The striatum receives segregated and integrative white matter tracts from the cortex facilitating information processing in the cortico-basal ganglia network. The authors examined both types of input tracts in the striatal associative loop in chronic schizophrenia patients and healthy control subjects.

Structural and diffusion MRI scans were acquired on a 3-T system from 26 chronic schizophrenia patients and 26 matched healthy control subjects. Using FreeSurfer, the associative cortex was parcellated into ventrolateral prefrontal cortex and dorsolateral prefrontal cortex subregions. The striatum was manually parcellated into its associative and sensorimotor functional subregions. Fractional anisotropy and normalized streamlines, an estimate of fiber counts, were assessed in four frontostriatal tracts (dorsolateral prefrontal cortex-associative striatum, dorsolateral prefrontal cortex-sensorimotor striatum, ventrolateral prefrontal cortex-associative striatum, and ventrolateral prefrontal cortex-sensorimotor striatum). Furthermore, these measures were correlated with a measure of cognitive control, the Trail-Making Test, Part B.

Results showed reduced fractional anisotropy and fewer streamlines in chronic schizophrenia patients for all four tracts, both segregated and integrative. Post hoc t tests showed reduced fractional anisotropy in the left ventrolateral prefrontal cortex-associative striatum and left ventrolateral prefrontal cortex-sensorimotor striatum and fewer normalized streamlines in the right dorsolateral prefrontal cortex-sensorimotor striatum and in the left and right ventrolateral prefrontal cortex-sensorimotor striatum in chronic schizophrenia patients. Furthermore, normalized streamlines in the right dorsolateral prefrontal cortex-sensorimotor striatum negatively correlated with Trail-Making Test, Part B, time spent in healthy control subjects but not in chronic schizophrenia patients.

These findings demonstrated that structural connectivity is reduced in both segregated and integrative tracts in the striatal associative loop in chronic schizophrenia and that reduced normalized streamlines in the right-hemisphere dorsolateral prefrontal cortex-sensorimotor striatum predicted worse cognitive control in healthy control subjects but not in chronic schizophrenia patients, suggesting a loss of a “normal” brain-behavior correlation in chronic schizophrenia.

纹状体从皮质接收分离的和整合的白质束，从而促进皮质基底神经节网络中的信息处理。作者检查了慢性精神分裂症患者和健康对照者的纹状体结合环中的两种输入管道。

在3-T系统上从26位慢性精神分裂症患者和26位匹配的健康对照受试者中进行了结构和扩散MRI扫描。使用FreeSurfer，将联想皮层分成腹侧前额叶皮层和背外侧前额叶皮层子区域。纹状体被手动分成其联想和感觉运动功能子区域。在四个额骨道（背外侧前额叶皮层相关纹状体，背外侧前额叶皮层相关运动纹状体，腹侧前额叶皮层相关性纹状体和腹侧前额叶皮层运动型）中评估了分数各向异性和归一化流线（纤维计数的估计值）。此外，这些措施与认知控制措施（试行测试，B部分）相关。

结果显示，对于慢性精神分裂症患者，无论是隔离的还是整合的所有四个管道，其分数各向异性均得到降低，流线性降低。事后检验显示，左腹外侧前额叶皮层相关纹状体和左腹外侧前额叶皮层-感觉运动纹状体的分数各向异性减小，并且右背外侧前额叶皮层-感觉运动纹状体以及左右腹侧前额叶皮层-感觉运动纹状体的标准化流线较少在慢性精神分裂症患者中。此外，右背外侧前额叶皮层-感觉运动纹状体的正常化流线与Trail-Making Test，B部分，在健康对照组中所花费的时间呈负相关，而在慢性精神分裂症患者中却没有。

这些发现表明，慢性精神分裂症的纹状体相关环的分离和整合通道结构连接性均降低，并且右半球背外侧前额叶皮层-感觉运动纹状体的标准化流线减少预示着健康对照者的认知控制较差，而慢性对照者则没有精神分裂症患者，提示慢性精神分裂症患者的“正常”脑行为相关性丧失。