Neuromodulation and hippocampal neurogenesis in depression: A scoping review

• Published in: Brain research bulletin Vol. 188; pp. 92 - 107
• Main Authors: Flores, Angelo D., Yu, Wing Shan, Fung, Man-Lung, Lim, Lee Wei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2022; Elsevier
• Subjects: Adult hippocampal neurogenesis; Animals; Antidepressant; Antidepressive Agents - metabolism; Antidepressive Agents - pharmacology; Antidepressive Agents - therapeutic use; Cell proliferation; Depression; Depression - drug therapy; Hippocampus - metabolism; Hypothalamo-Hypophyseal System; Neurogenesis - physiology; Neuromodulation; Pituitary-Adrenal System; Cell proliferation; Antidepressant; Depression; Neuromodulation; Adult hippocampal neurogenesis
• ISSN: 0361-9230; 1873-2747; 1873-2747
• DOI: 10.1016/j.brainresbull.2022.07.009

The ‘neurogenesis hypothesis of depression’ emphasizes the importance of upregulated hippocampal neurogenesis for the efficacy of antidepressant treatment. Neuromodulation is a promising therapeutic method that stimulates neural circuitries to treat neuropsychiatric illnesses. We conducted a scoping review on the neurogenic and antidepressant outcomes of neuromodulation in animal models of depression. PubMed, Web of Science, and PsycInfo were comprehensively searched for full-text English articles from inception to October 5, 2021. Data screening and extraction were conducted independently by two researchers. Seventeen eligible studies were included in this review. The majority of studies used non-invasive neuromodulation (n = 14) and assessed neurogenesis using neural proliferation (n = 16) and differentiation markers (n = 9). Limited reports (n = 2) used neurogenic inhibitors to evaluate the role of neurogenesis on the depressive-like behavioral outcomes. Overall, neuromodulation substantially effectuated both hippocampal cell proliferation and antidepressant-like behavior in animal models of depression, with some providing evidence for enhanced neuronal differentiation and maturation. The proposed neurogenic-related mechanisms mediating the neuromodulation efficacies included neurotrophic processes, anti-apoptotic pathways, and normalization of HPA axis functions. Further research is warranted to explore the role of neuromodulation-induced neurogenic effects on treatment efficacies and to elucidate the underlying molecular mechanisms. [Display omitted] •Neuromodulation are promising therapeutic tools for treating depression.•Studies show antidepressant effects of neuromodulation in depression models.•Upregulated hippocampal cell proliferation and differentiation were also observed.•There are neurogenesis-dependent and -independent effects of neuromodulation.•Further research is needed to explore underlying molecular mechanisms.