The brain of Patient H.M.

(Image credit: Jacopo Annese)Patient H.M. became an iconic case in neuroscience when he developed a peculiar form of amnesia after parts of his brain were removed during surgery in 1953. After H.M.'s death in 2008, Jacopo Annese and his colleagues at the Brain Observatory in San Diego dissected his frozen brain into 2,400 thin slices, to learn about his brain lesions that caused his amnesia.

The frozen brain

(Image credit: Diego Mariscal)Image of the frozen brain at the level of the temporal lobes during the cutting procedure.

Cutting process

(Image credit: Diego Mariscal)Jacopo Annese dissecting the brain of H.M.

Cutting process

(Image credit: Annese et al.)Image of the frozen brain at the level of the frontal lobes during the cutting procedure.

Preparing solutions

(Image credit: Jacopo Annese)Researcher Paul Maechler making a solution to treat the brain tissue.

Brain slides

(Image credit: Annese et al.)Tissue sections mounted on glass slides before staining.

Brain slides

(Image credit: Jacopo Annese)Researcher Colleen Sheh examining a thin slice of the brain.