Perceptual and Semantic Representations at Encoding Contribute to True and False Recognition of Objects

Naspi, Loris; Hoffman, Paul; Devereux, Barry; Morcom, Alexa M.

doi:10.1523/jneurosci.0677-21.2021

Cited by 18 publications

(15 citation statements)

References 69 publications

(96 reference statements)

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“…We first identified brain regions that coded for visual and semantic object representations during perception, independent of memory encoding. As in the studies by Clarke and Tyler (2014) and Naspi et al (2021), this was done by including all trials in RSA analyses of model-brain regardless of their subsequent memory status. As illustrated by Figure 5, a one-sample Wilcoxon signed-rank test revealed that in young adults, visual representations were reliably represented in all 5 ventral pathway ROIs, including EVC (T = 171, p < 0.001), LG (T = 169, p < 0.001), FG (T = 169, p < 0.001), LOC (T = 165, p < 0.001), and vATL (T = 162, p < 0.001).…”

Section: Resultsmentioning

confidence: 99%

“…In a second analysis, we investigated whether visual and semantic representations differentially contributed to later recall memory in young and older adults. Although recent studies suggest that these dimensions are a key factor in the young adults (Davis et al, 2021; Naspi et al, 2021), little is known about their contribution to memory in older adults (but see Deng et al, 2021). Our analytical method involved 4 steps.…”

Section: Methodsmentioning

confidence: 99%

“…The ROIs used in the current study are shown in Figure 1. These regions were selected because they significantly predicted subsequent memory in two recent studies with young adults (Davis et al, 2021; Naspi et al, 2021) and age-related differences in memory reactivation (Deng et al, 2021). We defined five ROIs, including areas spanning the posterior and anterior ventral stream, which have been implicated in visual and semantic feature-based object recognition processes (Clarke and Tyler, 2014, 2015; Lambon Ralph et al, 2017; Devereux et al, 2018).…”

Section: Methodsmentioning

confidence: 99%

“…It is well-established that visual object processing progresses along the occipito-temporal cortex (OTC), from the analysis of simple visual features in early visual cortex to the analysis of objects’ identities and categories in anterior temporal and ventral frontal areas (Mishkin et al, 1983; Murray and Bussey, 1999; Murray and Richmond, 2001). It is also known that these regions store visual and semantic object representations during object encoding and that the quality of these neural representations predict later object memory (Davis et al, 2021; Naspi et al, 2021). Moreover, we know that aging is associated with a reduction in the specificity of object representations in OTC (Carp et al, 2011; Koen et al, 2019; Trelle et al, 2019), and that this deficit—known as dedifferentiation (Koen and Rugg, 2019) — correlates with poor cognitive performance in older adults, particularly episodic memory (Park et al, 2010; Du et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…RSA was used to measure the quality of visual and semantic object representations stored during encoding, which was then used to predict subsequent object memory. In addition to the two regions of interest (ROIs) investigated by Deng et al (2021), EVC and vATL, we also examined the lingual gyrus (LG), the fusiform gyrus (FG), and the lateral occipital cortex (LOC), which are regions known to store object representations and predict subsequent object memory (Davis et al, 2021; Naspi et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Effects of aging on successful object encoding: Enhanced semantic representations compensate for impaired visual representations

Naspi

Stensholt

Karlsson

et al. 2022

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Whereas episodic memory and visual processing decline substantially with healthy aging, semantic knowledge is generally spared. There is evidence that older adults can take advantage of their spared semantic knowledge to support their performance in episodic memory and visual tasks. Here, we used fMRI combined with representational similarity analyses (RSA) to examine how visual and semantic representations stored during encoding predict subsequent object memory. Young and older adults encoded images of objects during fMRI scanning and recalled these images while rating the vividness of their memories. After scanning, participants discriminated between studied images and similar lures. RSA based on a deep convolutional neural network and normative concept feature data was used to link patterns of neural activity during encoding to visual and semantic representations. The quality of visual representations was reduced in older adults, consistent with dedifferentiation, whereas the quality of semantic representations was enhanced in older adults, consistent with hyperdifferentiation. Despite dedifferentiation, visual representations stored in early visual cortex predicted later recall with high vividness in both young and older adults, with no age-related differences. In contrast, semantic representations in lingual and fusiform gyrus were associated with better subsequent object picture recall in older but not in young adults. This finding is consistent with evidence that older adults rely on semantic knowledge to compensate for cognitive deficits. Taken together, the results suggest that the age-related neural dedifferentiation for visual information in posterior regions might be partly counteracted by a boost on semantic representations in more anterior areas.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of aging on successful object encoding: Enhanced semantic representations compensate for impaired visual representations

Naspi

Stensholt

Karlsson

et al. 2022

Preprint

Self Cite

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Representational formats of human memory traces

et al. 2023

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Neural representations are internal brain states that constitute the brain’s model of the external world or some of its features. In the presence of sensory input, a representation may reflect various properties of this input. When perceptual information is no longer available, the brain can still activate representations of previously experienced episodes due to the formation of memory traces. In this review, we aim at characterizing the nature of neural memory representations and how they can be assessed with cognitive neuroscience methods, mainly focusing on neuroimaging. We discuss how multivariate analysis techniques such as representational similarity analysis (RSA) and deep neural networks (DNNs) can be leveraged to gain insights into the structure of neural representations and their different representational formats. We provide several examples of recent studies which demonstrate that we are able to not only measure memory representations using RSA but are also able to investigate their multiple formats using DNNs. We demonstrate that in addition to slow generalization during consolidation, memory representations are subject to semantization already during short-term memory, by revealing a shift from visual to semantic format. In addition to perceptual and conceptual formats, we describe the impact of affective evaluations as an additional dimension of episodic memories. Overall, these studies illustrate how the analysis of neural representations may help us gain a deeper understanding of the nature of human memory.

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Dynamic changes in neural representations underlie the repetition effect on false memory

et al. 2022

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Perceptual and Semantic Representations at Encoding Contribute to True and False Recognition of Objects

Cited by 18 publications

References 69 publications

Effects of aging on successful object encoding: Enhanced semantic representations compensate for impaired visual representations

Effects of aging on successful object encoding: Enhanced semantic representations compensate for impaired visual representations

Representational formats of human memory traces

Dynamic changes in neural representations underlie the repetition effect on false memory

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