Henry Gustav Molaison, known widely as H.M., was an American who had a bilateral medial temporal lobectomy to surgically resect the anterior two thirds of his hippocampi, parahippocampal cortices, entorhinal cortices, piriform cortices, and amygdalae in an attempt to cure his epilepsy. Although the surgery was partially successful in controlling his epilepsy, a severe side effect was that he became unable to form new memories. His unique case also helped define ethical standards in neurological research, emphasizing the need for patient consent and the consideration of long-term impacts of medical interventions. Furthermore, Molaison's life after his surgery highlighted the challenges and adaptations required for living with significant memory impairments, serving as an important case study for healthcare professionals and caregivers dealing with similar conditions.
Molaison in 1953 before his surgery
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, it would be impossible for language, relationships, or personal identity to develop. Memory loss is usually described as forgetfulness or amnesia.
Olin Levi Warner's 1896 illustration, Memory, now housed in the Thomas Jefferson Building at the Library of Congress in Washington, D.C.
The garden of oblivion, illustration by Ephraim Moses Lilien
Regulatory sequence in a promoter at a transcription start site with a paused RNA polymerase and a TOP2B-induced double-strand break
Brain regions involved in memory formation including medial prefrontal cortex (mPFC)
