Brenda Milner

Before the age of three, Brenda Milner crawled around on her parents’ bed, reading snippets from the newspapers strewn there. Of course, she couldn’t understand the politics or economics, but she enjoyed the words. Her behavior presaged a driving curiosity about the people and events around her.

As an undergraduate at Cambridge University, she devoured the encyclopedic Handbook of Experimental Psychology the summer before she formally entered that field. Fearful of becoming a factory inspector, a fate that greeted mediocre psychology graduates, she dedicated herself to her studies. On her final exams, she earned the highest mark possible—one that was rarely given—a “starred first.”

In 1950, Milner began working with neurosurgeon Wilder Penfield. He was controlling his patients’ epilepsy by removing part of the temporal lobe region of the brain. They generally did well afterward, but when seizures persisted, Penfield performed a more extensive operation. In one such case, the patient could not cement new experiences after the second surgery. Initially, the medical team thought that his predicament was a quirk, but then another patient suffered a similar outcome.

At the time, conventional wisdom about memory drew from the effects of brain surgery on maze learning in rats. The animals’ abilities depended on the amount of tissue loss, not its location. Although some neurologists suspected a more nuanced situation in humans, these experiments had a huge impact on the field.

The Penfield team’s report of its two case studies in 1955 caught the attention of neurosurgeon William Scoville, who recognized that one of his patients had met a similar fate. Milner began working with this individual, H.M., who would become the most famous patient in the field of neuroscience.

H.M. retained memories from childhood, but could not recollect what he ate for breakfast. He could recall new things—strings of numbers, for instance—if he continually repeated them to himself. But shifting his attention, even briefly, obliterated the numbers. He had lost the ability to commit new events to long-term memory.

Milner decided to check whether H.M. could learn a new skill. She asked him to trace a path between the two lines of a double-contoured five-pointed star. A screen blocked direct view of the star, and it was visible only in a mirror. At each of the points, people whose brains operate normally first choose the wrong direction. With practice, they move their pencil the correct way.

Given that H.M. could not consolidate new memories, Milner figured he would perform poorly. He underwent 30 trials in three days. From one session to the next, he did not remember her, nor did he recall having done the task. Much to Milner’s surprise, however, he gradually improved. One part of H.M.’s brain acquired a skill that he did not know he had practiced. Milner realized that multiple memory systems must exist—and that different parts of the brain handle each type.

Later, Milner challenged other dogma. For example, she was one of the first to demonstrate that the frontal lobes—thought to affect intelligence only moderately—strongly shape problem-solving flexibility.

Milner has contributed groundbreaking work that has extended into all areas of neuropsychology. Her imprint on the field is immeasurable.

Author: Evelyn Strauss, Ph.D.