Histological studies suggest that hippocampal subfields are differently affected by aging and Alzheimer's disease (AD). The aims of this study were: (1) To test if hippocampal subfields can be identified and marked using anatomical landmarks on high resolution MR images obtained on a 4T magnet. (2) To test if age-specific volume changes of subfields can be detected. Forty-two healthy controls (21-85 years) and three AD subjects (76-86 years) were studied with a high resolution T2 weighted fast spin echo sequence. The entorhinal cortex (ERC), subiculum, CA1, CA2 and CA3/4 and dentate were marked. A significant correlation between age and CA1 (r=-0.51, p=0.0002) which was most pronounced in the seventh decade of life was found in healthy controls. In AD subjects, CA1 and subiculum were smaller than in age-matched controls. These preliminary findings suggest that measurement of hippocampal subfields may be helpful to distinguish between normal aging and AD.

Context Sickle cell anemia (SCA) is a chronic illness causing progressive deterioration in quality of life. Brain dysfunction may be the most important and least studied problem affecting individuals with this disease. Objective To measure neurocognitive dysfunction in neurologically asymptomatic adults with SCA vs healthy control individuals. Design, Setting, and Participants Cross-sectional study comparing neuropsychological function and neuroimaging findings in neurologically asymptomatic adults with SCA and controls from 12 SCA centers, conducted between December 2004 and May 2008. Participants were patients with SCA (hemoglobin [Hb] SS and hemoglobin level ≤10 mg/dL) aged 19 to 55 years and of African descent (n=149) or community controls (Hb AA and normal hemoglobin level) (n=47). Participants were stratified on age, sex, and education. Main Outcome Measures The primary outcome measure was nonverbal function assessed by the Wechsler Adult Intelligence Scale, third edition (WAIS-III) Performance IQ Index. Secondary exploratory outcomes included performance on neurocognitive tests of executive function, memory, attention, and language and magnetic resonance imaging measurement of total intracranial and hippocampal volume, cortical gray and white matter, and lacunae. Results The mean WAIS-III Performance IQ score of patients with SCA was significantly lower than that of controls (adjusted mean, 86.69 for patients with SCA vs 95.19 for controls [mean difference, −5.50; 95% confidence interval {CI}, −9.55 to −1.44]; P =.008), with 33% performing more than 1 SD (<85) below the population mean. Among secondary measures, differences were observed in adjusted mean values for global cognitive function (full-scale IQ) (90.47 for patients with SCA vs 95.66 for controls [mean difference, −5.19; 95% CI, −9.24 to −1.13]; P =.01), working memory (90.75 vs 95.25 [mean difference, −4.50; 95% CI, −8.55 to −0.45]; P =.03), processing speed (86.50 vs 97.95 [mean difference, −11.46; 95% CI, −15.51 to −7.40]; P <.001), and measures of executive function. Anemia was associated with poorer neurocognitive function in older patients. No differences in total gray matter or hippocampal volume were observed. Lacunae were more frequent in patients with SCA but not independently related to neurocognitive function. Conclusion Compared with healthy controls, adults with SCA had poorer cognitive performance, which was associated with anemia and age.

Context Most neuroimaging studies of posttraumatic stress disorder (PTSD) have focused on potential abnormalities in the whole hippocampus, but the subfields of this structure, which have distinctive histological characteristics and specialized functions, have not been investigated. Studies of individual subfields may clarify the role of the hippocampus in PTSD. Objective To determine if PTSD is associated with structural alterations in specific subfields of the hippocampus. Design Case-control study. Participants A total of 17 male veterans with combat trauma and PTSD (mean [SD] age, 41[12] years) and 19 age-matched male veterans without PTSD who were recruited from the outpatient mental health clinic of the San Francisco Veterans Affairs Medical Center and by advertising in the community. Interventions High-resolution magnetic resonance imaging at 4 T. Main Outcome Measure Volumes of hippocampal subfields. Results Posttraumatic stress disorder was associated with 11.4%(1.5%) (P = .02) smaller mean (SD) cornu ammonis 3 (CA3)/dentate gyrus subfield volumes, irrespective of age-related alterations, whereas other subfields were spared. Age was associated with reduced volume of the CA1 subfield (P = .03). Total hippocampal volume was also reduced in PTSD by a mean (SD) of 6.5%(0.6%) but, related to both PTSD (P = .05) and age (P = .01), was consistent with the measurements in the subfields. Conclusions The findings indicate for the first time in humans that PTSD is associated with selective volume loss of the CA3/dentate gyrus subfields, consistent with animal studies, implying that chronic stress suppresses neurogenesis and dendritic branching in these structures.

Community-dwelling HD who are not in alcoholism treatment have brain metabolite changes that are associated with lower brain function and are likely of behavioral significance. Age, FH, and binge drinking modulate brain metabolite abnormalities. Metabolite changes in active HD are less pronounced and present with a different spatial and metabolite pattern than reported in abstinent alcoholics.