Semantic Memory Tasks Research Articles

Registered report: Age-preserved semantic memory and the CRUNCH effect manifested as differential semantic control networks: An fMRI study.

Semantic memory representations are generally well maintained in aging, whereas semantic control is thought to be more affected. To explain this phenomenon, this study tested the predictions of the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), focusing on task demands in aging as a possible framework. The CRUNCH effect would manifest itself in semantic tasks through a compensatory increase in neural activation in semantic control network regions but only up to a certain threshold of task demands. This study compares 39 younger (20-35 years old) with 39 older participants (60-75 years old) in a triad-based semantic judgment task performed in an fMRI scanner while manipulating task demand levels (low versus high) through semantic distance. In line with the CRUNCH predictions, differences in neurofunctional activation and behavioral performance (accuracy and response times) were expected in younger versus older participants in the low- versus high-demand conditions, which should be manifested in semantic control Regions of Interest (ROIs). Our older participants had intact behavioral performance, as proposed in the literature for semantic memory tasks (maintained accuracy and slower response times (RTs)). Age-invariant behavioral performance in the older group compared to the younger one is necessary to test the CRUNCH predictions. The older adults were also characterized by high cognitive reserve, as our neuropsychological tests showed. Our behavioral results confirmed that our task successfully manipulated task demands: error rates, RTs and perceived difficulty increased with increasing task demands in both age groups. We did not find an interaction between age group and task demand, or a statistically significant difference in activation between the low- and high-demand conditions for either RTs or accuracy. As for brain activation, we did not find the expected age group by task demand interaction, or a significant main effect of task demand. Overall, our results are compatible with some neural activation in the semantic network and the semantic control network, largely in frontotemporoparietal regions. ROI analyses demonstrated significant effects (but no interactions) of task demand in the left and right inferior frontal gyrus, the left posterior middle temporal gyrus, the posterior inferior temporal gyrus and the prefrontal gyrus. Overall, our test did not confirm the CRUNCH predictions.

The Quebec Semantic Memory Battery: Development, Standardization, and Psychometric Assessment of a Semantic Memory Battery in French.

People with aphasia often experience semantic memory (SM) impairment. To improve diagnostic outcomes, SM tasks should recruit various sensory input channels (oral, written, and pictographic), permitting accessible, complete evaluation. There is a need for SM batteries for French-speaking Quebecers that use multiple input channels. The present study, therefore, describes the development of a novel French-language semantic battery: la Batterie québécoise de la mémoire sémantique (BQMS), the assessment of the BQMS's psychometric properties, and the establishment of normative data for the BQMS. We first developed eight SM tasks. Following a pilot validation study, we determined the BQMS's reliability and validity, to ensure consistent, accurate detection of SM impairment. Among French-speaking Quebecers with cerebrovascular aphasia (n = 10), people with the semantic variant of Primary Progressive Aphasia (n = 4), and healthy controls (n = 14), we examined its convergent validity, concurrent validity, test-retest reliability, and internal consistency. Finally, we established normative data for the BQMS by calculating cut-off scores per task that indicate SM impairment (in 93 cognitively healthy French-speaking Quebecers), stratified by sociodemographic variables associated with performance. The BQMS shows high concurrent, discriminant, and convergent validity, as well as good test-retest reliability and internal consistency. The cut-off score indicating SM impairment ranged from the 2nd to 25th percentiles (stratified by task, age, and sex). The BQMS's psychometric properties indicate that it could be a valuable clinical tool for detecting SM impairment. Our normative data will help clinicians detect such impairments.

Evidence of Impaired Remote Experience-near Semantic Memory in Medial Temporal Lobe Amnesia.

Neuropsychological research suggests that "experience-near" semantic memory, meaning knowledge attached to a spatiotemporal or event context, is commonly impaired in individuals who have medial temporal lobe amnesia. It is not known if this impairment extends to remotely acquired experience-near knowledge, which is a question relevant to understanding hippocampal/medial temporal lobe functioning. In the present study, we administered a novel semantic memory task designed to target knowledge associated with remote, "dormant" concepts, in addition to knowledge associated with active concepts, to four individuals with medial temporal lobe amnesia and eight matched controls. We found that the individuals with medial temporal lobe amnesia generated significantly fewer experience-near semantic memories for both remote concepts and active concepts. In comparison, the generation of abstract or "experience-far" knowledge was largely spared in the individuals with medial temporal lobe amnesia, regardless of whether the targets for retrieval were remote or active concepts. We interpret these findings as evidence that the medial temporal lobes may have a sustained role in the retrieval of semantic memories associated with spatiotemporal and event contexts, which are cognitive features often ascribed to episodic memory. These results align with recent theoretical models proposing that the hippocampus/medial temporal lobes support cognitive processes that are involved in, but not exclusive to, episodic memory.

Differential effects of remotely supervised transcranial direct current stimulation on recognition memory depending on task order.

Prior work has shown positive effects of High Definition transcranial direct current stimulation (HD-tDCS) over the dorsolateral prefrontal cortex (DLPFC) on semantic memory performance and metamemory monitoring accuracy. However, HD-tDCS requires setup by a trained researcher, which is not always feasible. Few studies have used remotely supervised (rs) tDCS in healthy populations, and remote supervision has strong practical benefits. The goal of the current study was to test if previously shown effects of HD-tDCS over the left DLPFC on semantic memory performance and metamemory monitoring accuracy extended to conventional rs-tDCS, which is less focal than HD-tDCS, and to episodic memory and metamemory tasks. A total of 36 healthy participants completed 6 weeks of rs-tDCS sessions, with either active left or right anodal DLPFC stimulation, or sham. Participants completed semantic and episodic memory and metamemory tasks, which each lasted for three consecutive sessions, and session order was counterbalanced across participants. Overall, there were no main effects of rs-tDCS on metamemory monitoring accuracy or memory performance for either the semantic or the episodic tasks. However, there were effects of rs-tDCS that depended on the order of completing the episodic and semantic task sessions. When participants completed the semantic task sessions after the episodic task sessions, semantic recognition was greater in the left anodal DLPFC condition. In a parallel effect, when participants completed the episodic task sessions after the semantic task sessions, episodic recognition was greater in the right anodal DLPFC condition. Prior experience with tDCS is a factor for effects of rs-tDCS on cognition. Additionally, the current experiment provides evidence for the feasibility of fully remotely supervised tDCS in healthy participants.

Differences in electroencephalography oscillations between normal aging and mild cognitive impairment during semantic memory retrieval.

Semantic memory remains relatively stable with normal cognitive aging and declines in early stages of neurodegenerative disease. We measured electroencephalography (EEG) oscillatory correlates of semantic memory retrieval to examine the effects of normal and pathological aging. Twenty-nine cognitively healthy young adults (YA), 22 cognitively healthy aging adults (HA) and 20 patients with mild cognitive impairment (MCI) completed a semantic memory retrieval task with concurrent EEG recording in which they judged whether two words (features of objects) led to retrieval of an object (retrieval) or not (non-retrieval). Event-related power changes contrasting the two conditions (retrieval vs. non-retrieval) within theta, alpha, low-beta and high-beta EEG frequency bands were examined for normal aging (YA vs. HA) and pathological aging effects (HA vs. MCI). With no behavioural differences between the two normal age groups, we found later theta and alpha event-related power differences between conditions only in YA and a high-beta event-related power difference only in HA. For pathological aging effects, with reduced accuracy in MCI, we found different EEG patterns of early event-related beta power differences between conditions in MCI compared with HA and an event-related low-beta power difference only in HA. Beta oscillations were correlated with behavioural performance only in HA. We conclude that the aging brain relies on faster (beta) oscillations during the semantic memory task. With pathological aging, retrieval accuracy declines and pattern of beta oscillation changes. The findings provide insights about age-related neural mechanisms underlying semantic memory and have implications for early detection of pathological aging.

Disturbed medication management in older adults with good cognitive health and mild cognitive impairment associated with semantic memory impairment: The Wakuya Project

For older adults with mild cognitive impairment or mild dementia, maintaining daily lives at home is also ideal for quality of life. However, they have serious problems with medication management. Although the Dementia Assessment Sheet in community-based integrated care system-21 items and the regimen comprehension scale are assessment scales for medication, there have been no reports evaluating both semantic memory and actual performance. A total of 180 older adults aged ≥75 years were entered in the Wakuya Project. They underwent the Clinical Dementia Rating, with two original tests: (i) the original semantic memory task for taking medication including the Dementia Assessment Sheet in community-based integrated care system-21 items; and (ii) the actual performance task related to medication including regimen comprehension scale. Non-demented participants were classified into two groups based on reports from their families; that is, a good management group (n=66) and a poor management group (n=42), and the two original tests were analyzed as explanatory variables. There were no differences between the two groups for the actual performance task related to medication including regimen comprehension scale. The success rates for the actual performance task related to medication including regimen comprehension scale (good management group/poor management group) were: regimen comprehension scale 40.9/23.8, One-Day Calendar 93.9/90.5, Medicine Chest 36.4/23.8 and Sequential Behavior Task 66.7/66.7, respectively. In the original semantic memory task for taking medication including the Dementia Assessment Sheet in community-based integrated care system-21 items, logistic regression analysis showed that only the mechanism of action remained (B -2.38, SE 1.10, Wald 4.69, P-value=0.03, OR 0.09, 95%CI 0.01-0.80). Our results suggest that disruption of medicine management might also be associated with drug semantic memory impairment between the two groups, with no difference in general cognitive and executive functions. Geriatr Gerontol Int 2023; 23: 319-325.

Shared and distinct routes in speech and gesture imitation: Evidence from stroke

Dual-route models of high-level (praxis) actions distinguish between an “indirect” semantic route mediating meaningful gesture imitation, and a “direct” sensory-motor route mediates meaningless gesture imitation. Similarly, dual-route language models distinguish between an indirect route mediating production and repetition of words, and a direct route mediating non-word repetition. Although aphasia and limb apraxia frequently co-occur following left-hemisphere cerebrovascular accident (LCVA), it is unclear which aspects of these functional-neuroanatomic dual-route architectures are shared across praxis and language domains. This study focused on gesture imitation to test the hypothesis that semantic information (and portions of the indirect route) are shared across domains, whereas two distinct dorsal routes mediate sensory-motor mapping. Forty chronic LCVA and 17 neurotypical controls completed semantic memory and language tasks and imitated 3 types of gesture stimuli: (1) labeled/“named” meaningful, (2) unnamed meaningful, and (3) meaningless gestures. The comparison of accuracy between meaningless versus unnamed meaningful gestures examined the benefits of semantic information, while the comparison of unnamed meaningful versus named meaningful imitation examined additional benefits of linguistic cueing. Mixed-effects models examined group by task interaction effects on gesture ability. We found that for patients with LCVA, unnamed meaningful gestures were imitated more accurately than meaningless gestures, suggesting that semantic information was beneficial, but there was no benefit of labeling. Reduced benefit of semantic information on gesture accuracy was associated with lesions to inferior frontal and posterior temporal regions as well as semantic memory performance on a pictorial (non-gesture) task. In contrast, there was no relationship between meaningless gesture imitation and nonword repetition, indicating that measures of direct route performance are not associated across language and action. These results provide preliminary evidence that portions of the indirect semantic route are shared across the language and action domains, while two direct sensory-motor mapping routes mediate word repetition and gesture imitation.

Comparing event-related potentials of retrospective and prospective metacognitive judgments during episodic and semantic memory

It is unclear whether metacognitive judgments are made on the basis of domain-generality or domain-specificity. In the current study, we compared both behavioral and event-related potential (ERP) correlates of retrospective (retrospective confidence judgments: RCJs), and prospective (feeling of knowing: FOK) metacognitive judgments during episodic and semantic memory tasks in 82 participants. Behavioral results indicated that FOK judgments reflect a domain-specific process, while RCJ reflect a domain-general process. RCJ and FOK judgments produced similar ERP waveforms within the memory tasks, but with different temporal dynamics; thus supporting the hypothesis that retrospective and prospective metacognitive judgments are distinct processes. Our ERP results also suggest that metacognitive judgments are linked to distributed neural substrates, rather than purely frontal lobe functioning. Furthermore, the role of intra-subject and inter-subject differences in metacognitive judgments across and within the memory tasks are highlighted.

How is semantic memory affected in Mild Cognitive Impairment?

AbstractBackgroundMild cognitive impairment (MCI) is a condition considered by many as a transitional stage between healthy aging and Alzheimer’s disease. Although its diagnosis is typically based on the assessment of episodic memory, evidences show that impairment in semantic memory would be one of the first manifestations of cognitive impairment. This study aims to investigate how semantic memory is affected in MCI. Precisely, we will explore if core memory of common knowledge is impaired in MCI, and if the performance in semantic memory task vary with the modality of presentation of the stimuli (verbal vs visual).MethodA group of healthy people aged between 60 and 90 years old (mean: 77.4 N = 43), and a age‐matched group meeting the criteria for MCI (N = 32), who have lived in Quebec (Canada) for at least 30 years, completed two neuropsychological tests evaluating the semantic memory of famous people, which have been proven to be the most sensible way to detect even subtle variation in semantic memory.ResultResults indicate that performance in both tests is impaired in the MCI group, compared to the healthy elderly group. This means that the MCI group have more difficulty to name famous people (t (69) = 5,173, p < 0.01), as well as answer basic questions on them (ex: their profession, nationality, etc.), when presented from their picture (t (69) = 4.849, p < 0.01) or their name (t (65) = 3.488, p < 0.01), compared to healthy people of the same age. There was no difference between their performances when the stimuli was presented in the visual or verbal modality (t (30) = 0.928, p > 0.05).ConclusionThis study demonstrates that semantic memory of famous people is impaired in MCI, and that impairment affects the capacity to name famous people as well as remembering facts about them. In addition, there are no difference if the stimuli are presented visually or verbally. This suggests that the impairment in semantic memory in MCI is due to a degradation of the memory, and is not modulated by other cognitive functions or modality.

Dissociations between musical semantic memory and verbal memory in a patient with behavioral variant frontotemporal dementia

Objectives Patients with dementia show dissociations between musical semantic memory (i.e., spared musical lexicon) and other memory modalities, except in some severe cases. We aim to study, from a neuropsychological point of view, the dissociation between musical semantic memory compared to language and verbal memory in a patient with severe Behavioral Variant Frontotemporal Dementia (bvFTD). We hypothesize a single dissociation between these domains will be found, with sparing of musical semantic memory. Methods LC, a patient with severe bvFTD, and three matched controls were assessed through language, semantic, and episodic memory, and musical semantic memory tasks. The control group had similar music taste as LC: to participate as controls, tango must be one of their favorite musical genres. Results LC showed impairment in all Verbal Memory tasks, but not in musical tasks. There was a dissociation between musical semantic memory, and language and verbal semantic memory. Conclusions The musical lexicon can be preserved in advanced stages of dementia, which supports the idea that music can be a therapeutic tool in patients with severe dementia.

Local detour centrality: a novel local centrality measure for weighted networks

Centrality, in some sense, captures the extent to which a vertex controls the flow of information in a network. Here, we propose Local Detour Centrality as a novel centrality-based betweenness measure that captures the extent to which a vertex shortens paths between neighboring vertices as compared to alternative paths. After presenting our measure, we demonstrate empirically that it differs from other leading central measures, such as betweenness, degree, closeness, and the number of triangles. Through an empirical case study, we provide a possible interpretation for Local Detour Centrality as a measure that captures the extent to which a word is characterized by contextual diversity within a semantic network. We then examine the relationship between our measure and the accessibility to knowledge stored in memory. To do so, we show that words that occur in several different and distinct contexts are significantly more effective in facilitating the retrieval of subsequent words than are words that lack this contextual diversity. Contextually diverse words themselves, however, are not retrieved significantly faster than non-contextually diverse words. These results were obtained for a serial semantic memory task, where the word’s location constitutes a significant mediator in the relationship between the proposed measure and accessibility to knowledge stored in memory.

Bidirectional Regulation of Hippocampal Synaptic Plasticity and Modulation of Cumulative Spatial Memory by Dopamine D2-Like Receptors.

Dopamine is a key factor in the enablement of cognition and hippocampal information processing. Its action in the hippocampus is mediated by D1/D5 and D2-like (D2, D3, D4) receptors. While D1/D5-receptors are well recognized as strong modulators of hippocampal synaptic plasticity and information storage, much less is known about the role of D2-like receptors (D2R) in these processes. Here, we explored to what extent D2R contribute to synaptic plasticity and cumulative spatial memory derived from semantic and episodic-like information storage. In freely behaving adult rats, we also assessed to what extent short and long-term forms of synaptic plasticity are influenced by pharmacological activation or blockade of D2R. Antagonism of D2R by means of intracerebral treatment with remoxipride, completely prevented the expression of both short-term (<1 h) and long-term potentiation (>4 h), as well as the expression of short-term depression (STD, <1 h) in the hippocampal CA1 region. Scrutiny of involvement of D2R in spatial learning revealed that D2R-antagonism prevented retention of a semantic spatial memory task, and also significantly impaired retention of recent spatiotemporal aspects of an episodic-like memory task. Taken together, these findings indicate that D2R are required for bidirectional synaptic plasticity in the hippocampal CA1 region. Furthermore, they are critically involved in enabling cumulative and episodic-like forms of spatial learning.

Sensitive Measures of Cognition in Mild Cognitive Impairment.

Sensitive measures of cognition are needed in preclinical and prodromal Alzheimer's disease (AD) to track cognitive change and evaluate potential interventions. Neurofibrillary tangle pathology in AD is first observed in Brodmann Area 35 (BA35), the medial portion of the perirhinal cortex. The importance of the perirhinal cortex for semantic memory may explain early impairments of semantics in preclinical AD. Additionally, our research has tied figurative language impairment to neurodegenerative disease. We aim to identify tasks that are sensitive to cognitive impairment in individuals with mild cognitive impairment (MCI), and that are sensitive to atrophy in BA35. Individuals with MCI and cognitively normal participants (CN) were tested on productive and receptive experimental measures of semantic memory and experimental tests of figurative language comprehension (including metaphor and verbal analogy). Performance was related to structural imaging and standard neuropsychological assessment. On the experimental tests of semantics and figurative language, people with MCI performed worse than CN participants. The experimental semantic memory tasks are sensitive and specific; performance on the experimental semantic memory tasks related to medial temporal lobe structural integrity, including BA35, while standard neuropsychological assessments of semantic memory did not, demonstrating the sensitivity of these experimental measures. A visuo-spatial analogy task did not differentiate groups, confirming the specificity of semantic and figurative language tasks. These experimental measures appear sensitive to cognitive change and neurodegeneration early in the AD trajectory and may prove useful in tracking cognitive change in clinical trials aimed at early intervention.

A model-based analysis of the impairment of semantic memory

We use cognitive models to evaluate three theories of the change in semantic memory caused by Alzheimer's disease. We use data from 14,096 clinical assessments of 3602 Alzheimer's patients and their caregivers. Each patient completed a semantic memory task involving the odd-one-out comparison of animal names. Each patient was also independently evaluated to determine their level of impairment. Our cognitive models assume a feature-based representation of the animals and odd-one-out choice probabilities based on common-feature similarities. We find no evidence for the restructured representation hypothesis, which claims that impairment causes changes in the features used to represent stimuli. We also find no evidence for the attention change hypothesis, which claims that impairment causes greater attention to be given to concrete features at the expense of more abstract features. We do find evidence for the noisy access hypothesis, which claims that odd-one-out choices become less determined by semantic similarity and more prone to the simple response strategy of choosing the last option. We conclude that the noisy access hypothesis provides a simple account of odd-one-out choice behavior throughout the progression of Alzheimer's disease. More elaborate theories involving changes to underlying mental representations and attention processes need to provide evidence they are superior to the noisy access account.

Differences between episodic and semantic memory in predicting observation-based activities of daily living in mild cognitive impairment and Alzheimer’s disease

Individuals with mild cognitive impairment (MCI) can often progress into Alzheimer’s Disease (AD). Research suggests that decline in episodic memory and semantic memory, as well as functional abilities, can be sensitive in predicting disease progression. This study aimed to (a) investigate episodic and semantic memory performance differences between AD and MCI, (b) determine if memory performance predicts observation-based activities of daily living (ADLs), and (c) explore whether semantic memory mediates the relationship between episodic memory and ADLs. Fifty-eight AD, 53 MCI, and 72 healthy control participants were administered the Rey-O, California Verbal Learning Test, Animal Fluency Test, Boston Naming Test, and Direct Assessment of Functional Status (DAFS). The results revealed, first, that AD participants performed significantly lower than the MCI participants across semantic memory and episodic memory tasks, with the exception of the Boston Naming Test. Second, hierarchical-stepwise regression analyses found that semantic memory significantly predicted DAFS orientation, communication, and financial skills in AD, but episodic memory predicted shopping skills. Furthermore, semantic memory significantly predicted DAFS transportation skills in AD and MCI. Third, within the overall sample, semantic memory mediated the relationship between episodic memory and ADLs. Taken together, the findings suggest decline in semantic memory (as measured by confrontational naming and category fluency) and episodic memory (as measured by list and complex visual design learning and recall) may lead to decline in different and specific aspects of functional abilities in AD and MCI.

Assessing abstract thought and its relation to language with a new nonverbal paradigm: Evidence from aphasia

In recent years, language has been shown to play a number of important cognitive roles over and above the communication of thoughts. One hypothesis gaining support is that language facilitates thought about abstract categories, such as democracy or prediction. To test this proposal, a novel set of semantic memory task trials, designed for assessing abstract thought non-linguistically, were normed for levels of abstractness. The trials were rated as more or less abstract to the degree that answering them required the participant to abstract away from both perceptual features and common setting associations corresponding to the target image. The normed materials were then used with a population of people with aphasia to assess the relationship of abstract thought to language. While the language-impaired group with aphasia showed lower overall accuracy and longer response times than controls in general, of special note is that their response times were significantly longer as a function of a trial's degree of abstractness. Further, the aphasia group's response times in reporting their degree of confidence (a separate, metacognitive measure) were negatively correlated with their language production abilities, with lower language scores predicting longer metacognitive response times. These results provide some support for the hypothesis that language is an important aid to abstract thought and to metacognition about abstract thought.

Semantic memory and reading comprehension: the relationship through adulthood and aging.

Literature shows a relationship between working memory and reading comprehension during lifespan and aging. In addition, a difference between genres of text was shown: the expository text affects the already limited cognitive resources of the older adults, whereas narrative text comprehension seems to be preserved. Undoubtedly, also semantic knowledge plays a key role in reading comprehension; though, and to our knowledge, there are no studies clearly showing the relation between semantic knowledge and reading comprehension in aging. In the current study, we administered to younger adults and older adults a semantic working memory task, two word-span tasks and two reading comprehension tests (narrative and expository genre) to investigate the role of semantic knowledge during comprehension. In line with previous findings, we found that younger adults used flexibly either taxonomic or thematic knowledge, whereas the older adults mainly used thematic knowledge (better preserved from age-related decline). Originally, we found that in younger adults, thematic knowledge accounted for narrative text comprehension, whereas backward span performance accounted for expository text comprehension. On the contrary, in older adults no specific predictors were found for narrative text comprehension, whereas both thematic knowledge and education level were significant predictors of expository text comprehension. Results were discussed in the light of the possible protective role of some factors such as education level and mostly, as an instance of cognitive reserve exemplified by use of thematic knowledge as a residual ability.

Egocentric Navigation Abilities Predict Episodic Memory Performance.

The medial temporal lobe supports both navigation and declarative memory. On this basis, a theory of phylogenetic continuity has been proposed according to which episodic and semantic memories have evolved from egocentric (e.g., path integration) and allocentric (e.g., map-based) navigation in the physical world, respectively. Here, we explored the behavioral significance of this neurophysiological model by investigating the relationship between the performance of healthy individuals on a path integration and an episodic memory task. We investigated the path integration performance through a proprioceptive Triangle Completion Task and assessed episodic memory through a picture recognition task. We evaluated the specificity of the association between performance in these two tasks by including in the study design a verbal semantic memory task. We also controlled for the effect of attention and working memory and tested the robustness of the results by including alternative versions of the path integration and semantic memory tasks. We found a significant positive correlation between the performance on the path integration the episodic, but not semantic, memory tasks. This pattern of correlation was not explained by general cognitive abilities and persisted also when considering a visual path integration task and a non-verbal semantic memory task. Importantly, a cross-validation analysis showed that participants' egocentric navigation abilities reliably predicted episodic memory performance. Altogether, our findings support the hypothesis of a phylogenetic continuity between egocentric navigation and episodic memory and pave the way for future research on the potential causal role of egocentric navigation on multiple forms of episodic memory.

Children with ASD Show Impaired Item-Space Recollection, But Preserved Item-Color Recollection.

Although individuals with autism spectrum disorder (ASD) have been often shown to display similar memory performance on semantic memory tasks compared to typically developing (TD) children, there is ongoing debate about whether and how their ability to remember specific past events (i.e., episodic memory) is impaired. We assessed a sample of 62 children with ASD and 72 TD children, ranging in age between 8 and 12 years on 2 memory tasks. Participants encoded a series of images and their association with either where they appeared on the screen (item-space association task) or with the color of an image's border (item-color association task). Children with ASD showed worse memory in the item-space association task compared to their TD peers, but comparable memory for the item-color association task. These differences persisted when age, intellectual quotient, and general item recognition memory were accounted for statistically. We interpret these results in light of evidence for specific deficits along the dorsal stream affecting processing of spatiotemporal information in ASD. Autism Res 2020, 13: 1985-1997. © 2020 International Society for Autism Research and Wiley Periodicals LLC LAY SUMMARY: Episodic memory requires the ability to bind contextual details (such as color, location, etc.) to an item or event in order to remember the past with specific detail. Here, we compared children with autism spectrum disorder (ASD) and typically developing (TD) children on tasks examining episodic memory. Children with ASD recalled more poorly previously seen items and their associated space-related details, but they performed comparably to TD children on color details. We discuss the possible mechanisms that contribute to worse spatial processing/recall in ASD.

Characterizing Strategy Use During the Performance of Hippocampal-Dependent Tasks.

Recalling the past, thinking about the future, and navigating in the world are linked with a brain structure called the hippocampus. Precisely, how the hippocampus enables these critical cognitive functions is still debated. The strategies people use to perform tasks associated with these functions have been under-studied, and yet, such information could augment our understanding of the associated cognitive processes and neural substrates. Here, we devised and deployed an in-depth protocol to examine the explicit strategies used by 217 participants to perform four naturalistic tasks widely acknowledged to be hippocampal-dependent, namely, those assessing scene imagination, autobiographical memory recall, future thinking, and spatial navigation. In addition, we also investigated strategy use for three laboratory-based memory tasks, one of which is held to be hippocampal-dependent – concrete verbal paired associates (VPA) – and two tasks, which are likely hippocampal-independent – abstract VPA and the dead or alive semantic memory test. We found that scene visual imagery was the dominant strategy not only when mentally imagining scenes, but also during autobiographical memory recall, when thinking about the future and during navigation. Moreover, scene visual imagery strategies were used most frequently during the concrete VPA task, whereas verbal strategies were most prevalent for the abstract VPA task and the dead or alive semantic memory task. The ubiquity of specifically scene visual imagery use across a range of tasks may attest to its, perhaps underappreciated, importance in facilitating cognition, while also aligning with perspectives that emphasize a key role for the hippocampus in constructing scene imagery.