ACC-BLA functional connectivity disruption in allergic inflammation is associated with anxiety

Microelectrode Arrays for Detection of Neural Activity in Depressed Rats: Enhanced Theta Activity in the Basolateral Amygdala

Depression is a common and severely debilitating neuropsychiatric disorder. Multiple studies indicate a strong correlation between the occurrence of immunological inflammation and the presence of depression. The basolateral amygdala (BLA) is crucial in the cognitive and physiological processing and control of emotion. However, due to the lack of detection tools, the neural activity of the BLA during depression is not well understood. In this study, a microelectrode array (MEA) based on the shape and anatomical location of the BLA in the brain was designed and manufactured. Rats were injected with lipopolysaccharide (LPS) for 7 consecutive days to induce depressive behavior. We used the MEA to detect neural activity in the BLA before modeling, during modeling, and after LPS administration on 7 consecutive days. The results showed that after LPS treatment, the spike firing of neurons in the BLA region of rats gradually became more intense, and the local field potential power also increased progressively. Further analysis revealed that after LPS administration, the spike firing of BLA neurons was predominantly in the theta rhythm, with obvious periodic firing characteristics appearing after the 7 d of LPS administration, and the relative power of the local field potential in the theta band also significantly increased. In summary, our results suggest that the enhanced activity of BLA neurons in the theta band is related to the depressive state of rats, providing valuable guidance for research into the neural mechanisms of depression.

BLA-involved circuits in neuropsychiatric disorders

The basolateral amygdala (BLA) is the subregion of the amygdala located in the medial of the temporal lobe, which is connected with a wide range of brain regions to achieve diverse functions. Recently, an increasing number of studies have focused on the participation of the BLA in many neuropsychiatric disorders from the neural circuit perspective, aided by the rapid development of viral tracing methods and increasingly specific neural modulation technologies. However, how to translate this circuit-level preclinical intervention into clinical treatment using noninvasive or minor invasive manipulations to benefit patients struggling with neuropsychiatric disorders is still an inevitable question to be considered. In this review, we summarized the role of BLA-involved circuits in neuropsychiatric disorders including Alzheimer's disease, perioperative neurocognitive disorders, schizophrenia, anxiety disorders, depressive disorders, posttraumatic stress disorders, autism spectrum disorders, and pain-associative affective states and cognitive dysfunctions. Additionally, we provide insights into future directions and challenges for clinical translation.

Olfactory bulb-medial prefrontal cortex theta synchronization is associated with anxiety

Anxiety is among the most fundamental mammalian behaviors. Despite the physiological and pathological importance, its underlying neural mechanisms remain poorly understood. Here, we recorded the activity of olfactory bulb (OB) and medial prefrontal cortex (mPFC) of rats, which are critical structures to brain's emotional processing network, while exploring different anxiogenic environments. Our results show that presence in anxiogenic contexts increases the OB and mPFC regional theta activities. Also, these local activity changes are associated with enhanced OB-mPFC theta power- and phase-based functional connectivity as well as OB-to-mPFC information transfer. Interestingly, these effects are more prominent in the unsafe zones of the anxiogenic environments, compared to safer zones. This consistent trend of changes in diverse behavioral environments as well as local and long-range neural activity features suggest that the dynamics of OB-mPFC circuit theta oscillations might underlie different types of anxiety behaviors, with possible implications for anxiety disorders.

Asthma is a risk factor for general fatigue of long COVID in Japanese nation-wide cohort study

BACKGROUND

Multiple prolonged symptoms are observed in patients who recover from an acute COVID-19 infection, which is defined as long COVID. General fatigue is frequently observed in patients with long COVID during acute and post-acute phases. This study aimed to identify the specific risk factors for general fatigue in long COVID.

METHODS

Hospitalized patients with COVID-19 aged over 18 years were enrolled in a multicenter cohort study at 26 medical institutions. Clinical data during hospitalization and patient-reported outcomes after discharge were collected from medical records, paper-based questionnaires, and smartphone apps.

RESULTS

Among prolonged symptoms through 1-year follow-ups, general fatigue was the most interfering symptom in daily life. Patients with protracted fatigue at all follow-up periods had lower quality of life scores at the 12-month follow-up. Univariate logistic regression analysis of the presence or absence of general fatigue at the 3-month, 6-month, and 12-month follow-ups identified asthma, younger age, and female sex as risk factors for prolonged fatigue. Multivariable logistic regression analysis revealed that asthma was an independent risk factor for persistent fatigue during the 12-month follow-up period. Longitudinal changes in the symptoms of patients with or without asthma demonstrated that general fatigue, not cough and dyspnea, was significantly prolonged in patients with asthma.

CONCLUSIONS

In a Japanese population with long COVID, prolonged general fatigue was closely linked to asthma. A preventive approach against COVID-19 is necessary to avoid sustained fatigue and minimize social and economic losses in patients with asthma.

Neuroimmune pathways regulating airway inflammation

Airways diseases are typically accompanied by inflammation, which has long been known to contribute to obstruction, mucus hypersecretion, dyspnea, cough, and other characteristic symptoms displayed in patients. Clinical interventions, therefore, often target inflammation to reverse lung pathology and reduce morbidity. The airways and lungs are densely innervated by subsets of nerve fibers, which are not only impacted by pulmonary inflammation but, in addition, likely serve as important regulators of immune cell function. This bidirectional neuroimmune crosstalk is supported by close spatial relationships between immune cells and airway nerve fibers, complementary neural and immune signaling pathways, local specialized airway chemosensory cells, and dedicated reflex circuits. In this article, we review the recent literature on this topic and present state-of-the-art evidence supporting the role of neuroimmune interactions in airway inflammation. In addition, we extend this evidence to synthesize considerations for the clinical translation of these discoveries to improve the management of patients with airway disease.

Brain response in asthma: the role of "lung-brain" axis mediated by neuroimmune crosstalk

In addition to typical respiratory symptoms, patients with asthma are frequently accompanied by cognitive decline, mood disorders (anxiety and depression), sleep disorders, olfactory disorders, and other brain response manifestations, all of which worsen asthma symptoms, form a vicious cycle, and exacerbate the burden on families and society. Therefore, studying the mechanism of neurological symptoms in patients with asthma is necessary to identify the appropriate preventative and therapeutic measures. In order to provide a comprehensive reference for related research, we compiled the pertinent literature, systematically summarized the latest research progress of asthma and its brain response, and attempted to reveal the possible "lung-brain" crosstalk mechanism and treatment methods at the onset of asthma, which will promote more related research to provide asthmatic patients with neurological symptoms new hope.

Allergen induces depression-like behavior in association with altered prefrontal-hippocampal circuit in male rats

Allergic asthma is a common chronic inflammatory condition associated with psychiatric comorbidities. Notably depression, correlated with adverse outcomes in asthmatic patients. Peripheral inflammation's role in depression has been shown previously. However, evidence regarding the effects of allergic asthma on the medial prefrontal cortex (mPFC)-ventral hippocampus (vHipp) interactions, an important neurocircuitry in affective regulation, is yet to be demonstrated. Herein, we investigated the effects of allergen exposure in sensitized rats on the immunoreactivity of glial cells, depression-like behavior, brain regions volume, as well as activity and connectivity of the mPFC-vHipp circuit. We found that allergen-induced depressive-like behavior was associated with more activated microglia and astrocytes in mPFC and vHipp, as well as reduced hippocampus volume. Intriguingly, depressive-like behavior was negatively correlated with mPFC and hippocampus volumes in the allergen-exposed group. Moreover, mPFC and vHipp activity were altered in asthmatic animals. Allergen disrupted the strength and direction of functional connectivity in the mPFC-vHipp circuit so that, unlike normal conditions, mPFC causes and modulates vHipp activity. Our results provide new insight into the underlying mechanism of allergic inflammation-induced psychiatric disorders, aiming to develop new interventions and therapeutic approaches for improving asthma complications.

Cognitive Impairments in Patients with Bronchial Asthma

The course of bronchial asthma can be accompanied by cognitive impairments. However, the relationship between cognitive dysfunction and asthma has not been fully revealed, nor has it been fully established what causes cognitive impairments in patients with asthma. There is an opinion that transient hypoxia and persistent systemic inflammation with insufficient control of bronchial asthma can be accompanied by neurotoxicity in relation to the hippocampus and indirectly lead to deterioration of cognitive functions. Comorbid conditions, such as obesity, allergic rhinitis, and depressive states can increase cognitive dysfunction in asthmatics. The review considers the pathophysiology of cognitive dysfunction in patients with bronchial asthma, as well as the impact of comorbid conditions on the cognitive status. This information will allow systematizing the available knowledge about the state of cognitive functions in asthma for timely detection and correction of their impairments and, ultimately, optimization of the management of these patients.

Neural signature of attention impairment in allergic asthma: an ERP study

Background Cognitive impairments are linked to poor treatment response and disease control in allergic asthma. However, there are no studies exploring attention-related functional brain alterations in allergic asthma. Here, we explore attention deficit and its association with clinical characteristics and common neuropsychiatric disorders in patients with allergic asthma.Methods We recruited 38 participants, equally distributed into healthy and asthma groups. Behavioral, neurophysiological, and lung function assessment tools were used in this study.Results Our behavioral data show that allergic asthma induces attention impairment. Additionally, the event-related potentials (ERP) analysis reveals that this attention deficit is associated with a disruption in cognitive processing capability in frontal brain areas. These behavioral and neurophysiological abnormalities were strongly correlated with disease severity and neuropsychiatric comorbidities of asthmatic patients.Conclusion Together, here we propose that disrupted neurophysiological responses in frontal brain areas might lead to attention impairments in patients with allergic asthma. These findings could help characterizing the neuro-pathophysiology of cognitive disorders in allergic asthma, possibly opening the way for development of novel treatment strategies.

New Insights into the Pivotal Role of the Amygdala in Inflammation-Related Depression and Anxiety Disorder

Depression and anxiety disorders are the two most prevalent psychiatric diseases that affect hundreds of millions of individuals worldwide. Understanding the etiology and related mechanisms is of great importance and might yield new therapeutic strategies to treat these diseases effectively. During the past decades, a growing number of studies have pointed out the importance of the stress-induced inflammatory response in the amygdala, a kernel region for processing emotional stimuli, as a potentially critical contributor to the pathophysiology of depression and anxiety disorders. In this review, we first summarized the recent progress from both animal and human studies toward understanding the causal link between stress-induced inflammation and depression and anxiety disorders, with particular emphasis on findings showing the effect of inflammation on the functional changes in neurons in the amygdala, at levels ranging from molecular signaling, cellular function, synaptic plasticity, and the neural circuit to behavior, as well as their contributions to the pathology of inflammation-related depression and anxiety disorders. Finally, we concluded by discussing some of the difficulties surrounding the current research and propose some issues worth future study in this field.