How Stress Moves From the Mind to the Immune System

Independent science writer Stephanie Jyet Quan Loo traces the biological pathway from a psychological stressor to physical changes in the immune system — beginning with the amygdala flagging an emotional threat, signaling the hypothalamus, and triggering downstream hormonal cascades that, as Hans Selye observed in his foundational rat experiments, eventually shrink immune organs like the thymus and spleen. The piece bridges Selye's classic 'father of stress research' framework with modern findings on how everyday stressors (deadlines, social tension, uncertainty) produce the same kinds of immune effects.