Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, Saint Louis, MO 63130, USA.
Cereb Cortex. 2013 Feb;23(2):488-98. doi: 10.1093/cercor/bhs042. Epub 2012 Feb 23.
Spatial and temporal variations in cortical growth were studied in the neonatal ferret to illuminate the mechanisms of folding of the cerebral cortex. Cortical surface representations were created from magnetic resonance images acquired between postnatal day 4 and 35. Global measures of shape (e.g., surface area, normalized curvature, and sulcal depth) were calculated. In 2 ferrets, relative cortical growth was calculated between surfaces created from in vivo images acquired at P14, P21, and P28. The isocortical surface area transitions from a slower (12.7 mm(2)/day per hemisphere) to a higher rate of growth (36.7 mm(2)/day per hemisphere) approximately 13 days after birth, which coincides with the time of transition from neuronal proliferation to cellular morphological differentiation. Relative cortical growth increases as a function of relative geodesic distance from the origin of the transverse neurogenetic gradient and is related to the change in fractional diffusion anisotropy over the same time period. The methods presented here can be applied to study cortical growth during development in other animal models or human infants. Our results provide a quantitative spatial and temporal description of folding in cerebral cortex of the developing ferret brain, which will be important to understand the underlying mechanisms that drive folding.
研究了新生雪貂皮质生长的时空变化，以阐明大脑皮质折叠的机制。从出生后第 4 天至 35 天获取的磁共振图像创建皮质表面表示。计算了全局形状度量（例如，表面积、归一化曲率和脑沟深度）。在 2 只雪貂中，在 P14、P21 和 P28 获得的体内图像创建的表面之间计算了相对皮质生长。大约在出生后 13 天，同形皮质表面积从较慢的生长速度（每半球 12.7mm2/天）转变为更高的生长速度（每半球 36.7mm2/天），这与从神经元增殖到细胞形态分化的转变时间一致。相对皮质生长是相对于横向神经发生梯度原点的相对测地线距离的函数而增加的，并且与同一时间段内分数各向异性扩散的变化相关。本文提出的方法可用于研究其他动物模型或人类婴儿发育过程中的皮质生长。我们的结果提供了发育中的雪貂大脑皮质折叠的定量空间和时间描述，这对于理解驱动折叠的潜在机制非常重要。
