Neuroimaging H.M.: a 10-year follow-up examination

Area of Science:

• Neuroscience
• Neuroimaging
• Neuropathology

Background:

• Patient H.M. underwent extensive medial temporal lobe resection for epilepsy in 1953, resulting in profound anterograde amnesia.
• Previous magnetic resonance imaging (MRI) studies in 1992-1993 delineated the surgical resection boundaries.
• Advanced neuroimaging techniques allow for more detailed anatomical and pathological assessments.

Observation:

• High-resolution T1-weighted, diffusion tensor imaging (DTI), and T2-weighted MRI scans were acquired from patient H.M. on multiple occasions.
• Novel MRI analysis techniques were applied to assess brain morphometry, white matter microstructure, and deep white matter integrity.
• Scans revealed previously undocumented changes in H.M.'s brain anatomy and pathology.

Findings:

• Cortical thinning and atrophy of deep gray matter structures were observed.
• A significant volume of abnormal white matter and deep gray matter signal was detected.
• These recent alterations suggest pathological changes not apparent in earlier scans.

Implications:

• The findings highlight the utility of advanced MRI in characterizing brain pathology over time.
• Age and hypertension are identified as potential contributing factors to the observed recent brain changes.
• This detailed anatomical and pathological account provides further insights into the long-term consequences of brain injury and aging.