Defining neuroplasticity

Brain Connectivity, Neural Networks, and Resilience in Aging and Neurodegeneration

The importance of complex systems has become increasingly evident in recent years. The nervous system is one such example, with neural networks sitting at the intersection of complex networks and biology. A particularly exciting feature is the resilience of complex systems. For example, the ability of the nervous system to perform even in the face of challenges that include neuronal loss, neuroinflammation, protein accumulation, axonal disruptions, and metabolic stress is an intriguing and exciting line of investigation. In neurodegenerative diseases, neural network resilience is responsible for the time between the earliest disease-linked changes and clinical symptom onset and disease diagnosis. In this way, connectivity resilience of neurons within the complex network of cells that make up the nervous system has significant implications. This review provides an overview of relevant concepts related to complex systems with a focus on the connectivity of the nervous system. It discusses the development of the neural network and how a delicate balance determines how this complex system responds to injury, with examples illustrating maladaptive plasticity. The review then addresses the implications of these concepts, methods to understand brain connectivity and neural networks, and recent research efforts aimed at understanding neurodegeneration from this perspective. This study aims to provide foundational knowledge and an overview of current research directions in this evolving and exciting area of neuroscience.

Role of SIRT1-mediated synaptic plasticity and neurogenesis: Sex-differences in antidepressant-like efficacy of catalpol

BACKGROUND

Catalpol, an important compound found in Rehmannia glutinosa (a plant with high nutritional and antidepressant medicinal value), exhibits various biological activities and has the ability to penetrate the blood-brain barrier. Our recent studies revealed a gender difference in the antidepressant activity of Rehmannia glutinosa with females showing better responses than males. Catalpol is likely the key compound responsible for this gender-specific difference, which caters to current clinical observations that the severity and impact of depression are approximately two to three times higher in females than in males. However, the sex-specific mechanism of catalpol's antidepressant effects remains unclear.

PURPOSE AND METHODS

Our recent molecular network predictions suggest that the gender-specific antidepressant properties of catalpol primarily involve the regulation of SIRT1-mediated synaptic plasticity and neurogenesis. Building on this, the present study used a well-established chronic unpredictable mild stress model of depression in mice to confirm the sex-specific antidepressant characteristics of catalpol over time and intensity. Furthermore, using SIRT1 inhibitors and activators, behavioral tests, hematoxylin & eosin, Nissl, and Golgi staining, western blotting, immunofluorescence, and real-time PCR, we evaluated the key indicators of depressive behavior, synaptic plasticity, and neurogenesis before and after SIRT1 intervention to comprehensively assess whether the sex-specific antidepressant mechanism of catalpol indeed involves SIRT1-mediated synaptic plasticity and neurogenesis.

RESULTS

The gender-dependent antidepressant effects of catalpol are characterized by a faster onset and stronger effects in females compared to males, with females showing stronger regulation of SIRT1-mediated synaptic plasticity and neurogenesis. Activation of SIRT1 preserved the gender differences in catalpol's effects on depressive behavior, hippocampal synaptic plasticity (including neuronal consolidation, neuronal density, dendritic spines, and PSD95 and SYP gene and protein expression), and neurogenesis (including enhancement of GAP43 and MAP2 expression, activation of c-myc, cyclinD1, Ngn2, and NeuroD1 mRNA levels, and upregulation of the Wnt3a/β-catenin/GSK-3β pathway), while inhibition of SIRT1 abolished these gender differences in the effects of catalpol.

CONCLUSIONS

Catalpol exhibits higher antidepressant activity in female mice compared to male mice, and the mechanism underlying this gender difference in antidepressant effects may depend on catalpol's higher sensitivity in improving hippocampal SIRT1-mediated synaptic plasticity and neurogenesis in females. The novelty of this study lies in its first-time revelation of the gender-specific phenotypes, targets, and molecular mechanisms of the antidepressant effects of catalpol.

Strengthening Neuroplasticity in Substance Use Recovery Through Lifestyle Intervention

The incidence of substance use and behavioral addictions continues to increase throughout the world. The Global Burden of Disease Study shows a growing impact in disability-adjusted life years due to substance use. Substance use impacts families, communities, health care, and legal systems; yet, the vast majority of individuals with substance use disorders do not seek treatment. Within the United States, new legislation has attempted to increase the availability of buprenorphine, but the impact of substance use continues. Although medications and group support therapy have been the mainstay of treatment for substance use, lifestyle medicine offers a valuable adjunct therapy that may help strengthen substance use recovery through healthy neuroplastic changes.

Exercise-induced neuroplasticity: a new perspective on rehabilitation for chronic low back pain

Chronic low back pain patients often experience recurrent episodes due to various peripheral and central factors, leading to physical and mental impairments, affecting their daily life and work, and increasing the healthcare burden. With the continuous advancement of neuropathological research, changes in brain structure and function in chronic low back pain patients have been revealed. Neuroplasticity is an important mechanism of self-regulation in the brain and plays a key role in neural injury repair. Targeting neuroplasticity and regulating the central nervous system to improve functional impairments has become a research focus in rehabilitation medicine. Recent studies have shown that exercise can have beneficial effects on the body, such as improving cognition, combating depression, and enhancing athletic performance. Exercise-induced neuroplasticity may be a potential mechanism through which exercise affects the brain. This article systematically introduces the theory of exercise-induced neuroplasticity, explores the central effects mechanism of exercise on patients with chronic low back pain, and further looks forward to new directions in targeted neuroplasticity-based rehabilitation treatment for chronic low back pain.

Panax notoginseng saponins stimulates the differentiation and neurite development of C17.2 neural stem cells against OGD/R injuries via mTOR signaling

Ischemic stroke remains a major disease worldwide, and most stroke patients often suffer from serious sequelae. Endogenous neurogenesis matters in the repair and regeneration of impaired neural cells after stroke. We have previously reported in vivo that PNS could strengthen the proliferation and differentiation of neural stem cells (NSCs), modulate synaptic plasticity and protect against ischemic brain injuries in cerebral ischemia rats, which could be attributed to mTOR signaling activation. Next, to obtain further insights into the function mechanism of PNS, we evaluated the direct influence of PNS on the survival, differentiation and synaptic development of C17.2 NSCs in vitro. The oxygen glucose deprivation/reperfusion (OGD/R) model was established to mimic ischemic brain injuries. We found that after OGD/R injuries, PNS improved the survival of C17.2 cells. Moreover, PNS enhanced the differentiation of C17.2 cells into neurons and astrocytes, and further promoted synaptic plasticity by significantly increasing the expressions of synapse-related proteins BDNF, SYP and PSD95. Meanwhile, PNS markedly activated the Akt/mTOR/p70S6K pathway. Notably, the mTOR inhibitor rapamycin pretreatment could reverse these desirable results. In conclusion, PNS possessed neural differentiation-inducing properties in mouse C17.2 NSCs after OGD/R injuries, and Akt/mTOR/p70S6K signaling pathway was proved to be involved in the differentiation and synaptic development of C17.2 cells induced by PNS treatment under the in vitro ischemic condition. Our findings offer new insights into the mechanisms that PNS regulate neural plasticity and repair triggered by NSCs, and highlight the potential of mTOR signaling as a therapeutic target for neural restoration after ischemic stroke.

Gut microbiota, nutrition, and mental health

The human brain remains one of the greatest challenges for modern medicine, yet it is one of the most integral and sometimes overlooked aspects of medicine. The human brain consists of roughly 100 billion neurons, 100 trillion neuronal connections and consumes about 20-25% of the body's energy. Emerging evidence highlights that insufficient or inadequate nutrition is linked to an increased risk of brain health, mental health, and psychological functioning compromise. A core component of this relationship includes the intricate dynamics of the brain-gut-microbiota (BGM) system, which is a progressively recognized factor in the sphere of mental/brain health. The bidirectional relationship between the brain, gut, and gut microbiota along the BGM system not only affects nutrient absorption and utilization, but also it exerts substantial influence on cognitive processes, mood regulation, neuroplasticity, and other indices of mental/brain health. Neuroplasticity is the brain's capacity for adaptation and neural regeneration in response to stimuli. Understanding neuroplasticity and considering interventions that enhance the remarkable ability of the brain to change through experience constitutes a burgeoning area of research that has substantial potential for improving well-being, resilience, and overall brain health through optimal nutrition and lifestyle interventions. The nexus of lifestyle interventions and both academic and clinical perspectives of nutritional neuroscience emerges as a potent tool to enhance patient outcomes, proactively mitigate mental/brain health challenges, and improve the management and treatment of existing mental/brain health conditions by championing health-promoting dietary patterns, rectifying nutritional deficiencies, and seamlessly integrating nutrition-centered strategies into clinical care.

Poria cocos (Schw.) Wolf, a Traditional Chinese Edible Medicinal Herb, Promotes Neuronal Differentiation, and the Morphological Maturation of Newborn Neurons in Neural Stem/Progenitor Cells

Neurogenesis in the adult brain comprises the entire set of events of neuronal development. It begins with the division of precursor cells to form a mature, integrated, and functioning neuronal network. Adult neurogenesis is believed to play an important role in animals' cognitive abilities, including learning and memory. In the present study, significant neuronal differentiation-promoting activity of 80% (v/v) ethanol extract of P. cocos (EEPC) was found in Neuro-2a cells and mouse cortical neural stem/progenitor cells (NSPCs). Subsequently, a total of 97 compounds in EEPC were identified by UHPLC-Q-Exactive-MS/MS. Among them, four major compounds-Adenosine; Choline; Ethyl palmitoleate; and L-(-)-arabinitol-were further studied for their neuronal differentiation-promoting activity. Of which, choline has the most significant neuronal differentiation-promoting activity, indicating that choline, as the main bioactive compound in P. cocos, may have a positive effect on learning and memory functions. Compared with similar research literature, this is the first time that the neuronal differentiation-promoting effects of P. cocos extract have been studied.

Gender differences in plasma glial cell line-derived neurotrophic factor levels of patients with bipolar disorder

BACKGROUND

The glial cell line-derived neurotrophic factor (GDNF) has an important role in neurons and is closely associated with psychiatric disorders. The development of bipolar disorder (BD) may differ between genders. Existing studies have shown that plasma GDNF levels are altered in patients with BD. In this study, we investigate whether the GDNF levels in patients with BD differ in terms of gender.

METHODS

Participants were divided into the BD group (n = 76, with 26 males and 50 females) and healthy control (HC) group (n = 89, with 35 males and 54 females). Plasma GDNF levels were detected via multifactor assay. Clinical symptoms of patients with BD were collected and assessed using the Hamilton Depression-17 Inventory, Hamilton Anxiety-17 Inventory, Young's Mania Rating Scale, and Brief Psychiatric Rating Scale.

RESULTS

The GDNF levels were significantly higher in all participants in the HC group (F = 4.262, p < 0.05) compared with those in the BD group. In the HC group, the males (t = 4.814, p < 0.001) presented significantly higher levels than the females. The plasma GDNF levels in males in the BD group (t = 3.022, p < 0.05) were significantly lower than those in males in the HC group.

CONCLUSION

Differences in plasma GDNF levels are associated with the gender of patients with BD.

Environmental Enrichment Enhances Cerebellar Compensation and Develops Cerebellar Reserve

The brain is able to change its structure and function in response to environmental stimulations. Several human and animal studies have documented that enhanced stimulations provide individuals with strengthened brain structure and function that allow them to better cope with damage. In this framework, studies based on the exposure of animals to environmental enrichment (EE) have provided indications of the mechanisms involved in such a beneficial action. The cerebellum is a very plastic brain region that responds to every experience with deep structural and functional rearrangement. The present review specifically aims to collect and synthesize the evidence provided by animal models on EE exposure effects on cerebellar structure and function by considering the studies on healthy subjects and on animals exposed to EE both before and after damage involving cerebellar functionality. On the whole, the evidence supports the role of EE in enhancing cerebellar compensation and developing cerebellar reserve. However, since studies addressing this issue are still scarce, large areas of inconsistency and lack of clarity remain. Further studies are required to provide suggestions on possible mechanisms of enhancement of compensatory responses in human patients following cerebellar damage.