Age-related effects on cortical thickness patterns of the Rhesus monkey brain

Cortical surface modeling in three individual monkeys of different ages (a-c: age 6.3 years; d-f: age 15.2 years; g-i: age 24.4) viewed in axial, coronal and sagittal sections. Right hemisphere gray matter/csf and gray/white matter surface models are marked in red and blue lines, respectively. The rightmost column shows three-dimensional representation of the corresponding gray/csf surface model for each monkey brain overlaid with the corresponding cortical thickness map.

Average Rhesus monkey brain surface. Left: lateral view of the left hemisphere. Right: medial view of the left hemisphere. Abbreviated anatomical terms are given as labels, and the abbreviation list is given in Table 2.

Mean cortical thickness maps of the group of sex-matched young (a) and old monkeys (b).

Group regional mean cortical thickness analysis for the young and old age groups (left and right hemispheres are analyzed separately). The regional lobe-wise parcellation is given in panel (I), where a = prefrontal lobe, b = frontal lobe, c = parietal lobe, d = superior temporal lobe (temporal auditory cortex), e = inferior temporal lobe (temporal visual cortex), f = occipital lobe, g = temporal limbic region, h = cingulate cortex. In each bar graph: “Y”—young, “O”—old. Asterisk (*) denotes statistically significant difference at significant level p < 0.05, and doubled asterisk (**) denotes statistically significant difference at significant level p < 0.01.

Vertex-wise analysis of mean cortical thickness—group comparison between young and old monkeys. Upper panels—medial views of both hemispheres, lower panels—lateral views. Statistically significant differences (under random permutation based correction) are marked in color (green-blue: decrease/red-green: increase). The color bar is scaled to represent p-values between 0.01 and 0.05.

Correlation analyses between cortical thickness and age for the entire group of monkeys in this study. Medial (upper row) and lateral (lower row) views of both hemispheres. Significant age-correlations (under random permutation based correction) are marked in colors. The color bar is scaled to represent p-values between p < 0.05 and p < 0.01. The blue scale denotes decrease and the red scale denotes increase in cortical thickness with age.