Ageing and the Brain

Abstract

Anatomical, neurochemical and functional characteristics of the mammalian brain change with age. Although some of these changes are generalized, many aspects of the brain are affected differentially.

Keywords: atrophy; basal ganglia; hippocampus; magnetic resonance imaging; prefrontal cortex; ventricles; white matter

Figure 1.

Ventriculomegaly, sulcal expansion and white matter hyperintensities are typical in the brains of asymptomatic elderly. The brain images of two women aged (a) 25 years and (b) 82 years are compared. Note numerous punctate lesions of the white matter, periventricular caps and relatively large areas of white matter hyperintensity in the brain of the older person. The magnetic resonance (MR) images were acquired using a T2‐weighted fast‐spin echo sequence (repetition time/echo time=3300/90 ms) in a 1.5 T magnet. In this mode of MR image acquisition, the white matter appears dark and the fluid‐filled spaces white. Axial images through the basal ganglia are presented.

Figure 2.

Comparison of three cerebral structures in a young (24 years old) and an older (81 years old) person. (a) Parasagittal slice containing the hippocampus. (b) Coronal slice through the prefrontal cortex and prefrontal white matter. (c) Axial slice through the basal ganglia and ventricular system. The images were acquired in an axial plane on a 1.5 T magnetic resonance imaging scanner using SPGR sequence with echo time TE=5 ms, repetition time TR=24 ms, flip angle=30°, matrix=256×192. Coronal and sagittal images were reconstructed from the original axial set.

Figure 3.

Regression of the magnitude of age effect on Flechsig myelination precedence rank for 11 cortical regions measured in vivo. Greater rank corresponds to later myelination of the region; greater F value obtained from a general linear model indicates stronger association between age and the regional volume, controlling for sex and body size (height). DLPFC, dorsolateral prefrontal cortex; OFC, orbitofrontal cortex; IT, inferior temporal; IPL, inferior parietal lobule; SPC, superior parietal cortex; ACG, anterior cingulate gyrus; MC, motor cortex; VC, visual cortex; HC, hippocampus; SSC, somatosensory cortex; FG, fusiform gyrus. From Raz .

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Further Reading

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Sullivan EV and Pfefferbaum A (2003) Diffusion tensor imaging in normal aging and neuropsychiatric disorders. European Journal of Radiology 45: 244–255.

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Raz, Naftali(Sep 2005) Ageing and the Brain. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0004063]