Representational Similarity Analyses

Dimsdale-Zucker, Halle R.; Ranganath, Charan

doi:10.1016/b978-0-12-812028-6.00027-6

Cited by 81 publications

(50 citation statements)

References 48 publications

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“…By examining other load levels (e.g., 1-back, 3-back) it could be better determined whether there are qualitative differences that make some load levels more distinct from others (e.g., 2-back and 3-back may be more similar to each other than they are to 0-back or 1-back). Indeed, although there is a growing literature utilizing MVPA decoding approaches within the domain of WM and cognitive control (D'Esposito & Postle, 2015), the use of pattern similarity measures is still sparse in this domain, relative to its adoption in other cognitive domains, such as perceptual coding (Chikazoe, Lee, Kriegeskorte, & Anderson, 2014;Kriegeskorte et al, 2008) and episodic memory (Dimsdale-Zucker & Ranganath, 2018;LaRocque et al, 2013;Xue et al, 2010). We hope that the utility of the pattern similarity approach demonstrated here will encourage other researchers to begin applying it to a broader range of questions in WM and executive control.…”

Section: Neural Coding Of Wm Load In Fpnmentioning

confidence: 96%

Pattern Similarity Analyses of FrontoParietal Task Coding: Individual Variation and Genetic Influences

et al. 2020

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Pattern similarity analyses are increasingly used to characterize coding properties of brain regions, but relatively few have focused on cognitive control processes in FrontoParietal regions. Here, we use the Human Connectome Project (HCP) N-back task functional magnetic resonance imaging (fMRI) dataset to examine individual differences and genetic influences on the coding of working memory load (0-back, 2-back) and perceptual category (Face, Place). Participants were grouped into 105 monozygotic twin, 78 dizygotic twin, 99 nontwin sibling, and 100 unrelated pairs. Activation pattern similarity was used to test the hypothesis that FrontoParietal regions would have higher similarity for same load conditions, while Visual regions would have higher similarity in same perceptual category conditions. Results confirmed this highly robust regional double dissociation in neural coding, which also predicted individual differences in behavioral performance. In pair-based analyses, anatomically selective genetic relatedness effects were observed: relatedness predicted greater activation pattern similarity in FrontoParietal only for load coding and in Visual only for perceptual coding. Further, in related pairs, the similarity of load coding in FrontoParietal regions was uniquely associated with behavioral performance. Together, these results highlight the power of task fMRI pattern similarity analyses for detecting key coding and heritability features of brain regions.

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Section: Neural Coding Of Wm Load In Fpnmentioning

confidence: 96%

Pattern Similarity Analyses of FrontoParietal Task Coding: Individual Variation and Genetic Influences

et al. 2020

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“…Recently we showed that DMN up-regulation and down-regulation learning are negatively correlated [12]. Therefore it is feasible that the present results would be reversed using a hippocampal up-regulation task.…”

Section: Limitations and Future Directionsmentioning

confidence: 66%

“…White matter microstructure is altered in cognitively normal middle-aged APOE-ε4 homozygotes [10] and a previously established increase in default mode network (DMN) connectivity during β-amyloid accumulation [2] appears to be compensating for decreasing functional connectivity of the left hippocampus [3], that specializes in the representation of objects' episodic context [11]. Age and psychiatric pathology exert significant effects on neurofeedback (NF) performance of the DMN [12] and we have developed an open-source virtual reality (VR) NF environment for real-time fMRI (rt-fMRI), to systematize further investigations [13].…”

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confidence: 99%

The effect of APOE genotype and streamline density volume, on hippocampal CA1 down-regulation: a real-time fMRI virtual reality neurofeedback study

Skouras

Torner

Anderson

et al. 2019

Preprint

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† The complete list of collaborators of the ALFA Study can be found in the acknowledgements section *Correspondence to: jlmolinuevo@barcelonabeta.org Highlights • APOE-ε4 alleles impact hippocampal down-regulation neurofeedback performance.• Hippocampal streamline density volume is associated with decreased hippocampal down-regulation performance.• Bilaterally cohesive hippocampal activity is associated with better memory performance.• We provide a novel paradigm to investigate self-regulation and brain function. AbstractHippocampal hyperactivity is a precursor of Alzheimer's disease and more prominent in APOE-ε4 carriers. It is therefore important to investigate the processes of hippocampal self-regulation, to monitor therapeutic efficacy of preclinical interventions. We have developed a closed-loop, virtual reality neurofeedback paradigm for real-time fMRI, that provides a standardized method for quantifying processes of hippocampal self-regulation. We acquired multi-modal neuroimaging data from a sample of 53 cognitively unimpaired subjects at risk for AD and applied standard methods of structural and functional connectomics. The analyses reveal significant negative associations between hippocampal CA1 down-regulation performance and APOE-ε4 alleles, as well as hippocampal streamline density volume.Better memory performance was associated with increased, bilateral hippocampal functional connectivity during the neurofeedback task. These are the first results to link neurofeedback performance to a genetic risk factor and structural connectivity.Further, these are the first evidence that functional cohesion between the hippocampi can reflect subtle differences in memory function, in cognitively unimpaired individuals at risk for AD. We provide a novel method to assess hippocampal function in preclinical AD, and propose it can be used to derive proxies for neural reserve. IntroductionRecent fMRI studies have renewed hope for identifying subtle functional changes preceding irreversible neurodegeneration due to Alzheimer's disease (AD) [1][2][3]. In-depth literature review suggests that the hippocampus is the only brain region that is consistently and bilaterally both a) implicated in memory encoding processes, as indicated by a meta-analysis of 72 fMRI studies of subsequent memory effects [4] and b) differing in activity between AD patients and controls, as indicated by a quantitative meta-analysis of 11 fMRI studies on memory encoding [5].Moreover, recent evidence suggests hippocampal hyperactivity as a precursor of amyloid deposition [1], which is accepted as the earliest sign of preclinical AD [6].Similarly, APOE-ε4 carriers, exhibit hippocampal hyperactivity during a memory task designed to assess pattern separation [7], suggesting the possibility of a genetic mechanism linked to the concepts of neural reserve and neural efficiency [8][9].

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“…The assumptions and rules of these approaches differ substantially. However, these methods answer different questions and provide complementary information 104,105 . A standard univariate fMRI analysis approach would examine the difference at each voxel between the averages across experimental conditions (for instance: emotion categories).…”

Section: Fmri Data Acquisition and Preprocessingmentioning

confidence: 99%

Distinct medial-temporal lobe mechanisms of encoding and amygdala-mediated memory reinstatement for disgust and fear

Riegel

Wierzba

Wypych

et al. 2019

Preprint

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Many associative memory traces are charged with emotion that can either impair or enhance subsequent retrieval. Various factors may influence such emotion effects, including the nature of associations and type of emotions. We show that long-term recognition memory of very close verbal associations was enhanced for emotionally charged material, and these effects differed between two negative emotion categories matched for arousal level. Specifically, memory was better for word pairs related to disgust than word pairs related to fear. Furthermore, these two emotions distinctively modulated neural processes during encoding and its relationship with retrieval, regardless of arousal evoked by word pairs. Amygdala and perirhinal cortex activity were associated with enhanced memory for disgust-related unitizations, whereas better memory for fear-related unitizations engaged parahippocampal cortex and hippocampus. Finally, the magnitude of amygdala activation during encoding was related to the subsequent fidelity of hippocampal activity patterns during retrieval. These results show that dissociable neural pathways and reinstatement mechanisms are involved in associative memory for different emotion categories and that arousal alone cannot fully explain emotional influences on associative memory.individually control for the effects of valence and arousal dimensions. Most importantly, this paradigm enabled us to compare the encoding-retrieval similarity of brain activation patterns elicited across two different emotion categories and determine which brain regions promoted this measure of neural reinstatement.We found a memory enhancement effect due to emotion. Moreover, word pairs related to disgust were remembered better than word pairs related to fear, and this effect could not be explained by differences in arousal. We found distinctive neural pathways preferentially engaged in encoding modulation by disgust or fear. Specifically, the left AMY and left PRC were more activated during successful encoding of disgust-related unitized word pairs, whereas right PHC and HC were more activated for fear-related unitized word pairs, even when the level of arousal was regressed out from the analysis. Moreover, during successful encoding of disgust-compared to fearrelated word pairs, we observed an increase in functional connectivity between AMY, PRC and PHC. Finally, for disgusting compared to fearful word pairs, the left AMY encoding activation was found to be critical for the level of trial-by-trial encodingretrieval similarity of brain activation patterns.Altogether, the results show that behavioural and neuronal mechanisms of long-term associative memory can be differently modulated by basic emotion categories, over and above of valence and arousal dimensions. For the first time, we revealed that due to AMY and PRC engagement, disgust as opposed to fear has a strong influence on reinstatement and recognition memory of unitized word pairs, which is in line with its distinctive and perhaps evolutionary-driven role in memorizing ...

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Representational Similarity Analyses

Cited by 81 publications

References 48 publications

Pattern Similarity Analyses of FrontoParietal Task Coding: Individual Variation and Genetic Influences

Pattern Similarity Analyses of FrontoParietal Task Coding: Individual Variation and Genetic Influences

The effect of APOE genotype and streamline density volume, on hippocampal CA1 down-regulation: a real-time fMRI virtual reality neurofeedback study

Distinct medial-temporal lobe mechanisms of encoding and amygdala-mediated memory reinstatement for disgust and fear

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