Core Viewpoint - Chronic pain is a major cause of disability and disease burden globally, affecting over 20% of the population, highlighting the urgent need for safe and effective pain management methods [2] Group 1: Research Findings - A study published in Cell Research indicates that daily exposure to 40 Hz flickering light for 2 hours can effectively alleviate chronic pain and even "erase" pain memory [3][4] - The study reveals that 40 Hz flickering light serves as a novel non-invasive pain management method, elucidating the unique retinal-central amygdala pathway and adenosine signaling mechanism involved in pain control [4][6] - The research team found that 40 Hz flickering light significantly alleviates mechanical pain in mouse models of inflammatory and neuropathic pain, with effects lasting over 6 hours post-exposure [8] Group 2: Mechanisms of Action - The study identifies a previously unknown pathway from the retina to the central amygdala, acting as a "pain relief hotline" to the brain [10] - It was discovered that the analgesic effect is mediated not by intrinsic photosensitive retinal ganglion cells but by conventional retinal ganglion cells [11] - On a molecular level, 40 Hz light stimulation rapidly and persistently elevates extracellular adenosine levels in the central amygdala, which is crucial for the pain relief effect [13] Group 3: Pain Memory Erasure - The study addresses the challenge of "pain memory," where the brain continues to remember pain even after the original injury has healed [16] - 40 Hz light exposure can disrupt the reconsolidation process of pain memory, indicating that the central amygdala is key in eliminating pain memory [17] - This suggests that 40 Hz light not only alleviates current pain but also rewrites the brain's pain memory, preventing the recurrence of previously alleviated pain [17] Group 4: Clinical Implications - The research presents significant theoretical and practical value, marking the first discovery of a direct functional connection between the eyes and the brain's pain center [19] - It offers a non-invasive treatment option for chronic pain patients, with advantages over drug and surgical treatments, including high safety, accessibility, and the ability for patients to self-administer at home [19] - The study also highlights frequency specificity, intensity dependence, and the treatment window for effective pain management [19]

Core Viewpoint - The study highlights that adenosine signaling drives the antidepressant effects of ketamine and electroconvulsive therapy (ECT), presenting a potential target for developing scalable non-invasive antidepressant therapies [4]. Group 1: Mechanism of Action - Ketamine and ECT rapidly alleviate symptoms of treatment-resistant depression, but their mechanisms remain unclear, which is crucial for improving treatment precision [5]. - The research team identified adenosine signaling as the core pathway through which these interventions exert their antidepressant effects using mouse models [5]. Group 2: Key Findings - Experiments with genetically encoded adenosine sensors and real-time optical recordings showed that both therapies induce a significant surge in adenosine levels in key emotional regulation brain regions, including the medial prefrontal cortex (mPFC) and hippocampus [6]. - Disruption of A1 and A2A adenosine receptors genetically or pharmacologically eliminates the antidepressant effects of ketamine and ECT, establishing the critical role of adenosine signaling in these effects [6]. Group 3: Implications for Treatment - Adenosine signaling specifically in the mPFC drives the antidepressant effects, with ketamine enhancing adenosine levels through metabolic regulation without causing excessive neuronal activity [8]. - The research team developed ketamine derivatives that enhance adenosine signaling and demonstrate better antidepressant effects with fewer side effects at therapeutic doses [8]. - Acute intermittent hypoxia, a non-drug intervention that lowers oxygen levels, can also increase brain adenosine levels and produce antidepressant effects, similar to ketamine and ECT [8].