Fears during the Covid-19 pandemics and their influence on physical health: A cross-sectional study on the general population in Spain

Background/objective: This study examines the paths through which Covid-19 can negatively impact health and lead to somatic symptoms. Based on the dual process theory, fears can impair health in two ways: through psychological distress, which is an automatic reaction to fear, and through a more conscious and deliberative rumination process. Method: Data from a representative sample of the Spanish population (N = 3083 subjects,18 years or older) were obtained from a Survey by the Sociological Research Center (CIS). The dual path model was tested, and a longer sequence was included where the two mediators act sequentially to produce an impact on somatic symptoms. Results: The results showed how Covid-19 fears translate into somatic problems. Beyond the direct relations, and after comparing with other possible alternative models, our findings support a process where rumination mediates between fears and psychological distress, and psychological distress in turn leads to somatic problems. Conclusions: This process reveals a plausible mechanism that explains the somatization of health problems during the Covid-19 pandemic, and it provides theoretical and practical inputs to better understand the role of fears in health in crisis contexts. (AU)

Fears during the Covid-19 pandemics and their influence on physical health: A cross-sectional study on the general population in Spain.

Background/objective: This study examines the paths through which Covid-19 can negatively impact health and lead to somatic symptoms. Based on the dual process theory, fears can impair health in two ways: through psychological distress, which is an automatic reaction to fear, and through a more conscious and deliberative rumination process. Method: Data from a representative sample of the Spanish population (N = 3083 subjects,18 years or older) were obtained from a Survey by the Sociological Research Center (CIS). The dual path model was tested, and a longer sequence was included where the two mediators act sequentially to produce an impact on somatic symptoms. Results: The results showed how Covid-19 fears translate into somatic problems. Beyond the direct relations, and after comparing with other possible alternative models, our findings support a process where rumination mediates between fears and psychological distress, and psychological distress in turn leads to somatic problems. Conclusions: This process reveals a plausible mechanism that explains the somatization of health problems during the Covid-19 pandemic, and it provides theoretical and practical inputs to better understand the role of fears in health in crisis contexts.

Influence of Social Support and Subjective Well-Being on the Perceived Overall Health of the Elderly.

Scientific interest in the positive aspects of aging and the development of healthy aging has increased, given the need to ensure older people well-being and quality of life. In this sense, social support and some sociodemographic variables may have a not yet entirely clear role. The main objective of this work was to analyze the predictive relationships of age, marital status, social support and subjective well-being on the general perception of the health of a group of elderly people. The participants were 137 people (77.4% women) between 61 and 91 years old (M = 73.11; SD = 6.22); 56.9% of them had a partner and 40.1% did not. The path analysis tested indicates that social support has an indirect predictive value on perceived overall health through its influence on subjective well-being. Age and life satisfaction are the most important direct predictors of perceived overall health. Conclusions highlight the need to delve into the study of explanatory factors of the general perception of the health of the elderly and promote interventions to facilitate the development of an appropriate social support network and increase the subjective well-being of this group.

Neural oscillations in the infralimbic cortex after electrical stimulation of the amygdala. Relevance to acute stress processing.

The stress system coordinates the adaptive reactions of the organism to stressors. Therefore, dysfunctions in this circuit may correlate to anxiety-related disorders, including depression. Comprehending the dynamics of this network may lead to a better understanding of the mechanisms that underlie these diseases. The central nucleus of the amygdala (CeA) activates the hypothalamic-pituitary-adrenal axis and brainstem nodes by triggering endocrine, autonomic and behavioral stress responses. The medial prefrontal cortex plays a significant role in regulating reactions to stressors, and is specifically important for limiting fear responses. Brain oscillations reflect neural systems activity. Synchronous neuronal assemblies facilitate communication and synaptic plasticity, mechanisms that cooperatively support the temporal representation and long-term consolidation of information. The purpose of this article was to delve into the interactions between these structures in stress contexts by evaluating changes in oscillatory activity. We particularly analyzed the local field potential in the infralimbic region of the medial prefrontal cortex (IL) in urethane-anesthetized rats after the electrical activation of the central nucleus of the amygdala by mimicking firing rates induced by acute stress. Electrical CeA activation induced a delayed, but significant, change in the IL, with prominent slow waves accompanied by an increase in the theta and gamma activities, and spindles. The phase-amplitude coupling of both slow waves and theta oscillations significantly increased with faster oscillations, including theta-gamma coupling and the nesting of spindles, theta and gamma oscillations in the slow wave cycle. These results are further discussed in neural processing terms of the stress response and memory formation.

Causal relationships between neurons of the nucleus incertus and the hippocampal theta activity in the rat.

KEY POINTS: The nucleus incertus is a key node of the brainstem circuitry involved in hippocampal theta rhythmicity. Synchronisation exists between the nucleus incertus and hippocampal activities during theta periods. By the Granger causality analysis, we demonstrated a directional information flow between theta rhythmical neurons in the nucleus incertus and the hippocampus in theta-on states. The electrical stimulation of the nucleus incertus is also able to evoke a phase reset of the hippocampal theta wave. Our data suggest that the nucleus incertus is a key node of theta generation and the modulation network. ABSTRACT: In recent years, a body of evidence has shown that the nucleus incertus (NI), in the dorsal tegmental pons, is a key node of the brainstem circuitry involved in hippocampal theta rhythmicity. Ascending reticular brainstem system activation evokes hippocampal theta rhythm with coupled neuronal activity in the NI. In a recent paper, we showed three populations of neurons in the NI with differential firing during hippocampal theta activation. The objective of this work was to better evaluate the causal relationship between the activity of NI neurons and the hippocampus during theta activation in order to further understand the role of the NI in the theta network. A Granger causality analysis was run to determine whether hippocampal theta activity with sensory-evoked theta depends on the neuronal activity of the NI, or vice versa. The analysis showed causal interdependence between the NI and the hippocampus during theta activity, whose directional flow depended on the different neuronal assemblies of the NI. Whereas type I and II NI neurons mainly acted as receptors of hippocampal information, type III neuronal activity was the predominant source of flow between the NI and the hippocampus in theta states. We further determined that the electrical activation of the NI was able to reset hippocampal waves with enhanced theta-band power, depending on the septal area. Collectively, these data suggest that hippocampal theta oscillations after sensory activation show dependence on NI neuron activity, which could play a key role in establishing optimal conditions for memory encoding.

Characterization of oscillatory changes in hippocampus and amygdala after deep brain stimulation of the infralimbic prefrontal cortex.

Deep brain stimulation (DBS) is a new investigational therapy that has generated positive results in refractory depression. Although the neurochemical and behavioral effects of DBS have been examined, less attention has been paid to the influence of DBS on the network dynamics between different brain areas, which could contribute to its therapeutic effects. Herein, we set out to identify the effects of 1 h DBS in the infralimbic cortex (IL) on the oscillatory network dynamics between hippocampus and basolateral amygdala (BLA), two regions implicated in depression and its treatment. Urethane-anesthetized rats with bilaterally implanted electrodes in the IL were exposed to 1 h constant stimulation of 130 Hz of frequency, 60 µA of constant current intensity and biphasic pulse width of 80 µsec. After a period of baseline recording, local field potentials (LFP) were recorded with formvar-insulated stainless steel electrodes. DBS of the IL increased the power of slow wave (SW, <1.5 Hz) and theta (3-12 Hz) frequencies in the hippocampus and BLA Furthermore, IL DBS caused a precise coupling in different frequency bands between both brain structures. The increases in SW band synchronization in hippocampus and BLA after DBS suggest that these changes may be important for the improvement of depressive behavior. In addition, the augmentation in theta synchrony might contribute to improvement in emotional and cognitive processes.

Regular theta-firing neurons in the nucleus incertus during sustained hippocampal activation.

This paper describes the existence of theta-coupled neuronal activity in the nucleus incertus (NI). Theta rhythm is relevant for cognitive processes such as spatial navigation and memory processing, and can be recorded in a number of structures related to the hippocampal activation including the NI. Strong evidence supports the role of this tegmental nucleus in neural circuits integrating behavioural activation with the hippocampal theta rhythm. Theta oscillations have been recorded in the local field potential of the NI, highly coupled to the hippocampal waves, although no rhythmical activity has been reported in neurons of this nucleus. The present work analyses the neuronal activity in the NI in conditions leading to sustained hippocampal theta in the urethane-anaesthetised rat, in order to test whether such activation elicits a differential firing pattern. Wavelet analysis has been used to better define the neuronal activity already described in the nucleus, i.e., non-rhythmical neurons firing at theta frequency (type I neurons) and fast-firing rhythmical neurons (type II). However, the most remarkable finding was that sustained stimulation activated regular-theta neurons (type III), which were almost silent in baseline conditions and have not previously been reported. Thus, we describe the electrophysiological properties of type III neurons, focusing on their coupling to the hippocampal theta. Their spike rate, regularity and phase locking to the oscillations increased at the beginning of the stimulation, suggesting a role in the activation or reset of the oscillation. Further research is needed to address the specific contribution of these neurons to the entire circuit.