Rosenthal J M, Amiel S A, Yágüez L, Bullmore E, Hopkins D, Evans M, Pernet A, Reid H, Giampietro V, Andrew C M, Suckling J, Simmons A, Williams S C
Department of Diabetes, Endocrinology, and Internal Medicine, Guy's, King's and St. Thomas' School of Medicine, Denmark Hill Campus, Bessemer Road, London SE5 9PJ, U.K.
Diabetes. 2001 Jul;50(7):1618-26. doi: 10.2337/diabetes.50.7.1618.
The authors' aim was to examine the regional anatomy of brain activation by cognitive tasks commonly used in hypoglycemia research and to assess the effect of acute hypoglycemia on these in healthy volunteers. Eight right-handed volunteers performed a set of cognitive tasks-finger tapping (FT), simple reaction time (SRT), and four-choice reaction time (4CRT)-twice during blood oxygen level-dependent (BOLD) functional magnetic resonance imaging of the brain on two occasions. In study 1 (n = 6), plasma glucose was maintained at euglycemia (5 mmol/l) throughout. In study 2 (n = 6), plasma glucose was reduced to 2.5 mmol/l for the second set. Performance of the tasks resulted in specific group brain activation maps. During hypoglycemia, FT slowed (P = 0.026), with decreased BOLD activation in right premotor cortex and supplementary motor area and left hippocampus and with increased BOLD activation in left cerebellum and right frontal pole. Although there was no significant change in SRT, BOLD activation was reduced in right cerebellum and visual cortex. The 4CRT deteriorated (P = 0.020), with reduction in BOLD activation in motor and visual systems but increased BOLD signal in a large area of the left parietal association cortex, a region involved in planning. Hypoglycemia impairs simple brain functions and is associated with task-specific localized reductions in brain activation. For a task with greater cognitive load, the increased BOLD signal in planning areas is compatible with recruitment of brain regions in an attempt to limit dysfunction. Further investigation of these mechanisms may help devise rational treatment strategies to limit cortical dysfunction during acute iatrogenic hypoglycemia.
作者的目的是研究低血糖研究中常用认知任务引起的脑激活区域解剖结构，并评估急性低血糖对健康志愿者这些脑激活区域的影响。8名右利手志愿者在两次脑血氧水平依赖（BOLD）功能磁共振成像期间，执行了一组认知任务——手指敲击（FT）、简单反应时间（SRT）和四选一反应时间（4CRT），每种任务执行两次。在研究1（n = 6）中，血浆葡萄糖全程维持在正常血糖水平（5 mmol/l）。在研究2（n = 6）中，第二次执行任务时血浆葡萄糖降至2.5 mmol/l。执行这些任务产生了特定的组脑激活图谱。低血糖期间，FT减慢（P = 0.026），右侧运动前皮质、辅助运动区、左侧海马体的BOLD激活减少，左侧小脑和右侧额极的BOLD激活增加。虽然SRT没有显著变化，但右侧小脑和视觉皮质的BOLD激活减少。4CRT变差（P = 0.020），运动和视觉系统的BOLD激活减少，但左侧顶叶联合皮质大片区域（一个参与计划的区域）的BOLD信号增加。低血糖损害简单脑功能，并与特定任务的脑激活局部减少有关。对于认知负荷更大的任务，计划区域中增加的BOLD信号与大脑区域的募集一致，试图限制功能障碍。对这些机制的进一步研究可能有助于制定合理的治疗策略，以限制急性医源性低血糖期间的皮质功能障碍。
