RELATION BETWEEN CEREBRAL-ACTIVITY AND FORCE IN THE MOTOR AREAS OF THE HUMAN BRAIN
RELATION BETWEEN CEREBRAL-ACTIVITY AND FORCE IN THE MOTOR AREAS OF THE HUMAN BRAIN
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DOI：
10.1152/jn.1995.74.2.802
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发表时间：
1995-08-01
影响因子：
2.5
通讯作者：
FRACKOWIAK, RSJ
中科院分区：
文献类型：
--
作者：
DETTMERS, C;FINK, GR;FRACKOWIAK, RSJ
1.对6名正常右利手男性志愿者（年龄30 ± 3岁）进行了正电子发射断层扫描（PET）研究，以研究右食指屈曲时通过相对局部脑血流量（rCBF）测量的脑激活与施加的力峰值之间的关系。其目的是确定哪些中枢运动结构的活动与重复执行运动的力量直接相关。使用（H2O）-O-15作为灌注示踪剂，对每位志愿者进行12次PET rCBF测量。志愿者在PET相机中以仰卧位躺下时，用右手食指重复按压莫尔斯键2分钟。该装置配有应变仪，以测量施加在其上的力峰值。在五个不同的施加力峰值水平和静止状态下，分别收集两次扫描。将个体和群体结果与解剖磁共振图像（MRT）进行配准.分组分析显示，四个主要地区之间的rCBF和不同程度的重复施加的力量峰值的高度相关性。1例位于左侧表面的手臂区域[初级躯体感觉和运动皮层（SI，MI）]。第二个区域位于大脑的左内侧表面，在前连合（AC）的后面，并包括扣带回沟背侧的第一回。该区域被认为与猴的辅助运动区（SMA）的后部同源。第三区为后扣带沟背侧。第四个显示rCBF与力峰值显著相关的区域是小脑蚓部.将个体PET数据与每个个体的MRI进行共配准，以精确识别结构的位置，从而证明rCBF和力峰值之间的正相关性。近中表面上的激活区域由组数据中观察到的相同的两个不同区域组成。在三个科目的重点对侧表面的皮质似乎延伸到尾部运动前区，在两个延伸到喙部的上级顶叶区。在受试者中，前扣带区和前SMA的血流均未显示与施加的力相关。所有受试者的小脑相关性均存在于小脑蚓部。除了初级感觉运动皮层的激活外，所有激活条件与静息状态的比较显示，小脑蚓部、左壳核/屏状核、双侧岛叶皮层、右侧和左侧腹外侧运动前区、双侧顶叶盖区（SII）、左侧腹后SMA和双侧背后SMA的显著激活。在右手食指施加的最低力水平下，右侧初级感觉运动皮层的rCBF相对于休息时下降了5.9%。在更高的力水平下，rCBF显示出8.7%的增加。这与左肩肌肉收缩的肌电图证据有关。rCBF的相对增加和力峰值之间的关系是对数的，在较高的力水平下，rCBF的初始急剧增加达到平台。初始斜率在MI中最陡。该区域与后扣带回运动区和后SMA的腹侧部分一起构成负责由食指执行受控力脉冲的执行运动系统。该系统是与手指运动的生成相关的区域的子集，并且负责共同导致所需数字力的应用的所有组件。
1. Positron emission tomography (PET) studies were performed in six normal right-handed male volunteers (age 30 +/- 3) to investigate the relationship between cerebral activation as measured by relative regional cerebral blood flow (rCBF) and force peak exerted during right index finger flexion. The purpose was to determine in which central motor structures activity is directly correlated with force for repeatedly executed movements.2. Twelve PET rCBF measurements were performed in each volunteer with the use of (H2O)-O-15 as a perfusion tracer. Volunteers pressed a Morse-key repetitively with their right index finger for 2 min while lying in a supine position in the PET camera. The device was fitted with strain gauges to measure the force peaks exerted upon it. Scans were collected twice each at five different levels of exerted force peak and in a resting state. Individual and group results were co-registered with anatomic magnetic resonance images (MRT).3. Group analysis revealed four major regions with a high correlation between rCBF and different degrees of repetitively exerted force peaks. One was located in the arm area of the left lateral surface [primary somatosensory and motor cortex (SI, MI)]. The second area was situated on the left mesial surface of the brain, posterior to the anterior commissure (AC) and encompassing the first gyrus dorsal to the cingulate sulcus. This area is thought to be homologous to the posterior part of the supplementary motor area (SMA) in the monkey. The third area was the dorsal bank of the posterior cingulate sulcus. The fourth area showing a significant correlation between rCBF and force peaks was in the cerebellar vermis.4. Individual PET data were co-registered with each individual's MRI in order to identify precisely the locations of structures demonstrating a positive correlation between rCBF and force peak. Activated areas on the mesial surface consisted of the same two distinct regions seen in the group data. In three subjects the focus on the lateral surface of the cortex appeared to extend into the caudal premotor area; in two it extended into the rostral part of the superior parietal area. In no subject did blood flow in the anterior cingulate areas and anterior SMA show a correlation with the force exerted. Cerebellar correlations were present in the vermis in all subjects.5. In addition to the activation in the primary sensorimotor cortex, a comparison of all activated conditions with the resting state revealed a significant activation in the cerebellar Vermis, left putamen/claustrum, bilateral insular cortices, right and left ventrolateral premotor areas, bilateral parietal opercular regions (SII), left ventral posterior SMA, and bilateral dorsal posterior SMA.6. At the lowest force level exerted by the right index finger, rCBF in the right primary sensorimotor cortex showed a decrease relative to rest of 5.9%. At higher force levels, rCBF showed an 8.7% increase. This was associated with electromyographic evidence of contractions of left shoulder muscles.7. The relationship between relative increase of rCBF and force peaks was logarithmic with an initial steep increase in rCBF reaching a plateau at higher force levels. The initial slope was steepest in MI. This area, together with the posterior cingulate motor area and the ventral part of the posterior SMA constitute an executive motor system responsible for the execution of controlled force pulses by the index finger. This system is a subset of the areas associated with the generation of finger movements and is responsible for all the components that together result in application of the required digital force.