字母与矩阵工作记忆功能磁共振成像研究

目的:利用功能磁共振成像(fMRI)技术,研究健康成人工作记忆的脑激活功能区。材料和方法:12例健康成人进行字母与矩阵工作记忆两个任务的n-back试验,任务为组块设计,2-back为记忆任务,0-back为内对照;GE3.0TMRI扫描采集图像;以AFNI软件对数据分析和功能定位。结果:①字母与矩阵工作记忆2-back任务的执行正确率均低于0-back任务(P<0.01),所有受试者执行任务正确率均超过75%。②字母工作记忆激活脑区为左侧Broca区(BA44/45)、右侧与左侧前额叶腹侧(BA9/46)、右侧与左侧顶叶后部(BA7/40)、右侧与左侧前运动区(BA6)及辅助运动区(SMA,BA6/8),上述脑区激活强度(2-back相对于0-back任务激活信号改变百分比)均数分别为1.62%、3.27%、3.49%、2.42%、3.53%、2.95%、3.51%与1.79%,其中左半球激活更显著(P<0.05)。③矩阵工作记忆激活脑区为右侧与左侧BA9/46、右侧与左侧BA7/40、右侧与左侧BA6及BA6/8,激活强度分别为:4.96%、4.36%、2.60%、2.50%、2.94%、3.45%与1.83%,其中左侧BA6激活大于右侧BA6,右侧BA9/46与BA7/40激活分别大于左侧BA9/46与BA7/40(P<0.05)。结论:工作记忆存在双分离的脑功能基础,字母工作记忆为"语音环路"前额区BA9/46、左侧Broca区与BA6,左侧激活较右侧强;矩阵工作记忆为"空间模板"前额区BA9/46、BA7/40与BA6,BA9/46、BA7/40右侧激活较左侧强。     

利用fMRI研究衰老对听觉数字工作记忆的影响

目的:利用功能磁共振研究衰老对数字工作记忆的影响.材料和方法:6个青年和3个老年被试者参加了有关正序和反序记忆阿拉伯数字的工作记忆实验,同时,fMRI被用来记录大脑的反应.结果:①在青年组中,编码阶段,反序记忆左侧BA9-46区激活高于正序记忆;提取阶段,反序记忆在双侧BA7区激活点体积高于正序记忆.②老年组与青年组比较,在编码阶段反序记忆中青年组左侧BA 9-46区激活高于老年组.结论:功能磁共振有助于加深对衰老的理解.     

肝硬化患者工作记忆任务的fMRI研究

目的：通过n-back语义工作记忆任务的功能磁共振成像（~MRI）技术探讨肝硬化患者语义工作记忆损伤的神经病理学机制。方法：对10例轻微肝性脑病（MHE组）、14例单纯肝硬化（non-HE组）患者及16例正常对照者（对照组）行n-back语义工作记忆任务的fMRI研究。n-back实验采用组块设计,对照状态为0-back,任务状态为1-back和2-back。采用基于MATLAB的SPM8软件对数据进行处理分析。采用单样本t检验分析三组受试者在两种任务状态下的大脑激活情况,采用单因素方差分析观察三组受试者两种任务状态（1和2-back）下脑区激活的差异,采用Pearson相关分析行工作记忆任务脑激活区与任务执行正确率及反应时间之间的相关性。结果：在n-back任务中,三组受试者均表现为额顶叶脑网络的激活,包括双侧前额叶、双侧顶叶、双侧前运动区以及辅助运动区。在1-back任务下,non-HE组及MHE组主要表现为工作记忆部分脑区激活的增加;在2-back任务下,non-HE组及MHE组表现为工作记忆相关脑区激活的减低。肝硬化患者左侧额中回激活与2-back任务执行正确率密切相关。结论：肝硬化患者存在语义工作记忆相关脑区的损害。1-back任务时主要表现为脑区的代偿,但MHE较单纯肝硬化代偿能力减低;2-back任务难度超出代偿限度,主要表现为激活下降,且MHE较单纯肝硬化损伤更明显。     

额叶外伤后早期数字工作记忆的fMRI研究

目的:利用功能磁共振成像技术研究额叶外伤后,执行工作记忆任务时脑结构损伤与脑激活功能区的改变。材料和方法:对10例额叶外伤后早期患者(伤后平均31d,其中男性7例,女性3例;平均年龄30.1年)和12例正常志愿者作为对照组(男性7例,女性5例;平均年龄26.9年)分别进行2位和4位数字的正反序工作记忆的实验,使用single-trial设计方法;GE3.0T磁共振机扫描、采集图像,运用AFNI软件包进行数据分析。结果:①正常对照组反序4位数字任务大于正序4位数字脑区有辅助运动区SMA,双侧背外侧前额叶,左侧顶叶,右侧角回;②患者组反序4位数字任务大于正序4位数字的脑区有左侧枕叶;③正常对照组反序4位数字任务大于患者组的部位有左侧DLPFC,左侧角回;正序4位数字大于患者组的部位有左侧枕叶,右侧角回;④患者组反序4位数字任务时大于对照组的部位有楔状回,右侧Broca区;正序4位数字大于对照组的部位有右侧初级运动区MA,右侧额极区。结论:前额叶在脑工作记忆网络中处于重要节点,大脑右侧半球在工作记忆系统中起到巨大代偿作用的脑资源,fMRI提供认知功能损伤的影像学依据,应在临床上发挥更大作用。     

Functional magnetic resonance imaging of mental strategy in a simulated aviation performance task.

BACKGROUND: The objective of this study was to analyze the sensory and cognitive functions associated with activated brain regions characterizing mental strategy relative to degree of expertise in aviation-related tasks. METHODS: We used echo-planar functional magnetic resonance imaging (fMRI) technique to examine brain activity in expert pilots (n = 6) compared with novice pilots (n = 6) during performance of a simulated aviation track-following task at 200 knots vs. 100 knots. RESULTS: Expert pilots showed reduced activity in visual and motor regions that contrasted with predominant activation within anterior structures including the frontal and prefrontal cortices; structures involved in visual working memory, planning, selective attention and decision making functions. Novice pilots showed widespread activation of anterior and posterior brain structures, with a rise in activity in the visual, parietal and motor cortices as task difficulty increased. CONCLUSIONS: A high level of performance in the track-following task related to a high degree of expertise in the aviation field. This corresponded to experts performing perceptual and mnemonic processing through a network of specialized functions from visual through multiple prefrontal areas. By contrast, the novice pilots predominantly show activity associated with non-specific perceptual processing and without subsequent representation of selective information in working memory.     

Working Memory in Patients with Mild Traumatic Brain Injury: Functional MR Imaging Analysis

Purpose: To analyze brain activation patterns in response to tests of working memory after a mild traumatic brain injury (MTBI). Materials and Methods: Research ethics committee approval and patient written informed consent were obtained. Brain activation patterns in response to n-back working memory tasks (n = 1, 2, 3) were assessed with functional magnetic resonance (MR) imaging in 20 patients with MTBI within 1 month after their injury and in 18 healthy control subjects. In n-back working memory tasks, participants monitored a series of number stimuli and were to indicate when the presented number was the same as that presented n back previously. Nine (45%) MTBI patients underwent follow-up functional MR imaging studies 6 weeks later. Digit span, a memory test for how many numbers a person can remember in sequence, and continuous performance test (CPT), a test that measures a person's sustained and selective attention and impulsivity, were also performed before functional MR imaging studies and outside the imager for each participant. Clinical data were analyzed by using t and χ(2) tests. Within-group, between-group, and initial and follow-up differences of functional MR imaging data were analyzed by using one-sample, two-sample, and paired t tests, respectively. Results: Groups were similar for sex (P = .75), years of education (P = .069), digit span (P = .37 for total score), CPT (P = .31, .27, and .43 for omission error, commission error, and hit reaction time, respectively), and accuracy of n-back working memory performance (P = .90, .11, and .39 for one-, two-, and three-back tasks, respectively). Brain activation patterns differed between MTBI patients and controls in response to increasing working memory loads (P < .01, uncorrected). Control subjects maintained their ability to increase activation in the working memory circuitry with each increase in working memory load. In contrast, MTBI patients were impaired in their ability to increase activation in working memory circuitry under both moderate and high working memory load conditions. However, MTBI patients did show cerebral plasticity, as evidenced by more activation in some areas outside and inside the working memory circuitry as compared with control subjects (P < .01, uncorrected). In the 6-week follow-up study, compared with baseline, MTBI patients showed an improvement of activation in response to increasing working memory loads (P < .05, uncorrected). Conclusion: MTBI-induced differences in working memory functional activity were observed even though differences in behavioral performance between MTBI patients and controls were absent, which suggests that this approach may increase sensitivity to MTBI compared with neuropsychological evaluation alone. ? RSNA, 2012.     

数字记忆广度与数字工作记忆的功能磁共振比较研究

目的比较数字记忆广度与数字工作记忆的脑区激活特点与差异。方法利用Siemens 1.5T MR机对12名右利手志愿者进行7位数数字记忆广度与2位数数字工作记忆实验,实验采用组块设计,2组任务均设相应对照任务,将记忆任务与对照任务比较,数据采用SPM99软件进行分析和脑功能区定位。结果进行2组任务时,志愿者额叶的Brodmann6区、9区和47区,顶叶的7区和40区,扣带回,海马结构,纹状体以及小脑均有激活。进行数字记忆广度测试时,双侧枕叶Brodmann18区、19区的激活尤其显著,无明显的半球优势,双侧颞叶Brodmann37区也有激活,而进行数字工作记忆时,则在额叶的激活最为显著,额叶和顶叶的激活都表现为左侧半球优势。结论脑区在进行不同要求的短时数字记忆任务时所参与的阶段和所起的作用不同,通过fMRI的研究对推断大脑进行数字信息的处理过程有一定的帮助。     

模拟失重对人脑工作记忆的影响:系列功能磁共振成像研究

目的 采用功能性磁共振技术研究微重力环境对工作记忆的影响. 方法 9名健康男性青年头低位卧床4周.卧床前、卧床1周时和卧床4周后各对其进行1次倒数2项工作记忆任务的功能磁共振成像扫描. 结果 模拟失重前,工作记忆任务激活的脑区有双侧额叶(BA46/9、47、6)、前扣带回(BA32)、双侧顶叶(BA7)、双侧枕叶(19/18)和左侧丘脑.模拟失重1周时,激活脑区的范围和信号强度变化显著.模拟失重4周后,激活脑区与卧床前趋于相似. 结论 ①模拟失重状态时,人脑工作记忆功能状态有明显的变化,主要表现为功能脑区激活范围和部位的变化;②模拟失重环境对工作记忆信息的被动贮存影响不大,但对信息的主动复述维持及中央执行系统的信息操作功能有明显、可逆的影响;③失重1周时,人脑激活区变化显著.失重4周时,人脑已经开始逐步适应,但未正常化.     

Lack of sex effect on brain activity during a visuomotor response task: functional MR imaging study

BACKGROUND AND PURPOSE: As more individuals are enrolled in clinical functional MR imaging (fMRI) studies, an understanding of how sex may influence fMRI-measured brain activation is critical. METHODS: We used fixed- and random-effects models to study the influence of sex on fMRI patterns of brain activation during a simple visuomotor reaction time task in the group of 26 age-matched men and women. We evaluated the right visual, left visual, left primary motor, left supplementary motor, and left anterior cingulate areas. RESULTS: Volumes of activations did not significantly differ between the groups in any defined regions. Analysis of variance failed to show any significant correlations between sex and volumes of brain activation in any location studied. Mean percentage signal-intensity changes for all locations were similar between men and women. A two-way t test of brain activation in men and women, performed as a part of random-effects modeling, showed no significant difference at any site. CONCLUSION: Our results suggest that sex seems to have little influence on fMRI brain activation when we compared performance on the simple reaction-time task. The need to control for sex effects is not critical in the analysis of this task with fMRI.     

Functional heterogeneity of the supplementary motor area

BACKGROUND AND PURPOSE: The purpose of this study was to assess supplementary motor area (SMA) activation during motor, sensory, word generation, listening comprehension, and working memory tasks by using functional MR imaging (fMRI). Human supplementary motor area (SMA) has been shown to play roles in motor control and other various functions such as sensory, speech expression, and memory. However, topographical localizations of these functions in the SMA remain unclear. The purpose of this study was to assess SMA activation during motor, sensory, word generation, listening comprehension, and working memory tasks by using functional MR imaging (fMRI). METHODS: Sixteen healthy right-handed subjects (nine men and seven women) were imaged on a Siemens 1.5T system. Whole-brain functional maps were acquired by using blood oxygenation level-dependent echo-planar imaging sequences in the axial plane. Each paradigm consisted of five epochs of activation versus the control condition. The activation tasks consisted of left-finger complex movement, heat sensory stimulation of the left hand, word generation, listening comprehension, and working memory. The reference function was a boxcar waveform. Activation maps were thresholded at an uncorrected P = .0001. The thresholded activation maps were placed into MNI (Montreal Neurologic Institute) stereotactic coordinates, and the anatomic localization of activation within the SMA was compared across tasks. RESULTS: SMA activation was observed in 16 volunteers for the motor task, 11 for the sensory task, 15 for the word generation task, five for the listening comprehension task, and 15 for the working memory task. Although not statistically significant, qualitative differences in the location of activation within the SMA were present by task. The rostral aspects of the SMA tended to activate during word generation and working memory tasks, and the caudal aspect of the SMA tended to activate during the motor and sensory tasks. Right (contralateral) SMA activation was observed during the motor and sensory tasks, and left SMA activation during the word generation and memory tasks. CONCLUSION: Our results suggest that SMA is involved in a variety of functional tasks, including motor, sensory, word generation, and working memory. Some are tasks that are traditionally associated with this area (such as motor and sensory), and others are not (such as word generation and working memory). Qualitatively, the anterior and posterior portions of the SMA appeared to be engaged by different types of tasks.     

Heart rate variability of recently concussed athletes at rest and exercise

PURPOSE: The objective of this study was to assess the neuroautonomic cardiovascular regulation in recently concussed athletes at rest and in response to low-moderate steady-state exercise, using heart rate variability (HRV). METHODS: A 5-min ECG sample was taken at rest from the 14 concussed athletes at 1.8 (+/- 0.2) days postinjury and again at 5 d later. Once asymptomatic at rest, the concussed athletes and their matched controls (N = 14) participated in an exercise protocol. The protocol consisted of a 2-min warm-up with a pedaling frequency between 50 and 60 rpm against a load of 40 W. After the warm-up, the athletes engaged in a low-moderate intensity steady state 10-min exercise bout where the pedaling frequency and load increased to 80-90 rpm and 1.5 W x kg(-1) body weight, respectively. The protocol was repeated 5 d later. A 5-min ECG sample from minutes 4 to 9 of the low-moderate intensity steady state exercise bout was used to assess HRV during exercise. Mixed model ANOVA were used to analyze the data. RESULTS: No difference at rest was detected between the concussed athletes and their matched controls in any of the HRV variables measured. However, across both exercise tests, the concussed group demonstrated a significant decrease in the mean RR interval, and low- and high-frequency power (P < 0.05) in relation to their matched controls. CONCLUSION: Low-moderate steady-state exercise elicits a neuroautonomic cardiovascular dysfunction in concussed athletes that is not present in a rested state. This dysfunction alludes to an exercise induced uncoupling between the autonomic and cardiovascular systems.     

颈动脉狭窄或闭塞患者数字记忆的功能磁共振成像研究

目的:探讨左侧颈内动脉/大脑中动脉狭窄和闭塞患者与正常人数字工作记忆的激活脑区差异及其记忆障碍的脑加工机制。方法:对12例左侧颈动脉狭窄/闭塞患者(其中左侧颈内动脉狭窄4例,左侧颈内动脉闭塞2例,左侧大脑中动脉狭窄5例,左侧大脑中动脉闭塞1例,24例正常对照组进行数字记忆任务的功能磁共振成像,采用AFNI软件进行数据分析和脑功能区活动图像。结果:左侧颈内动脉/大脑中动脉狭窄和闭塞患者的反应时间较对照组显著延长(P0.05),正确率较对照组明显降低(P0.05)。脑激活图显示数字工作记忆的编码期、保持期、提取期患者组的脑激活明显少于正常对照组,而且脑激活的左侧半球优势减弱,右侧半球出现代偿性激活,其中提取期最为明显。结论:左侧颈动脉狭窄/闭塞患者数字记忆任务的脑激活区存在损害,功能磁共振成像研究能为早期诊断认知障碍提供影像学依据。     

哌醋甲酯治疗前后注意缺陷多动障碍儿童语义工作记忆功能MRI研究

目的:研究哌醋甲酯治疗后注意缺陷多动障碍(ADHD)儿童完成语义工作记忆任务下脑区功能状态的改变,评价fMRI用于研究ADHD治疗机制的可行性.方法:ADHD组儿童6例,男性4例,女性2例,平均年龄12.50±1.87岁,符合DSM-Ⅳ诊断标准.ADHD儿童在治疗前后(检查前3h口服哌醋甲酯,0.2～0.3mg/kg)两种情况下进行行为学评估和功能MRI检查,两次间隔2～4周.刺激任务采用N-BACK模式下的语义工作记忆任务,BLOCK设计方法.fMRI扫描采用GE 3.0T磁共振机,采用配对t检验统计方法.结果:ADHD患儿治疗后脑功能区的激活多于治疗前,1-BACK任务下左侧额中回、双侧额下回、左顶下小叶、双侧基底节等脑区激活与治疗前差异有统计学意义,在2-BACK任务下同时有左颞叶和扣带回激活不同,与认知测试成绩改善具有一定的相关性.结论:哌醋甲酯能增加ADHD患儿的工作记忆功能脑区的激活,fMRI是研究哌醋甲酯治疗ADHD机制的新方法.     

Nonlinear changes in brain activity during continuous word repetition: an event-related multiparametric functional MR imaging study

BACKGROUND AND PURPOSE: Changes in brain activation as a function of continuous multiparametric word recognition have not been studied before by using functional MR imaging (fMRI), to our knowledge. Our aim was to identify linear changes in brain activation and, what is more interesting, nonlinear changes in brain activation as a function of extended word repetition. MATERIALS AND METHODS: Fifteen healthy young right-handed individuals participated in this study. An event-related extended continuous word-recognition task with 30 target words was used to study the parametric effect of word recognition on brain activation. Word-recognition-related brain activation was studied as a function of 9 word repetitions. fMRI data were analyzed with a general linear model with regressors for linearly changing signal intensity and nonlinearly changing signal intensity, according to group average reaction time (RT) and individual RTs. RESULTS: A network generally associated with episodic memory recognition showed either constant or linearly decreasing brain activation as a function of word repetition. Furthermore, both anterior and posterior cingulate cortices and the left middle frontal gyrus followed the nonlinear curve of the group RT, whereas the anterior cingulate cortex was also associated with individual RT. CONCLUSION: Linear alteration in brain activation as a function of word repetition explained most changes in blood oxygen level-dependent signal intensity. Using a hierarchically orthogonalized model, we found evidence for nonlinear activation associated with both group and individual RTs.     

脑功能MRI在青少年非自杀性自伤中的研究进展

非自杀性自伤（NSSI）是指没有自杀意图且以自伤行为为主的精神障碍,脑功能MRI（fMRI）可揭示NSSI病人的异常脑活动特征。静息态fMRI的不同功能连接模式对NSSI的诊断和疗效评估具有重要价值,基于不同任务状态的fMRI的异常脑激活可评估NSSI病人的脑功能改变。就不同分析方法（基于种子点、独立成分分析和图论的分析方法）的静息态fMRI连接模式和不同任务状态（情绪、社交和奖赏任务）下fMRI的脑活动在NSSI中的研究进展予以综述。     

Functional MR Imaging of Working Memory in the Human Brain

Objective

In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed.

Materials and Methods

In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks.

Results

The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere.

Conclusion

The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.     

注意缺陷多动障碍儿童语义工作记忆的功能MRI研究

目的 研究注意缺陷多动障碍（ADHD）儿童在语义工作记忆任务下不同脑区的功能状态。方法 ADHD儿童与正常学龄儿童各9名，分别进行行为学评估和功能MR（MR）扫描，刺激任务采用区组（BLOCK）设计的倒退N计数（N—BACK）模式下语义工作记忆任务。MR扫描采用GE3．0 T MR记录提取阶段大脑的反应。结果 ADHD儿童在语义工作记忆任务下激活普遍低于正常组，在1-BACK任务中双侧额中回、额下回、双侧顶上小叶、顶下小叶、右基底节激活低于正常组，而在2-BACK任务中双侧额中回、额下回、双侧顶上小叶、左侧顶下小叶、右基底节及前扣带回激活低于正常组。结论 ADHD儿童的工作记忆功能区包括双侧背外侧前额叶及双侧顶叶存在功能低下，在高负荷的2-BACK任务下并有执行功能区（前扣带回）的激活降低。     

Comparison of fMRI data from passive listening and active‐response story processing tasks in children

Purpose

To use functional MRI (fMRI) methods to visualize a network of auditory and language‐processing brain regions associated with processing an aurally‐presented story. We compare a passive listening (PL) story paradigm to an active‐response (AR) version including online performance monitoring and a sparse acquisition technique.

Materials and Methods

Twenty children (ages 11–13 years) completed PL and AR story processing tasks. The PL version presented alternating 30‐second blocks of stories and tones; the AR version presented story segments, comprehension questions, and 5‐second tone sequences, with fMRI acquisitions between stimuli. fMRI data was analyzed using a general linear model approach and paired t‐test identifying significant group activation.

Results

Both tasks showed activation in the primary auditory cortex, superior temporal gyrus bilaterally, and left inferior frontal gyrus (IFG). The AR task demonstrated more extensive activation, including the dorsolateral prefrontal cortex and anterior/posterior cingulate cortex. Comparison of effect size in each paradigm showed a larger effect for the AR paradigm in a left inferior frontal region‐of‐interest (ROI).

Conclusion

Activation patterns for story processing in children are similar in PL and AR tasks. Increases in extent and magnitude of activation in the AR task are likely associated with memory and attention resources engaged across acquisition intervals. J. Magn. Reson. Imaging 2009;29:971–976. © 2009 Wiley‐Liss, Inc.     

Physiologically initiated and inhibited phantosmia: cyclic unirhinal, episodic, recurrent phantosmia revealed by brain fMRI

PURPOSE: Our goal was to use functional magnetic resonance imaging (fMRI) to demonstrate brain activation in patients with unirhinal, episodic, recurrent phantosmia who induced their phantosmia by coughing, sneezing, laughing or vigorous nasal inhalation and expiration, and inhibited it by sleep or performance of a Valsalva type maneuver. METHODS: Three patients with unirhinal phantosmia without change in taste or smell acuity were studied by fast low angle shot (FLASH) MRI and by echo planar imaging (EPI). Brain activation was measured following memory of two tastants (salt, sweet), memory of two odorants (banana and peppermint), actual smell of three odors (amyl acetate, menthone, pyridine), memory of phantosmia (and phantageusia, where applicable), phantosmia initiated spontaneously or by vigorous nasal inhalation and exhalation, phantosmia after inhibition by Valsalva, and these stimuli before and after treatment with the neuroleptic thioridazine. Activation images were derived using correlation analysis and ratios of areas of brain activated to total brain areas were calculated. Total activated pixel cluster counts were also used to quantitative total and regional brain activation. RESULTS: Sensory-specific brain activation was present in each section in each patient following memory of tastants and odorants, actual smell of each odor and memory, and initiation of and inhibition of phantosmia. Activation to odor memory after phantosmia initiation was very robust, whereas after phantosmia inhibition it was similar to that in normal subjects. Brain activation to unirhinal phantosmia was bihemispheric, independent of whether it was left or right sided or patient handedness. While phantosmia memory (in the absence of initiated phantosmia) produced extremely robust brain activation, after initiation and inhibition of phantosmia apparent brain activation decreased. These changes need to be related to shifting state of baseline brain activation and should be interpreted to reflect increased rather than decreased brain activation over that of phantosmia memory alone. Treatment with thioridazine inhibited brain activation to all stimuli including phantosmia and phantageusia memory, as it did previously in patients with birhinal phantosmia. CONCLUSIONS: 1) Unirhinal phantosmia can be demonstrated by brain fMRI as can birhinal phantosmia; 2) unirhinal phantosmia can be initiated and inhibited by physiological maneuvers reflected by changes in fMRI brain activation; 3) fMRI brain activation of unirhinal phantosmia is bihemispheric and independent of peripheral side of phantosmia or patient handedness; 4) anterior frontal brain region plays a significant role in both phantosmia initiation and inhibition as, to some extent, do temporal brain regions; 5) activation of brain GABAergic systems appears to play a role in inhibition of unirhinal phantosmia; and 6) unirhinal phantosmia, similar to birhinal phantosmia, may reflect a type of maladaptive brain plasticity similar to that hypothesized to be responsible for phantom limb pain.     

儿童额顶叶工作记忆任务的功能性磁共振成像研究

目的:联合应用血氧水平依赖(BOLD)-fMRI和扩散张量成像(DTI)两种功能磁共振成像技术,研究正常儿童工作记忆任务中额顶叶皮层激活强度与额顶叶各部位白质纤维束扩散特性之间的关系.方法:搜集健康志愿者12例,男女各6例,平均年龄11.4岁.以步进式视觉累加实验(PVSAT)作为刺激模式,对所有儿童进行BOLDfMR...