Memory and reward systems coproduce 'nostalgic' experiences in the brain

EEG microstates are associated with music training experience

Background

Music training facilitates the development of individual cognitive functions and influences brain plasticity. A comprehensive understanding of the pathways and processes through which music affects the human brain, as well as the neurobiological mechanisms underlying human brain perception of music, is necessary to fully harness the plasticity that music offers for brain development.

Aims

To investigate the resting-state electroencephalogram (EEG) activity of individuals with and without music training experience, and explore the microstate patterns of EEG signals.

Method

In this study, an analysis of electroencephalogram (EEG) microstates from 57 participants yielded temporal parameters(mean duration, time coverage, occurrence, and transition probability)of four classic microstate categories (Categories A, B, C, and D) for two groups: those with music training experience and those without. Statistical analysis was conducted on these parameters between groups.

Results

The results indicate that compared to individuals without music training experience, participants with music training experience exhibit significantly longer mean durations of microstate A, which is associated with speech processing. Additionally, they show a greater time coverage of microstate B, which is associated with visual processing. Transition probabilities from microstate A to microstate B were greater in participants with music training experience compared to those without. Conversely, transition probabilities from microstate A to microstate C and from microstate C to microstate D were greater in participants without music training experience.

Conclusion

Our study found differences in characteristic parameters of certain microstates between individuals with and without music training experience. This suggests distinct brain activity patterns during tasks related to speech, vision, and attention regulation among individuals with varying levels of music training experience. These findings support an association between music training experience and specific neural activities. Furthermore, they endorse the hypothesis of music training experience influencing brain activity during resting states. Additionally, they imply a facilitative role of music training in tasks related to speech, vision, and attention regulation, providing initial evidence for further empirical investigation into the cognitive processes influenced by music training.

EEG Microstate Associated with Trait Nostalgia

Nostalgia, a self-related emotion characterized by its bittersweet yet predominantly positive nature, plays a vital role in shaping individual psychology and behavior. This includes impacts on mental and physical health, behavioral patterns, and cognitive functions. However, higher levels of trait nostalgia may be linked to potential adverse outcomes, such as increased loneliness, heightened neuroticism, and more intense experiences of grief. The specific electroencephalography (EEG) feature associated with individuals exhibiting trait nostalgia, and how it differs from others, remains an area of uncertainty. To address this, our study employs microstate analysis to investigate the differences in resting-state EEG between individuals with varying levels of trait nostalgia. We assessed trait nostalgia in 63 participants using the Personal Inventory of Nostalgia and collected their resting-state EEG signals with eyes closed. The results of the regression analysis indicate a significant correlation between trait nostalgia and the temporal characteristics of microstates A, B, and C. Further, the occurrence of microstate B was significantly more frequent in the high trait nostalgia group than in the low trait nostalgia group. Independent samples t-test results showed that the transition probability between microstates A and B was significantly higher in the high trait nostalgia group. These results support the hypothesis that trait nostalgia is reflected in the resting state brain activity. Furthermore, they reveal a deeper sensory immersion in nostalgia experiences among individuals with high levels of trait nostalgia, and highlight the critical role of self-referential and autobiographical memory processes in nostalgia.

Episodic memory and personal semantics as triggers of nostalgia: its relationships between abstraction of memory content and temporal distance

Nostalgia, an autobiographically relevant positive emotion, is a sentimental longing or wistful affection for the past. Autobiographical memory, which is one of the cognitive bases of nostalgia, includes both abstract semantic and detailed episodic memories. Recent studies have defined and classified memories that are located between semantic and episodic memory as personal semantics. Although autobiographical memory and personal semantics range over a continuum, past nostalgia research has not focused on or controlled them. In two experiments, undergraduate students retrieved episodic memory and personal semantics and rated cognitive and affective items. The intensity of nostalgia differed according to the types of memory content and temporal distance of the memory from the present. These results revealed that not only unique events but also repeated events and autobiographical facts induced nostalgia; furthermore, repeated events from both the distant and recent past (primary and high school, respectively) consistently induced relatively greater nostalgia, but in some cases, they were not significantly different from other types of memory (i.e., unique events and autobiographical facts). These findings suggest that both episodic memory and personal semantics are involved in the occurrence of nostalgia.

Theory of brain complexity and marital behaviors: The application of complexity science and neuroscience to explain the complexities of marital behaviors

The extant theories on the quality and stability of marital relationships have some difficulties in explaining some of the complexities of marital behaviors. The present article is an initial attempt to explain the complexities of marital behaviors based on the science of complexity and neuroscience. This article proposes a new theoretical framework relying on this simple argument that marital behaviors, as one of the most complex human behaviors, are the product of one's brain's complex adaptive system (CAS). Hence, to understand the complexities of marital behaviors, a movement toward familiarity with the brain's CAS involved in marital behaviors needs to be started. The article presents the theory of brain complexity and marital behaviors (BCM) and outlines its assumptions, concepts, and propositions. Then, BCM is compared with the extant theories on happy and stable marriage, and finally, it was concluded by discussing the testability and the potential application of the theory. This article might inspire interdisciplinary studies of marital relationships, complex systems, and neuroscience and may have considerable practical implications.

Nostalgia in the brain

Nostalgia, a complex emotion that arises from one's yearnful memories, involves multiple psychological processes. Cognitive neuroscience research has shed light on the neural mechanism of nostalgia as well as its adaptive functions. Nostalgia involves brain regions implicated in self-reflection, autobiographical memory, emotion regulation and reward processing. Also, nostalgia buffers various psychological and physical threats by modulating activities in brain regions implicated in emotion regulatory processing (i.e., both top-down emotion regulation and bottom-up sensory and attention processing) and reward processing. These findings deepen understanding of nostalgia and have implications for its application in clinical situations.

Advances in the understanding and enhancement of the human cognitive functions of learning and memory

Learning and memory are among the key cognitive functions that drive the human experience. As such, any defective condition associated with these cognitive domains could affect our navigation through everyday life. For years, researchers have been working toward having a clear understanding of how learning and memory work, as well as ways to improve them. Many advances have been made, as well as some challenges that have also been faced in the process. That notwithstanding, there are prospects with regards to the frontier of the enhancement of learning and memory in humans. This review article selectively highlights four broad areas of focus in research into the understanding and enhancement of learning and memory. Brain stimulation, effects of sleep, effects of stress and emotion, and synaptic plasticity are the main focal areas of this review, in terms of some pivotal research works, findings and theories.

The analgesic effect of nostalgia elicited by idiographic and nomothetic approaches on thermal stimulus

Nostalgia is shown to relieve an individual's perception of pain evoked by cold water, pressure, and thermal stimuli. However, there is no direct evidence to show the analgesic effects of different nostalgia-inducing methods on various stimulus intensities. We conducted two studies to examine the analgesic effect, at different pain intensities, after inducing nostalgia either idiographically or nomothetically. Study 1 (N = 118) induced nostalgia through an idiographic approach (i.e., event reflection task) and found that nostalgia relieved both high and low thermal pain. Study 2 (N = 66) induced nostalgia through a nomothetic approach (i.e., viewing nostalgic pictures) and found that nostalgia relieved low but not high thermal pain. The findings verify the analgesic effect of nostalgia on thermal pain and suggest the potential moderating role of the nostalgia induction approach and pain intensity. Practically, these findings have implications for using nostalgia as a nonpharmacological treatment for pain.

Use of autobiographical stimuli as a mood manipulation procedure: Systematic mapping review

Background

In recent years, mood induction procedures have been developed in experimental settings that are designed to facilitate studying the impact of mood states on biological and psychological processes. The aim of the present study was to conduct a systematic mapping review with the intention of describing the state of the art in the use of different types of autobiographical stimuli for mood induction procedures.

Methods

Based on a search for publications from the period 2000–2021, conducted in four recognised databases (Scopus, Medline (PubMed), PsycINFO and Web of Science), we analysed a total of 126 published articles. Text mining techniques were used to extract the main themes related.

Results

The induction of emotions through autobiographical memories is an area under construction and of growing interest. The data mining approach yielded information about the main types of stimuli used in these procedures, highlighting those that only employ a single type of cue, as well as the preference for verbal cues over others such as musical, olfactory and visual cues. This type of procedure has been used to induce both positive and negative emotions through tasks that require access to personal memories of specific events from a cue, requiring the person to set in motion different cognitive processes. The use of the latest technologies (fMRI, EEG, etc.) is also shown, demonstrating that this is a cutting-edge field of study.

Conclusions

Despite the study of mood induction procedures still being a growing field, the present review provides a novel overview of the current state of the art in the field, which may serve as a framework for future studies on the topic.

Compulsory volunteers' nostalgia and its relationships with positive memories, age, past experiences, and volunteer intention

While nostalgia has been explored in various contexts, no research has so far investigated how individuals' nostalgia can be generated by volunteer experiences in compulsory settings and how nostalgic feelings extend their future behavior. To fill this research gap, this study explored how nostalgia regarding compulsory volunteering is related to positive memories, age, and past experiences and how such nostalgia translates to volunteer intention. A total of 605 responses were collected from university students who had completed compulsory volunteering at sporting events and analyzed using structural equation modeling. Results showed that positive memories contributed to all five factors of volunteer nostalgia, while past experiences only predicted volunteer environment, volunteer socialization, and volunteer personal identity. Age was not a significant antecedent to any of the volunteer nostalgia factors. Nostalgia regarding volunteer experience and volunteer personal identity mediated the relationship between positive memories and volunteer intention. This study confirmed previous claims concerning the relationships among nostalgia, positive memories, age, and past experiences in the context of compulsory volunteering. Specifically, individuals can develop nostalgia for coerced experiences if they have fond memories of them. Also, past experiences are more essential to nostalgia than age but not as much as positive memories, and nostalgia can turn compulsory volunteers into continued volunteers.

The Effect of Nostalgic Contents on Self-Esteem: The Mediating Role of Loneliness

Background

Research has demonstrated that nostalgia can improve self-esteem as a positive psychological resource in Western culture. Moreover, nostalgia is cross-culturally consistent. Therefore, nostalgia triggered by an event reflection task affects self-esteem in Eastern cultures. However, it is unknown whether the collective or personal content of nostalgia affects self-esteem and the role of loneliness in this process.

Purpose

This study examined the cross-cultural consistency of nostalgia’s impact on self-esteem, whether nostalgic content affects self-esteem levels, and what role loneliness plays in this process.

Methods

We conducted two experiments in this study. Experiment 1 used an event reflection task with different instructions to prime the nostalgia and control groups. Participants were asked to complete the Positive and Negative Affect Scale and a revised positive version of the Rosenberg Self-Esteem Scale after priming. Experiment 2 used different instructions and pictures to prime the social and personal nostalgia groups. The PANAS, a revised positive version of the Rosenberg Self-Esteem Scale, and the Russell Loneliness Scale were then administered to the groups.

Results

Experiment 1 showed that in the nostalgic condition, self-esteem was higher than in the control condition. In the nostalgia condition, participants felt more positive than in the control condition. Experiment 2 revealed that self-esteem was higher in the collective nostalgic context than in the personal nostalgic context. Regarding the positive effect, participants felt more positive in the collective nostalgic context than in the personal nostalgic context. Loneliness also had a mediating effect on this process.

Conclusion

Results show that nostalgia affects self-esteem through cross-cultural consistency and social nostalgia can be a resource for positive mental health. Moreover, loneliness plays a significant role in mediating nostalgia’s effect on self-esteem.

Patterns of brain activity associated with nostalgia: a social-cognitive neuroscience perspective

Nostalgia arises from tender and yearnful reflection on meaningful life events or important persons from one's past. In the last two decades, the literature has documented a variety of ways in which nostalgia benefits psychological well-being. Only a handful of studies, however, have addressed the neural basis of the emotion. In this prospective review, we postulate a neural model of nostalgia. Self-reflection, autobiographical memory, regulatory capacity and reward are core components of the emotion. Thus, nostalgia involves brain activities implicated in self-reflection processing (medial prefrontal cortex, posterior cingulate cortex and precuneus), autobiographical memory processing (hippocampus, medial prefrontal cortex, posterior cingulate cortex and precuneus), emotion regulation processing (anterior cingulate cortex and medial prefrontal cortex) and reward processing (striatum, substantia nigra, ventral tegmental area and ventromedial prefrontal cortex). Nostalgia's potential to modulate activity in these core neural substrates has both theoretical and applied implications.

Nostalgia evocation through seasonality-conscious purchasing behavior revealed by online survey using vegetable names

Food can be a valuable mediator of nostalgia. Japanese food culture places a great emphasis on seasons, and thus there may be a relationship between nostalgic foods and seasonality. In this study, we hypothesized that participants who emphasized seasonality at the time of vegetable purchase (seasonality-oriented; hereafter, SO) would be more likely to feel vegetable-evoked nostalgia than those who did not (non-seasonality-oriented; hereafter, non-SO). To test this hypothesis, we administered an online survey to older Japanese adults regarding 103 representative vegetables considered to be seasonal foods. After participants selected vegetables that they had eaten, they then selected those that evoked nostalgia (hereafter, nostalgic vegetables). For each nostalgic vegetable, they evaluated the degree of nostalgia and state if a past event (autobiographical memory) was recalled. If an autobiographical memory was recalled for a certain nostalgic vegetable, nostalgia for that memory was evaluated. Comparing between SO and non-SO participants, SO participants had significantly higher numbers of nostalgic vegetables with associated autobiographical memories, as well as nostalgia for those vegetables and autobiographical memories. The results supported our hypothesis, suggesting that seasonality-conscious purchasing behavior evokes nostalgia.

Neural correlates of product attachment to cosmetics

The neurobiological basis of brand and product attachment has received much attention in consumer neuroscience research, although it remains unclear. In this study, we conducted functional MRI experiments involving female users of famous luxury brand cosmetics as participants, based on the regions of interest involved in human attachment and object attachment. The results showed that the left ventral pallidum (VP), which is involved in positive reward, and the right posterior cingulate cortex (PCC), which is involved in self-concept, a key concept in object attachment, are the core regions in cosmetic attachment. Moreover, the performed psychophysiological interaction analyses showed that VP-temporoparietal junction connectivity positively correlated with activity in the dorsal raphe nucleus, and PCC-anterior hippocampus (aHC) connectivity positively correlated with subjective evaluation of attachment. The former suggests that object attachment is a human-like attachment and a stronger tendency of anthropomorphism is associated with stronger feelings of security. The latter suggests that the individual's concept of attachment as well as the relationships with the attached cosmetics are represented in the aHC, and the PCC-aHC associations produce subjective awareness of the attachment relationships. These associations between memory and reward systems have been shown to play critical roles in cosmetic attachment.

The Predictive Utility of Reward-Based Motives Underlying Excessive and Problematic Social Networking Site Use

Compulsive seeking of reward is a hallmark feature of drug addiction, but the role of reward is less well understood in behavioural addictions. The present study investigated the predictive utility of ten reward-based motives, which we identified in the literature, in explaining excessive and problematic use of social networking sites (SNSs). These motives were examined in a cross-sectional survey of 411 young adults, revealing that prolonged use and excessive checking were predicted by distinctly different motives. More frequent checking of SNSs was most closely associated with motives related to obtaining social rewards (impression management/social comparisons/fear of missing out) and the desire to find/consume enjoyable content. In contrast, the amount of time an individual spends on SNSs was predicted by the desire to engage in negative social interactions or to fulfil personal needs (self-expression/documentation of life events). Problematic SNS use was best explained by the motivation to obtain social rewards and to a lesser extent by enjoyment and negative social potency (e.g., trolling) motives. Our results highlight the importance of social reward in explaining excessive and problematic SNS use, suggesting that a focus on reducing the desire to obtain social reward (e.g., through likes, social comparisons, continual connection) may be most beneficial in tackling problematic SNS behaviours.

Nostalgia enhances detection of death threat: neural and behavioral evidence

An experiment examined the potency of nostalgia-a sentimental longing for one's past-to facilitate detection of death-related stimuli, using functional magnetic resonance imaging (fMRI) and behavioral techniques (i.e., judgmental accuracy, reaction times). We hypothesized and found that, at the neural level, nostalgic (relative to control) participants evinced more intense activation in right amygdala in response to death-related (vs. neutral) words. We also hypothesized and found that, at the behavioral level, nostalgic (relative to control) participants manifested greater accuracy in judging whether two death-related (vs. neutral) words belonged in the same category. Exploratory analyses indicated that nostalgic (relative to control) participants did not show faster reaction times to death-related (vs. neutral) words. In all, nostalgia appeared to aid in death threat detection. We consider implications for the relevant literatures.

Empathetic listening boosts nostalgia levels and positive emotions in autobiographical narrators

Nostalgic memories serve to increase human resilience. Here, we hypothesized that emotional impressions on a narrator's nostalgic memory change depending on the level of empathy in the listener's response. This independent-measures study was conducted in 120 healthy Japanese undergraduates (66 women, 54 men, M _age 20.3 ± 1.9 years). Nostalgia was induced using a medley of Japanese pop songs from the years 2006-2010. Thirty minutes later each participant was randomly allocated to be interviewed by an experimenter who applied one of three listening conditions: empathy, non-empathy, or non-response. Output measures were participant's talking time, nostalgia ratings, and positive and negative emotion ratings. Data were analyzed by analysis of variance followed by a multiple comparisons test. Empathy group participants had a significantly longer talking time than non-empathy or non-response participants, higher nostalgia scores than non-response participants, and higher positive emotion scores than non-empathy and non-response participants, but lower negative emotion scores than non-reponse participants. Participants were then divided into a less nostalgia-prone and a more nostalgia-prone group using the Southampton Nostalgia Rating Scale and the data were reanalyzed for each experimental condition. The results showed that a person more prone to nostalgia felt more nostalgic and more positive toward their autobiographical memory than those who are less nostalgia-prone. The present findings have implications for human interaction in everyday life and in therapeutic settings.

Bittersweet: The Neuroscience of Ambivalent Affect

Ambivalent affective states, such as bittersweetness, nostalgia, and longing, which are felt as having both positive and negative aspects, are an important component of human experience but have received little attention. The most influential theoretical frameworks in affective neuroscience focus largely on univalenced states. As a result, it is not known whether ambivalent affect corresponds to a simultaneously positive and negative valenced state or whether it results from a rapid vacillation between positive and negative states. Here we hypothesize that ambivalent affect involves both mechanisms, that is, rapid vacillation and simultaneity of positive and negative affect, albeit at different neurobiological levels. Rapidly vacillating univalent emotions could give rise to an ambivalent feeling, a mechanism that depends on brainstem nuclei that facilitate rapid action programs of emotional behavior while inhibiting opposing behaviors. This reciprocal inhibition prevents organisms from simultaneously implementing responses to conflicting emotions but also allows for rapid switching between emotions triggered by counterfactual thinking and rapid reappraisal of situations. We propose that as these transitions occur and respective interoceptive information reaches the insular cortex, further processing of this "emotional moment" would allow separate emotional events to be experienced as one "mixed" and integrated feeling.

Effect of a 5-HT1D receptor agonist on the reinstatement phase of the conditioned place preference test and hippocampal long-term potentiation in methamphetamine-treated rats

Methamphetamine (METH)-seeking relapse is associated with memory and synaptic plasticity changes. Serotonin is a key neuromodulator in this process. While there is a known distribution of 5-HT_1D receptors in reward and memory areas, such as the hippocampus, its physiological function is currently unknown. Here, we evaluated effect of a 5-HT_1D receptor agonist, PNU142633, on the reinstatement of METH-seeking behavior and long-term potentiation. Rats were implanted with a cannula into lateral ventricle, then treated with saline or METH (5 mg/kg) during the acquisition phase of the conditioned place preference (CPP) test. On day 13 of the extinction phase, METH groups were divided into four groups: METH (0: saline, 1, or 2.5 (priming METH) mg/kg; i.p.) + vehicle (5 µl/rat) or a priming dose of METH (2.5 mg/kg; i.p.) + PNU (2 µg/5 µl; i.c.v.) and their preference scores were calculated on reinstatement day (day 14). Immediately following this, electrophysiology was performed to assay the field excitatory postsynaptic potential (fEPSP) slope and population spike (PS) amplitude between groups. The results showed that CPP induction by METH gradually declined to extinction on days 12 and 13. A priming METH treatment significantly increased preference for the METH-paired chamber when compared with other groups, but pre-treatment with PNU significantly attenuated this effect. PS amplitude and fEPSP slopes in vehicle + priming METH rats were greater when compared with other groups. Furthermore, PNU attenuated the priming METH-induced increase in PS amplitude. These findings suggest that PNU can decrease synaptic transmission and prevent METH reinstatement in rats.

5-HTTLPR polymorphism is associated with nostalgia proneness: The role of neuroticism

Nostalgia, a sentimental longing for the past, is a self-relevant and social emotion. Nostalgia proneness is associated with alleviation of distress or instability (e.g., neuroticism). Although nostalgia proneness is heritable, the specific molecular contributors to this heritability are unknown. We focused on a polymorphism in the promoter of the serotonin transporter gene (5-HTTLPR) as a possible biological basis of nostalgia proneness, because the serotonin system has been associated with sensitivity to negative experience. Participants (N = 397 adults) who had reported levels of nostalgia proneness were genotyped. A subsample also completed a measure of neuroticism. Participants with the 5-HTTLPR short allele were higher on nostalgia proneness than those without this allele. Neuroticism mediated the relation between 5-HTTLPR and nostalgia proneness. These findings enrich our understanding of the genetic and personality underpinnings of nostalgia.

Positive autobiographical memory retrieval reduces temporal discounting

People generally prefer rewards sooner rather than later. This phenomenon, temporal discounting, underlies many societal problems, including addiction and obesity. One way to reduce temporal discounting is to imagine positive future experiences. Since there is overlap in the neural circuitry associated with imagining future experiences and remembering past events, here we investigate whether recalling positive memories can also promote more patient choice. We found that participants were more patient after retrieving positive autobiographical memories, but not when they recalled negative memories. Moreover, individuals were more impulsive after imagining novel positive scenes that were not related to their memories, showing that positive imagery alone does not drive this effect. Activity in the striatum and temporo parietal junction during memory retrieval predicted more patient choice, suggesting that to the extent that memory recall is rewarding and involves perspective-taking, it influences decision-making. Furthermore, representational similarity in the ventromedial prefrontal cortex between memory recall and decision phases correlated with the behavioral effect across participants. Thus, we have identified a novel manipulation for reducing temporal discounting-remembering the positive past-and have begun to characterize the psychological and neural mechanisms behind it.

Dissociating maternal responses to sad and happy facial expressions of their own child: An fMRI study

Background

Maternal sensitive behavior depends on recognizing one’s own child’s affective states. The present study investigated distinct and overlapping neural responses of mothers to sad and happy facial expressions of their own child (in comparison to facial expressions of an unfamiliar child).

Methods

We used functional MRI to measure dissociable and overlapping activation patterns in 27 healthy mothers in response to happy, neutral and sad facial expressions of their own school-aged child and a gender- and age-matched unfamiliar child. To investigate differential activation to sad compared to happy faces of one’s own child, we used interaction contrasts. During the scan, mothers had to indicate the affect of the presented face. After scanning, they were asked to rate the perceived emotional arousal and valence levels for each face using a 7-point Likert-scale (adapted SAM version).

Results

While viewing their own child’s sad faces, mothers showed activation in the amygdala and anterior cingulate cortex whereas happy facial expressions of the own child elicited activation in the hippocampus. Conjoint activation in response to one’s own child happy and sad expressions was found in the insula and the superior temporal gyrus.

Conclusions

Maternal brain activations differed depending on the child’s affective state. Sad faces of the own child activated areas commonly associated with a threat detection network, whereas happy faces activated reward related brain areas. Overlapping activation was found in empathy related networks. These distinct neural activation patterns might facilitate sensitive maternal behavior.