When Emotions Matter: Focusing on Emotion Improves Working Memory Updating in Older Adults

Motivation and emotional distraction interact and affect executive functions

Previous research on cool-hot executive function (EF) interactions has examined the effects of motivation and emotional distraction on cool EF separately, focusing on one EF component at a time. Although both incentives and emotional distractors have been shown to modulate attention, how they interact and affect cool EF processes is still unclear. Here, we used an experimental paradigm that manipulated updating, inhibition, and shifting demands to determine the interactions of motivation and emotional distraction in the context of cool EF. Forty-five young adults (16 males, 29 females) completed the go/no-go (inhibition), two-back (updating), and task-switching (shifting) tasks. Monetary incentives were implemented to manipulate motivation, and task-irrelevant threatening or neutral faces were presented before the target stimulus to manipulate emotional distraction. We found that incentives significantly improved no-go accuracy, two-back accuracy, and reaction time (RT) switch cost. While emotional distractors had no significant effects on overall task performance, they abolished the incentive effects on no-go accuracy and RT switch cost. Altogether, these findings suggest that motivation and emotional distraction interact in the context of cool EF. Specifically, transient emotional distraction disrupts the upregulation of control activated by incentives. The present investigation has advanced knowledge about the relationship between cool and hot EF and highlights the importance of considering motivation-emotion interactions for a fuller understanding of control.

The assessment of executive function abilities in healthy and neurodegenerative aging-A selective literature review

Numerous studies have examined executive function (EF) abilities in cognitively healthy older adults and those living with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Currently, there are no standard accepted protocols for testing specific EFs; thus, researchers have used their preferred tool, which leads to variability in assessments of decline in a particular ability across studies. Therefore, there is a need for guidance as to the most sensitive tests for assessing EF decline. A search of the most current literature published between 2000 and 2022 on EF studies assessing cognitively healthy older adults and individuals living with MCI and AD was conducted using PubMed/Medline, PsycINFO, Embase, Web of Science, and Google Scholar. Emphasis was placed on the EF's dual-tasking, inhibition, shifting or switching, and working memory updating. Many tasks and their outcomes were reviewed. Of particular importance was the difference in outcomes for tasks applied to the same group of participants. These various EF assessment tools demonstrate differences in effectively identifying decline in EF ability due to the aging process and neurodegenerative conditions, such as MCI and AD. This review identifies various factors to consider in using particular EF tasks in particular populations, including task demand and stimuli factors, and also when comparing differing results across studies.

Neurocognitive effects a combined polyphenolic-rich herbal extract in healthy middle-aged adults - a randomised, double-blind, placebo-controlled study

Objective: This study assessed whether polyphenolic rich supplement containing Bacopa monnieri (BM: 300 mg), Panax quinquefolius ginseng (PQ: 100 mg) and whole coffee fruit extract (WCFE: 100 mg) could enhance cognitive performance, affect and cerebral-cortical activation over 28-days of intervention.Method: A randomised, double-blind, placebo-controlled, between-group study of 52 healthy adults between 35 and 65 years (M = 50.20, SD = 9.37) was conducted. Measures of cognition, affect and brain activity were measured at three time points: baseline, 28 days post intervention and 14 days post washout. At each time point, haemodynamic response in the prefrontal cortex (PFC) was measured using functional near-infrared spectroscopy (fNIRS), and serum brain-derived neurotrophic factor (BDNF).Results: The polyphenolic-rich supplement reliably improved positive affect and delayed recall compared to placebo following 28 days of supplementation. For the brain, those in the active condition showed greater PFC activation on performance of the 2-back tasks post supplementation compared to placebo (p < .05, d = 0.6).Discussion: This is the first report of a 28-day supplement intervention and 2-week follow-up study to assess changes in affect, cognition, cerebral haemodynamic response and BDNF in healthy middle-aged adults. The potential synergistic effects of polyphenolic compounds on neurocognitive function in middle-aged adults through emotional-cognitive processing and cognitive reserve are important for promoting brain and cognitive health.

The effect of negative emotion processing on spatial navigation: an experimental study using virtual reality

Finding one's way in unfamiliar environments is an essential ability. When navigating, people are overwhelmed with an enormous amount of information. However, some information might be more relevant than others. Despite the mounting knowledge about the mechanisms underlying orientational skills, and the notable effects of facial emotions on human behavior, little is known about emotions' effects on spatial navigation. Hereby, this study aimed to explore how exposure to others' negative emotional facial expressions affects wayfinding performances. Moreover, gender differences that characterize both processes were considered. Fifty-five participants (31 females) entered twice in three realistic virtual reality environments: the first time, to encode a route to find an object and then to recall the learned path to reach the same object again. In between the two explorations of the virtual environment, participants were asked to undergo a gender categorization task during which they were exposed to sixty faces showing either neutral, fearful, or angry expressions. Results showed a significant interaction between emotions, time, and gender. In particular, the exposition to fearful faces, but not angry and neutral ones, decreased males' wayfinding performances (i.e., travel times and distance travelled), while females' performances were unaffected. Possible explanations for such gender and emotional dissimilarities are discussed.

Amygdala activity and amygdala-hippocampus connectivity: Metabolic diseases, dementia, and neuropsychiatric issues

With rapid aging of the population worldwide, the number of people with dementia is dramatically increasing. Some studies have emphasized that metabolic syndrome, which includes obesity and diabetes, leads to increased risks of dementia and cognitive decline. Factors such as insulin resistance, hyperglycemia, high blood pressure, dyslipidemia, and central obesity in metabolic syndrome are associated with synaptic failure, neuroinflammation, and imbalanced neurotransmitter levels, leading to the progression of dementia. Due to the positive correlation between diabetes and dementia, some studies have called it "type 3 diabetes". Recently, the number of patients with cognitive decline due to metabolic imbalances has considerably increased. In addition, recent studies have reported that neuropsychiatric issues such as anxiety, depressive behavior, and impaired attention are common factors in patients with metabolic disease and those with dementia. In the central nervous system (CNS), the amygdala is a central region that regulates emotional memory, mood disorders, anxiety, attention, and cognitive function. The connectivity of the amygdala with other brain regions, such as the hippocampus, and the activity of the amygdala contribute to diverse neuropathological and neuropsychiatric issues. Thus, this review summarizes the significant consequences of the critical roles of amygdala connectivity in both metabolic syndromes and dementia. Further studies on amygdala function in metabolic imbalance-related dementia are needed to treat neuropsychiatric problems in patients with this type of dementia.

Posttraumatic stress, visual working memory, and visual imagery in military personnel

Posttraumatic stress disorder (PTSD) is characterized by disruptions to cognitive functioning. Two studies were conducted to examine the relevance of military-related PTSD to two cognitive functions - visual working memory and visual imagery. Participants were military personnel who reported their PTSD diagnosis history and completed a self-administered screening tool for PTSD, the PTSD Checklist - Military Version. In Study 1, 138 personnel also completed a memory span task and a 2-back task using colored words in which Stroop interference was introduced via the semantic content of the words. In Study 2, a separate group of 211 personnel completed measures of perceived imagery vividness and spontaneous use of visual imagery. Interference effects on working memory in PTSD-diagnosed military personnel were not replicated. However, ANCOVA and structural equation modelling revealed that PTSD-intrusions were associated with poorer working memory whereas PTSD-arousal was associated with spontaneous use of visual imagery. We interpret these results as evidence that intrusive flashbacks disrupt working memory performance not by limiting memory capacity nor by interfering directly with memory functions such as inhibition, but by adding internal noise in the form of task-irrelevant memories and emotions. Visual imagery appears to be unrelated to these flashbacks but with arousal symptoms of PTSD, perhaps in the form of flashforwards about feared/anticipated threats.

Aging and distractor resistance in working memory: Does emotional valence matter?

Background

Emotional stimuli used as targets of working memory (WM) tasks can moderate age-related differences in WM performance, showing that aging is associated with reductions in negativity bias. This phenomenon is referred to as the positivity effect. However, there is little research on whether emotional distractors have a similar moderating effect. Moreover, the underlying neural mechanism of this effect has not been studied. In this study, we examined the behavioral and neurophysiological basis for age differences in resistance to emotional distractors within WM.

Methods

Older adults (n = 30, ages 60–74) and young adults (n = 35, ages 19–26) performed a 2-back task in which a digit was superimposed on a face with a happy, angry, or neutral expression as a distractor. Event-related potential (ERP) was simultaneously recorded to assess P2, N2, and later positive potential (LPP) amplitudes.

Results

Older adults were less accurate and slower than young adults on the WM task. Moreover, the results demonstrated a significant interaction between age and emotional valence on response accuracy, young adults' performance was worse when the distractor was neutral or positive than when it was negative, but there was no effect of the emotional valence of distractors on older adults’ WM performance. ERP analyses revealed greater P2 amplitude in older adults than young adults, regardless of the emotional valence of distractors. However, older adults and young adults did not differ on N2 or LPP amplitude, and negative distractors elicited greater N2 than positive distractors in both age groups.

Conclusions

The behavioral findings provided evidence of age-related reductions in negativity bias. Thus, the behavioral measures indicated a positivity effect in WM. However, the ERP results did not show this same interaction. These discrepant results raise questions about whether and to what extent older and young adults differ in controlling the effect of emotional distractors in WM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-022-00953-y.

Emotion Processing Dysfunction in Alzheimer's Disease: An Overview of Behavioral Findings, Systems Neural Correlates, and Underlying Neural Biology

We described behavioral studies to highlight emotional processing deficits in Alzheimer's disease (AD). The findings suggest prominent deficit in recognizing negative emotions, pronounced effect of positive emotion on enhancing memory, and a critical role of cognitive deficits in manifesting emotional processing dysfunction in AD. We reviewed imaging studies to highlight morphometric and functional markers of hippocampal circuit dysfunction in emotional processing deficits. Despite amygdala reactivity to emotional stimuli, hippocampal dysfunction conduces to deficits in emotional memory. Finally, the reviewed studies implicating major neurotransmitter systems in anxiety and depression in AD supported altered cholinergic and noradrenergic signaling in AD emotional disorders. Overall, the studies showed altered emotions early in the course of illness and suggest the need of multimodal imaging for further investigations. Particularly, longitudinal studies with multiple behavioral paradigms translatable between preclinical and clinical models would provide data to elucidate the time course and underlying neurobiology of emotion processing dysfunction in AD.

Electrophysiological Studies of Cognitive Reappraisal Success and Failure in aMCI

BACKGROUND

Although successful reappraisal relies on cognitive resources, how cognitive impairment affects brain processes related to cognitive reappraisal is not yet clear.

METHODS

Forty-four amnestic mild cognitive impairment (aMCI) subjects and 72 healthy elderly controls (HECs) were divided into the MCI-Failure (n = 23), MCI-Success (n = 21), HEC-Failure (n = 26), and HEC-Success (n = 46) groups according to changes in self-reported affect using reappraisal. All participants viewed 30 negative and 30 neutral images preceded by straightforward descriptions of these images and 30 negative images preceded by more neutral descriptions.

RESULTS

Reappraisal failure was found to be more common in people with MCI. Reappraisal failure is associated with altered neurophysiological indices of negative-reappraisal stimuli processing that are reflected in smaller theta responsivity to negative-reappraisal stimuli between 350-550 ms. The MCI-Success group showed enhanced LPP for negative-reappraisal stimuli from 1200 to 3500 ms, reflecting compensatory effort to complete the reappraisal task, while subjects in other groups showed reduced LPP for negative-reappraisal stimuli from 550 to 1200 ms.

CONCLUSIONS

These findings deepen our understanding of how cognitive decline impacts reappraisal and informs early diagnosis and interventions for MCI.

Memory updating through aging: different patterns for socially meaningful (and not) stimuli

BACKGROUND

Updating is a crucial function responsible of working memory integrity, allowing relevant information to be active and inhibiting irrelevant one; updating has been studied mainly with verbal stimuli, less with faces, stimuli with high adaptive value and social meaning.

AIM

Our aim was to test age-related differences in updating for different stimuli in three different age groups: young adults (range 20-30 years), young-old (range 60-75 years) and older-old participants (range 77-87 years).

METHODS

To this end, we administered control measures (i.e., vocabulary and visuospatial tasks), span tasks (forward, backward) and two updating tasks: one with no socially relevant material (i.e., letters) and another one with socially relevant material (i.e., human faces, where, in particular, the combination between facial expression and gaze direction was manipulated). In both tasks we collected response times (RTs) at different steps of an updating task (i.e., encoding, maintaining, and updating goal-relevant information).

RESULTS AND DISCUSSION

We found that age linearly produces an increase in processing speed regardless the stimulus considered, either letter or human face. However, with face stimuli, the magnitude of the difference is greater for the letter updating task, than for the face updating task. In turn, the results claim for a stimulus-specific updating process as the age-related decline is less pronounced when socially meaningful stimuli are involved than when no socially meaningful ones are.

Threatening Facial Expressions Impact Goal-Directed Actions Only if Task-Relevant

Facial emotional expressions are a salient source of information for nonverbal social interactions. However, their impact on action planning and execution is highly controversial. In this vein, the effect of the two threatening facial expressions, i.e., angry and fearful faces, is still unclear. Frequently, fear and anger are used interchangeably as negative emotions. However, they convey different social signals. Unlike fear, anger indicates a direct threat toward the observer. To provide new evidence on this issue, we exploited a novel design based on two versions of a Go/No-go task. In the emotional version, healthy participants had to perform the same movement for pictures of fearful, angry, or happy faces and withhold it when neutral expressions were presented. The same pictures were shown in the control version, but participants had to move or suppress the movement, according to the actor’s gender. This experimental design allows us to test task relevance’s impact on emotional stimuli without conflating movement planning with target detection and task switching. We found that the emotional content of faces interferes with actions only when task-relevant, i.e., the effect of emotions is context-dependent. We also showed that angry faces qualitatively had the same effect as fearful faces, i.e., both negative emotions decreased response readiness with respect to happy expressions. However, anger has a much greater impact than fear, as it increases both the rates of mistakes and the time of movement execution. We interpreted these results, suggesting that participants have to exploit more cognitive resources to appraise threatening than positive facial expressions, and angry than fearful faces before acting.

Individual differences impact memory for a crime: A study on executive functions resources

Previous studies demonstrated that memory accuracy is affected by the availability of the individual's cognitive resources. A predominant role in complex cognition has been postulated for executive functions (EF). The aim of the present study was to verify if there are differences in remembering a crime with respect to the individual's EF availability (i.e., Shifting, Inhibition, and Updating). We showed participants a video of a violent crime. Next, they were requested to imagine to be an eyewitness of the crime and report a testimony as detailed as possible. A subsequent memory test was run after ten days. EF resources were assessed in a third session through three neuropsychological tasks. Findings showed that high EF individuals reported more correct details and fewer memory distortions (i.e., omissions and commissions) than low EF individuals. Our results underline that individual EF resources are implicated in the recalling of an event.

Delayed reconfiguration of a non-emotional task set through reactivation of an emotional task set in task switching: an ageing study

In our everyday life, we frequently switch between different tasks, a faculty that changes with age. However, it is still not understood how emotion impacts on age-related changes in task switching. Using faces with emotional and neutral expressions, Experiment 1 investigated younger (n = 29; 18-38 years old) and older adults' (n = 32; 61-80 years old) ability to switch between an emotional and a non-emotional task (i.e. responding to the face's expression vs. age). In Experiment 2, younger and older adults also viewed emotional and neutral faces, but switched between two non-emotional tasks (i.e. responding to the face's age vs. gender). Data from Experiment 1 demonstrated that switching from an emotional to a non-emotional task was slower when the expression of the new face was emotional rather than neutral. This impairment was observed in both age groups. In contrast, Experiment 2 revealed that neither younger nor older adults were affected by block-wise irrelevant emotion when switching between two non-emotional tasks. Overall, the findings suggest that task-irrelevant emotion can impair task switching through reactivation of the competing emotional task set. They also suggest that this effect and the ability to shield task-switching performance from block-wise irrelevant emotion are preserved in ageing.

Preserved Proactive Control in Ageing: A Stroop Study With Emotional Faces vs. Words

Previous studies regarding age-related changes in proactive control were inconclusive and the effects of emotion on proactive control in ageing are yet to be determined. Here, we assessed the role of task-relevant emotion on proactive control in younger and older adults. Proactive control was manipulated by varying the proportion of conflict trials in an emotional Stroop task. In Experiment 1, emotional target faces with congruent, incongruent or non-word distractor labels were used to assess proactive control in younger and older adults. To investigate whether the effects of emotion are consistent across different stimulus types, emotional target words with congruent, incongruent or obscured distractor faces were used in Experiment 2. Data from this study showed that older adults successfully deployed proactive control when needed and that task-relevant emotion affected cognitive control similarly in both age groups. It was also found that the effects of emotion on cognitive performance were qualitatively different for faces and words, with facilitating effects being observed for happy faces and for negative words. Overall, these results suggest that the effects of emotion and age on proactive control depend on the task at hand and the chosen stimulus set.

Differential effects of angry faces on working memory updating in younger and older adults

Research suggests that cognition-emotion interactions change with age. In the present study, younger and older adults completed a 2-back task, and the effects of negative stimuli were analyzed as a function of their status in the n-back sequence. Older adults were found to benefit more from angry than from neutral probes relative to younger adults. However, they were slower when lures were angry and less accurate when lures and probes had the same emotion. The results suggest that recollection of the n-back sequence was reduced in older adults, making them more susceptible to the facilitating and impairing effects of negative emotion.