Effects of cue focality on the neural mechanisms of prospective memory: A meta-analysis of neuroimaging studies

Self-reported strategy use and prospective memory: The roles of cue focality and task importance

Interest in the metacognitive aspects of prospective memory (PM) is growing. Yet, the interplay between participants' metacognitive awareness of PM task demands and features that contribute to successful PM require further attention. To this aim, participants in the current study completed laboratory-based PM tasks of varying difficulty (cue focality: focal, nonfocal-category, or nonfocal-syllable) and reported their strategy use and perceptions of PM task importance. Most participants reported using a strategy regardless of cue focality. However, only under the most challenging condition (i.e., nonfocal-syllable) did participants who reported using a strategy exhibit better PM performance compared to those who did not use a strategy. Additionally, strategy use and cue focality were independently associated with greater costs to ongoing task performance: strategy users exhibited greater slowing relative to individuals who did not use a strategy, and the extent of slowing was greater as the task difficulty increased across cue focality. Finally, perceived task importance appeared to play an important role in the interactive link between cue focality and strategy use on PM performance for the more challenging, nonfocal PM tasks. Specifically, moderation analyses suggested that greater perceived task importance alone may improve the likelihood of PM success for moderately challenging PM tasks (i.e., nonfocal-category), but for the most challenging PM tasks (i.e., nonfocal-syllable), individuals' strategy use was still associated with better PM performance. The present study expands our understanding of metacognition's role in PM performance and has implications for everyday PM performance.

Further clarification of cognitive processes of prospective memory in schizophrenia by comparing eye-tracking and ecologically-valid measurements

The aim of this study is to compare ecologically-valid measure (the Cambridge Prospective Memory Test, CAMPROMPT) and laboratory measure (eye-tracking paradigm) in assessing prospective memory (PM) in individuals with schizophrenia spectrum disorders (SSDs). In addition, eye-tracking indices are used to examine the relationship between PM and other cognitive domains in SSDs patients. Initially, the study sample was formed by 32 SSDs patients and 32 healthy control subjects (HCs) who were matched in sociodemographic profile and the performance on CAMPROMPT. An eye-tracking paradigm was employed to examine the differences in PM accuracy and key cognitive processes (e.g., cue monitoring) between the two groups. Additional 31 patients were then recruited to investigate the relationship between PM cue monitoring, other cognitive functions, and the severity of clinical symptoms within the SSDs group. The monitoring of PM cue was reflected in total fixation time and total fixation counts for distractor words. Cognitive functions were assessed using the Chinese version of the MATRICS Consensus Cognitive Battery (MCCB). The Positive and Negative Syndrome Scale (PANSS) was applied to assess psychopathology. SSDs patients exhibited fewer total fixation counts for distractor words and lower PM accuracy compared to HCs, even though they were priori matched on CAMPROMPT. Correlation analysis within the SSDs group (63 cases) indicated a negative correlation between PM accuracy and PANSS total score, and a positive correlation with working memory and attention/vigilance. Regression analysis within the SSDs group revealed that higher visual learning and lower PANSS total scores independently predicted more total fixation counts on distractor words. Impairment in cue monitoring is a critical factor in the PM deficits in SSDs. The eye-tracking laboratory paradigm has advantages over the ecologically-valid measurement in identifying the failure of cue detection, making it a more sensitive tool for PM deficits in patients with SSDs.

Sensory modality affects the spatiotemporal dynamics of alpha and theta oscillations associated with prospective memory

BACKGROUND

The maintenance of an intention in memory (Prospective Memory, PM) while performing a task is associated with a cost in terms of both performance (longer response times and lower accuracy) and neurophysiological modulations, which extent depends on several features of the stimuli.

AIM

This study explores the neural patterns associated with PM in different sensory modalities, to identify differences depending on this variable and discuss their functional meaning.

METHOD

Data were collected using a High-Density EEG during a baseline and a PM condition, proposed in a visual and an auditory version. Theta and alpha oscillations were compared between the two conditions within each modality using a cluster-based permutation approach.

RESULTS

PM conditions were associated with clusters of decreased alpha and theta activity in both modalities. However, different spatiotemporal dynamics were elicited as a function of sensory modality: alpha decreases displayed an overlapping onset between modalities, but different durations, lasting longer in the auditory modality. Conversely, the clusters of decreased theta activity presented similar durations between modalities, but different temporal and spatial onsets, appearing at different moments over the respective sensory areas.

CONCLUSIONS

The similar spatiotemporal properties of alpha suppression between modalities indicate that such oscillations may represent a supramodal, top-down process, presumably reflecting the external direction of attention to successfully detect the prospective cue (strategic monitoring). In theta, the clusters showed more modality-specific differences, which temporal and spatial properties correspond to the ones necessary to perform the ongoing task, suggesting a shift in resource allocation in favor of the PM task.

Parietal cortical alpha/beta suppression during prospective memory retrieval

Prospective memory (PM) impairment is among the most frequent memory complaints, yet little is known about the underlying neural mechanisms. PM for a planned intention may be achieved through strategic monitoring of the environment for cues, involving ongoing attentional processes, or through spontaneous retrieval. We hypothesized that parietal spectral power modulation accompanies prospectively encoded intention retrieval, irrespective of PM retrieval approach. A cognitively engaging arithmetic-based ongoing task (OGT) was employed to encourage spontaneous retrieval, with a focal, internally generated PM cue to eliminate OGT/PM trial differentiation based on perceptual or conceptual PM cue features. Two PM repetition frequencies were used to vary the extent of strategic monitoring. We observed a transient parietal alpha/beta spectral power reduction directly preceding the response, which was distinguishable on a single trial basis, as revealed by an OGT/PM trial classification rate exceeding 70% using linear discriminant analysis. The alpha/beta idling rhythm reflects cortical inhibition. A disengagement of task-relevant neural assemblies from this rhythm, reflected in alpha/beta power reduction, is deemed to increase information content, facilitate information integration, and enable engagement of neural assemblies in task-related cortical networks. The observed power reduction is consistent with the Dual Pathways model, where PM strategies converge at the PM retrieval stage.

Thinking about it: the impact of COVID-19-related stimuli on prospective memory

Background

Since 2020, information regarding COVID-19 has been a constant presence in the news, in our conversations and thoughts. Continuous exposure to this type of stimuli could have an impact on cognitive processes essential for our everyday activities, such as prospective memory (PM). PM is the ability to remember to perform an intention at a specific point in the future, like remembering to take prescribed medicines at a specific time or to turn off the stove after cooking. Do COVID-related stimuli affect our ability to perform a PM task?

Methods

To answer this question, we proposed a novel version of the classical paradigm used to investigate PM. Namely, this paradigm includes a baseline condition, in which an ongoing task is presented alone, and a PM condition in which the same task is proposed again together with a second (prospective) task. In this study, a short video clip was presented between the baseline and the PM condition. The video clip displayed either neutral, negative, or COVID-related content. Additionally, participants were asked to respond to two questionnaires and a series of questions regarding their well-being and experience with the pandemic. Namely, the DASS-21 scale (evaluating depression, anxiety, and stress), and the COVID-19-PTSD questionnaire (a questionnaire evaluating post-traumatic stress disorder symptoms related to the pandemic experience) were administered. Participants' performance and responses were analyzed using a linear mixed effect (LME) model approach, and correlation analyses were run to highlight possible correlations between participants' scores in the DASS-21, the COVID-19-PTSD, and the additional questions on their personal experience with the pandemic.

Results

The LME models revealed significant effects of the displayed video on performance: in line with previous studies, the clip displaying standard negative contents led to impaired accuracy in the ongoing task in the PM condition, compared to the Baseline. In contrast, participants who saw the COVID-related clip showed improved accuracy in the ongoing task compared to the other participants, selectively in the block performed after the video clip was displayed (PM condition). Furthermore, the explanatory power of the LME model calculated on accuracy to the ongoing trials was enhanced by the inclusion of the scores in the anxiety subscale of the DASS-21, suggesting a detrimental role of anxiety. Altogether, these results indicate a different effect of the exposure to classical negative contents (associated with a cost in terms of accuracy in the ongoing task between the baseline and the PM condition) and the pandemic-related one, which was instead characterized by a higher accuracy to ongoing trials compared to the other video clips. This counterintuitive finding seems to suggest that COVID-related stimuli are processed as "acute stressors" rather than negative stimuli, thus inducing a state of increased alertness and responsivity.

Envisioning the future: An ALE meta-analysis on neural correlates of future thinking, prospective memory and delay discounting

Our representations of the future are processed in the service of several different cognitive functions, including episodic future thinking, prospective memory, and temporal discounting. The present meta-analysis used the Activation Likelihood Estimation method to understand whether there is a core network underlying future-oriented cognition and to identify the specific brain regions that support future-related processes in each function. Following the PRISMA guidelines, a total of 24, 19, and 27 neuroimaging studies were included for future thinking, prospective memory, and temporal discounting, respectively. Results showed that there is no specific region or network for the future. Instead, the 'future' seems to be represented on an anterior-posterior tangibility gradient, based on the level of abstractness/concreteness of the simulated scenario. Additionally, future-oriented cognition is mediated by two distinct networks: the Default Network and the Salience Network. The Default Network is mainly active in supporting future thinking, whereas the Salience Network is primarily involved in prospective memory and delay discounting.

The deficient cue monitoring and the facilitating effect of prosocial intention on prospective memory in patients with schizophrenia spectrum disorders

The study aimed to investigate the cognitive processing of prospective memory (PM) in patients with schizophrenia spectrum disorders (SSDs) by using an eye-tracking paradigm. In addition, the facilitating effects of prosocial intention (the desire to help others) on PM in SSDs were also examined. In phase 1, 26 patients (group1) and 25 healthy controls (HCs) were compared in an eye-tracking PM paradigm in terms of the PM accuracy and eye-tracking indices. In phase 2, 21 more patients (group2) were recruited, and a prosocial intention was introduced in the eye-tracking PM paradigm. Their PM accuracy and eye-tracking indices were compared with those in group1. The PM cue monitoring was indicated by the total fixation counts and fixation time on distractor words. In phase 1, group1 showed lower PM accuracy, fewer fixation counts and less fixation time on distractor words than HCs. In phase 2, group2 (with prosocial intention) performed significantly better than group1 (with typical instruction) on both PM accuracy and fixation time on distractor words. In both groups of SSDs, the PM accuracy was significantly correlated with both the fixation counts and the fixation time of distractor words. After controlling for the cue monitoring indices, the difference in PM accuracy remained significant between group1 and HCs but disappeared between group1 and group2. The cue monitoring deficit contributes to the PM impairment in SSDs. The facilitating effect of prosocial intention disappears after the control of cue monitoring, also indicating its critical role in PM.

EXPRESS: The Impact of Sensory Modality on Prospective Memory: Differences between Visual and Auditory Processing

Prospective memory (PM) is the ability to perform an intended action when the appropriate conditions occur. Several features play a role in the successful retrieval of an intention: The activity we are concurrently engaged in, the number of intentions we are maintaining, where our attention is focused (outward vs. to inner states), and how outstanding the trigger of the intention is. Another factor that may play a crucial role is sensory modality: Do auditory and visual stimuli prompt PM processing in the same way? In this study, we explored for the first time the nature of PM for auditory stimuli and the presence of modality-dependent differences in PM processing. To do so, an identical paradigm composed of multiple PM tasks was administered in two versions, one with auditory stimuli and one with visual ones. Each PM task differed for features such as focality, saliency, and number of intentions (factors that are known in literature to modulate the monitoring and maintenance requests of PM) to explore the impact of sensory modality on a broad variety of classical PM tasks. In general, PM processing showed similar patterns between modalities, especially for low demanding prospective instructions. Conversely, substantial differences were found when the prospective load was increased and monitoring requests enhanced, as participants were significantly slower and less accurate with acoustic stimuli. These results represent the first evidence that modality-dependent effects arise in PM processing, especially in its interaction with features such as the difficulty of the task and the increased monitoring load.

Longitudinal declines in event-based, but not time-based, prospective memory among community-dwelling older adults

Age-related deficits in prospective memory (PM) are well established, but it is not known whether PM is stable over time among older adults. In this study, 271 community-dwelling older adults underwent abaseline neuropsychological evaluation and up to three follow-up visits, approximately 2.4 years apart. Mixed effects linear longitudinal models revealed small, but significant linear declines and between-subjects variability in event-based PM performance. There were no changes in performance on measures of time-based PM, retrospective memory, or executive functions. Changes in event-based PM were not associated with age, retrospective memory, executive functions, or everyday functioning. Among older adults, event-based PM appears to be more susceptible to linear declines than does time-based PM, which future research might examine with regard to the possible underlying cognitive mechanisms of cue encoding, monitoring, detection, and retrieval processes.

A new cognitive model of long-term memory for intentions

In this paper, we propose a new mathematical model of retrieval of intentions from long-term memory. We model retrieval as a stochastic race between a plurality of potentially relevant intentions stored in long-term memory. Psychological theories are dominated by two opposing conceptions of the role of memory in temporally extended agency - as when a person has to remember to make a phone call in the afternoon because, in the morning, she promised she would do so. According to the Working Memory conception, remembering to make the phone call is explained in terms of the construction and maintenance of intentions in working-memory. According to the Long-Term Memory conception, we should explain the episode in terms of an ability to store intentions in long-term memory. The two conceptions predict different processing profiles. The aim of this paper is to present a new mathematical model of the type of memory mechanism that could realise the long-term memory representations of intentions necessary for the Long-Term Memory conception. We present and illustrate the formal model and propose a new type of experimental paradigm that could allow us to test which of the two conceptions provides the best explanation of the role of memory in temporally extended agency.

Wait a second . . . Boundary conditions on delayed responding theories of prospective memory

Research suggests that forcing participants to withhold responding for as brief as 600 ms eliminates one of the most reliable findings in prospective memory (PM): the cue focality effect. This result undermines the conventional view that controlled attentional monitoring processes support PM, and instead suggests that cue detection results from increased response thresholds that allow more time for PM information to accumulate. Given the significance of such findings, it is critical to examine the generalizability of the delay mechanism. Experiments 1-4 examined boundary conditions of the delay theory of PM, whereas Experiment 5 more directly tested contrasting theoretical predictions from monitoring theory (e.g., multiprocess framework) and delay theory. Using the same (Experiment 1) or conceptually similar (Experiment 2) delay procedure and identical cues (nonfocal "tor" intention) from the original study failed to show any influence of delay on performance. Using a different nonfocal intention (first letter "S") similarly did not influence performance (Experiment 3), and the difference between focal and nonfocal cue detection was never completely eliminated even with delays as long as 2,500 ms (Experiment 4). Experiment 5 did find the anticipated reduction in the focality effect with increased delays with a larger sample (n = 249). However, the focality effect was not moderated by attention control ability despite the fact that participants with impoverished attention control should benefit most from the delay procedure. These results suggest that any theory of PM that considers only a delay mechanism may not fully capture the dynamic attention processes that support cue detection. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Future and past autobiographical memory in persons with HIV disease

Objective: While HIV disease is associated with impairment in declarative memory, the ability of people with HIV (PWH) to describe past and future autobiographical events is not known. Method: Participants included 63 PWH and 28 seronegative individuals ages 50-78 who completed standardized neurocognitive and everyday functioning assessments. Participants described four events from the recent past and four imagined events in the near future, details from which were classified as internal or external to the main event. Result: PWH produced fewer autobiographical details with small-to-medium effect sizes but did not differ from seronegative participants in meta-cognitive ratings of their performance. Performance of the study groups did not vary across past or future probes or internal versus external details; however, within the entire sample, past events were described in greater detail than future events, and more external than internal details were produced. Within the PWH group, the production of fewer internal details for future events was moderately associated with poorer prospective memory, executive dysfunction, and errors on a laboratory-based task of medication management. Conclusion: Older PWH may experience difficulty generating autobiographical details from the past and simulated events in the future, which may be related to executive dyscontrol of memory processes. Future studies might examine the role of future thinking in health behaviors such as medication adherence and retention in healthcare among PWH. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

From retrospective to prospective memory research: a framework for investigating the deactivation of intentions

The definition of episodic memory has evolved into a multifaceted concept that gathered great attention in several research areas in psychology and neuroscience. Prospective memory (PM), or the ability to remember to perform delayed intentions at a later moment in the future, represents one side of this capacity for which that has been a growing interest. In this review, we examined a counterintuitive finding: PM intentions may persist and affect our behaviour despite successful goal attainment and task completion, which in daily life may be as serious as taking medication twice. This review aims to elucidate the existing knowledge and identify some unresolved questions concerning this specific memory failure. Therefore, this review provides an overview of the uprising research dedicated to both PM omission and commission errors, including an analysis of its definitions, of the current theoretical approaches of PM retrieval, and the main procedures used in this field to offer an integrative perspective on this topic. Finally, the last section is devoted to discussing future directions to test the predictions of our suggested theoretical explanations for PM deactivation. This might be an avenue for research that is likely to extend our understanding of episodic memory's usefulness in everyday life.

How Does Performing Demanding Activities Influence Prospective Memory? A Systematic Review

This paper is the first systematic review on the role of ongoing task load in prospective remembering, which was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Forty articles published between 1995 and 2020 were included. They evaluated prospective memory (PM) performance (i.e., the ability to remember to execute a delayed intention) in adult samples aged between 19 and 50 years old when the PM cue appeared under cognitively demanding conditions. The results revealed that people are more likely to fail to remember to perform a delayed intention at the appropriate circumstances or time in the future when their cognitive resources are taxed by demanding ongoing activities. We conclude the review by highlighting that the degree of working memory and executive resources seems to account for some of the discrepant findings and by proposing directions for future research.

Deficits in Spontaneous Cognition as an Early Marker of Alzheimer's Disease

In the absence of a pharmacological cure, finding the most sensitive early cognitive markers of Alzheimer's disease (AD) is becoming increasingly important. In this article we review evidence showing that brain mechanisms of spontaneous, but stimulus-dependent, cognition overlap with key hubs of the default mode network (DMN) that become compromised by amyloid pathology years before the clinical symptoms of AD. This leads to the formulation of a novel hypothesis which predicts that spontaneous, but stimulus-dependent, conscious retrieval processes, that are generally intact in healthy aging, will be particularly compromised in people at the earliest stages of AD. Initial evidence for this hypothesis is presented across diverse experimental paradigms (e.g., prospective memory, mind-wandering), and new avenues for research in this area are outlined.

One-year stability of prospective memory symptoms and performance in aging and HIV disease

Introduction: HIV disease and aging can both affect prospective memory (PM), which describes the complex process of executing delayed intentions and plays an essential role in everyday functioning. The current study investigated the course of PM symptoms and performance over approximately one year in younger and older persons with and without HIV disease. Method: Participants included 77 older (>50 years) and 35 younger (<40 years) HIV+ individuals and 44 older and 27 younger seronegative adults. Participants completed the Memory for Intentions Test to measure PM in the laboratory, the Prospective and Retrospective Memory Questionnaire to measure PM symptoms in daily life, and several clinical measures of executive functions and retrospective memory as a part of a comprehensive neurocognitive evaluation at baseline and at 14-month follow-up. Results: Findings showed additive, independent main effects of HIV and aging on time- and event-based PM performance in the laboratory, but no change in PM over time. There were no interactions between time and HIV or age groups. Parallel findings were observed for clinical measures of retrospective memory and executive functions. Older HIV+ adults endorsed the greatest frequency of PM symptoms, but there was no change in PM symptom severity over time and no interactions between time and HIV or age groups. There were no effects of HIV or aging on naturalistic PM performance longitudinally. Conclusion: Overall these findings suggest that PM symptoms and performance in the laboratory are stably impaired over the course of a year in the setting of aging and HIV disease.

Prospective Memory: Age related change is influenced by APOE genotype

Non-focal prospective memory (PM) is sensitive to age-related decline; an additional impairment in focal PM is characteristic of mild stage Alzheimer's disease. This research explored whether, by mid-adulthood, the distinct demands of focal and non-focal PM expose differences in carriers of an APOE ε4 allele, a genetic risk factor for Alzheimer's disease. Thirty-three young and 55 mid-age adults, differentiated by APOE genotype, completed a category-decision task with a concurrent focal or non-focal PM demand. Only mid-age ε4 carriers showed a cost of carrying a focal PM intention. In addition, mid-age ε4 carriers showed a significantly greater cost of carrying a non-focal PM intention than young ε4 carriers, supporting a profile of accelerated aging. Consistency in the profile of cost differences observed in mid-age ε4 carriers and pathological aging may indicate premature vulnerability. Future research correlating a shift in PM performance with early genotype differences in brain-based markers of decline is important.

Age-related changes in neural mechanisms of prospective memory

The capability to remember and execute intentions in the future - termed prospective memory (PM) - may be of special significance for older adults to enable successful completion of important activities of daily living. Despite the importance of this cognitive function, mixed findings have been obtained regarding age-related decline in PM, and, currently, there is limited understanding of potential contributing mechanisms. In the current study, older (N=41) and younger adults (N=47) underwent task-functional MRI during performance of PM conditions that encouraged either spontaneous retrieval (Focal) or sustained attentional monitoring (Non-focal) to detect PM targets. Older adults exhibited a reduction in PM-related sustained activity within the anterior prefrontal cortex (aPFC) and associated dorsal frontoparietal cognitive control network, due to an increase in non-specific sustained activation in (no-PM) control blocks (i.e., an age-related compensatory shift). Transient PM-trial specific activity was observed in both age groups within a ventral parietal memory network that included the precuneus. However, within a left posterior inferior parietal node of this network, transient PM-related activity was selectively reduced in older adults during the non-focal condition. These age differences in sustained and transient brain activity statistically mediated age-related declines in PM performance, and were potentially linked via age-related changes in functional connectivity between the aPFC and precuneus. Together, they support an account consistent with the Dual Mechanisms of Control framework, in which age-related PM declines are due to neural mechanisms that support proactive cognitive control processes, such as sustained attentional monitoring, while leaving reactive control mechanisms relatively spared.

Prospective memory under acute stress: The role of (output) monitoring and ongoing-task demands

Prospective memory (PM) refers to the ability to postpone retrieval and execution of intended actions until the appropriate situation (PM cue) has come, while engaging in other ongoing activities or tasks. In everyday live we often perform PM tasks in stressful situations. While it has been shown that acute stress does not impair PM-cue identification and intention retrieval, little is known about acute stress effects on PM performance and memory for having performed an action (output monitoring) under varying ongoing-task demands. Here we investigated this in eighty healthy participants who performed event-based PM tasks during low- and high-demanding ongoing working memory tasks after having undergone either a standardized stress induction (Maastricht Acute Stress Test) or a standardized control protocol. Successful stress induction in the stress group compared to the no-stress group was confirmed by increased salivary cortisol, an indicator of stress-related hypothalamus-pituitaryadrenal axis activity, throughout the event-based PM tasks. Nevertheless, not-only PM-cue identification but also output monitoring remained fully intact after stress induction. The absence of these effects was independent of ongoing-task demands. Nonetheless, we replicated recent findings of a stress-induced reduction in performance cost of monitoring for PM-cue occurrences. Taken together our findings suggest that acute stress alters PM monitoring by enhancing selective attention, decreasing PM response thresholds or by shifting performance towards more automatic processes in PM, while not affecting PM-cue identification and output monitoring.

Stress and prospective memory: What is the role of cortisol?

Studies investigating effects of acute stress on Prospective Memory (PM) so far yielded heterogeneous findings. Although results were commonly attributed to stress-induced changes in cortisol, past research did not disentangle effects of cortisol from the effects of sympathetic nervous system (SNS) activation and cognitive reappraisal. The present study therefore aimed at investigating the mere effect of cortisol on PM tasks that differently involve prefrontal brain regions (nonfocal vs. focal PM tasks) via a placebo-controlled oral pharmacological intake of 10 mg hydrocortisone mimicking physiological responses to stress. Contrary to our prediction, enhanced levels of cortisol did not affect PM accuracy and monitoring costs, neither for the focal nor the nonfocal PM tasks. These results suggest that changes of cortisol levels do not underlie potential stress effects on PM. Further exploratory results revealed that PM performance was higher in the 3 pm than in the 1 pm placebo group. This means that PM performance, independently of effects of cortisol, seem to vary throughout the day.

Where is the "where" in the brain? A meta-analysis of neuroimaging studies on spatial cognition

Spatial representations are processed in the service of several different cognitive functions. The present study capitalizes on the Activation Likelihood Estimation (ALE) method of meta-analysis to identify: (a) the shared neural activations among spatial functions to reveal the "core" network of spatial processing; (b) the specific neural activations associated with each of these functions. Following PRISMA guidelines, a total of 133 fMRI and PET studies were included in the meta-analysis. The overall analysis showed that the core network of spatial processing comprises regions that are symmetrically distributed on both hemispheres and that include dorsal frontoparietal regions, presupplementary motor area, anterior insula, and frontal operculum. The specific analyses revealed the brain regions that are selectively recruited for each spatial function, such as the right temporoparietal junction for shift of spatial attention, the right parahippocampal gyrus, and the retrosplenial cortex for navigation and spatial long-term memory. The findings are integrated within a systematic review of the neuroimaging literature and a new neurocognitive model of spatial cognition is proposed.

Neuropsychological profile of mild temporal lobe epilepsy

OBJECTIVE

In the current literature, whether patients with mild mesial temporal lobe epilepsy (mMTLE) have typical neurocognitive profile similar to patients with treatment-refractory seizures still remains unknown. The purpose of the present work was to analyze the neuropsychological profile in a group of consecutive patients with mMTLE.

METHODS

Forty consecutive patients whose conditions were diagnosed with mMTLE and 30 healthy controls (HC) were evaluated with an extensive neuropsychological battery. In addition, self-report questionnaires were also administered to evaluate the subjective impairments in prospective and retrospective memories. Finally, the levels of depression and anxiety were evaluated using the Beck Depression Inventory II (BDI-II) and the State-Trait Anxiety Inventory - Form Y1 (STAI-YI e 2).

RESULTS

Patients with mMTLE patients showed higher BDI-II scores (15.9 ± 13.9 vs 7.2 ± 6.7; p =, 002), and higher STAI-Y1 (41.2 ± 14.6 vs 32.6 ± 9.8; p =, 005) together with both objective and subjective memory deficits. Although BDI-II and STAI scores strongly correlated to the outcome in Rey Auditory Verbal Learning Test (RAVLT) and prospective and retrospective memory questionnaire (PRMQ) (p < 0.0021), these results did not change without depression scores.

CONCLUSION

We showed that a specific neurocognitive profile in patients with mMTLE exists. The neuropsychological features are mood depression, verbal memory immediate and delayed deficits, and subjective prospective and retrospective memory deficits.

Exercise and Prospective Memory

The purpose of this paper was to review the literature to evaluate the potential effects of exercise on prospective memory (PM). A narrative review was employed. In this review, we provide a brief description of PM; indicate the effects of PM on health; evaluate the effects of age and neurological impairment on PM; examine the neural correlates of PM; provide a description of specific components that subserve PM; identify non-behavioral strategies used to enhance PM; and evaluate the literature and plausibility through which exercise behavior may influence PM. Regarding the latter, this paper aims to burgeon the development of a new research paradigm that will play a critical role in patient health, given that memory function, and in particular, the prospective (vs. retrospective) component of memory, is highly sensitive to aging and is critically associated with health status. This is an emerging line of research that has critical implications for patient health.

Deficits in prospective memory following damage to the medial subdivision of the mediodorsal thalamic nucleus

Identifying the neurocognitive mechanisms that lead individuals remembering to execute an intention at the right moment (prospective memory, PM) and how such mechanisms are influenced by the features of that intention is a fundamental theoretical challenge. In particular, the functional contribution of subcortical regions to PM is still unknown. This study was aimed at investigating the role of the medial subdivision of the mediodorsal thalamic nucleus (mMDT) in PM, with particular focus on the processes that are mediated by the projections from/to this structure. We analysed the performance of a patient (OG) with a right-sided lesion involving the mMDT in a series of PM tasks that varied for focality (i.e., overlapping of processes for the PM and ongoing tasks) and emotional valence of the stimuli, comparing the patient's performance with that of a control group. We found that the mMDT damage led to deficits in PM that were modulated by focality and emotional valence. OG indeed showed: a greater cost in the ongoing performance when a non-focal PM task was added; a slowing down in retrieving the intentions, in particular when these were associated with focal PM cues; an abnormal performance in the task with positive PM cues. Our findings provide evidence of a contribution of mMDT to PM and suggest a modulation of prefrontal-dependent strategic monitoring and a possible interaction with the limbic structures in the integration of emotion and PM processes. They also give support to the still controversial idea that connections with the perirhinal cortex mediate familiarity-based recognition.

The Neural Bases of Event Monitoring across Domains: a Simultaneous ERP-fMRI Study

The ability to check and evaluate the environment over time with the aim to detect the occurrence of target stimuli is supported by sustained/tonic as well as transient/phasic control processes, which overall might be referred to as event monitoring. The neural underpinning of sustained attentional control processes involves a fronto-parietal network. However, it has not been well-defined yet whether this cortical circuit acts irrespective of the specific material to be monitored and whether this mediates sustained as well as transient monitoring processes. In the current study, the functional activity of brain during an event monitoring task was investigated and compared between two cognitive domains, whose processing is mediated by differently lateralized areas. Namely, participants were asked to monitor sequences of either faces (supported by right-hemisphere regions) or tools (left-hemisphere). In order to disentangle sustained from transient components of monitoring, a simultaneous EEG-fMRI technique was adopted within a block design. When contrasting monitoring versus control blocks, the conventional fMRI analysis revealed the sustained involvement of bilateral fronto-parietal regions, in both task domains. Event-related potentials (ERPs) showed a more positive amplitude over frontal sites in monitoring compared to control blocks, providing evidence of a transient monitoring component. The joint ERP-fMRI analysis showed that, in the case of face monitoring, this transient component relies on right-lateralized areas, including the inferior parietal lobule and the middle frontal gyrus. In the case of tools, no fronto-parietal areas correlated with the transient ERP activity, suggesting that in this domain phasic monitoring processes were masked by tonic ones. Overall, the present findings highlight the role of bilateral fronto-parietal regions in sustained monitoring, independently of the specific task requirements, and suggest that right-lateralized areas subtend transient monitoring processes, at least in some task contexts.

Prospective memory mediated by interoceptive accuracy: a psychophysiological approach

Previous studies on prospective memory (PM), defined as memory for future intentions, suggest that psychological stress enhances successful PM retrieval. However, the mechanisms underlying this notion remain poorly understood. We hypothesized that PM retrieval is achieved through interaction with autonomic nervous activity, which is mediated by the individual accuracy of interoceptive awareness, as measured by the heartbeat detection task. In this study, the relationship between cardiac reactivity and retrieval of delayed intentions was evaluated using the event-based PM task. Participants were required to detect PM target letters while engaged in an ongoing 2-back working memory task. The results demonstrated that individuals with higher PM task performance had a greater increase in heart rate on PM target presentation. Also, higher interoceptive perceivers showed better PM task performance. This pattern was not observed for working memory task performance. These findings suggest that cardiac afferent signals enhance PM retrieval, which is mediated by individual levels of interoceptive accuracy.This article is part of the themed issue 'Interoception beyond homeostasis: affect, cognition and mental health'.