Grachev I D, Apkarian A V
Department of Radiology, SUNY Upstate Medical University, 750 E. Adams Street, IHP 4109, Syracuse, NY 13210, USA.
Brain Res Cogn Brain Res. 2001 Apr;11(2):185-97. doi: 10.1016/s0926-6410(00)00068-9.
We recently described the chemical network properties of the human brain using in vivo proton magnetic resonance spectroscopy ((1)H MRS). In a separate study of aging we found increased concentration of chemicals in the prefrontal and sensorimotor cortices up to the third decade of life, and subsequent decrease of chemical concentrations in the same brain regions after the third decade between young and middle age. We anticipated that these age-dependent differences in chemical concentrations might be a reflection of the chemical network reorganization of the brain during aging. The pattern of chemical connectivity within and across brain regions for all regional chemicals, and specific patterns of chemical connectivity for each chemical type were examined for young and middle age groups using (1)H MRS and correlation analysis. For all studied ages, the dominant positive correlations occurred within brain regions and negative correlations were seen across brain regions. However, the pattern of negative chemical connectivity across brain regions was weaker in middle-aged group (F = 40.4, P < 10(-7) comparing r-values between the two age groups, ANOVA). Within brain regions, the age effects on chemical correlations were seen in the cingulate cortex (46% decrease in the middle-aged group, F = 7.2, P < 0.007) and sensorimotor cortex (SMC) (27% decrease, F = 8.9, P<0.003). Between brain regions, the age effects on chemical correlations were seen in the chemical interactions between the thalamus (433.3% increase in the middle-aged group, F = 11.7, P < 0.003), SMC (280% increase, F=20.1, P < 10(-5)), cingulate cortex (100.7% increase, F = 21.3, P < 10(-7)), and other brain regions. We found also age-differential patterns of chemical connectivity across the studied brain regions for most chemical types. The results provide evidence that normal aging is associated with reorganization of chemical network of the human brain.
我们最近利用体内质子磁共振波谱（(1)H MRS）描述了人类大脑的化学网络特性。在另一项关于衰老的研究中，我们发现前额叶和感觉运动皮层中的化学物质浓度在生命的第三个十年之前有所增加，而在第三个十年之后，在青年和中年之间，同一脑区的化学物质浓度随后下降。我们预计，这些化学物质浓度随年龄变化的差异可能反映了衰老过程中大脑化学网络的重组。使用(1)H MRS和相关分析，对青年和中年组所有区域化学物质在脑区内和脑区之间的化学连接模式以及每种化学物质类型的特定化学连接模式进行了研究。对于所有研究的年龄组，主要的正相关出现在脑区内，而负相关则出现在脑区之间。然而，中年组中脑区之间负性化学连接的模式较弱（F = 40.4，比较两个年龄组r值时P < 10(-7)，方差分析）。在脑区内，扣带回皮层（中年组下降46%，F = 7.2，P < 0.007）和感觉运动皮层（SMC）（下降27%，F = 8.9，P < 0.003）中观察到年龄对化学相关性的影响。在脑区之间，丘脑（中年组增加433.3%，F = 11.7，P < 0.003）、SMC（增加280%，F = 20.1，P < 10(-5)）、扣带回皮层（增加100.7%，F = 21.3，P < 10(-7)）与其他脑区之间的化学相互作用中观察到年龄对化学相关性的影响。我们还发现，大多数化学物质类型在研究的脑区之间存在随年龄变化的化学连接模式。这些结果提供了证据，表明正常衰老与人类大脑化学网络的重组有关。
