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Mecklinger A, Kamp SM. Observing memory encoding while it unfolds: Functional interpretation and current debates regarding ERP subsequent memory effects. Neurosci Biobehav Rev 2023; 153:105347. [PMID: 37543177 DOI: 10.1016/j.neubiorev.2023.105347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/10/2023] [Accepted: 08/01/2023] [Indexed: 08/07/2023]
Abstract
Our ability to remember the past depends on neural processes set in train in the moment an event is experienced. These processes can be studied by segregating brain activity according to whether an event is later remembered or forgotten. The present review integrates a large number of studies examining this differential brain activity, labeled subsequent memory effect (SME), with the ERP technique, into a functional organization and discusses routes for further research. Based on the reviewed literature, we suggest that memory encoding is implemented by multiple processes, typically reflected in three functionally different subcomponents of the ERP SME elicited by study stimuli, which presumably interact with preparatory SME activity preceding the to be encoded event. We argue that ERPs are a valuable method in the SME paradigm because they have a sufficiently high temporal resolution to disclose the subcomponents of encoding-related brain activity. Implications of the proposed functional organization for future studies using the SME procedure in basic and applied settings will be discussed.
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Affiliation(s)
- Axel Mecklinger
- Experimental Neuropsychology Unit, Saarland University, Campus A 2-4, 66123 Saarbrücken, Germany.
| | - Siri-Maria Kamp
- Neurocognitive Psychology Unit, Universität Trier, Johanniterufer 15, 54290 Trier, Germany
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2
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Kolisnyk M, Pereira AE, Tozios CJI, Fukuda K. Dissociating the Impact of Memorability on Electrophysiological Correlates of Memory Encoding Success. J Cogn Neurosci 2023; 35:603-627. [PMID: 36626358 DOI: 10.1162/jocn_a_01960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Despite its unlimited capacity, not all visual information we encounter is encoded into visual long-term memory. Traditionally, variability in encoding success has been ascribed to variability in the types and efficacy of an individual's cognitive processes during encoding. Accordingly, past studies have identified several neural correlates of variability in encoding success, namely, frontal positivity, occipital alpha amplitude, and frontal theta amplitude, by contrasting the electrophysiological signals recorded during successful and failed encoding processes (i.e., subsequent memory). However, recent research demonstrated individuals remember and forget consistent sets of stimuli, thereby elucidating stimulus-intrinsic factors (i.e., memorability) that determine the ease of memory encoding independent of individual-specific variability in encoding processes. The existence of memorability raises the possibility that canonical EEG correlates of subsequent memory may reflect variability in stimulus-intrinsic factors rather than individual-specific encoding processes. To test this, we recorded the EEG correlates of subsequent memory while participants encoded 600 images of real-world objects and assessed the unique contribution of individual-specific and stimulus-intrinsic factors on each EEG correlate. Here, we found that frontal theta amplitude and occipital alpha amplitude were only influenced by individual-specific encoding success, whereas frontal positivity was influenced by stimulus-intrinsic and individual-specific encoding success. Overall, our results offer novel interpretations of canonical EEG correlates of subsequent memory by demonstrating a dissociable impact of stimulus-intrinsic and individual-specific factors of memory encoding success.
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Affiliation(s)
- Matthew Kolisnyk
- University of Toronto Mississauga, Ontario, Canada.,Western University, London, Ontario, Canada
| | | | | | - Keisuke Fukuda
- University of Toronto Mississauga, Ontario, Canada.,University of Toronto, Ontario, Canada
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3
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Yeh N, Koen JD. Informative and uninformative prestimulus cues at encoding benefit familiarity and source memory. Memory 2023; 31:367-379. [PMID: 36546483 PMCID: PMC10085852 DOI: 10.1080/09658211.2022.2156546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022]
Abstract
Previous research has shown that neural activity elicited by informative prestimulus cues during encoding differ with respect to subsequent memory outcomes. These findings indicate prestimulus cues create a "brain state" associated with subsequent memory that, potentially, also has downstream effects benefitting processes associated with successful encoding and subsequent memory performance. However, previous studies have not included the conditions necessary to appropriately test this latter assumption. The present study examines how informative and uninformative prestimulus encoding cues affect memory accuracy for upcoming stimuli compared to a no cue condition. At encoding, participants made one of two semantic judgments on words preceded by an informative prestimulus cue that identified the upcoming semantic judgment, an uninformative prestimulus cue that signalled an upcoming trial but no information about the semantic judgment, or no cue. Dual process estimates of familiarity, but not recollection, demonstrated a graded pattern with the informativeness of the prestimulus cues (i.e., informative > uninformative > no cues). Moreover, both informative and uninformative prestimulus cues enhanced subsequent source memory accuracy for the encoding task compared to the no cue condition. These findings suggest that prestimulus cues can strengthen the processes that support successful memory encoding and benefit subsequent familiarity and source memory.
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4
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Koen JD. Age-related neural dedifferentiation for individual stimuli: an across-participant pattern similarity analysis. NEUROPSYCHOLOGY, DEVELOPMENT, AND COGNITION. SECTION B, AGING, NEUROPSYCHOLOGY AND COGNITION 2022; 29:552-576. [PMID: 35189773 PMCID: PMC8960356 DOI: 10.1080/13825585.2022.2040411] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Age-related neural dedifferentiation - reductions in the regional specificity and precision of neural representations - is proposed to compromise the ability of older adults to form sufficiently distinct neural representations to support episodic memory encoding. The computational model that spurred investigations of age-related neural dedifferentiation initially characterized this phenomenon as a reduction in the specificity of neural patterns for individual items or stimuli. Most investigations have focused on reductions in neural differentiation for patterns of neural activity associated with category-level information, such as reduced neural selectivity between categories of visual stimuli (e.g., scenes, objects, and faces). Here, I report a novel across-participant pattern similarity analysis method to measure neural distinctiveness for individual stimuli that were presented to participants on a single occasion. Measures of item-level pattern similarity during encoding showed a graded positive subsequent memory effect in younger, with no significant subsequent memory effect in older adults. These results suggest that age-related reductions in the distinctiveness of neural patterns for individual stimuli during age differences in memory encoding. Moreover, a measure of category-level similarity demonstrated a significant subsequent memory effect associated with item recognition (regardless of an object source memory detail), whereas the effect in older was associated with source memory. These results converge with predictions of computational models of dedifferentiation showing age-related reductions in the distinctiveness of neural patterns across multiple levels of representation.
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5
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On the role of item encoding mechanisms in associative memory in young and older adults: A mass univariate ERP study. Neurobiol Learn Mem 2022; 189:107588. [DOI: 10.1016/j.nlm.2022.107588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 01/06/2022] [Accepted: 01/29/2022] [Indexed: 11/22/2022]
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6
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Cohen N, Ben-Yakov A, Weber J, Edelson MG, Paz R, Dudai Y. Prestimulus Activity in the Cingulo-Opercular Network Predicts Memory for Naturalistic Episodic Experience. Cereb Cortex 2021; 30:1902-1913. [PMID: 31740917 DOI: 10.1093/cercor/bhz212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 11/13/2022] Open
Abstract
Human memory is strongly influenced by brain states occurring before an event, yet we know little about the underlying mechanisms. We found that activity in the cingulo-opercular network (including bilateral anterior insula [aI] and anterior prefrontal cortex [aPFC]) seconds before an event begins can predict whether this event will subsequently be remembered. We then tested how activity in the cingulo-opercular network shapes memory performance. Our findings indicate that prestimulus cingulo-opercular activity affects memory performance by opposingly modulating subsequent activity in two sets of regions previously linked to encoding and retrieval of episodic information. Specifically, higher prestimulus cingulo-opercular activity was associated with a subsequent increase in activity in temporal regions previously linked to encoding and with a subsequent reduction in activity within a set of regions thought to play a role in retrieval and self-referential processing. Together, these findings suggest that prestimulus attentional states modulate memory for real-life events by enhancing encoding and possibly by dampening interference from competing memory substrates.
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Affiliation(s)
- Noga Cohen
- Department of Special Education and The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, University of Haifa, Haifa 3498838, Israel
| | - Aya Ben-Yakov
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, CB2 2EF, UK
| | - Jochen Weber
- Department of Psychology, Columbia University, New York, NY, 10027, USA
| | - Micah G Edelson
- Department of Economics, University of Zurich, Zürich, CH-8032, Switzerland
| | - Rony Paz
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Yadin Dudai
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, 76100, Israel
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7
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Liu ES, Koen JD, Rugg MD. Effects of Age on Prestimulus Neural Activity Predictive of Successful Memory Encoding: An fMRI Study. Cereb Cortex 2021; 31:917-932. [PMID: 32959047 DOI: 10.1093/cercor/bhaa265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/17/2020] [Accepted: 08/13/2020] [Indexed: 11/13/2022] Open
Abstract
Prestimulus subsequent memory effects (SMEs)-differences in neural activity preceding the onset of study items that are predictive of later memory performance-have consistently been reported in young adults. The present functional magnetic resonance imaging experiment investigated potential age-related differences in prestimulus SMEs. During study, healthy young and older participants made one of two semantic judgments on images, with the judgment signaled by a preceding cue. In test phase, participants first made an item recognition judgment and, for each item judged old, a source memory judgment. Age-invariant prestimulus SMEs were observed in left dorsomedial prefrontal cortex, left hippocampus, and right subgenual cortex. In each case, the effects reflected lower blood oxygen level dependent signal for later recognized items, regardless of source accuracy, than for unrecognized items. A similar age-invariant pattern was observed in left orbitofrontal cortex, but this effect was specific to items attracting a correct source response compared to unrecognized items. In contrast, the left angular gyrus and fusiform cortex demonstrated negative prestimulus SMEs that were exclusive to young participants. The findings indicate that age differences in prestimulus SMEs are regionally specific and suggest that prestimulus SMEs reflect multiple cognitive processes, only some of which are vulnerable to advancing age.
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Affiliation(s)
- E Song Liu
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX 75235, USA.,School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Joshua D Koen
- Department of Psychology, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Michael D Rugg
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX 75235, USA.,School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,School of Psychology, University of East Anglia, Norwich NR4 7TJ, UK
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8
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Kamp SM. Neurocognitive mechanisms of guided item and associative encoding in young and older adults. Brain Cogn 2020; 145:105626. [DOI: 10.1016/j.bandc.2020.105626] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 08/21/2020] [Accepted: 09/02/2020] [Indexed: 10/23/2022]
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9
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Neural Differentiation is Moderated by Age in Scene-Selective, But Not Face-Selective, Cortical Regions. eNeuro 2020; 7:ENEURO.0142-20.2020. [PMID: 32341120 PMCID: PMC7242814 DOI: 10.1523/eneuro.0142-20.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 04/17/2020] [Indexed: 11/21/2022] Open
Abstract
The aging brain is characterized by neural dedifferentiation, an apparent decrease in the functional selectivity of category-selective cortical regions. Age-related reductions in neural differentiation have been proposed to play a causal role in cognitive aging. Recent findings suggest, however, that age-related dedifferentiation is not equally evident for all stimulus categories and, additionally, that the relationship between neural differentiation and cognitive performance is not moderated by age. In light of these findings, in the present experiment, younger and older human adults (males and females) underwent fMRI as they studied words paired with images of scenes or faces before a subsequent memory task. Neural selectivity was measured in two scene-selective (parahippocampal place area (PPA) and retrosplenial cortex (RSC)] and two face-selective [fusiform face area (FFA) and occipital face area (OFA)] regions using both a univariate differentiation index and multivoxel pattern similarity analysis. Both methods provided highly convergent results, which revealed evidence of age-related reductions in neural dedifferentiation in scene-selective but not face-selective cortical regions. Additionally, neural differentiation in the PPA demonstrated a positive, age-invariant relationship with subsequent source memory performance (recall of the image category paired with each recognized test word). These findings extend prior findings suggesting that age-related neural dedifferentiation is not a ubiquitous phenomenon, and that the specificity of neural responses to scenes is predictive of subsequent memory performance independently of age.
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10
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Age differences in the neural correlates of the specificity of recollection: An event-related potential study. Neuropsychologia 2020; 140:107394. [PMID: 32061829 DOI: 10.1016/j.neuropsychologia.2020.107394] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/13/2019] [Accepted: 02/10/2020] [Indexed: 01/26/2023]
Abstract
In young adults, the neural correlates of successful recollection vary with the specificity (or amount) of information retrieved. We examined whether the neural correlates of recollection are modulated in a similar fashion in older adults. We compared event-related potential (ERP) correlates of recollection in samples of healthy young and older adults (N = 20 per age group). At study, participants were cued to make one of two judgments about each of a series of words. Subsequently, participants completed a memory test for studied and unstudied words in which they first made a Remember/Know/New (RKN) judgment, followed by a source memory judgment when a word attracted a 'Remember' (R) response. In young adults, the 'left parietal effect' - a putative ERP correlate of successful recollection - was largest for test items endorsed as recollected (R judgment) and attracting a correct source judgment, intermediate for items endorsed as recollected but attracting an incorrect or uncertain source judgment, and, relative to correct rejections, absent for items endorsed as familiar only (K judgment). In marked contrast, the left parietal effect was not detectable in older adults. Rather, regardless of source accuracy, studied items attracting an R response elicited a sustained, centrally maximum negative-going deflection relative to both correct rejections and studied items where recollection failed (K judgment). A similar retrieval-related negativity has been described previously in older adults, but the present findings are among the few to link this effect specifically to recollection. Finally, relative to correct rejections, all classes of correctly recognized old items elicited an age-invariant, late-onsetting positive deflection that was maximal over the right frontal scalp. This finding, which replicates several prior results, suggests that post-retrieval monitoring operations were engaged to an equivalent extent in the two age groups. Together, the present results suggest that there are circumstances where young and older adults engage qualitatively distinct retrieval-related processes during successful recollection.
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11
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Evans LH, Herron JE. Pre-retrieval event-related potentials predict source memory during task switching. Neuroimage 2019; 194:174-181. [PMID: 30910727 PMCID: PMC6547053 DOI: 10.1016/j.neuroimage.2019.03.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 03/05/2019] [Accepted: 03/18/2019] [Indexed: 11/29/2022] Open
Abstract
Neural activity preceding memory probes differs according to retrieval goals. These divergences have been linked to retrieval orientations, which are content-specific memory states that bias retrieval towards specific contents. Here, participants were cued to retrieve either spatial location or encoding operations. On the first trial of each memory task (‘switch’ trials), preparatory ERPs preceding correct source memory judgments differed according to retrieval goal, but this effect was absent preceding memory errors. Initiating appropriate retrieval orientations therefore predicted criterial recollection. Preparatory ERPs on the second trial of each memory task (i.e. ‘stay’ trials) also differed according to retrieval goal, but the polarity of this effect was reversed from that observed on switch trials and the effect did not predict memory accuracy. This was interpreted as a correlate of retrieval orientation maintenance, with initiation and maintenance forming dissociable components of these goal-directed memory states. More generally, these findings highlight the importance of pre-retrieval processes in episodic memory. Pre-retrieval ERPs diverged according to cues signalling two different episodic tasks. This index predicted memory accuracy on the first trial of each task. The initiation of task-specific retrieval orientations influences criterial recollection. An orientation effect of reversed polarity on subsequent trials was linked with maintenance. All pre-retrieval ERP effects were maximal at frontal electrode sites.
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Affiliation(s)
- Lisa H Evans
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, CF24 4HQ, Wales, UK
| | - Jane E Herron
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, CF24 4HQ, Wales, UK.
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12
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Strunk J, Duarte A. Prestimulus and poststimulus oscillatory activity predicts successful episodic encoding for both young and older adults. Neurobiol Aging 2019; 77:1-12. [PMID: 30763880 DOI: 10.1016/j.neurobiolaging.2019.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 11/28/2022]
Abstract
Healthy aging is associated with declines in episodic memory performance that are due in part to deficits in encoding. Emerging results from young adult studies suggest that the neural activity during the time preceding stimulus presentation is sensitive to episodic memory performance. It is unknown whether age-related declines in episodic memory are due solely to changes in the recruitment of processes elicited by stimuli during encoding or also in processes recruited in anticipation of these stimuli. Here, we recorded oscillatory electroencephalography while young and old participants encoded visual and auditory words that were preceded by cues indicating the stimulus modality. Individual differences in alpha oscillatory activity preceding, and following, stimulus onset was predictive of subsequent memory performance similarly across age. Poststimulus theta power correlated positively with episodic memory performance for old but not young adults, potentially reflecting older adults' tendency to self-generate associations during encoding. Collectively, these results suggest that the preparatory mobilization of neural processes before encoding that benefits episodic memory performance is not affected by age but instead dependent on the individual's propensity to preemptively mobilize task-specific processes.
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Affiliation(s)
- Jon Strunk
- Department of Psychology, Georgia Institute of Technology, Atlanta, GA.
| | - Audrey Duarte
- Department of Psychology, Georgia Institute of Technology, Atlanta, GA
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13
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The Relationship between Age, Neural Differentiation, and Memory Performance. J Neurosci 2018; 39:149-162. [PMID: 30389841 DOI: 10.1523/jneurosci.1498-18.2018] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 10/21/2018] [Accepted: 10/23/2018] [Indexed: 11/21/2022] Open
Abstract
Healthy aging is associated with decreased neural selectivity (dedifferentiation) in category-selective cortical regions. This finding has prompted the suggestion that dedifferentiation contributes to age-related cognitive decline. Consistent with this possibility, dedifferentiation has been reported to negatively correlate with fluid intelligence in older adults. Here, we examined whether dedifferentiation is associated with performance in another cognitive domain-episodic memory-that is also highly vulnerable to aging. Given the proposed role of dedifferentiation in age-related cognitive decline, we predicted there would be a stronger link between dedifferentiation and episodic memory performance in older than in younger adults. Young (18-30 years) and older (64-75 years) male and female humans underwent fMRI scanning while viewing images of objects and scenes before a subsequent recognition memory test. We computed a differentiation index in two regions of interest (ROIs): parahippocampal place area (PPA) and lateral occipital complex (LOC). This index quantified the selectivity of the BOLD response to preferred versus nonpreferred category of an ROI (scenes for PPA, objects for LOC). The differentiation index in the PPA, but not the LOC, was lower in older than in younger adults. Additionally, the PPA differentiation index predicted recognition memory performance for the studied items. This relationship was independent of and not moderated by age. The PPA differentiation index also predicted performance on a latent "fluency" factor derived from a neuropsychological test battery; this relationship was also age invariant. These findings suggest that two independent factors, one associated with age, and the other with cognitive performance, influence neural differentiation.SIGNIFICANCE STATEMENT Aging is associated with neural dedifferentiation-reduced neural selectivity in "category-selective" cortical brain regions-which has been proposed to contribute to cognitive aging. Here, we examined whether neural differentiation is predictive of episodic memory performance, and whether the relationship is moderated by age. A neural differentiation index was estimated for scene-selective (PPA) and object-selective (LOC) cortical regions while participants studied images for a subsequent memory test. Age-related reductions were observed for the PPA, but not for the LOC, differentiation index. Importantly, the PPA differentiation index demonstrated age-invariant correlations with subsequent memory performance and a fluency factor derived from a neuropsychological battery. Together, these findings suggest that neural differentiation is associated with two independent factors: age and cognitive performance.
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