Sakatani K, Katayama Y, Yamamoto T, Suzuki S
Department of Neurosurgery, Nihon University School of Medicine, Japan.
J Neurol Neurosurg Psychiatry. 1999 Dec;67(6):769-73. doi: 10.1136/jnnp.67.6.769.
Blood oxygenation level dependent (BOLD) contrast functional MRI images show activated cortical areas by detecting a reduced concentration of deoxyhaemoglobin (deoxy-Hb) during neuronal activity; however, near infrared spectroscopy (NIRS) has shown various patterns of cerebral blood oxygenation (CBO) changes in the frontal lobe during cognitive tasks. To determine if various patterns of CBO changes occur in the frontal lobe when the brain is directly stimulated, changes in CBO in the frontal lobe induced by deep brain stimulation in patients with implanted electrodes were evaluated.
Six patients were studied, including five with Parkinson's disease and one with essential tremor. To reduce tremor or rigidity, the electrodes were implanted at the thalamic nucleus ventralis intermedius (VIM: three Parkinson's disease and one essential tremor) or the globus pallidus internus (GPi: two Parkinson's disease). Using NIRS, changes of deoxy-Hb, oxyhaemoglobin (oxy-Hb) and total haemoglobin (total Hb) were measured in the bilateral frontal lobes during various stimulus conditions.
High frequency (120 Hz) GPi stimulation consistently increased oxy-Hb and total Hb with a decrease of deoxy-Hb in an intensity and time dependent manner. Oxy-Hb and total Hb increased immediately after the onset of stimulation and then gradually decreased when stimulation was continued. By contrast, high frequency (120 Hz) VIM stimulation decreased oxy-Hb, deoxy Hb and total Hb in an intensity dependent manner. In the severe tremor patient with VIM stimulation, frequency response was examined by decreasing stimulus frequencies; deoxy-Hb increased at high frequencies (70-40 Hz), and then decreased below the control level at low frequencies (30-0 Hz), whereas oxy-Hb and total Hb increased consistently at high and low frequencies.
The electrical stimulation of GPi and VIM caused various CBO changes in the frontal lobe, which were similar to those found during cognitive tasks. Such a multiplicity of CBO changes in the frontal lobe may be caused by complex neuronal circuits in the frontal lobe which has many neuronal connections to other cortical areas or the basal ganglia.
血氧水平依赖（BOLD）对比功能磁共振成像通过检测神经元活动期间脱氧血红蛋白（deoxy-Hb）浓度降低来显示激活的皮质区域；然而，近红外光谱（NIRS）已显示在认知任务期间额叶的脑血氧合（CBO）变化存在多种模式。为了确定当大脑受到直接刺激时额叶是否会出现多种CBO变化模式，对植入电极的患者进行深部脑刺激诱导的额叶CBO变化进行了评估。
对6例患者进行了研究，其中包括5例帕金森病患者和1例特发性震颤患者。为了减轻震颤或僵硬，电极植入丘脑腹中间核（VIM：3例帕金森病患者和1例特发性震颤患者）或苍白球内侧部（GPi：2例帕金森病患者）。使用NIRS，在各种刺激条件下测量双侧额叶中脱氧血红蛋白、氧合血红蛋白（oxy-Hb）和总血红蛋白（total Hb）的变化。
高频（120 Hz）GPi刺激持续以强度和时间依赖性方式增加氧合血红蛋白和总血红蛋白，同时脱氧血红蛋白减少。刺激开始后氧合血红蛋白和总血红蛋白立即增加，而在持续刺激时逐渐减少。相比之下，高频（120 Hz）VIM刺激以强度依赖性方式降低氧合血红蛋白、脱氧血红蛋白和总血红蛋白。在接受VIM刺激的严重震颤患者中，通过降低刺激频率来检查频率反应；脱氧血红蛋白在高频（70 - 40 Hz）时增加，然后在低频（30 - 0 Hz）时降至对照水平以下，而氧合血红蛋白和总血红蛋白在高频和低频时均持续增加。
GPi和VIM的电刺激在额叶引起了多种CBO变化，这与在认知任务期间发现的变化相似。额叶中这种多种CBO变化可能是由额叶中复杂的神经元回路引起的，额叶与其他皮质区域或基底神经节有许多神经元连接。
