/jneurosci.1969-18.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/19/2018] [Accepted: 10/23/2018] [Indexed: 11/21/2022] Open
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57
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An Optimal Oscillatory Phase for Pattern Reactivation during Memory Retrieval. Curr Biol 2018; 28:3383-3392.e6. [DOI: 10.1016/j.cub.2018.08.065] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 08/10/2018] [Accepted: 08/31/2018] [Indexed: 11/23/2022]
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58
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Price MH, Johnson JD. Failure to reactivate salient episodic information during indirect and direct tests of memory retrieval. Brain Res 2018; 1699:9-18. [DOI: 10.1016/j.brainres.2018.06.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 05/18/2018] [Accepted: 06/28/2018] [Indexed: 11/27/2022]
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59
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Lee H, Samide R, Richter FR, Kuhl BA. Decomposing Parietal Memory Reactivation to Predict Consequences of Remembering. Cereb Cortex 2018; 29:3305-3318. [DOI: 10.1093/cercor/bhy200] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 07/26/2018] [Accepted: 07/28/2018] [Indexed: 11/14/2022] Open
Abstract
Abstract
Memory retrieval can strengthen, but also distort memories. Parietal cortex is a candidate region involved in retrieval-induced memory changes as it reflects retrieval success and represents retrieved content. Here, we conducted an fMRI experiment to test whether different forms of parietal reactivation predict distinct consequences of retrieval. Subjects studied associations between words and pictures of faces, scenes, or objects, and then repeatedly retrieved half of the pictures, reporting the vividness of the retrieved pictures (“retrieval practice”). On the following day, subjects completed a recognition memory test for individual pictures. Critically, the test included lures highly similar to studied pictures. Behaviorally, retrieval practice increased both hit and false alarm (FA) rates to similar lures, confirming a causal influence of retrieval on subsequent memory. Using pattern similarity analyses, we measured two different levels of reactivation during retrieval practice: generic “category-level” reactivation and idiosyncratic “item-level” reactivation. Vivid remembering during retrieval practice was associated with stronger category- and item-level reactivation in parietal cortex. However, these measures differentially predicted subsequent recognition memory performance: whereas higher category-level reactivation tended to predict FAs to lures, item-level reactivation predicted correct rejections. These findings indicate that parietal reactivation can be decomposed to tease apart distinct consequences of memory retrieval.
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Affiliation(s)
- Hongmi Lee
- Department of Psychology, New York University, New York, NY, USA
| | | | | | - Brice A Kuhl
- Department of Psychology, University of Oregon, Eugene, OR, USA
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60
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O'Bryan SR, Worthy DA, Livesey EJ, Davis T. Model-based fMRI reveals dissimilarity processes underlying base rate neglect. eLife 2018; 7:36395. [PMID: 30074478 PMCID: PMC6108825 DOI: 10.7554/elife.36395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 08/01/2018] [Indexed: 11/13/2022] Open
Abstract
Extensive evidence suggests that people use base rate information inconsistently in decision making. A classic example is the inverse base rate effect (IBRE), whereby participants classify ambiguous stimuli sharing features of both common and rare categories as members of the rare category. Computational models of the IBRE have posited that it arises either from associative similarity-based mechanisms or from dissimilarity-based processes that may depend on higher-level inference. Here we develop a hybrid model, which posits that similarity- and dissimilarity-based evidence both contribute to the IBRE, and test it using functional magnetic resonance imaging data collected from human subjects completing an IBRE task. Consistent with our model, multivoxel pattern analysis reveals that activation patterns on ambiguous test trials contain information consistent with dissimilarity-based processing. Further, trial-by-trial activation in left rostrolateral prefrontal cortex tracks model-based predictions for dissimilarity-based processing, consistent with theories positing a role for higher-level symbolic processing in the IBRE.
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Affiliation(s)
- Sean R O'Bryan
- Department of Psychological Sciences, Texas Tech University, Lubbock, United States
| | - Darrell A Worthy
- Department of Psychology, Texas A&M University, College Station, United States
| | - Evan J Livesey
- School of Psychology, University of Sydney, Sydney, Australia
| | - Tyler Davis
- Department of Psychological Sciences, Texas Tech University, Lubbock, United States
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61
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Multi-voxel pattern classification differentiates personally experienced event memories from secondhand event knowledge. Neuroimage 2018; 176:110-123. [DOI: 10.1016/j.neuroimage.2018.04.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 03/25/2018] [Accepted: 04/10/2018] [Indexed: 02/03/2023] Open
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62
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Wahlheim CN, Zacks JM. Memory guides the processing of event changes for older and younger adults. J Exp Psychol Gen 2018; 148:30-50. [PMID: 29985021 DOI: 10.1037/xge0000458] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Memory for related past experiences can guide current perceptions. However, memory can lead one astray if situational features have changed. Thus, to adaptively use memory to guide perception, one needs to retrieve relevant memories and also to register differences between remembered and current events. Event Memory Retrieval and Comparison Theory proposes that observers associatively activate memories of related previous episodes, and that this guides their ongoing perception. Conflicts between previous and current event features can hurt immediate performance, but if changes are registered and encoded they can lead to highly effective encoding of the prior event, current event, and their relationship. Disruption of these mechanisms could play a role in older adults' greater susceptibility to event memory interference. Two experiments tested these hypotheses by asking participants to watch movies depicting two fictive days of an actor. Some activities were repeated across days, others were repeated with a changed feature (e.g., waking up to an alarm clock or a phone alarm), and others were performed only on Day 2. One week after watching the Day 2 movie, participants completed a cued-recall test. Changes that participants detected but did not remember led to proactive interference in recall, but changes that were successfully detected and remembered led to facilitation. Younger adults detected and remembered more changes than older adults, which partly explained older adults' differential memory deficit for changed activities. These findings suggest a role for episodic reminding in event perception and a potential source of age differences in event memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
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63
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Petrican R, Levine BT. Similarity in functional brain architecture between rest and specific task modes: A model of genetic and environmental contributions to episodic memory. Neuroimage 2018; 179:489-504. [PMID: 29936311 DOI: 10.1016/j.neuroimage.2018.06.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/05/2018] [Accepted: 06/19/2018] [Indexed: 01/06/2023] Open
Abstract
The ability to keep a mental record of specific past events, dubbed episodic memory (EM), is key to lifespan adaptation. Nonetheless, the neural mechanisms underlying its typical inter-individual variability remain poorly understood. To address this issue, we tested whether individual differences in EM could be predicted from levels of functional brain re-organization between rest and task modes relevant to the transformation of perceptual information into mental representations (relational processing, meaning extraction, online maintenance versus updating of bound perceptual features). To probe the trait specificity of our model, we included three additional core mental functions, processing speed, abstract reasoning, and cognitive control. Finally, we investigated the extent to which our proposed model reflected genetic versus environmental contributions to EM variability. Hypotheses were tested by applying graph theoretical analysis and structural equation modeling to resting state and task fMRI data from two samples of participants in the Human Connectome Project (Sample 1: N = 338 unrelated individuals; Sample 2: N = 268 monozygotic vs. dizygotic twins [134 same-sex pairs]). Levels of functional brain reorganization between rest and the scrutinized task modes, particularly relational processing and online maintenance of bound perceptual features, contributed substantially to variations in both EM and abstract reasoning (but not in cognitive control or processing speed) among the younger adults in our sample, implying a substantial neurofunctional overlap, at least during this life stage. Similarity in functional organization between rest and each of the scrutinized task modes drew on distinguishable neural resources and showed differential susceptibility to genetic versus environmental influences. Our results suggest that variability on complex traits, such as EM, is supported by neural mechanisms comprising multiple components, each reflecting a distinct pattern of genetic versus environmental contributions and whose relative importance may vary across typical versus psychopathological development.
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Affiliation(s)
| | - Brian T Levine
- Rotman Research Institute and Departments of Psychology and Neurology, University of Toronto, M6A 2E1, Canada
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64
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Bainbridge WA, Rissman J. Dissociating neural markers of stimulus memorability and subjective recognition during episodic retrieval. Sci Rep 2018; 8:8679. [PMID: 29875370 PMCID: PMC5989217 DOI: 10.1038/s41598-018-26467-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 05/02/2018] [Indexed: 11/21/2022] Open
Abstract
While much of memory research takes an observer-centric focus looking at participant performance, recent work has pinpointed important item-centric effects on memory, or how intrinsically memorable a given stimulus is. However, little is known about the neural correlates of memorability during memory retrieval, or how such correlates relate to subjective memory behavior. Here, stimuli and blood-oxygen-level dependent data from a prior functional magnetic resonance imaging (fMRI) study were reanalyzed using a memorability-based framework. In that study, sixteen participants studied 200 novel face images and were scanned while making recognition memory judgments on those faces, interspersed with 200 unstudied faces. In the current investigation, memorability scores for those stimuli were obtained through an online crowd-sourced (N = 740) continuous recognition test that measured each image's corrected recognition rate. Representational similarity analyses were conducted across the brain to identify regions wherein neural pattern similarity tracked item-specific effects (stimulus memorability) versus observer-specific effects (individual memory performance). We find two non-overlapping sets of regions, with memorability-related information predominantly represented within ventral and medial temporal regions and memory retrieval outcome-related information within fronto-parietal regions. These memorability-based effects persist regardless of image history, implying that coding of stimulus memorability may be a continuous and automatic perceptual process.
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Affiliation(s)
- Wilma A Bainbridge
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA.
| | - Jesse Rissman
- Department of Psychology, University of California, Los Angeles, CA, USA
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
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65
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Xue G. The Neural Representations Underlying Human Episodic Memory. Trends Cogn Sci 2018; 22:544-561. [DOI: 10.1016/j.tics.2018.03.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/23/2018] [Accepted: 03/08/2018] [Indexed: 11/16/2022]
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66
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Extracting orthogonal subject- and condition-specific signatures from fMRI data using whole-brain effective connectivity. Neuroimage 2018; 178:238-254. [PMID: 29753842 PMCID: PMC6057306 DOI: 10.1016/j.neuroimage.2018.04.070] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/16/2018] [Accepted: 04/30/2018] [Indexed: 12/19/2022] Open
Abstract
The study of brain communication based on fMRI data is often limited because such measurements are a mixture of session-to-session variability with subject- and condition-related information. Disentangling these contributions is crucial for real-life applications, in particular when only a few recording sessions are available. The present study aims to define a reliable standard for the extraction of multiple signatures from fMRI data, while verifying that they do not mix information about the different modalities (e.g., subjects and conditions such as tasks performed by them). In particular, condition-specific signatures should not be contaminated by subject-related information, since they aim to generalize over subjects. Practically, signatures correspond to subnetworks of directed interactions between brain regions (typically 100 covering the whole brain) supporting the subject and condition identification for single fMRI sessions. The key for robust prediction is using effective connectivity instead of functional connectivity. Our method demonstrates excellent generalization capabilities for subject identification in two datasets, using only a few sessions per subject as reference. Using another dataset with resting state and movie viewing, we show that the two signatures related to subjects and tasks correspond to distinct subnetworks, which are thus topologically orthogonal. Our results set solid foundations for applications tailored to individual subjects, such as clinical diagnostic.
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67
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Visser RM, Lau-Zhu A, Henson RN, Holmes EA. Multiple memory systems, multiple time points: how science can inform treatment to control the expression of unwanted emotional memories. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170209. [PMID: 29352036 PMCID: PMC5790835 DOI: 10.1098/rstb.2017.0209] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2017] [Indexed: 01/04/2023] Open
Abstract
Memories that have strong emotions associated with them are particularly resilient to forgetting. This is not necessarily problematic, however some aspects of memory can be. In particular, the involuntary expression of those memories, e.g. intrusive memories after trauma, are core to certain psychological disorders. Since the beginning of this century, research using animal models shows that it is possible to change the underlying memory, for example by interfering with its consolidation or reconsolidation. While the idea of targeting maladaptive memories is promising for the treatment of stress and anxiety disorders, a direct application of the procedures used in non-human animals to humans in clinical settings is not straightforward. In translational research, more attention needs to be paid to specifying what aspect of memory (i) can be modified and (ii) should be modified. This requires a clear conceptualization of what aspect of memory is being targeted, and how different memory expressions may map onto clinical symptoms. Furthermore, memory processes are dynamic, so procedural details concerning timing are crucial when implementing a treatment and when assessing its effectiveness. To target emotional memory in its full complexity, including its malleability, science cannot rely on a single method, species or paradigm. Rather, a constructive dialogue is needed between multiple levels of research, all the way 'from mice to mental health'.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'.
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Affiliation(s)
- Renée M Visser
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
| | - Alex Lau-Zhu
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Richard N Henson
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
| | - Emily A Holmes
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
- Karolinska Institutet, Division of Psychology, Department of Clinical Neuroscience, Stockholm, Sweden
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68
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Hermans EJ, Kanen JW, Tambini A, Fernández G, Davachi L, Phelps EA. Persistence of Amygdala-Hippocampal Connectivity and Multi-Voxel Correlation Structures During Awake Rest After Fear Learning Predicts Long-Term Expression of Fear. Cereb Cortex 2018; 27:3028-3041. [PMID: 27242028 DOI: 10.1093/cercor/bhw145] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
After encoding, memories undergo a process of consolidation that determines long-term retention. For conditioned fear, animal models postulate that consolidation involves reactivations of neuronal assemblies supporting fear learning during postlearning "offline" periods. However, no human studies to date have investigated such processes, particularly in relation to long-term expression of fear. We tested 24 participants using functional MRI on 2 consecutive days in a fear conditioning paradigm involving 1 habituation block, 2 acquisition blocks, and 2 extinction blocks on day 1, and 2 re-extinction blocks on day 2. Conditioning blocks were preceded and followed by 4.5-min rest blocks. Strength of spontaneous recovery of fear on day 2 served as a measure of long-term expression of fear. Amygdala connectivity primarily with hippocampus increased progressively during postacquisition and postextinction rest on day 1. Intraregional multi-voxel correlation structures within amygdala and hippocampus sampled during a block of differential fear conditioning furthermore persisted after fear learning. Critically, both these main findings were stronger in participants who exhibited spontaneous recovery 24 h later. Our findings indicate that neural circuits activated during fear conditioning exhibit persistent postlearning activity that may be functionally relevant in promoting consolidation of the fear memory.
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Affiliation(s)
- Erno J Hermans
- Department of Psychology.,Donders Institute for Brain, Cognition and Behaviour.,Department for Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen 6525 EN, The Netherlands
| | - Jonathan W Kanen
- Department of Psychology.,Behavioural and Clinical Neuroscience Institute, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Arielle Tambini
- Center for Neural Science, New York University, New York, NY 10003, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720
| | - Guillén Fernández
- Donders Institute for Brain, Cognition and Behaviour.,Department for Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen 6525 EN, The Netherlands
| | - Lila Davachi
- Department of Psychology.,Center for Neural Science, New York University, New York, NY 10003, USA
| | - Elizabeth A Phelps
- Department of Psychology.,Center for Neural Science, New York University, New York, NY 10003, USA.,Nathan Kline Institute, Orangeburg, NY 10962, USA
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69
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Jiang X, Shamie I, K Doyle W, Friedman D, Dugan P, Devinsky O, Eskandar E, Cash SS, Thesen T, Halgren E. Replay of large-scale spatio-temporal patterns from waking during subsequent NREM sleep in human cortex. Sci Rep 2017; 7:17380. [PMID: 29234075 PMCID: PMC5727134 DOI: 10.1038/s41598-017-17469-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/27/2017] [Indexed: 01/20/2023] Open
Abstract
Animal studies support the hypothesis that in slow-wave sleep, replay of waking neocortical activity under hippocampal guidance leads to memory consolidation. However, no intracranial electrophysiological evidence for replay exists in humans. We identified consistent sequences of population firing peaks across widespread cortical regions during complete waking periods. The occurrence of these “Motifs” were compared between sleeps preceding the waking period (“Sleep-Pre”) when the Motifs were identified, and those following (“Sleep-Post”). In all subjects, the majority of waking Motifs (most of which were novel) had more matches in Sleep-Post than in Sleep-Pre. In rodents, hippocampal replay occurs during local sharp-wave ripples, and the associated neocortical replay tends to occur during local sleep spindles and down-to-up transitions. These waves may facilitate consolidation by sequencing cell-firing and encouraging plasticity. Similarly, we found that Motifs were coupled to neocortical spindles, down-to-up transitions, theta bursts, and hippocampal sharp-wave ripples. While Motifs occurring during cognitive task performance were more likely to have more matches in subsequent sleep, our studies provide no direct demonstration that the replay of Motifs contributes to consolidation. Nonetheless, these results confirm a core prediction of the dominant neurobiological theory of human memory consolidation.
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Affiliation(s)
- Xi Jiang
- Neurosciences Graduate Program, University of California at San Diego, La Jolla, CA, 92093, USA.
| | - Isaac Shamie
- Department of Radiology, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Werner K Doyle
- Comprehensive Epilepsy Center, New York University School of Medicine, St George's, NY, 10016, USA
| | - Daniel Friedman
- Comprehensive Epilepsy Center, New York University School of Medicine, St George's, NY, 10016, USA
| | - Patricia Dugan
- Comprehensive Epilepsy Center, New York University School of Medicine, St George's, NY, 10016, USA
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, New York University School of Medicine, St George's, NY, 10016, USA
| | - Emad Eskandar
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Sydney S Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Thomas Thesen
- Comprehensive Epilepsy Center, New York University School of Medicine, St George's, NY, 10016, USA.,Department of Physiology & Neuroscience, St. George's University, West Indies, Grenada
| | - Eric Halgren
- Department of Radiology, University of California at San Diego, La Jolla, CA, 92093, USA. .,Department of Neurosciences, University of California at San Diego, La Jolla, CA, 92093, USA.
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70
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Faw M, Faw B. Response to 'Hippocampus as a wormhole: gateway to consciousness'. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2017; 8. [PMID: 28834415 DOI: 10.1002/wcs.1447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Reply to: Behrendt R-P. Hippocampus as a wormhole: gateway to consciousness. WIREs Cogn Sci 2017, e1446. doi: 10.1002/wcs.1446.
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Affiliation(s)
| | - Bill Faw
- Brewton-Parker College, Mt. Vernon, GA, USA
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71
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Kragel JE, Ezzyat Y, Sperling MR, Gorniak R, Worrell GA, Berry BM, Inman C, Lin JJ, Davis KA, Das SR, Stein JM, Jobst BC, Zaghloul KA, Sheth SA, Rizzuto DS, Kahana MJ. Similar patterns of neural activity predict memory function during encoding and retrieval. Neuroimage 2017; 155:60-71. [PMID: 28377210 PMCID: PMC5789770 DOI: 10.1016/j.neuroimage.2017.03.042] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/22/2017] [Accepted: 03/20/2017] [Indexed: 02/06/2023] Open
Abstract
Neural networks that span the medial temporal lobe (MTL), prefrontal cortex, and posterior cortical regions are essential to episodic memory function in humans. Encoding and retrieval are supported by the engagement of both distinct neural pathways across the cortex and common structures within the medial temporal lobes. However, the degree to which memory performance can be determined by neural processing that is common to encoding and retrieval remains to be determined. To identify neural signatures of successful memory function, we administered a delayed free-recall task to 187 neurosurgical patients implanted with subdural or intraparenchymal depth electrodes. We developed multivariate classifiers to identify patterns of spectral power across the brain that independently predicted successful episodic encoding and retrieval. During encoding and retrieval, patterns of increased high frequency activity in prefrontal, MTL, and inferior parietal cortices, accompanied by widespread decreases in low frequency power across the brain predicted successful memory function. Using a cross-decoding approach, we demonstrate the ability to predict memory function across distinct phases of the free-recall task. Furthermore, we demonstrate that classifiers that combine information from both encoding and retrieval states can outperform task-independent models. These findings suggest that the engagement of a core memory network during either encoding or retrieval shapes the ability to remember the past, despite distinct neural interactions that facilitate encoding and retrieval.
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Affiliation(s)
- James E Kragel
- Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Youssef Ezzyat
- Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Richard Gorniak
- Department of Radiology, Thomas Jefferson University Hospital, Philadelphia PA 19107, USA
| | | | - Brent M Berry
- Department of Neurology, Mayo Clinic, Rochester MN 55905, USA
| | - Cory Inman
- Department of Neurosurgery, Emory School of Medicine, Atlanta GA 30322, USA
| | - Jui-Jui Lin
- Department of Neurosurgery, University of Texas Southwestern, Dallas TX 75390, USA
| | - Kathryn A Davis
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sandhitsu R Das
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joel M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia PA 19104, USA
| | - Barbara C Jobst
- Department of Neurology, Dartmouth Medical Center, Lebanon NH 03756, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institutes of Health, Bethesda MD 20814, USA
| | - Sameer A Sheth
- Department of Neurosurgery, Columbia University Medical Center, New York NY 10032, USA
| | - Daniel S Rizzuto
- Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA.
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72
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Khanna P, Bhat PS, Jacob J. Frontal lobe executive dysfunction and cerebral perfusion study in alcohol dependence syndrome. Ind Psychiatry J 2017; 26:134-139. [PMID: 30089959 PMCID: PMC6058449 DOI: 10.4103/ipj.ipj_26_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Long-term alcohol use leading to frontal lobe impairment has been a cause of concern for many decades. However, there are very few studies from India of evaluation of frontal lobe executive dysfunction among alcoholics. Hence, this study was undertaken to evaluate the frontal executive dysfunction using Wisconsin Card Sorting Test (WCST) and perfusion deficits by Single-Photon Emission Computerized Tomography (SPECT) among alcohol-dependent patients. AIM The aim of this study is to evaluate the frontal executive dysfunction using WCST and frontal lobe perfusion deficits by SPECT among alcohol-dependent patients. MATERIALS AND METHODS This was a cross-sectional study involving 20 alcohol dependence syndrome patients in a tertiary care center. After ethical clearance and informed consent, all were evaluated using WCST and SPECT. RESULTS About 45% patients had impairment on WCST, and it was related to the duration of drinking. About 55% showed reduced frontal lobe perfusion on SPECT scan and they had a long duration of drinking compared to controls. Among the patients showing impairment on WCST subscores, more than 50% had reduced frontal lobe perfusion on SPECT. CONCLUSION This study not only confirmed the executive function impairment and frontal lobe perfusion deficits in alcohol-dependent patients but also showed a concomitant presence of both in patients with chronic alcohol abuse.
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Affiliation(s)
- Puneet Khanna
- Deparment of Psychiatry, INHS Asvini, Mumbai, Maharashtra, India
| | | | - J Jacob
- Department of Nuclear Medicine, Army Hospital (R&R), New Delhi, India
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73
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Shadlen MN, Shohamy D. Decision Making and Sequential Sampling from Memory. Neuron 2017; 90:927-39. [PMID: 27253447 DOI: 10.1016/j.neuron.2016.04.036] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/18/2016] [Accepted: 04/22/2016] [Indexed: 12/16/2022]
Abstract
Decisions take time, and as a rule more difficult decisions take more time. But this only raises the question of what consumes the time. For decisions informed by a sequence of samples of evidence, the answer is straightforward: more samples are available with more time. Indeed, the speed and accuracy of such decisions are explained by the accumulation of evidence to a threshold or bound. However, the same framework seems to apply to decisions that are not obviously informed by sequences of evidence samples. Here, we proffer the hypothesis that the sequential character of such tasks involves retrieval of evidence from memory. We explore this hypothesis by focusing on value-based decisions and argue that mnemonic processes can account for regularities in choice and decision time. We speculate on the neural mechanisms that link sampling of evidence from memory to circuits that represent the accumulated evidence bearing on a choice. We propose that memory processes may contribute to a wider class of decisions that conform to the regularities of choice-reaction time predicted by the sequential sampling framework.
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Affiliation(s)
- Michael N Shadlen
- Howard Hughes Medical Institute and Department of Neuroscience, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science, Columbia University, New York, NY 10032, USA.
| | - Daphna Shohamy
- Department of Psychology, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science, Columbia University, New York, NY 10032, USA.
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74
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Chow TE, Rissman J. Neurocognitive mechanisms of real‐world autobiographical memory retrieval: insights from studies using wearable camera technology. Ann N Y Acad Sci 2017; 1396:202-221. [DOI: 10.1111/nyas.13353] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 03/13/2017] [Accepted: 03/20/2017] [Indexed: 12/30/2022]
Affiliation(s)
| | - Jesse Rissman
- Department of Psychology
- Department of Psychiatry and Biobehavioral Sciences
- Brain Research Institute
- Integrative Center for Learning and Memory University of California Los Angeles Los Angeles California
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75
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Brogaard B, Gatzia DE. Unconscious Imagination and the Mental Imagery Debate. Front Psychol 2017; 8:799. [PMID: 28588527 PMCID: PMC5440590 DOI: 10.3389/fpsyg.2017.00799] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/02/2017] [Indexed: 11/13/2022] Open
Abstract
Traditionally, philosophers have appealed to the phenomenological similarity between visual experience and visual imagery to support the hypothesis that there is significant overlap between the perceptual and imaginative domains. The current evidence, however, is inconclusive: while evidence from transcranial brain stimulation seems to support this conclusion, neurophysiological evidence from brain lesion studies (e.g., from patients with brain lesions resulting in a loss of mental imagery but not a corresponding loss of perception and vice versa) indicates that there are functional and anatomical dissociations between mental imagery and perception. Assuming that the mental imagery and perception do not overlap, at least, to the extent traditionally assumed, then the question arises as to what exactly mental imagery is and whether it parallels perception by proceeding via several functionally distinct mechanisms. In this review, we argue that even though there may not be a shared mechanism underlying vision for perception and conscious imagery, there is an overlap between the mechanisms underlying vision for action and unconscious visual imagery. On the basis of these findings, we propose a modification of Kosslyn's model of imagery that accommodates unconscious imagination and explore possible explanations of the quasi-pictorial phenomenology of conscious visual imagery in light of the fact that its underlying neural substrates and mechanisms typically are distinct from those of visual experience.
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Affiliation(s)
- Berit Brogaard
- The Brogaard Lab for Multisensory Research, University of Miami, MiamiFL, United States.,Department of Philosophy, University of OsloOslo, Norway
| | - Dimitria Electra Gatzia
- Department of Philosophy, University of Akron Wayne College, AkronOH, United States.,Centre for Philosophical Psychology, University of AntwerpAntwerp, Belgium
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76
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Lu H, Chan SSM, Fung AWT, Lam LCW. Beyond a Differential Diagnosis: Cognitive and Morphometric Decoding of Information Processing Speed in Senior Adults with DSM-5 Mild Neurocognitive Disorders. J Alzheimers Dis 2017; 58:927-937. [PMID: 28527207 DOI: 10.3233/jad-161122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Processing speed has been highlighted as a diagnostic item for neurocognitive disorders (NCD) in DSM-5. The utility of information processing speed (IPS) enclosed with multiscale constructs in the diagnosis of NCD warrants exploration. OBJECTIVE We aimed to investigate the IPS with two types of measurements in the patients with NCD due to vascular disease (NCD-vascular) and NCD due to Alzheimer's disease (NCD-AD), and examine the associations between IPS measures and morphometric features. METHODS The IPS was evaluated using trail making test (TMT) and flanker test (n = 204). Direct scores, derived scores, and reaction time (RT) were used as IPS measures. Further, surface-based morphometry cortical volume was calculated in a subsample (n = 44) with structural MRI data. RESULTS All IPS measures showed a significant value to differentiate NCD patients from healthy subjects. Only mean RT could distinguish NCD-AD from NCD-vascular groups. TMT-B score and difference score were correlated with gray matter volume (GMV) of inferior frontal gyrus, precuneus and superior temporal cortex. Mean RT was associated with the GMV of post-central gyrus (r = -0.327, p = 0.035), and executive speed was associated with inferior frontal cortex (r = -0.475, p = 0.001), cingulate gyrus (r = -0.497, p = 0.001), and superior temporal gyrus (r = -0.36, p = 0.019). CONCLUSION The cognitive and morphometric correlates of IPS measures indicate that complex IPS might be decomposed into the domain-specific components with corresponding neural underpinnings. Our findings may also provide essential insights into the diagnostic item of NCD.
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Affiliation(s)
- Hanna Lu
- Department of Psychiatry, The Chinese University of Hong Kong, Tai Po Hospital, Hong Kong SAR, China.,Guangzhou Brain Hospital, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Sandra S M Chan
- Department of Psychiatry, The Chinese University of Hong Kong, Tai Po Hospital, Hong Kong SAR, China
| | - Ada W T Fung
- Department of Psychiatry, The Chinese University of Hong Kong, Tai Po Hospital, Hong Kong SAR, China
| | - Linda C W Lam
- Department of Psychiatry, The Chinese University of Hong Kong, Tai Po Hospital, Hong Kong SAR, China
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77
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Bainbridge WA, Dilks DD, Oliva A. Memorability: A stimulus-driven perceptual neural signature distinctive from memory. Neuroimage 2017; 149:141-152. [DOI: 10.1016/j.neuroimage.2017.01.063] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/24/2017] [Accepted: 01/26/2017] [Indexed: 11/16/2022] Open
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78
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Hanson GK, Chrysikou EG. Attention to Distinct Goal-relevant Features Differentially Guides Semantic Knowledge Retrieval. J Cogn Neurosci 2017; 29:1178-1193. [PMID: 28294713 DOI: 10.1162/jocn_a_01121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A critical aspect of conceptual knowledge is the selective activation of goal-relevant aspects of meaning. Although the contributions of ventrolateral prefrontal and posterior temporal areas to semantic cognition are well established, the precise role of posterior parietal cortex in semantic control remains unknown. Here, we examined whether this region modulates attention to goal-relevant features within semantic memory according to the same principles that determine the salience of task-relevant object properties during visual attention. Using multivoxel pattern analysis, we decoded attentional referents during a semantic judgment task, in which participants matched an object cue to a target according to concrete (i.e., color, shape) or abstract (i.e., function, thematic context) semantic features. The goal-relevant semantic feature participants attended to (e.g., color or shape, function or theme) could be decoded from task-associated cortical activity with above-chance accuracy, a pattern that held for both concrete and abstract semantic features. A Bayesian confusion matrix analysis further identified differential contributions to representing attentional demands toward specific object properties across lateral prefrontal, posterior temporal, and inferior parietal regions, with the dorsolateral pFC supporting distinctions between higher-order properties and the left intraparietal sulcus being the only region supporting distinctions across all semantic features. These results are the first to demonstrate that patterns of neural activity in the parietal cortex are sensitive to which features of a concept are attended to, thus supporting the contributions of posterior parietal cortex to semantic control.
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79
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Episodic Memory Retrieval Benefits from a Less Modular Brain Network Organization. J Neurosci 2017; 37:3523-3531. [PMID: 28242796 DOI: 10.1523/jneurosci.2509-16.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 11/21/2022] Open
Abstract
Most complex cognitive tasks require the coordinated interplay of multiple brain networks, but the act of retrieving an episodic memory may place especially heavy demands for communication between the frontoparietal control network (FPCN) and the default mode network (DMN), two networks that do not strongly interact with one another in many task contexts. We applied graph theoretical analysis to task-related fMRI functional connectivity data from 20 human participants and found that global brain modularity-a measure of network segregation-is markedly reduced during episodic memory retrieval relative to closely matched analogical reasoning and visuospatial perception tasks. Individual differences in modularity were correlated with memory task performance, such that lower modularity levels were associated with a lower false alarm rate. Moreover, the FPCN and DMN showed significantly elevated coupling with each other during the memory task, which correlated with the global reduction in brain modularity. Both networks also strengthened their functional connectivity with the hippocampus during the memory task. Together, these results provide a novel demonstration that reduced modularity is conducive to effective episodic retrieval, which requires close collaboration between goal-directed control processes supported by the FPCN and internally oriented self-referential processing supported by the DMN.SIGNIFICANCE STATEMENT Modularity, an index of the degree to which nodes of a complex system are organized into discrete communities, has emerged as an important construct in the characterization of brain connectivity dynamics. We provide novel evidence that the modularity of the human brain is reduced when individuals engage in episodic memory retrieval, relative to other cognitive tasks, and that this state of lower modularity is associated with improved memory performance. We propose a neural systems mechanism for this finding where the nodes of the frontoparietal control network and default mode network strengthen their interaction with one another during episodic retrieval. Such across-network communication likely facilitates effective access to internally generated representations of past event knowledge.
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80
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Galeano Weber EM, Hahn T, Hilger K, Fiebach CJ. Distributed patterns of occipito-parietal functional connectivity predict the precision of visual working memory. Neuroimage 2017; 146:404-418. [DOI: 10.1016/j.neuroimage.2016.10.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/15/2016] [Accepted: 10/02/2016] [Indexed: 11/26/2022] Open
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81
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Lingering representations of stimuli influence recall organization. Neuropsychologia 2017; 97:72-82. [PMID: 28132858 DOI: 10.1016/j.neuropsychologia.2017.01.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 01/24/2017] [Accepted: 01/26/2017] [Indexed: 12/12/2022]
Abstract
Several prominent theories posit that information about recent experiences lingers in the brain and organizes memories for current experiences, by forming a temporal context that is linked to those memories at encoding. According to these theories, if the thoughts preceding an experience X resemble the thoughts preceding an experience Y, then X and Y should show an elevated probability of being recalled together. We tested this prediction by using multi-voxel pattern analysis (MVPA) of fMRI data to measure neural evidence for lingering processing of preceding stimuli. As predicted, memories encoded with similar lingering thoughts about the category of preceding stimuli were more likely to be recalled together. Our results demonstrate that the "fading embers" of previous stimuli help to organize recall, confirming a key prediction of computational models of episodic memory.
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82
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Thakral PP, Wang TH, Rugg MD. Decoding the content of recollection within the core recollection network and beyond. Cortex 2016; 91:101-113. [PMID: 28077212 DOI: 10.1016/j.cortex.2016.12.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/12/2016] [Accepted: 12/13/2016] [Indexed: 10/20/2022]
Abstract
Recollection - retrieval of qualitative information about a past event - is associated with enhanced neural activity in a consistent set of neural regions (the 'core recollection network') seemingly regardless of the nature of the recollected content. Here, we employed multi-voxel pattern analysis (MVPA) to assess whether retrieval-related functional magnetic resonance imaging (fMRI) activity in core recollection regions - including the hippocampus, angular gyrus, medial prefrontal cortex, retrosplenial/posterior cingulate cortex, and middle temporal gyrus - contain information about studied content and thus demonstrate retrieval-related 'reinstatement' effects. During study, participants viewed objects and concrete words that were subjected to different encoding tasks. Test items included studied words, the names of studied objects, or unstudied words. Participants judged whether the items were recollected, familiar, or new by making 'remember', 'know', and 'new' responses, respectively. The study history of remembered test items could be reliably decoded using MVPA in most regions, as well as from the dorsolateral prefrontal cortex, a region where univariate recollection effects could not be detected. The findings add to evidence that members of the core recollection network, as well as at least one neural region where mean signal is insensitive to recollection success, carry information about recollected content. Importantly, the study history of recognized items endorsed with a 'know' response could be decoded with equal accuracy. The results thus demonstrate a striking dissociation between mean signal and multi-voxel indices of recollection. Moreover, they converge with prior findings in suggesting that, as it is operationalized by classification-based MVPA, reinstatement is not uniquely a signature of recollection.
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Affiliation(s)
| | - Tracy H Wang
- Department of Psychology, University of Texas at Austin, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas at Dallas, USA
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83
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Lewis-Peacock JA, Cohen JD, Norman KA. Neural evidence of the strategic choice between working memory and episodic memory in prospective remembering. Neuropsychologia 2016; 93:280-288. [PMID: 27845034 PMCID: PMC5148635 DOI: 10.1016/j.neuropsychologia.2016.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/07/2016] [Indexed: 11/29/2022]
Abstract
Theories of prospective memory (PM) posit that it can be subserved either by working memory (WM) or episodic memory (EM). Testing and refining these multiprocess theories of PM requires a way of tracking participants' reliance on WM versus EM. Here we use multi-voxel pattern analysis (MVPA) to derive a trial-by-trial measure of WM use in prospective memory. We manipulated strategy demands by varying the degree of proactive interference (which impairs EM) and the memory load required to perform the secondary task (which impairs WM). For the condition in which participants were pushed to rely more on WM, our MVPA measures showed 1) greater WM use and 2) a trial-by-trial correlation between WM use and PM behavior. Finally, we also showed that MVPA measures of WM use are not redundant with other behavioral measures: in the condition in which participants were pushed more to rely on WM, using neural and behavioral measures together led to better prediction of PM accuracy than either measure on its own.
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Affiliation(s)
- Jarrod A Lewis-Peacock
- Department of Psychology and Imaging Research Center, University of Texas at Austin, Austin, TX 78712, USA.
| | - Jonathan D Cohen
- Department of Psychology and Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
| | - Kenneth A Norman
- Department of Psychology and Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
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84
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Brogaard B, Gatzia DE. Is Color Experience Cognitively Penetrable? Top Cogn Sci 2016; 9:193-214. [PMID: 27797145 DOI: 10.1111/tops.12221] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 01/30/2015] [Accepted: 07/24/2016] [Indexed: 12/01/2022]
Abstract
Is color experience cognitively penetrable? Some philosophers have recently argued that it is. In this paper, we take issue with the claim that color experience is cognitively penetrable. We argue that the notion of cognitive penetration that has recently dominated the literature is flawed since it fails to distinguish between the modulation of perceptual content by non-perceptual principles and genuine cognitive penetration. We use this distinction to show that studies suggesting that color experience can be modulated by factors of the cognitive system do not establish that color experience is cognitively penetrable. Additionally, we argue that even if color experience turns out to be modulated by color-related beliefs and knowledge beyond non-perceptual principles, it does not follow that color experience is cognitively penetrable since the experiences of determinate hues involve post-perceptual processes. We conclude with a brief discussion of the implications that these ideas may have on debates in philosophy.
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85
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Long NM, Kahana MJ. Modulation of task demands suggests that semantic processing interferes with the formation of episodic associations. J Exp Psychol Learn Mem Cogn 2016; 43:167-176. [PMID: 27617775 DOI: 10.1037/xlm0000300] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although episodic and semantic memory share overlapping neural mechanisms, it remains unclear how our pre-existing semantic associations modulate the formation of new, episodic associations. When freely recalling recently studied words, people rely on both episodic and semantic associations, shown through temporal and semantic clustering of responses. We asked whether orienting participants toward semantic associations interferes with or facilitates the formation of episodic associations. We compared electroencephalographic (EEG) activity recorded during the encoding of subsequently recalled words that were either temporally or semantically clustered. Participants studied words with or without a concurrent semantic orienting task. We identified a neural signature of successful episodic association formation whereby high-frequency EEG activity (HFA, 44-100 Hz) overlying left prefrontal regions increased for subsequently temporally clustered words, but only for those words studied without a concurrent semantic orienting task. To confirm that this disruption in the formation of episodic associations was driven by increased semantic processing, we measured the neural correlates of subsequent semantic clustering. We found that HFA increased for subsequently semantically clustered words only for lists with a concurrent semantic orienting task. This dissociation suggests that increased semantic processing of studied items interferes with the neural processes that support the formation of novel episodic associations. (PsycINFO Database Record
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Affiliation(s)
- Nicole M Long
- Department of Psychology, University of Pennsylvania
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86
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Memory Reactivation Predicts Resistance to Retroactive Interference: Evidence from Multivariate Classification and Pattern Similarity Analyses. J Neurosci 2016; 36:4389-99. [PMID: 27076433 DOI: 10.1523/jneurosci.4099-15.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/27/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Memory reactivation--the reinstatement of processes and representations engaged when an event is initially experienced--is believed to play an important role in strengthening and updating episodic memory. The present study examines how memory reactivation during a potentially interfering event influences memory for a previously experienced event. Participants underwent fMRI during the encoding phase of an AB/AC interference task in which some words were presented twice in association with two different encoding tasks (AB and AC trials) and other words were presented once (DE trials). The later memory test required retrieval of the encoding tasks associated with each of the study words. Retroactive interference was evident for the AB encoding task and was particularly strong when the AC encoding task was remembered rather than forgotten. We used multivariate classification and pattern similarity analysis (PSA) to measure reactivation of the AB encoding task during AC trials. The results demonstrated that reactivation of generic task information measured with multivariate classification predicted subsequent memory for the AB encoding task regardless of whether interference was strong and weak (trials for which the AC encoding task was remembered or forgotten, respectively). In contrast, reactivation of neural patterns idiosyncratic to a given AB trial measured with PSA only predicted memory when the strength of interference was low. These results suggest that reactivation of features of an initial experience shared across numerous events in the same category, but not features idiosyncratic to a particular event, are important in resisting retroactive interference caused by new learning. SIGNIFICANCE STATEMENT Reactivating a previously encoded memory is believed to provide an opportunity to strengthen the memory, but also to return the memory to a labile state, making it susceptible to interference. However, there is debate as to how memory reactivation elicited by a potentially interfering event influences subsequent retrieval of the memory. The findings of the current study indicate that reactivating features idiosyncratic to a particular experience during interference only influences subsequent memory when interference is relatively weak. Critically, reactivation of generic contextual information predicts subsequent source memory when retroactive interference is either strong and weak. The results indicate that reactivation of generic information about a prior episode mitigates forgetting due to retroactive interference.
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87
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Reactivation of Reward-Related Patterns from Single Past Episodes Supports Memory-Based Decision Making. J Neurosci 2016; 36:2868-80. [PMID: 26961943 DOI: 10.1523/jneurosci.3433-15.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Rewarding experiences exert a strong influence on later decision making. While decades of neuroscience research have shown how reinforcement gradually shapes preferences, decisions are often influenced by single past experiences. Surprisingly, relatively little is known about the influence of single learning episodes. Although recent work has proposed a role for episodes in decision making, it is largely unknown whether and how episodic experiences contribute to value-based decision making and how the values of single episodes are represented in the brain. In multiple behavioral experiments and an fMRI experiment, we tested whether and how rewarding episodes could support later decision making. Participants experienced episodes of high reward or low reward in conjunction with incidental, trial-unique neutral pictures. In a surprise test phase, we found that participants could indeed remember the associated level of reward, as evidenced by accurate source memory for value and preferences to re-engage with rewarded objects. Further, in a separate experiment, we found that high-reward objects shown as primes before a gambling task increased financial risk taking. Neurally, re-exposure to objects in the test phase led to significant reactivation of reward-related patterns. Importantly, individual variability in the strength of reactivation predicted value memory performance. Our results provide a novel demonstration that affect-related neural patterns are reactivated during later experience. Reactivation of value information represents a mechanism by which memory can guide decision making.
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88
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van Kesteren MTR, Brown TI, Wagner AD. Interactions between Memory and New Learning: Insights from fMRI Multivoxel Pattern Analysis. Front Syst Neurosci 2016; 10:46. [PMID: 27303274 PMCID: PMC4880566 DOI: 10.3389/fnsys.2016.00046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/09/2016] [Indexed: 01/28/2023] Open
Affiliation(s)
- Marlieke T R van Kesteren
- Department of Psychology, Stanford UniversityStanford, CA, USA; Section Educational Neuroscience, Faculty of Behavioural and Movement Sciences, Institute for Brain and Behaviour, Vrije Universiteit AmsterdamAmsterdam, Netherlands
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89
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Behavior, sensitivity, and power of activation likelihood estimation characterized by massive empirical simulation. Neuroimage 2016; 137:70-85. [PMID: 27179606 DOI: 10.1016/j.neuroimage.2016.04.072] [Citation(s) in RCA: 456] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/14/2016] [Accepted: 04/01/2016] [Indexed: 12/19/2022] Open
Abstract
Given the increasing number of neuroimaging publications, the automated knowledge extraction on brain-behavior associations by quantitative meta-analyses has become a highly important and rapidly growing field of research. Among several methods to perform coordinate-based neuroimaging meta-analyses, Activation Likelihood Estimation (ALE) has been widely adopted. In this paper, we addressed two pressing questions related to ALE meta-analysis: i) Which thresholding method is most appropriate to perform statistical inference? ii) Which sample size, i.e., number of experiments, is needed to perform robust meta-analyses? We provided quantitative answers to these questions by simulating more than 120,000 meta-analysis datasets using empirical parameters (i.e., number of subjects, number of reported foci, distribution of activation foci) derived from the BrainMap database. This allowed to characterize the behavior of ALE analyses, to derive first power estimates for neuroimaging meta-analyses, and to thus formulate recommendations for future ALE studies. We could show as a first consequence that cluster-level family-wise error (FWE) correction represents the most appropriate method for statistical inference, while voxel-level FWE correction is valid but more conservative. In contrast, uncorrected inference and false-discovery rate correction should be avoided. As a second consequence, researchers should aim to include at least 20 experiments into an ALE meta-analysis to achieve sufficient power for moderate effects. We would like to note, though, that these calculations and recommendations are specific to ALE and may not be extrapolated to other approaches for (neuroimaging) meta-analysis.
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90
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Age-related differences in the neural basis of the subjective vividness of memories: evidence from multivoxel pattern classification. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2016; 15:644-61. [PMID: 25855004 DOI: 10.3758/s13415-015-0352-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although older adults often show reduced episodic memory accuracy, their ratings of the subjective vividness of their memories often equal or even exceed those of young adults. Such findings suggest that young and older adults may differentially access and/or weight different kinds of information in making vividness judgments. We examined this idea using multivoxel pattern classification of fMRI data to measure category representations while participants saw and remembered pictures of objects and scenes. Consistent with our hypothesis, there were age-related differences in how category representations related to the subjective sense of vividness. During remembering, older adults' vividness ratings were more related, relative to young adults', to category representations in prefrontal cortex. In contrast, young adults' vividness ratings were more related, relative to older adults, to category representations in parietal cortex. In addition, category representations were more correlated among posterior regions in young than in older adults, whereas correlations between PFC and posterior regions did not differ between the 2 groups. Together, these results are consistent with the idea that young and older adults differentially weight different types of information in assessing subjective vividness of their memories.
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91
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Rissman J, Chow TE, Reggente N, Wagner AD. Decoding fMRI Signatures of Real-world Autobiographical Memory Retrieval. J Cogn Neurosci 2016; 28:604-20. [DOI: 10.1162/jocn_a_00920] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Abstract
Extant neuroimaging data implicate frontoparietal and medial-temporal lobe regions in episodic retrieval, and the specific pattern of activity within and across these regions is diagnostic of an individual's subjective mnemonic experience. For example, in laboratory-based paradigms, memories for recently encoded faces can be accurately decoded from single-trial fMRI patterns [Uncapher, M. R., Boyd-Meredith, J. T., Chow, T. E., Rissman, J., & Wagner, A. D. Goal-directed modulation of neural memory patterns: Implications for fMRI-based memory detection. Journal of Neuroscience, 35, 8531–8545, 2015; Rissman, J., Greely, H. T., & Wagner, A. D. Detecting individual memories through the neural decoding of memory states and past experience. Proceedings of the National Academy of Sciences, U.S.A., 107, 9849–9854, 2010]. Here, we investigated the neural patterns underlying memory for real-world autobiographical events, probed at 1- to 3-week retention intervals as well as whether distinct patterns are associated with different subjective memory states. For 3 weeks, participants (n = 16) wore digital cameras that captured photographs of their daily activities. One week later, they were scanned while making memory judgments about sequences of photos depicting events from their own lives or events captured by the cameras of others. Whole-brain multivoxel pattern analysis achieved near-perfect accuracy at distinguishing correctly recognized events from correctly rejected novel events, and decoding performance did not significantly vary with retention interval. Multivoxel pattern classifiers also differentiated recollection from familiarity and reliably decoded the subjective strength of recollection, of familiarity, or of novelty. Classification-based brain maps revealed dissociable neural signatures of these mnemonic states, with activity patterns in hippocampus, medial PFC, and ventral parietal cortex being particularly diagnostic of recollection. Finally, a classifier trained on previously acquired laboratory-based memory data achieved reliable decoding of autobiographical memory states. We discuss the implications for neuroscientific accounts of episodic retrieval and comment on the potential forensic use of fMRI for probing experiential knowledge.
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92
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Wang TH, Johnson JD, de Chastelaine M, Donley BE, Rugg MD. The Effects of Age on the Neural Correlates of Recollection Success, Recollection-Related Cortical Reinstatement, and Post-Retrieval Monitoring. Cereb Cortex 2016; 26:1698-1714. [PMID: 25631058 PMCID: PMC4785952 DOI: 10.1093/cercor/bhu333] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) was used to investigate whether age-related differences in episodic memory performance are accompanied by a reduction in the specificity of recollected information. We addressed this question by comparing recollection-related cortical reinstatement in young and older adults. At study, subjects viewed objects and concrete words, making 1 of 2 different semantic judgments depending on the study material. Test items were words that corresponded to studied words or the names of studied objects. Subjects indicated whether each test item was recollected, familiar, or novel. Reinstatement of information differentiating the encoding tasks was quantified both with a univariate analysis of the fMRI signal and with a multivoxel pattern analysis, using a classifier that had been trained to discriminate between the 2 classes of study episode. The results of these analyses converged to suggest that reinstatement did not differ according to age. Thus, there was no evidence that specificity of recollected information was reduced in older individuals. Additionally, there were no age effects in the magnitude of recollection-related modulations in regional activity or in the neural correlates of post-retrieval monitoring. Taken together, the findings suggest that the neural mechanisms engaged during successful episodic retrieval can remain stable with advancing age.
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Affiliation(s)
- Tracy H. Wang
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
| | - Jeffrey D. Johnson
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Marianne de Chastelaine
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
| | - Brian E. Donley
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
| | - Michael D. Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
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93
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Attention promotes episodic encoding by stabilizing hippocampal representations. Proc Natl Acad Sci U S A 2016; 113:E420-9. [PMID: 26755611 DOI: 10.1073/pnas.1518931113] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Attention influences what is later remembered, but little is known about how this occurs in the brain. We hypothesized that behavioral goals modulate the attentional state of the hippocampus to prioritize goal-relevant aspects of experience for encoding. Participants viewed rooms with paintings, attending to room layouts or painting styles on different trials during high-resolution functional MRI. We identified template activity patterns in each hippocampal subfield that corresponded to the attentional state induced by each task. Participants then incidentally encoded new rooms with art while attending to the layout or painting style, and memory was subsequently tested. We found that when task-relevant information was better remembered, the hippocampus was more likely to have been in the correct attentional state during encoding. This effect was specific to the hippocampus, and not found in medial temporal lobe cortex, category-selective areas of the visual system, or elsewhere in the brain. These findings provide mechanistic insight into how attention transforms percepts into memories.
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94
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Westphal AJ, Reggente N, Ito KL, Rissman J. Shared and distinct contributions of rostrolateral prefrontal cortex to analogical reasoning and episodic memory retrieval. Hum Brain Mapp 2015; 37:896-912. [PMID: 26663572 DOI: 10.1002/hbm.23074] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 11/18/2015] [Accepted: 11/23/2015] [Indexed: 12/11/2022] Open
Abstract
Rostrolateral prefrontal cortex (RLPFC) is widely appreciated to support higher cognitive functions, including analogical reasoning and episodic memory retrieval. However, these tasks have typically been studied in isolation, and thus it is unclear whether they involve common or distinct RLPFC mechanisms. Here, we introduce a novel functional magnetic resonance imaging (fMRI) task paradigm to compare brain activity during reasoning and memory tasks while holding bottom-up perceptual stimulation and response demands constant. Univariate analyses on fMRI data from twenty participants identified a large swath of left lateral prefrontal cortex, including RLPFC, that showed common engagement on reasoning trials with valid analogies and memory trials with accurately retrieved source details. Despite broadly overlapping recruitment, multi-voxel activity patterns within left RLPFC reliably differentiated these two trial types, highlighting the presence of at least partially distinct information processing modes. Functional connectivity analyses demonstrated that while left RLPFC showed consistent coupling with the fronto-parietal control network across tasks, its coupling with other cortical areas varied in a task-dependent manner. During the memory task, this region strengthened its connectivity with the default mode and memory retrieval networks, whereas during the reasoning task it coupled more strongly with a nearby left prefrontal region (BA 45) associated with semantic processing, as well as with a superior parietal region associated with visuospatial processing. Taken together, these data suggest a domain-general role for left RLPFC in monitoring and/or integrating task-relevant knowledge representations and showcase how its function cannot solely be attributed to episodic memory or analogical reasoning computations.
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Affiliation(s)
- Andrew J Westphal
- Department of Psychology, University of California Los Angeles, Los Angeles, California
| | - Nicco Reggente
- Department of Psychology, University of California Los Angeles, Los Angeles, California
| | - Kaori L Ito
- Department of Psychology, University of California Los Angeles, Los Angeles, California
| | - Jesse Rissman
- Department of Psychology, University of California Los Angeles, Los Angeles, California.,Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California.,Brain Research Institute, University of California Los Angeles, Los Angeles, California.,Integrative Center for Learning and Memory, University of California Los Angeles, Los Angeles, California
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95
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Dotson NM, Goodell B, Salazar RF, Hoffman SJ, Gray CM. Methods, caveats and the future of large-scale microelectrode recordings in the non-human primate. Front Syst Neurosci 2015; 9:149. [PMID: 26578906 PMCID: PMC4630292 DOI: 10.3389/fnsys.2015.00149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/19/2015] [Indexed: 12/30/2022] Open
Abstract
Cognitive processes play out on massive brain-wide networks, which produce widely distributed patterns of activity. Capturing these activity patterns requires tools that are able to simultaneously measure activity from many distributed sites with high spatiotemporal resolution. Unfortunately, current techniques with adequate coverage do not provide the requisite spatiotemporal resolution. Large-scale microelectrode recording devices, with dozens to hundreds of microelectrodes capable of simultaneously recording from nearly as many cortical and subcortical areas, provide a potential way to minimize these tradeoffs. However, placing hundreds of microelectrodes into a behaving animal is a highly risky and technically challenging endeavor that has only been pursued by a few groups. Recording activity from multiple electrodes simultaneously also introduces several statistical and conceptual dilemmas, such as the multiple comparisons problem and the uncontrolled stimulus response problem. In this perspective article, we discuss some of the techniques that we, and others, have developed for collecting and analyzing large-scale data sets, and address the future of this emerging field.
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Affiliation(s)
- Nicholas M. Dotson
- Department of Cell Biology and Neuroscience, Montana State UniversityBozeman, MT, USA
| | - Baldwin Goodell
- Department of Cell Biology and Neuroscience, Montana State UniversityBozeman, MT, USA
| | - Rodrigo F. Salazar
- Department of Cell Biology and Neuroscience, Montana State UniversityBozeman, MT, USA
- Faculty of Medicine, Department of Basic Neurosciences, University of GenevaGeneva, Switzerland
| | - Steven J. Hoffman
- Department of Cell Biology and Neuroscience, Montana State UniversityBozeman, MT, USA
| | - Charles M. Gray
- Department of Cell Biology and Neuroscience, Montana State UniversityBozeman, MT, USA
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96
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Martin CB, Cowell RA, Gribble PL, Wright J, Köhler S. Distributed category-specific recognition-memory signals in human perirhinal cortex. Hippocampus 2015; 26:423-36. [PMID: 26385759 DOI: 10.1002/hipo.22531] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2015] [Indexed: 01/24/2023]
Abstract
Evidence from a large body of research suggests that perirhinal cortex (PrC), which interfaces the medial temporal lobe with the ventral visual pathway for object identification, plays a critical role in item-based recognition memory. The precise manner in which PrC codes for the prior occurrence of objects, however, remains poorly understood. In the present functional magnetic resonance imaging (fMRI) study, we used multivoxel pattern analyses to examine whether the prior occurrence of faces is coded by distributed patterns of PrC activity that consist of voxels with decreases as well as increases in signal. We also investigated whether pertinent voxels are preferentially tuned to the specific object category to which judged stimuli belong. We found that, when no a priori constraints were imposed on the direction of signal change, activity patterns that allowed for successful classification of recognition-memory decisions included some voxels with decreases and others with increases in signal in association with perceived prior occurrence. Moreover, successful classification was obtained in the absence of a mean difference in activity across the set of voxels in these patterns. Critically, we observed a positive relationship between classifier accuracy and behavioral performance across participants. Additional analyses revealed that voxels carrying diagnostic information for classification of memory decisions showed category specificity in their tuning for faces when probed with an independent functional localizer in a nonmnemonic task context. These voxels were spatially distributed in PrC, and extended beyond the contiguous voxel clusters previously described as the anterior temporal face patch. Our findings provide support for proposals, recently raised in the neurophysiological literature, that the prior occurrence of objects is coded by distributed PrC representations. They also suggest that the stimulus category to which an item belongs shapes the organization of these distributed representations.
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Affiliation(s)
- Chris B Martin
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada.,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Rosemary A Cowell
- Department of Psychological and Brain Sciences, University of Massachusetts, Amherst, Massachusetts
| | - Paul L Gribble
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - Jessey Wright
- Rotman Institute of Philosophy, Western University, London, Ontario, Canada.,Department of Philosophy, Western University, London, Ontario, Canada
| | - Stefan Köhler
- Department of Psychology, The Brain and Mind Institute, Western University, London, Ontario, Canada.,Baycrest Centre, Rotman Research Institute, Toronto, Ontario, Canada
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97
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Ben-Yakov A, Dudai Y, Mayford MR. Memory Retrieval in Mice and Men. Cold Spring Harb Perspect Biol 2015; 7:cshperspect.a021790. [PMID: 26438596 DOI: 10.1101/cshperspect.a021790] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retrieval, the use of learned information, was until recently mostly terra incognita in the neurobiology of memory, owing to shortage of research methods with the spatiotemporal resolution required to identify and dissect fast reactivation or reconstruction of complex memories in the mammalian brain. The development of novel paradigms, model systems, and new tools in molecular genetics, electrophysiology, optogenetics, in situ microscopy, and functional imaging, have contributed markedly in recent years to our ability to investigate brain mechanisms of retrieval. We review selected developments in the study of explicit retrieval in the rodent and human brain. The picture that emerges is that retrieval involves coordinated fast interplay of sparse and distributed corticohippocampal and neocortical networks that may permit permutational binding of representational elements to yield specific representations. These representations are driven largely by the activity patterns shaped during encoding, but are malleable, subject to the influence of time and interaction of the existing memory with novel information.
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Affiliation(s)
- Aya Ben-Yakov
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yadin Dudai
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel Center for Neural Science, New York University, New York, New York 10003
| | - Mark R Mayford
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037
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98
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St-Laurent M, Abdi H, Buchsbaum BR. Distributed Patterns of Reactivation Predict Vividness of Recollection. J Cogn Neurosci 2015; 27:2000-18. [DOI: 10.1162/jocn_a_00839] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Abstract
According to the principle of reactivation, memory retrieval evokes patterns of brain activity that resemble those instantiated when an event was first experienced. Intuitively, one would expect neural reactivation to contribute to recollection (i.e., the vivid impression of reliving past events), but evidence of a direct relationship between the subjective quality of recollection and multiregional reactivation of item-specific neural patterns is lacking. The current study assessed this relationship using fMRI to measure brain activity as participants viewed and mentally replayed a set of short videos. We used multivoxel pattern analysis to train a classifier to identify individual videos based on brain activity evoked during perception and tested how accurately the classifier could distinguish among videos during mental replay. Classification accuracy correlated positively with memory vividness, indicating that the specificity of multivariate brain patterns observed during memory retrieval was related to the subjective quality of a memory. In addition, we identified a set of brain regions whose univariate activity during retrieval predicted both memory vividness and the strength of the classifier's prediction irrespective of the particular video that was retrieved. Our results establish distributed patterns of neural reactivation as a valid and objective marker of the quality of recollection.
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Affiliation(s)
- Marie St-Laurent
- 1Rotman Research Institute at Baycrest, Toronto, Ontario, Canada
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99
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Khader PH, Pachur T, Weber LAE, Jost K. Neural Signatures of Controlled and Automatic Retrieval Processes in Memory-based Decision-making. J Cogn Neurosci 2015; 28:69-83. [PMID: 26401812 DOI: 10.1162/jocn_a_00882] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Decision-making often requires retrieval from memory. Drawing on the neural ACT-R theory [Anderson, J. R., Fincham, J. M., Qin, Y., & Stocco, A. A central circuit of the mind. Trends in Cognitive Sciences, 12, 136-143, 2008] and other neural models of memory, we delineated the neural signatures of two fundamental retrieval aspects during decision-making: automatic and controlled activation of memory representations. To disentangle these processes, we combined a paradigm developed to examine neural correlates of selective and sequential memory retrieval in decision-making with a manipulation of associative fan (i.e., the decision options were associated with one, two, or three attributes). The results show that both the automatic activation of all attributes associated with a decision option and the controlled sequential retrieval of specific attributes can be traced in material-specific brain areas. Moreover, the two facets of memory retrieval were associated with distinct activation patterns within the frontoparietal network: The dorsolateral prefrontal cortex was found to reflect increasing retrieval effort during both automatic and controlled activation of attributes. In contrast, the superior parietal cortex only responded to controlled retrieval, arguably reflecting the sequential updating of attribute information in working memory. This dissociation in activation pattern is consistent with ACT-R and constitutes an important step toward a neural model of the retrieval dynamics involved in memory-based decision-making.
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100
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