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.

[12][13] Henry Molaison was born on February 26, 1926, in Manchester, Connecticut, and experienced intractable epilepsy that has sometimes been attributed to a bicycle accident at the age of seven.

[3] Scoville localized his epilepsy to the left and right medial temporal lobes (MTLs) and suggested their surgical resection.

His case was first reported by Scoville and Brenda Milner in 1957, who referred to him by "H.M."[14] His full name was not revealed to the wider public until after his death.

The researchers found, to their surprise, that half of H.M.'s hippocampal tissue had survived the 1953 surgery, which has deep implications on past and future interpretations of H.M.'s neurobehavioral profile and of the previous literature describing H.M. as a "pure" hippocampus lesion patient.

Consequently, the medial temporal lobes can be assumed to be a major component involved in the formation of semantic and episodic long-term memories (cf.

This was tested in a working memory experiment involving the recall of previously presented numbers; in fact, his performance was no worse than that of control subjects (Smith & Kosslyn, 2007).

Molaison's largely intact word retrieval provides evidence that lexical memory is independent of the medial temporal structures.

In a study conducted by Milner in the early 1960s, Molaison acquired the new skill of drawing a figure by looking at its reflection in a mirror (Corkin, 2002).

Milner concluded that the unconscious motor centers and parts of the brain responsible for procedural implicit memory such as the basal ganglia and cerebellum can remember things that the conscious mind has forgotten.

This finding is remarkable since Molaison had moved to the house five years after his surgery and hence, given his severe anterograde amnesia and insights from other cases, the common expectation was that the acquisition of topographical memories would have been impaired as well.

In addition to his topographical memory, Molaison showed some learning in a picture memorization-recognition task, as well as in a famous faces recognition test, but in the latter only when he was provided with a phonemic cue.

Molaison's positive performance in the picture recognition task might be due to spared parts of his ventral perirhinal cortex.

[22] Furthermore, Corkin (2002)[22] argues that despite Molaison's general inability to form new declarative memories, he seemed to be able to acquire small and impoverished pieces of information regarding public life (e.g., cued retrieval of celebrities' names).

These findings underscore the importance of Molaison's spared extrahippocampal sites in semantic and recognition memory and enhance our understanding of the interrelations between the different medial temporal lobe structures.

Molaison displayed a temporally graded retrograde amnesia in the way that he "could still recall childhood memories, but he had difficulty remembering events that happened during the years immediately preceding the surgery".

The article suggested that Corkin had destroyed research documents and data, and failed to obtain consent from Molaison's closest living kin.

[30] Psychologist Stuart Vyse writes about this controversy and the action of the two hundred scientists who responded to criticism of Corkin.

Vyse states that in their rush to defend Corkin they risked their credibility and authority "by weighing in on subjects outside their circle of knowledge".

[31] Baxendale (2004) cites Molaison's life as a partial inspiration for Christopher Nolan's 2000 film Memento, the influence of which led to its realistic portrayal of anterograde amnesia.