How the Adverse Affects of Stress Were Discovered

Lots of research has gone into trying to understand how maternal stress affects brain development. And we have begun to answer this question at the most intimate level possible: the level of cell and molecule. For this progress we mostly can thank the klutzy researcher Hans Selye. He is the founder of the modern concept of stress. As a young scientist, Selye would grind up “endocrine extracts”, which presumably contained active stress hormones, and inject them into rats to see what the rats would do. He was not good at it. His lab technique, to put it charitably, was horrible. He often dropped the poor lab animals he was attempting to inject. He had to chase them around with a broom, trying to get them back into their cages. Not surprisingly, the rats became anxious in his presence. Selye observed that he could create this physiological response just by showing up. His main job was to inject some animals with endocrine extract and others, in the control group, with saline. But he was perplexed to discover that both were getting ulcers, losing sleep, and becoming more susceptible to infectious diseases. After many observations, he concluded that anxiety was producing the effect, a concept surprisingly new at the time. If the rats couldn’t remove the source of anxiety or cope with it once it arrived, he found, it could lead to disease and other consequences. To describe the phenomenon, Selye eventually coined the term “stress.” Selye’s insight led to that rarest of all findings: the link between visible behaviors and invisible molecular processes. Selye’s work gave the research community permission to investigate how stressful perceptions could influence biological tissues, including brain development. We know a lot about how stress hormones affect growing neural tissues, including a baby’s, thanks to this pioneering insight. Though most of the research was done on rats, many of the same key processes have been found in humans, too.

A clumsy researcher stressed out his lab rats, causing infections and loss of sleep.