健康成人戴用软垫紧咬运动时脑激活区域的功能性磁共振成像研究

目的　应用功能性磁共振成像技术探讨戴软垫紧咬运动时人脑功能活动区域定位,试图从中枢机制探 讨垫的治疗作用机理。方法　选取10名健康成人受试者,采用时段设计,任务状态与休息状态交替。任务状态 分2组设计,实验组为戴软垫紧咬运动,对照组为不戴软垫紧咬运动。采用Elscint/GE 2.0T磁共振系统成像, 应用SPM99软件进行数据后处理及组分析。结果　实验组10名受试者在单侧或双侧的运动皮层、感觉皮层、前额 叶皮层、颞叶皮层、前运动皮层、脑岛、额盖、基底神经节壳核、顶叶皮层及扣带回等区域有明显激活。组分析结果 显示双侧运动皮层(BA6)、右侧感觉皮层、双侧基底神经节壳核、双侧脑岛等区域均出现明显激活,其中左侧运动皮 层的激活程度明显强于右侧。对照组紧咬运动组分析结果显示双侧运动皮层(BA6)、双侧感觉皮层、双侧基底神经 节壳核、左侧顶叶皮层等区域均出现明显激活,其中运动皮层的激活双侧基本对称。结论　戴软垫后紧咬运动 脑皮层激活区域尤其是运动皮层和感觉皮层的变化可能是垫作用机理的中枢机制。     

单侧咀嚼肌痉挛患者在不同条件下咀嚼运动的功能性磁共振成像研究

目的应用功能性磁共振成像（fMRI）技术，探讨单侧咀嚼肌痉挛（HMS）患者紧咬运动及戴软[牙合]垫紧咬运动诱发痉挛发作时，脑功能活动区域定位，试图探讨HMS发病的中枢机制及软[牙合]垫的治疗作用机制。方法4例HMS患者（2例右侧HMS，2例左侧HMS），fMRI成像采用Elscint／GE2．0T磁共振系统，时段设计，运动任务为紧咬运动及戴软[牙合]垫紧咬运动诱发痉挛发作，应用SPM99软件进行数据后处理。结果紧咬运动诱发痉挛发作时，3例表现出运动皮层的左侧优势，另1例为运动皮层双侧激活，4例均有扣带回的激活。戴软[牙合]垫紧咬运动诱发痉挛发作时，运动皮层的激活无左侧优势，3例未见扣带回的激活。结论HMS患者在戴软[牙合]垫前后紧咬运动诱发痉挛发作时，运动皮层激活的变化可能是软[牙合]垫的治疗作用机制，扣带回激活的变化可能与软[牙合]垫缓解咀嚼肌痛有关。     

前后牙早接触状态紧咬的脑激活区的比较研究

目的：比较前、后牙早接触状态紧咬时脑皮层定位的差异。方法：选择15名志愿者,在其口内前、后牙上预置人工咬合高点,利用功能磁共振技术分别获取其在前牙和后牙早接触状态紧咬时的脑扫描图,结果用SPM2软件进行分析比较。结果：前牙、后牙早接触状态紧咬比较存在显著性差异且前者强于后者的皮层激活区包括：前运动区（左侧BA8/右侧BA6,8）、前额叶皮层（左侧BA11/右侧BA9,10,11）、枕叶皮层（左侧BA17/右侧BA19）、扣带回（左侧BA23,24,29,30/右侧BA23,29,30,31）等;后者显著强于前者的皮层激活区包括：中央后回S1区、中央前回M1区、顶叶皮层（左侧BA7/右侧BA5）、前额叶皮层（左侧BA9,46,47/右侧BA46,47）、岛叶、扣带回（左侧BA31,32/右侧BA24）等。结论：前、后牙区早接触紧咬时皮层激活区的定位是不同的,中央后回S1区、中央前回M1区差异最显著。     

疼痛性冷刺激和非痛温热刺激口腔时对大脑皮层反应强度的影响

目的 探索疼痛性冷刺激和非痛温热刺激口腔时对大脑皮层反应强度的影响。方法 选取6名健康志愿者,采用组块设计方法,利用水传递装置分别用冷水（4 ℃）和温水（23 ℃）刺激其口腔,采集全脑血氧水平依赖对比的功能性磁共振成像（fMRI）扫描数据进行分析。结果 冷水和温水刺激共同激活了左侧中央前后回、岛叶/岛盖、前扣带回（ACC）、眶额皮层,右侧中脑红核和丘脑。此外,冷水刺激还激活了左侧枕叶、运动前皮层布罗德曼分区（BA）6、右侧BA44、舌回,以及顶叶BA7和BA40,初级躯体感觉皮层SⅠ。疼痛性冷水刺激激活的脑区多于无痛温水,而激活脑区的强度小于温水,但是疼痛冷水刺激在ACC的激活强度明显大于无痛温水刺激。结论 大脑皮层对疼痛性冷刺激口腔时反应的脑区的激活强度小于非痛性温热水刺激,但是ACC脑区的激活强度大于非痛性温水刺激。     

种植体支持义齿患者骨感知的大脑皮层适应性初步研究

目的 采用功能性核磁共振成像(functional MRI,fMBl)对"骨感知"的中枢神经基础进行初步探讨.方法 研究对象为北京大学口腔医学院·口腔医院种植中心2005-2007年无牙颌种植修复复查患者和无牙颌初诊患者20例,共分为3组进行紧咬状态的fMRI扫描,SPM 99软件包统计分析及结果判定.结果 常规全口义齿修复(A组=8例)患者在前额叶皮层激活显著,而与咀嚼运动相关的初级感觉运动皮层激活人数较少;种植体支持固定义齿(B组=3例)患者在紧咬时皮层激活与天然牙列者更为接近,在Broca'S区、初级感觉运动皮层、前运动皮层、岛叶、颞上回、丘脑、基底神经节、海马等激活较显著;种植体支持覆盖义齿(C组=9例)患者前额叶皮层、前运动皮层、顶上回、基底神经节、丘脑等激活较多见.结论 种植体支持固定义齿患者的中枢神经系统对种植体的感觉及运动反馈更加接近于天然牙列,提示种植体支持固定义齿的修复方式能够以更自然的方式恢复患者的咀嚼功能;而常规全口义齿修复患者在咀嚼功能的恢复方面与个体运用义齿的学习、记忆及适应性有更显著的关系,有更强的个体差异性.     

口腔内水刺激的脑功能成像研究

目的利用功能性磁共振成像（fMRI）技术探讨高级中枢如何解读口腔内水刺激。方法选取13名健康志愿者,利用自制水传递装置将水注入口腔内,采用水刺激信号减静息信号的组块设计方法,以SPM99软件分析数据获得口腔内水刺激与静息状态对比的fMRI脑功能图像。结果水刺激口腔时,广泛激活左侧岛叶、罗兰多区（BA1/3/4/43）、右侧眶额皮层（BA11）、额中回（BA10）,其次是右侧顶叶（BA7）、中脑红核、扣带回和左侧额下回、岛叶（BA13）。结论口腔内水刺激引起口腔感觉运动代表区的激活,还引起其他相关脑区激活;在研究味觉和温度觉的神经解剖研究过程中需要控制水和其他非味觉因素。     

口腔医学基础——口腔解剖生理学

下颌第二恒磨牙解剖特点及临床意义初步探讨；丝裂原活化蛋白激酶通路在髁突软骨细胞力学信号转导过程中的作用；健康成人戴用软牙合垫紧咬运动时脑激活区域的功能性磁共振成像研究；发育性偏颌畸形对咀嚼运动的影响；……[编者按]     

咸味觉的磁共振脑功能成像研究

目的：使用磁共振脑功能成像技术(fMRI)研究味觉刺激时的脑功能状态及脑激活模式。方法：对11例正常受试者，依照事件相关(event-related)设计，给予咸味和无味对照的味觉刺激，采集全脑血氧水平依赖对比(BOLD)的fMRI扫描数据，用SPM99软件包进行t检验统计分析，以获取成味刺激及无味对照刺激对比的脑功能图像。结果：在成味刺激下最大范围的激活信号出现在左右两侧扣带回(24区)，其次为双侧顶上小叶(5／7区)、豆状核、左侧脑岛和岛盖(22区)、双侧顶叶中央后回(2区)、右颞中回(21区)等脑区。结论：成味觉引起兴奋的脑区，除传统的神经解剖和神经生理学研究已证明为味觉各级中枢的脑岛、岛盖等，还包括扣带回顶上小叶、顶下小叶、豆状核及顶叶中央后回等，反映味觉刺激时脑功能状态及其激活模式的复杂性。     

人脑对牙髓冷刺激痛反应的功能性磁共振成像研究

目的:探讨牙髓冷刺激痛时的大脑皮层兴奋位点。方法:选取右上颌第一前磨牙冷刺激痛患者(P-R)及正常对照(N-R)各8名,采集右上颌第一前磨牙冷水刺激时全脑血氧水平依赖反应(BOLD)对比的fMRI扫描数据,利用SPM2软件包进行数据分析并产生脑功能图像。结果:P-R组右侧激活最强的岛叶/SII在左侧激活较低,右侧基底节、扣带回、中脑红核的强度都略高于左侧,BA7、丘脑为右侧单侧激活。而左侧激活最强的Broca运动语言区BA44、MII/PMC/BA4,6在右侧没有激活。N-R组激活较强的有SI/MI、MII/PMC、基底节、BA7、BA40。结论:牙痛时前运动皮质、辅助运动皮质和Broca运动语言区的激活较强,在多数皮层为双侧激活,与躯体痛相比某些脑区在同侧大脑半球的激活比对侧更强。     

初步探讨利用fMRI技术研究口腔内冷热刺激的中枢反应

目的:利用功能核磁共振成像技术探讨口腔内不同温度刺激的大脑皮层反应的可行性.方法:选取健康志愿者1名.采用自制水传递装置及采用口腔温度刺激过程(温度刺激信号减静息信号)的组块设计方法,fMRI扫描数据用SPM99软件包进行结果的数据分析.结果:本实验温、冷、热刺激左侧口腔黏膜,获得大脑激活区有显著不同,在23℃水刺激口腔时,双侧额上回BA8和额中回BA6、右侧中央前回BA6、顶叶BA40和颞上回BA38可见激活.4℃水刺激时,右侧脑干、岛叶、额上回BA5、额下回BA47、颞下回BA19,左舌回BA18可见激活.56℃水刺激时,双侧额下回BA45、中央前回和岛叶、右舌回、左颞上回可见激活.结论:冷热水刺激激活了不同大脑皮层不同区域,fMRI技术可用于探讨口腔温度感觉的中枢反应的研究.     

Comparison of cerebral activity during teeth clenching and fist clenching: a functional magnetic resonance imaging study

Using functional magnetic resonance imaging (fMRI), we compared the cerebral activity during bilateral light fist-clenching and light-teeth clenching to provide more information on the central processing mechanisms underlying awake bruxism. Fourteen subjects participated in our study. Statistical comparisons were used to identify brain regions with significant activation in the subtraction of light fist clenching and light teeth clenching activity minus baseline. Participants also evaluated the perceived effort of clenching for each task, using a visual analogue scale of 0-100, after fMRI was performed. Bilateral light fist-clenching significantly activated the bilateral sensorimotor cortex, while light teeth-clenching was significantly associated with activation of the bilateral sensorimotor cortex, supplementary motor area, dorsolateral prefrontal cortex, and posterior parietal cortex. The VAS scores for fist clenching and teeth clenching were not significantly different. As light teeth-clenching activates a more extensive cortical network compared with light fist-clenching, we suggest that the teeth clenching may induce a more complex cerebral activity compared with the performance of a hand motor task. The clinical significance of these findings remains unknown but could perhaps be related to the propensity to trigger awake bruxism.     

口腔内冷刺激的脑功能成像

目的：观察正常人口腔内冷水刺激时的大脑皮层反应,为其它口腔感觉的脑功能研究提供基础。方法：将16名口腔健康右利手志愿者分为两组各8名,采用软管注射装置分别进行口腔内左侧（G-L）及右侧（G-R）上颌前磨牙去离子冷水刺激,采用冷水刺激减静息的block组块设计方法,采集全脑血氧水平依赖对比的功能性磁共振成像扫描数据,并用SPM2软件包进行结果的数据分析获得口内冷刺激与静息状态对比的脑功能图像。结果：初级感觉运动区、前运动皮质、顶下小叶、楔前叶、岛叶、基底神经核有信号增强。结论：1.口内非味觉液体的温度刺激除引起口腔内体感及运动代表区的兴奋外,还引起其它相关脑区的激活;2．口内冷水感觉信息到达双侧大脑,感觉运动区为对侧激活。顶下小叶激活以同侧为主。     

Cortical activation resulting from painless vibrotactile dental stimulation measured by functional magnetic resonance imaging (FMRI)

There have been few investigations on hemodynamic responses in the human cortex resulting from dental stimulation. Identification of cortical areas involved in stimulus perception may offer new targets for pain treatment. This initial study aimed at establishing a cortical map of dental representation, based on non-invasive fMRI measurements. Five right-handed subjects were studied. Eight maxillary and 8 mandibular teeth were stimulated after the vibratory perception threshold was determined for each tooth. Suprathreshold stimulation was repeated thrice per session, in a total of three sessions performed on three consecutive days. Statistical inference on cluster level identified increased blood-oxygen-level-dependent signal during vibratory dental stimulation, primarily in the insular cortex bilaterally and in the supplementary motor cortex. No significant brain activation was observed in the somatosensory cortex with this stimulation protocol. These results agree with previous findings obtained from invasive direct electrical cortical stimulation of the human insula.     

Functional MRI study of cerebral cortical activation during volitional swallowing

Objectives To investigate the somatotopic distribution and lateralization of motor and sensory cortical activity during swallowing in healthy adult human subjects using functional MR imaging. Methods Nine healthy right-handed adult volunteers (6 men, 3 women; ages 22–38) were examined. Their cortical activities were evoked by having them swallow, five times, asmall bolus of water (3 ml) supplied through a plastic catheter. As a positive control, the subjects performed five repetitions of right-handed grasping tasks. Blood oxygenation level-dependent images were obtained using a 1.5 Tesla MR system (Magnetom Vision, Siemens Germany; TR/TE=0.96/0.66, FA=90°). T1 weighted anatomical images were obtained for the same slices in each subject. Results Cerebral activity was observed most notably in the primary motor cortex and primary somatosensory cortex, followed by the premotor cortex, anterior cingulate cortex, frontal operculum, and insula. The hand-grasping task activated relatively superior parts of the primary motor and somatosensory cortices. The swallowing task, on the other hand, activated the inferior parts of the pre- and postcentral gyri. The hand-grasping activation of motor and sensory cortices was localized absolutely on the contralateral side, whereas swallowing activated the motor cortex either bilaterally or unilaterally. Swallowing activated the sensory cortex almost always bilaterally. Conclusions This study suggested that fMRI could be used to identify the specific areas of cortical activation caused by various tasks, and to differentiate the locations of cortical activation between tasks.     

Analysis of brain and muscle activity during low‐level tooth clenching – a feasibility study with a novel biting device

In electromyographic (EMG) and functional magnetic resonance imaging (fMRI) studies, muscle and brain activity was compared during low levels of tooth clenching using a novel biting device to control bite force. A total of 21 healthy subjects performed motor tasks, comprising tooth clenching at 5, 10 and 20 N. During all measurements, subjects kept the novel bite device between the anterior teeth during tooth clenching. The EMG study (n = 15) characterised jaw muscle activity for the three motor tasks and demonstrated significant differences in root mean square (RMS) EMG amplitude between 5‐, 10‐ and 20‐N tooth clenching (F = 46·21, P < 0·001). There were no differences in variability of muscle activity between the three tooth‐clenching levels. In an fMRI pilot study (n = 6), statistical comparisons were used to identify brain regions with significant activation in the subtraction of baseline from 5‐ or 20‐N tooth‐clenching activity. 5‐ and 20‐N tooth clenching significantly and bilaterally activated the sensorimotor cortex, supplementary motor area, cerebellum and basal ganglia (P < 0·05, corrected for multiple comparisons). However, activation of each brain region did not differ significantly between two tooth‐clenching tasks. Based on these preliminary findings, we propose that the novel biting device may be useful in further fMRI studies on controlled jaw muscle activation patterns in different craniofacial pain conditions. In addition, our fMRI result suggests that there are no significant differences in brain activity within low levels of tooth clenching with controlled force.     

偏侧咀嚼对紧咬牙运动时海马旁回激活影响的探索

目的探索偏侧咀嚼对紧咬牙运动时脑功能活动的影响。方法选取左、右侧偏侧咀嚼患者各7例，在紧咬牙运动时采集全脑血氧水平依赖对比的功能性磁共振成像（functional magnetic resonance imaging，fMRI）扫描数据。结果7例左侧偏侧咀嚼患者中有4例出现海马旁回的激活，而右侧偏侧咀嚼患者均未见海马旁回的激活。结论发现了左侧偏侧咀嚼患者紧咬牙运动可激活与人类学习记忆能力有重要关系的海马旁回的现象。     

两种基本味觉的口腔感知对味觉中枢激活情况的探索

目的：应用脑磁共振功能成像技术对比研究口腔甜味觉及咸味觉感知对大脑初级味觉中枢和二级味觉中枢的激活情况。方法：对11例正常受试者,依照事件相关设计,给予甜味、咸味及无味对照的味觉刺激,采集全脑血氧水平依赖对比的fMRI扫描数据。用SPM99软件包进行t检验统计分析,以获取甜味刺激、咸味刺激与无味对照刺激对比的脑功能图像。结果：两种味觉均在双侧脑岛及岛盖等区引起激活。左侧前额皮质仅被甜味觉激活。两者激活最强的脑区均在右侧脑岛及岛盖。结论：基本味觉中的甜味觉及咸味觉在初级味觉中枢和二级味觉中枢的激活情况存在差异。