Department of Radiology University of Iowa Iowa City IA USA.
Department of Psychiatry University of Iowa Iowa City IA USA.
Brain Behav. 2017 Sep 14;7(10):e00802. doi: 10.1002/brb3.802. eCollection 2017 Oct.
Functional neuroimaging typically relies on the blood-oxygen-level-dependent (BOLD) contrast, which is sensitive to the influx of oxygenated blood following neuronal activity. A new method, functional T1 relaxation in the rotating frame (fT1ρ) is thought to reflect changes in local brain metabolism, likely pH, and may more directly measure neuronal activity. These two methods were applied to study activation of the visual cortex in participants with bipolar disorder as compared to controls.
Thirty-nine participants with bipolar disorder and 32 healthy controls underwent functional neuroimaging during a flashing checkerboard paradigm. Functional images were acquired in alternating blocks of BOLD and fT1ρ. Linear mixed-effect models were used to examine the relationship between these two functional imaging modalities and to test whether that relationship was altered in bipolar disorder.
BOLD and fT1ρ signal were strongly related in visual and cerebellar areas during the task in controls. The relationship between these two measures was reduced in bipolar disorder within the visual areas, cerebellum, striatum, and thalamus.
These results support a distinct mechanisms underlying BOLD and fT1ρ signals. The weakened relationship between these imaging modalities may provide a novel tool for measuring pathology in bipolar disorder and other psychiatric illnesses.
功能神经影像学通常依赖血氧水平依赖（BOLD）对比，该对比对神经元活动后含氧血液的流入敏感。一种新方法，即旋转框架下的功能 T1 弛豫（fT1ρ），被认为反映了局部脑代谢的变化，可能是 pH 值的变化，并且可能更直接地测量神经元活动。这两种方法都被应用于研究与对照组相比，双相情感障碍患者的视觉皮层激活。
39 名双相情感障碍患者和 32 名健康对照者在闪烁棋盘范式期间接受功能神经影像学检查。在交替的 BOLD 和 fT1ρ 块中采集功能图像。线性混合效应模型用于检查这两种功能成像方式之间的关系，并测试这种关系在双相情感障碍中是否发生改变。
在对照组的任务中，BOLD 和 fT1ρ 信号在视觉和小脑区域强烈相关。在双相情感障碍患者中，这两种测量方法之间的关系在视觉区域、小脑、纹状体和丘脑区域减弱。
这些结果支持 BOLD 和 fT1ρ 信号的不同机制。这两种成像方式之间关系的减弱可能为测量双相情感障碍和其他精神疾病的病理学提供一种新工具。
