The Human Brain Age 7–11 Years: A Volumetric Analysis Based on Magnetic Resonance Images

Abstract

Volumetric magnetic resonance image (MRI)-based morphometry was performed on the brains of 30 normal children (15 males and 15 males) with a mean age of 9 years (range 7-11 years). This age range lies in a late but critical phase of brain growth where not volumetric increment will be small but when the details of brain circuity are being fine-tuned to support the operations of the adult brain. The brain at this age is 95% the volume of the adult brain. The brain of the female child is 93% the volume of the male child. For more than 95% of brain structures, the volumetric differences in male and female child brain are uniformly scaled to the volume difference of the total brain in the two sexes. Exceptions to this pattern of uniform scaling are the caudate, hippocampus and pallidum, which are disproportionately larger in female than male child brain, and the amygdala, which is disproportionately smaller in the female child brain. The patterns of uniform scaling are generally sustained during the final volumetric increment in overall brain size between age 7-11 and adulthood. There are exceptions to this uniform scaling of child to adult brain, and certain of these exceptions are sexually dimorphic. Thus, with respect to major brain regions, the cerebellum in the female but not the male child is already at adult volume while the brainstem in both sexes must enlarge more than the brain as a whole. The collective subcortical gray matter structures of the forebrain of the female child are already at their adult volumes. The volumes of these same structures in the male child, by contrast, are greater than their adult volumes and, by implication, must regress in volume before adulthood. The volume of the central white matter, on the other hand, is disproportionately smaller in female than male child brain with respect to the adult volumes of cerebral central white matter. By implication, relative volumetric increase of cerebral central white matter by adulthood must be greater in the female than male brain. The juxtaposed progressive and regressive patterns of growth of brain structures implied by these observations in the human brain have a soundly established precedent in the developing rhesus brain. There is emerging evidence that sexually dimorphic abnormal regulation of these terminal patterns of brain development are associated with gravely disabling human disorders of obscure etiology.

Decreased Volume of the Brain Reward System in Alcoholism

“…Image analyses followed semi-automated procedures developed by the Center for Morphometric Analysis at MGH (44)(45)(46). Intracranial volumes were segmented on T2-TSE images, since cerebrospinal fluid has bright T2-TSE signal, allowing clear demarcation within the intracranial vault (meninges/dura).…”

Clinical correlations of grey matter reductions in the caudate nucleus of adults with attention deficit hyperactivity disorder

“…For the whole sample, the calculated volume of the portion of the right caudate that showed a low concentration of grey matter was 580 mm 3 (SD 0.08) for healthy controls and 525 mm 3 (SD 0.05) for ADHD patients (t 38 results of the comparisons between healthy women and ADHD women are presented in Figure 3. The ADHD men and women both had a smaller volume of the portion of the right caudate with low-concentration grey matter than their respective healthy controls.…”

Caudate Nucleus Volume and Cognitive Performance: Are They Related in Childhood Psychopathology?

“…In addition, individual brain structures appear to have developmental profiles that are distinct from general brain development (Caviness et al 1996;Herbert et al 2003;Piven et al 1996). In normal development, total brain volume is reported to peak around age 5 (Durston et al 2001), while caudate volume peaks in late childhood (Caviness et al 1996;Thompson et al 2000), then decreases with age (Hardan et al 2003;McAlonan et al 2002;Thompson et al 2000).…”