一项发表于《自然·医学》的研究为“安慰剂效应”提供了直接的人体证据，显示积极预期可增强疫苗诱导的免疫反应。来自特拉维夫大学的研究者招募了85名志愿者，聚焦与奖赏相关的中脑边缘网络，探索大脑如何调节免疫健康。研究利用实时神经反馈训练，使参与者学习用个性化的心理策略调控通常不受意识控制的脑活动。

志愿者被分为三组：一组训练激活奖赏系统，一组训练激活无关网络，第三组不设训练目标。各组完成4次训练后，所有人立即接受乙肝疫苗作为标准化免疫挑战。训练前后采集的血样显示，特定脑区活动与抗体水平存在显著关联。尤其是腹侧被盖区（VTA）的活动，在所有参与者中与疫苗诱导抗体水平呈正相关，这被认为是人类中首次直接证明脑—免疫调控系统的证据。

进一步分析表明，这种效应并非来自一般性的积极情绪，而是与“积极预期”——对未来的希望性想法——特异相关，且这种联系会随训练增强。研究者认为，更深入理解这一脑—体连接，或可催生非侵入性提升免疫健康的方法，应用于癌症免疫治疗和慢性炎症。同时，该发现为安慰剂效应的生物学机制奠定了更坚实的科学基础，尽管仍需更大规模的试验来验证其临床意义。

A study published in Nature Medicine provides direct human evidence for the placebo effect, showing that positive expectations can enhance vaccine-induced immune responses. Researchers at Tel Aviv University recruited 85 volunteers to probe how the brain regulates immune health, focusing on the reward-related mesolimbic network. Using real-time neurofeedback, participants learned personalised mental strategies to modulate brain activity typically outside conscious control.

Volunteers were split into three groups: one trained to activate the reward system, one an unrelated network, and one with no target. After four training sessions, everyone received a hepatitis B vaccination as a standardised immune challenge. Blood samples taken before and after revealed a striking association: activity in a specific region—the ventral tegmental area (VTA)—was positively correlated with vaccine-induced antibody levels across participants, offering the first direct evidence of a brain–immune regulatory system in humans.

Crucially, the effect tracked positive expectations—hopeful thoughts about the future—rather than general positive emotions, and strengthened with training. The findings suggest that clarifying this mind–body link could enable non-invasive ways to boost immune health, with potential applications in cancer immunotherapy and chronic inflammation. They also ground the biology of the placebo effect more firmly, though larger trials are needed to assess clinical impact.