FoundationalConceptsNeuroscience

who have been studied in attempts to elucidate brain mechanisms of
memory, by far the most famous is the patient H.M. This patient was
studied for more than fifty years by psychologists and neurologists
and for reasons of privacy was always referred to simply by his initials
in the dozens of scientific publications that came from working with
him. When he died in 2008 at the age of eighty-two, his identity was
revealed to the world—Henry Molaison (1926-2008).
Sometime around the age of ten, Henry began having seizures. His
epilepsy was idiopathic—the cause was unknown. It may have been
related to hitting his head in a bicycle accident several years before;
it may have been a result of genetic risk factors (Henry’s father had
several relatives who suffered from seizures); it may have been some
combination of these things. Through his teen years, Henry’s seizures
became increasingly frequent and severe. By the time he was in his
mid-twenties, he was considered a candidate for brain surgery that
would excise small parts of his brain that might be related to the onset
of his seizures.
Thus, in 1953, at the age of twenty-seven, Henry underwent the
surgical removal of portions of his medial temporal lobe, including
the hippocampus, and adjacent entorhinal cortex and amygdala from
both hemispheres of his brain (Fig. 19.2). After surgery the sever-
ity of his epilepsy was much decreased, but he was found to have a
profound impairment of memory. This was first reported in a 1957
publication by William Scoville (1906-1984), the neurosurgeon who
performed the surgery on H.M., and Brenda Milner (b. 1918), a neu-
ropsychologist who had previously studied with Donald Hebb and
Wilder Penfield. Milner continued to work with H.M. for many years,
and together they made significant contributions to the neuroscience
of memory. Here are some of the things they found.
Following surgery, H.M. had relatively normal working memory.