Homeostatic Regulation of Energetic Arousal During Acute Social Isolation: Evidence From the Lab and the Field.

Recent evidence suggests that social contact is a basic need governed by a social homeostatic system. Little is known, however, about how conditions of altered social homeostasis affect human psychology and physiology. Here, we investigated the effects of 8 hr of social isolation on psychological and physiological variables and compared this with 8 hr of food deprivation in a lab experiment (N = 30 adult women). Social isolation led to lowered self-reported energetic arousal and heightened fatigue, comparable with food deprivation. To test whether these findings would extend to a real-life setting, we conducted a preregistered field study during a COVID-19 lockdown (N = 87 adults; 47 women). The drop in energetic arousal after social isolation observed in the lab replicated in the field study for participants who lived alone or reported high sociability, suggesting that lowered energy could be part of a homeostatic response to the lack of social contact.

Towards understanding rTMS mechanism of action: Stimulation of the DLPFC causes network-specific increase in functional connectivity.

Transcranial magnetic stimulation (TMS) is a powerful non-invasive technique for the modulation of brain activity. While the precise mechanism of action is still unknown, TMS is applied in cognitive neuroscience to establish causal relationships between stimulation and subsequent changes in cerebral function and behavioral outcome. In addition, TMS is an FDA-approved therapeutic agent in psychiatric disorders, especially major depression. Successful repetitive TMS in such disorders is usually applied over the left dorso-lateral prefrontal cortex (DLPFC) and treatment response mechanism was therefore supposed to be based on modulations in functional networks, particularly the meso-cortico-limbic reward circuit. However, mechanistic evidence for the direct effects of rTMS over DLPFC is sparse. Here we show the specificity and temporal evolution of rTMS effects by comparing connectivity changes within 20 common independent components in a sham-controlled study. Using an unbiased whole-brain resting-state network (RSN) approach, we successfully demonstrate that stimulation of left DLPFC modulates anterior cingulate cortex (ACC) connectivity in one specific meso-cortico-limbic network, while all other networks are neither influenced by rTMS nor by sham treatment. The results of this study show that the neural correlates of TMS treatment response are also traceable in DLPFC stimulation of healthy brains and therefore represent direct effects of the stimulation procedure.

Visual image retention does not contribute to modulation of event-related potentials by mental rotation.

Rotation of a visual image in mind is associated with a slow posterior negative deflection of the event-related potential (ERP), termed rotation-related negativity (RRN). Retention of a visual image in short-term memory is also associated with a slow posterior negative ERP, termed negative slow wave (NSW). We tested whether short-term memory retention, indexed by the NSW, contributes to the RRN. ERPs were recorded in the same subjects in two tasks, a mental rotation task, eliciting the RRN, and a visual short-term memory task, eliciting the NSW. Over both right and left parietal scalp, no association was found between the NSW and the RRN amplitudes. Furthermore, adjusting for the effect of the NSW had no influence on a significant association between the RRN amplitude and response time, an index of mental rotation performance. Our data indicate that the RRN reflects manipulation of a visual image but not its retention in short-term memory.

Revealing the self in a digital world: A systematic review of adolescent online and offline self-disclosure.

Adolescence is an important stage of social development. While adolescents are prominent adopters of social media, little is known about whether digital interactions can fulfil the social needs of this age group. Here, we focus on one component of social interaction: self-disclosure. In a systematic review, we investigate the role of self-disclosure in adolescent relationships and the differences between online and offline self-disclosure. The results suggest that self-disclosure is associated with higher relationship quality and well-being. Online self-disclosure appears to be less fulfilling and beneficial for relationship quality than face-to-face self-disclosure. However, certain populations appear to benefit more from online than offline self-disclosure - such as highly anxious adolescents and boys aged 12-13 years, who prefer to first self-disclose online before engaging in offline self-disclosure. This suggests that both online and offline self-disclosure can play a role in fulfilling adolescent social needs.

Revealing the self in a digital world: a systematic review of adolescent online and offline self-disclosure.

Adolescence is an important stage of social development. While adolescents are prominent adopters of social media, little is known about whether digital interactions can fulfil the social needs of this age group. Here, we focus on one component of social interaction: self-disclosure. In a systematic review, we investigate the role of self-disclosure in adolescent relationships and the differences between online and offline self-disclosure. The results suggest that self-disclosure is associated with higher relationship quality and well-being. Online self-disclosure appears to be less fulfilling and beneficial for relationship quality than face-to-face self-disclosure. However, certain populations appear to benefit more from online than offline self-disclosure - such as highly anxious adolescents and boys aged 12-13 years, who prefer to first self-disclose online before engaging in offline self-disclosure. This suggests that both online and offline self-disclosure can play a role in fulfilling adolescent social needs.

Virtual social interaction and loneliness among emerging adults amid the COVID-19 pandemic.

Many social activities moved online during the global COVID-19 pandemic, yet research investigating whether virtual social interactions facilitate social connectedness has been inconclusive. In this study, participants completed online questionnaires assessing objective social isolation, loneliness, mental health, and virtual social interactions. There was clear evidence for worsening mental health among emerging adults during the COVID-19 pandemic characterized by large increases in depressive symptoms (mean increase = 8.35, 95% CI [6.97, 9.73], t(118) = 118, p < .001), and large decrements in happiness (mean decrease = -0.71, 95% CI [-0.84, -0.57], t(118) = 10.09, p < .001) and social satisfaction (mean decrease = -0.81, 95% CI [-1.00,-0.62], t(115) = 8.28, p < .001) post-pandemic onset. In line with expectations, those living in larger households amid the pandemic reported lower levels of loneliness and higher levels of happiness. A negative association was found between household size (an index of objective social isolation) and loneliness, b = -3.01, t(79) = 2.60, p = .011, 95% CI [-5.32, -0.71], and a positive association was found between household size and happiness, b = 22.86, t(75) = 3.30, p = .001, 95% CI [9.06, 36.65]. However, contrary to expectations, there was no association between loneliness and frequency of virtual social interactions. There was also no association between frequency of virtual social interactions and either happiness or depression. More research investigating social connectedness in the context of virtual social interactions is warranted.

The neuroscience of unmet social needs.

John Cacioppo has compared loneliness to hunger or thirst in that it signals that one needs to act and repair what is lacking. This paper reviews Cacioppo's and others' contributions to our understanding of neural mechanisms underlying social motivation in humans and in other social species. We focus particularly on the dopaminergic reward system and try to integrate evidence from animal models and human research. In rodents, objective social isolation leads to increased social motivation, mediated by the brains' mesolimbic dopamine system. In humans, social rejection can lead to either increased or decreased social motivation, and is associated with activity in the insular cortex; while chronic loneliness is typically associated with decreased social motivation but has been associated with altered dopaminergic responses in the striatum. This mixed pattern of cross-species similarities and differences may arise from the substantially different methods used to study unmet social needs across species, and suggests the need for more direct and deliberate cross-species comparative research in this critically important domain.

The effects of social deprivation on adolescent development and mental health.

Adolescence (the stage between 10 and 24 years) is a period of life characterised by heightened sensitivity to social stimuli and the increased need for peer interaction. The physical distancing measures mandated globally to contain the spread of COVID-19 are radically reducing adolescents' opportunities to engage in face-to-face social contact outside their household. In this interdisciplinary Viewpoint, we describe literature from a variety of domains that highlight how social deprivation in adolescence might have far-reaching consequences. Human studies have shown the importance of peer acceptance and peer influence in adolescence. Animal research has shown that social deprivation and isolation have unique effects on brain and behaviour in adolescence compared with other stages of life. However, the decrease in adolescent face-to-face contact might be less detrimental due to widespread access to digital forms of social interaction through technologies such as social media. The findings reviewed highlight how physical distancing might have a disproportionate effect on an age group for whom peer interaction is a vital aspect of development.

Acute social isolation evokes midbrain craving responses similar to hunger.

When people are forced to be isolated from each other, do they crave social interactions? To address this question, we used functional magnetic resonance imaging to measure neural responses evoked by food and social cues after participants (n = 40) experienced 10 h of mandated fasting or total social isolation. After isolation, people felt lonely and craved social interaction. Midbrain regions showed selective activation to food cues after fasting and to social cues after isolation; these responses were correlated with self-reported craving. By contrast, striatal and cortical regions differentiated between craving food and craving social interaction. Across deprivation sessions, we found that deprivation narrows and focuses the brain's motivational responses to the deprived target. Our results support the intuitive idea that acute isolation causes social craving, similar to the way fasting causes hunger.

Information about peer choices shapes human risky decision-making.

Humans frequently make choices that involve risk for health and well-being. At the same time, information about others' choices is omnipresent due to new forms of social media and information technology. However, while past research has shown that peers can exert a strong influence on such risky choices, understanding how information about risky decisions of others affects one's own risky decisions is still lacking. We therefore developed a behavioral task to measure how information about peer choices affects risky decision-making and call it the social Balloon Analogue Risk Task (sBART). We tested this novel paradigm in a sample of 52 college young adults. Here we show that risky decisions were influenced in the direction of the perceived choices of others - riskier choices of others led to riskier behavior whereas safer choices of others led to less risky behavior. These findings indicate that information about peer choices is sufficient to shape one's own risky behavior.

Transcranial magnetic stimulation of the left dorsolateral prefrontal cortex decreases cue-induced nicotine craving and EEG delta power.

BACKGROUND: TMS has high potential as smoking cessation treatment. However, the neural mechanisms underlying TMS induced reduction of tobacco craving remain unclear. Electroencephalographic (EEG) delta frequency has been associated with the activity of the dopaminergic brain reward system, which is crucial for nicotine induced effects, and decreases after nicotine admission in smokers. OBJECTIVE: The aim of this study was to investigate EEG delta power changes induced by hf rTMS of the left dorsolateral prefrontal cortex (DLPFC) in nicotine deprived smokers and it's relation to cue-induced nicotine craving. METHODS: Fourteen healthy smokers meeting ICD-10 criteria for tobacco addiction participated in this within-subject sham controlled study. Participants had to abstain from smoking 6 h before the experiment. Effects of high-frequency repetitive TMS (hf rTMS) (10 Hz) for verum (left DLPFC) and sham (vertex) stimulations on cue-induced nicotine craving and resting state EEG delta power were assessed before and three times within 40 min after rTMS. RESULTS: Both craving (P = 0.046) and EEG delta power (P = 0.048) were significantly lower after verum stimulation compared to sham stimulation across the whole post stimulation time period assessed. However, changes of craving ratings and delta power did not correlate. CONCLUSION: Hf rTMS applied to the left DLPFC reduces nicotine craving in short-term abstinent smokers. Changes in delta activity support the idea that stimulation induced effects are mediated by the dopaminergic brain reward system, which presumably plays a prominent, but probably not exclusive, role in this stimulation induced behavioral modulation, making this method a promising smoking cessation treatment candidate.