Time processing in neurological and psychiatric conditions.

A central question in understanding cognition and pathology-related cognitive changes is how we process time. However, time processing difficulties across several neurological and psychiatric conditions remain seldom investigated. The aim of this review is to develop a unifying taxonomy of time processing, and a neuropsychological perspective on temporal difficulties. Four main temporal judgments are discussed: duration processing, simultaneity and synchrony, passage of time, and mental time travel. We present an integrated theoretical framework of timing difficulties across psychiatric and neurological conditions based on selected patient populations. This framework provides new mechanistic insights on both (a) the processes involved in each temporal judgement, and (b) temporal difficulties across pathologies. By identifying underlying transdiagnostic time-processing mechanisms, this framework opens fruitful avenues for future research.

Brain correlates of declarative memory atypicalities in autism: a systematic review of functional neuroimaging findings.

The long-described atypicalities of memory functioning experienced by people with autism have major implications for daily living, academic learning, as well as cognitive remediation. Though behavioral studies have identified a robust profile of memory strengths and weaknesses in autism spectrum disorder (ASD), few works have attempted to establish a synthesis concerning their neural bases. In this systematic review of functional neuroimaging studies, we highlight functional brain asymmetries in three anatomical planes during memory processing between individuals with ASD and typical development. These asymmetries consist of greater activity of the left hemisphere than the right in ASD participants, of posterior brain regions-including hippocampus-rather than anterior ones, and presumably of the ventral (occipito-temporal) streams rather than the dorsal (occipito-parietal) ones. These functional alterations may be linked to atypical memory processes in ASD, including the pre-eminence of verbal over spatial information, impaired active maintenance in working memory, and preserved relational memory despite poor context processing in episodic memory.

Intact memory storage but impaired retrieval in visual memory in autism: New insights from an electrophysiological study.

In a recent study on visual episodic memory (Desaunay, Clochon, et al., 2020), we have shown event-related potentials (ERPs) differences associated with priming (150-300 msec), familiarity (350-470 msec), and recollection (600-700 msec), in young people with autism spectrum disorders (ASD) compared with typical development (TD). To go further into the study of the processes of storage and retrieval of the memory trace, we re-analyzed Desaunay, Clochon, et al's data using time-frequency analysis, that is, event-related synchronization and desynchronization (ERS/ERD). This allows a decomposition of the spectral power within frequency bands associated with these ERPs. We focused both on the same time windows and the same regions of interest as previously published. We mainly identified, in ASD compared with TD, reduced ERS in low-frequencies (delta, theta) in early time-windows, and non-significant differences in ERD in higher frequencies (alpha, beta1) in all time-windows. Reduced ERS during recognition confirmed previously reported diminution of priming effects and difficulties in manipulation and retrieval of both semantic and episodic information. Conversely, preserved ERD corroborates a preservation of memory storage processes. These observations are consistent with a cognitive model of memory in ASD, that suggests difficulties in cognitive operations or executive demand at retrieval, subsequent to successful long-term storage of information. LAY SUMMARY: We assessed the EEG synchronization and desynchronization, during visual episodic recognition. We observed, in youth with Autism, reduced synchronization in low-frequencies (delta, theta), suggesting reduced access to and manipulation of long-term stored information. By contrast, non-significant differences in desynchronization at higher frequencies (alpha, beta frequency bands), that support long-term stored semantic and episodic information, suggested preserved memory traces.

Ageing and autism: A longitudinal follow-up study of mental health and quality of life in autistic adults.

Background: Poor mental health is known to adversely affect functional abilities, social isolation, and quality of life (QoL). It is, therefore, crucial to consider the long-term impacts of mental health conditions as autistic adults grow older. Objectives: To explore, in a group of community-based autistic adults, the extent of: (i) autistic traits, co-occurring physical and mental health conditions; (ii) age-related differences in those conditions, and changes over time; and (iii) their impact on everyday living and QoL. Method: About Sixty-eight autistic adults (aged 19-80 years) participated in the first study (T1); 49 participants from T1 took part in a follow-up at T2 (mean retest interval 2.4 years). Standardised self-report measures of autistic traits, mental health, and QoL were completed at both time points. Results: Over two-thirds (71%) of autistic adult participants experienced at least one co-occurring condition, and over a third (37%) met the criteria for three or more co-occurring conditions. Mental and physical health difficulties were related to autistic traits and difficulties in everyday life and were consistent predictors of poor QoL at T1 and T2. Conclusion: Mental health difficulties in autism persisted into older age and did not improve over time. These findings have important implications for mental health provision for autistic adults in older age.

Arousal-modulated memory encoding and retrieval in adults with autism spectrum disorder.

Recently, we have shown that pupil dilation during a recognition memory task can serve as an index of memory retrieval difficulties in autism. At the time of publication, we were unaware of specific data-analysis methods that can be used to shed further light on the origins of such memory related pupil dilation. Specifically, by distinguishing "tonic" from "phasic" changes in pupil dilation and considering their temporal progression, it is possible to draw inferences about the functional integrity of a locus coeruleus-norepinephrine system (LC-NE) that is known to play a key role in regulating memory encoding and retrieval processes. We therefore apply these analyses to our previously published eye-tracking data of adults with ASD (N = 24) and neurotypical development (TD, N = 30) during the recognition memory task. In this re-analysis, we related pupil dilation during encoding and retrieval to recognition accuracy in a per-trial analysis of linear mixed models. In ASD, we replicated attenuated recognition accuracy, which was accompanied by attenuated pupil dilation during encoding and retrieval. Group differences in pupil dilation during retrieval occurred late during the trial (after 1.75 s) and indicated an altered top-down processing like attenuated attribution of semantic salience in response to previously encoded stimuli. In addition, only in the ASD group were higher pupil dilation during encoding and lower pupil dilation during retrieval associated with decreased recognition accuracy. This supports altered modulation of memory encoding and retrieval in ASD, with LC-NE phasic activity as promising underlying mechanism. LAY SUMMARY: We investigated the changes of pupil size during memory testing in autism spectrum disorder. Adults with ASD remembered fewer items correctly than neurotypical individuals (TD). This reduced memory was related to increased pupillary responses at study and decreased pupil dilation at test only for adults with ASD indicating a different modulation of memory by the locus coeruleus.

Local Processing Bias Impacts Implicit and Explicit Memory in Autism.

Autism spectrum disorder (ASD) is characterized by atypical perception, including processing that is biased toward local details rather than global configurations. This bias may impact on memory. The present study examined the effect of this perception on both implicit (Experiment 1) and explicit (Experiment 2) memory in conditions that promote either local or global processing. The first experiment consisted of an object identification priming task using two distinct encoding conditions: one favoring local processing (Local condition) and the other favoring global processing (Global condition) of drawings. The second experiment focused on episodic (explicit) memory with two different cartoon recognition tasks that favored either local (i.e., processing specific details) or a global processing (i.e., processing each cartoon as a whole). In addition, all the participants underwent a general clinical cognitive assessment aimed at documenting their cognitive profile and enabling correlational analyses with experimental memory tasks. Seventeen participants with ASD and 17 typically developing (TD) controls aged from 10 to 16 years participated to the first experiment and 13 ASD matched with 13 TD participants were included for the second experiment. Experiment 1 confirmed the preservation of priming effects in ASD but, unlike the Comparison group, the ASD group did not increase his performance as controls after a globally oriented processing. Experiment 2 revealed that local processing led to difficulties in discriminating lures from targets in a recognition task when both lures and targets shared common details. The correlation analysis revealed that these difficulties were associated with processing speed and inhibition. These preliminary results suggest that natural perceptual processes oriented toward local information in ASD may impact upon their implicit memory by preventing globally oriented processing in time-limited conditions and induce confusion between explicit memories that share common details.

What Can Performance in the IEDS Task Tell Us About Attention Shifting in Clinical Groups?

The Intra-Extra-dimensional set shift task (IEDS) is a widely used test of learning and attention, believed to be sensitive to aspects of executive function. The task proceeds through a number of stages, and it is generally claimed that patterns of errors across stages can be used to discriminate between reduced attention switching and more general reductions in rates of learning. A number of papers have used the IEDS task to argue for specific attention shifting difficulties in Autism Spectrum Disorder (ASD) and Schizophrenia, however, it remains unclear how well the IEDS really differentiates between reduced attention shifting and other causes of impaired performance. To address this issue, we introduce a simple computational model of performance in the IEDS task, designed to separate the competing effects of attention shifting and general learning rate. We fit the model to data from ASD and comparison individuals matched on age and IQ, as well as to data from four previous studies which used the IEDS task. Model fits do not show consistent evidence for reductions in attention shifting rates in ASD and Schizophrenia. Instead, we find performance is better explained by differences in learning rate, particularly from punishment, which we show correlates with IQ. We, therefore, argue that the IEDS task is not a good measure of attention shifting in clinical groups. LAY SUMMARY: The Intra-Extra-Dimensional Set shift task (IEDS) is often given to autistic individuals, who tend to make more errors relative to comparison groups. This higher error rate is taken to mean that autistic individuals struggle with attention control. Our computational model of the IEDS shows that the performance of ASD and some other clinical groups can be explained instead by differences in learning rate, rather than differences in attention control.

Eye-Tracking Reveals Absent Repetition Learning Across the Autism Spectrum: Evidence From a Passive Viewing Task.

In the domain of memory, autism is characterized by difficulties in explicitly remembering the specific order of stimuli, whereas implicit serial order memory appears to be preserved. This pattern is of considerable interest because serial order memory is known to play a critical role in children's language development. Currently, however, few paradigms exist that can effectively probe serial order memory across heterogeneous groups of children, including those who are minimally verbal. We present two experiments, involving 39 adults (20 ASD; 19 TD) and 130 children (86 ASD; 44 TD), that address this issue using an eye-tracking paradigm, which simply required participants to "watch out for a bunny" that appeared in repeating sequences of screen locations. The adults in Experiment 1 all had normative IQs, whereas Experiment 2 included children with and without substantial language and intellectual difficulties. In both experiments gaze latencies and anticipatory fixations to the bunny indicated reliable repetition learning effects in the TD but not the ASD groups. Importantly, we were able to acquire reliable data from around half of the children with significant language impairments in Experiment 2, indicating that the paradigm can shed light on important learning processes in this underrepresented group. We discuss the implications of these findings for theories of memory in ASD as well as for the utility of eye-tracking technology to probe repetition learning effects in autism. Autism Res 2020, 13: 1929-1946. © 2020 The Authors. Autism Research published by International Society for Autism Research and Wiley Periodicals LLC. LAY SUMMARY: Remembering the specific order of stimuli plays an important role in language development and is thought to be a source of difficulty for autistic individuals. Research in this area, however, rarely includes autistic participants who are minimally verbal. Here we develop an eye-tracking paradigm that demonstrates serial order learning difficulties across the autism spectrum. We discuss the implications of these findings for our understanding of the role of memory difficulties in the varied language profiles across the autism spectrum.

Exploring the Event-Related Potentials' Time Course of Associative Recognition in Autism.

Behavioral data on episodic recollection in autism spectrum disorders (ASD) point limited relational memory functioning. However, the involvement of successive memory processes in the profile of episodic memory in ASD needs more study. Here, we used event-related potentials (ERP) to investigate the time course of episodic recollection with an associative recognition paradigm with picture pairs. Twenty-two participants with ASD and 32 with typical development (TD), all right-handed, were included. Behavioral results confirmed difficulties in correctly recognizing identical pairs in the ASD relative to TD group. We found an unexpected amplitude decrement on the P2 (220-270 msec) and FN400 (350-470 msec) potentials, suggesting diminished priming and familiarity effects in the ASD relative to TD group. However, ERP data revealed that the recognition of associative information relies on the same electrophysiological process (old/new effect in the 600-700-msec late positive component) in ASD participants as in TD ones, with a parietal extension in the ASD group. These results suggest that the electrophysiological processes of associative recognition are qualitatively similar in individuals with and without ASD but may differ quantitatively. This difference may be driven by the reduced early processing of picture pairs that may in turn lead to their diminished integration into the semantic memory system, being partially compensated by a greater involvement of associative memory during the recollection process. Other studies would be useful to go further in identifying these cognitive processes involved in atypical recognition in ASD and their neural substrates. Autism Res 2020, 13: 1998-2016. © 2020 International Society for Autism Research and Wiley Periodicals LLC LAY SUMMARY: We identified diminished performance on the associative recognition of picture pairs in adolescents and young adults with autism when compared to typical development. Electrophysiological data revealed qualitative similarities but quantitative differences between-group, with diminished priming and familiarity processes partially compensated by an enhanced parietal recollection process.

Short-Term Memory Span and Cross-Modality Integration in Younger and Older Adults With and Without Autism Spectrum Disorder.

This study tested whether adults with autism spectrum disorder (ASD) show the same pattern of difficulties and absence of age-related differences in short-term memory (STM) as those that have been reported in episodic long-term memory (LTM). Fifty-three adults with ASD (age range: 25-65 years) were compared to 52 age-, biological sex-, and intelligence-matched typically developing (TD; age range: 21-67 years) adults on three STM span tasks, which tested STM performance for letters (Verbal), grid locations (Visuospatial), or letters in grid locations (Multimodal). A subsample of 34 TD and 33 ASD participants ranging in age from 25 to 64 years completed a fourth Multimodal Integration task. We also administered the Color Trails Test as a measure of executive function. ASD participants' accuracy was lower than that of the TD participants on the three span tasks (Cohen's d: 0.26-0.50). The Integration task difference was marginally significant (p = .07) but had a moderate effect size (Cohen's d = 0.50). Regression analyses confirmed reduced STM performance only for older TD participants. Analyses also indicated that executive processes played a greater role in the ASD group's performance. The demonstration of similar difficulties and age-related patterning of STM in ASD to those documented for LTM and the greater recruitment of executive processes by older ASD participants on the Integration task suggest a compensatory role of frontal processes both as a means of achieving undiminished task performance and as a possible protection against older age cognitive decline in ASD. Longitudinal research is needed to confirm this. Autism Res 2020, 13: 1970-1984. © 2020 The Authors. Autism Research published by International Society for Autism Research and Wiley Periodicals LLC. LAY SUMMARY: Little is known about short-term memory (STM) in younger and older adults with autism spectrum disorder (ASD). This study tested different kinds of STM and showed that ASD adults remembered shorter sequences of letters, crosses, or letters in grid cells less well than matched participants with typical development. However, older ASD individuals performed similarly to younger ASD individuals, nor showing the reduction in performance usually seen with older age. The data suggest that ASD individuals use different underlying mechanisms when performing the tasks and that this might help protect their memory as they grow older.

Self-guided mindfulness and cognitive behavioural practices reduce anxiety in autistic adults: A pilot 8-month waitlist-controlled trial of widely available online tools.

LAY ABSTRACT: Anxiety in autism is an important target for psychological therapies because it is very common and because it significantly impacts upon quality of life and well-being. Growing evidence suggests that cognitive behaviour therapies and mindfulness-based therapies can help autistic individuals learn to manage feelings of anxiety but access to such therapies remains problematic. In the current pilot study, we examined whether existing online cognitive behaviour therapy and mindfulness-based therapy self-help tools can help reduce anxiety in autistic adults. Specifically, 35 autistic adults were asked to try either an existing online cognitive behaviour therapy (n = 16) or mindfulness-based therapy (n = 19) programme while a further 19 autistic adults served as a waitlist comparison group. A first important finding was that 23 of the 35 (66%) participants who tried the online tools completed them, suggesting that such tools are, in principle, acceptable to many autistic adults. In addition, adults in the cognitive behaviour therapy and mindfulness-based therapy conditions reported significant decreases in anxiety over 3 and to some extent also 6 months that were less apparent in the waitlist group of participants. On broader measures of mental health and well-being, the benefits of the online tools were less apparent. Overall, the results suggest that online self-help cognitive behaviour therapy and mindfulness-based therapy tools should be explored further as a means of providing cost-effective mental health support to at least those autistic individuals who can engage effectively with such online tools.

Declarative Memory and Structural Language Impairment in Autistic Children and Adolescents.

Two experiments tested the hypothesis that a plausible contributory factor of structural language impairment in Autism Spectrum Disorder (ASD) is impaired declarative memory. We hypothesized that familiarity and recollection (subserving semantic and episodic memory, respectively) are both impaired in autistic individuals with clinically significant language impairment and learning disability (ASDLI/LD ); whereas recollection is selectively impaired in autistic individuals with typical language (ASDTL ). Teenagers with ASDLI/LD (n = 19) and primary school age children with ASDTL (n = 26) were compared with teenagers with learning disability (LD) (n = 26) without autism, and primary school aged typically developing (TD) children (n = 32). Both experiments provided strong support for the hypothesized links between declarative memory processes and lexical-semantic facets of language in the two autistic groups, but not in the TD group. Additional findings of interest were that declarative memory processes and lexical-semantic knowledge were also linked in the LD group and that the ASD groups-and to a lesser extent the LD group-may have compensated for declarative memory impairments using spared visual-perceptual abilities, a finding with potential educational implications. Relative difficulties with familiarity and recollection in ASDLI/LD and LD may help explain structural language impairment, as investigated here, but also the broader learning disabilities found in these populations. Autism Res 2020. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2020, 13: 1947-1958. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Language impairment and learning disability affect 45% of the autistic population yet the factors that may be contributing to them is remarkably under-researched. To date there are no explanations of the lexical semantic (word meaning) abnormalities observed in ASD. We found that declarative memory is associated with lexical semantic knowledge in autism and learning disability but not in typical development. Difficulties with declarative memory may also be compensated for using visual-perceptual abilities by autistic and learning-disabled adolescents, which has positive implications for educationalists.

Memory in autism spectrum disorder: A meta-analysis of experimental studies.

To address inconsistencies in the literature on memory in autism spectrum disorder (ASD), we report the first ever meta-analysis of short-term memory (STM) and episodic long-term memory (LTM) in ASD, evaluating the effects of type of material, type of retrieval and the role of interitem relations. Analysis of 64 studies comparing individuals with ASD and typical development (TD) showed greater difficulties in ASD compared with TD individuals in STM (Hedges' g = -0.53, 95% CI [-0.90, -0.16], p = .005, I² = 96%) compared with LTM (g = -0.30, 95% CI [-0.42, -0.17], p < .00001, I² = 24%), a small difficulty in verbal LTM (g = -0.21, p = .01), contrasting with a medium difficulty for visual LTM (g = -0.41, p = .0002) in ASD compared with TD individuals. We also found a general diminution in free recall compared with cued recall and recognition (LTM, free recall: g = -0.38, p < .00001, cued recall: g = -0.08, p = .58, recognition: g = -0.15, p = .16; STM, free recall: g = -0.59, p = .004, recognition: g = -0.33, p = .07). We discuss these results in terms of their relation to semantic memory. The limited diminution in verbal LTM and preserved overall recognition and cued recall (supported retrieval) may result from a greater overlap of these tasks with semantic long-term representations which are overall preserved in ASD. By contrast, difficulties in STM or free recall may result from less overlap with the semantic system or may involve additional cognitive operations and executive demands. These findings highlight the need to support STM functioning in ASD and acknowledge the potential benefit of using verbal materials at encoding and broader forms of memory support at retrieval to enhance performance. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

A Physiological Marker of Recognition Memory in Adults with Autism Spectrum Disorder? - The Pupil Old/New Effect.

This study investigated the pupil Old/New effect in individuals with Autism Spectrum Disorder (ASD) and typical development (TD). Participants studied verbal and visual meaningful and meaningless materials in black and white on a computer screen. Pupil sizes were measured while participants performed a Remember (episodic memory with context)/Know (semantic memory, no context) recognition memory test. ASD compared to TD individuals showed significantly reduced recognition rates for all materials. Both groups showed better memory for visual compared to verbal (picture superiority effect) and meaningful compared to meaningless materials. A pupil size ratio (pupil size for test item divided by baseline) for old (studied) and new (unstudied) materials indicated larger pupils for old compared to new materials only for the TD but not the ASD group. Pupil size in response to old versus new items was positively related to recognition accuracy, confirming that the pupil Old/New effect reflects a memory phenomenon in the ASD group. In addition, this study suggests an involvement of the noradrenergic neurotransmitter system in the abnormal hippocampal functioning in ASD. Implications of these findings, as well as their underlying neurophysiology, will be discussed in relation to current theories of memory in ASD. Autism Res 2020, 13: 627-640. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Most measures of memory in Autism Spectrum Disorder (ASD) depend on verbal answers. In addition to these verbal answers, this study measured the size of the participants' pupil in response to studied and unfamiliar materials revealing memory difficulties in ASD. Measuring pupil size works nonverbally, outside of conscious awareness and forms the basis of studies on less verbal persons with ASD. Mechanisms and brain regions underlying memory differences in ASD are discussed.

Spatial navigation from same and different directions: The role of executive functions, memory and attention in adults with autism spectrum disorder.

To resolve some of the inconsistencies in existing research into spatial navigation in autism spectrum disorder (ASD), we tested two large age- and ability-matched groups of ASD and typically developing (TD) participants for their spatial navigation abilities in a route learning task, which has been shown to shed light on the strategies participants employ when navigating complex environments. Participants studied a route through a virtual maze by watching a short video of a first-person perspective navigating a maze. The maze included four four-way intersections that were each marked with two unique landmarks in two corners of the intersection. At test, static images of the intersections, either as seen during the video or as approached from a different direction, were presented and participants had to indicate in which direction they would need to travel (straight, left, or right) in order to follow the originally studied route. On both types of test trials, the ASD group performed worse and their difficulties were related to reduced cognitive flexibility. Eye-movement data and follow-up item-memory tests suggested that navigation difficulties may have been related to differences in attention during encoding and less spontaneous use of landmarks as cues for navigation. Spatial navigation performance was best predicted by memory for landmarks as well as by executive functions. The results are discussed in relation to theories of underlying navigation-related brain regions. More research is needed to disentangle the influence of executive functions, memory and attention on spatial navigation. Autism Res 2018, 11: 798-810. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Navigating an environment is difficult for people with ASD independent of whether they are travelling in the same or in a different direction from that which they originally studied. The present study suggests that flexibility in alternating travel directions, difficulties in remembering landmarks as well as reduced attention to landmarks while learning a route play a role in the navigation difficulties in ASD. Guidance at route learning might help autistic individuals to improve their ability to navigate in their environments.

Allocentric Versus Egocentric Spatial Memory in Adults with Autism Spectrum Disorder.

Individuals with autism spectrum disorder (ASD) present difficulties in forming relations among items and context. This capacity for relational binding is also involved in spatial navigation and research on this topic in ASD is scarce and inconclusive. Using a computerised version of the Morris Water Maze task, ASD participants showed particular difficulties in performing viewpoint independent (allocentric) navigation, leaving viewpoint dependent navigation (egocentric) intact. Further analyses showed that navigation deficits were not related to poor visual short-term memory or mental rotation in the ASD group. The results further confirm the need of autistic individuals for support at retrieval and have important implications for the design of signposts and maps.

Problem-solving styles in autism spectrum disorder and the development of higher cognitive functions.

The Vygotsky Blocks Test assesses problem-solving styles within a theoretical framework for the development of higher mental processes devised by Vygotsky. Because both the theory and the associated test situate cognitive development within the child's social and linguistic context, they address conceptual issues around the developmental relation between language and thought that are pertinent to development in autism. Our aim was to document the performance of adults with autism spectrum disorder on the Vygotsky Blocks Test, and our results showed that they made more errors than the typically developing participants and that these errors correlated with performance IQ. The autism spectrum disorder group also required more cues than the typically developing group to discern the conceptual structure of the blocks, a pattern that correlated with Autism Diagnostic Observational Schedule-Communication and Imagination/Creativity sub-scales. When asked to categorize the blocks in new ways, the autism spectrum disorder participants developed fewer principles on which to base new categorizations, which in contrast to the typically developing group correlated with verbal IQ and with the Imagination/Creativity sub-scale of the ADOS. These results are in line with a number of existing findings in the autism spectrum disorder literature and confirm that conceptualization in autism spectrum disorder seems to rely more on non-verbal and less on imaginative processes than in typically developing individuals. The findings represent first steps to the possibility of outlining a testable account of psychological development in autism spectrum disorder that integrates verbal, non-verbal and social factors into the transition from elementary to higher level processes.

The Influence of task Demands, Verbal Ability and Executive Functions on Item and Source Memory in Autism Spectrum Disorder.

Autism Spectrum Disorder (ASD) is generally associated with difficulties in contextual source memory but not single item memory. There are surprising inconsistencies in the literature, however, that the current study seeks to address by examining item and source memory in age and ability matched groups of 22 ASD and 21 comparison adults. Results show that group differences in source memory are moderated by task demands but not by individual differences in verbal ability, executive function or item memory. By contrast, unexpected group differences in item memory could largely be explained by individual differences in source memory. These observations shed light on the factors underlying inconsistent findings in the memory literature in ASD, which has important implications for theory and practice.

An Eye-Movement Study of relational Memory in Adults with Autism Spectrum Disorder.

Persons with Autism Spectrum Disorder (ASD) demonstrate good memory for single items but difficulties remembering contextual information related to these items. Recently, we found compromised explicit but intact implicit retrieval of object-location information in ASD (Ring et al. Autism Res 8(5):609-619, 2015). Eye-movement data collected from a sub-sample of the participants are the focus of the current paper. At encoding, trial-by-trial viewing durations predicted subsequent retrieval success only in typically developing (TD) participants. During retrieval, TD compared to ASD participants looked significantly longer at previously studied object-locations compared to alternative locations. These findings extend similar observations recently reported by Cooper et al. (Cognition 159:127-138, 2017a) and demonstrate that eye-movement data can shed important light on the source and nature of relational memory difficulties in ASD.

Impact of Semantic Relatedness on Associative Memory: An ERP Study.

Encoding and retrieval processes in memory for pairs of pictures are thought to be influenced by inter-item similarity and by features of individual items. Using Event-Related Potentials (ERP), we aimed to identify how these processes impact on both the early mid-frontal FN400 and the Late Positive Component (LPC) potentials during associative retrieval of pictures. Twenty young adults undertook a sham task, using an incidental encoding of semantically related and unrelated pairs of drawings. At test, we conducted a recognition task in which participants were asked to identify target identical pairs of pictures, which could be semantically related or unrelated, among new and rearranged pairs. We observed semantic (related and unrelated pairs) and condition effects (old, rearranged and new pairs) on the early mid-frontal potential. First, a lower amplitude was shown for identical and rearranged semantically related pairs, which might reflect a retrieval process driven by semantic cues. Second, among semantically unrelated pairs, we found a larger negativity for identical pairs, compared to rearranged and new ones, suggesting additional retrieval processing that focuses on associative information. We also observed an LPC old/new effect with a mid-parietal and a right occipito-parietal topography for semantically related and unrelated old pairs, demonstrating a recollection phenomenon irrespective of the degree of association. These findings suggest that associative recognition using visual stimuli begins at early stages of retrieval, and differs according to the degree of semantic relatedness among items. However, either strategy may ultimately lead to recollection processes.