Rebecca E. Blanton, Shirin Badrtalei, Jennifer G. Levitt1, Paul M. Thompson, James T. McCracken1, Katherine L. Narr, Tonmoy Sharma2, and Arthur W. Toga
Laboratory of Neuro Imaging, Dept. Neurology, Division of Brain Mapping,
UCLA School of Medicine, Los Angeles CA 90095, USA, and
1UCLA Division of Child Psychiatry, and
2Institute of Psychiatry, London
Introduction. The involvement of the basal ganglia in motor functions is well established. In particular the caudate nucleus has been implicated in functions of motor control, preparation for action, formulation of strategies and response, and establishment and selection of emotional responses. It is also responsible for the development of habit patterns and skill learning (Saint-Cys et al., 1995). Recent postmortem and neuroimaging studies of human striatal anatomy have provided some evidence for age-related shrinkage of the caudate. However, little is known regarding the morphological development of the caudate during childhood and adult years. The goal of the present study was to examine age associated changes in both volume and shape of the caudate nucleus in 61 normal subjects ranging in age from 6-51 years.
Methods. Thirty-nine normal children (23 females, 16 males, mean age: 11.5 years) and 22 normal adults (13 females, 9 males, mean age: 33.1 years) were studied using T1-weighted structural magnetic resonance imaging (MRI). Images were acquired in the coronal plane with an image acquisition matrix of 256x256x124. All datasets were digitally transformed into the Talairach stereotaxic coordinate system using the anterior and posterior commissures as the centers of origin (Talairach and Tournoux, 1988). One rater blind to age and gender manually traced the caudate into three defined regions: the head, body, and caudate/putamen complex. This allowed for a regional analysis of caudate anatomy. To enable 3-dimensional comparison of anatomic variation and shape differences in the caudate, subjects were divided into two defined groups: child (6-16 years) and adult (20-51 years). Local anatomic variability maps within groups and average caudate displacement maps between defined groups were generated using a novel parametric mesh approach (Thompson et al., 1996). A multiple linear regression analysis was performed to assess age-related changes in caudate volume. In addition, gender effects and asymmetry differences were examined using a two-way analysis of variance (ANOVA).
Results. A significant main effect of age was found with a linear decrease in the volume of the left head and body with age (p < .01). Interestingly, male subjects were found to significantly decrease in size of the left and right head of the caudate (p = .008, p = .009) while no significant age-associated changes were seen in female subjects. Furthermore, adult subjects showed a significant nonlinear decrease in the head of the caudate while children were found to show decreases in the right caudate/putamen complex. Asymmetry measures revealed a robust effect of right-greater-than-left volume for the head of the caudate (p < .001) but not for the body nor the caudate/putamen complex. There were no significant differences between genders in caudate asymmetry.
Conclusions. In summary, our findings suggest decreases in the volume of the head of the caudate with age from childhood into adult years. Furthermore, this effect may be gender based as only male subjects exhibited age-related decreases in the size of the caudate. This gender related finding may be relevant in understanding the pathology of various neuropsychiatric disorders as the caudate has been implicated in disorders which preferentially affect males.
References.  Saint-Cys JS, Taylor AE, Nicholson K (1995) Behavioral neurology of movement disorders. Advances in Neurology, Vol. 65, New York, Weiner and Lang.  Talairach J, Tournoux P (1988) Co-planar stereotaxic atlas of the human brain. New York, Thieme Medical Publishers.  Thompson PM, Schwartz C, Lin RT, Khan AA, Toga AW (1996) 3D statistical analysis of sulcal variability in the human brain. J. Neurosci, 16:4261-4274.
Grant Support: (to P.T. and A.W.T.): NIMH/NIDA (P20 MH/DA52176), P41 NCRR (RR13642); (A.W.T.): NLM (LM/MH05639), NSF (BIR 93-22434), NCRR (RR05956) and NINCDS/NIMH (NS38753).
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