Spatio-temporal progression of the AEP P300 component using the cortical imaging technique

Summary The cortical imaging technique (CIT), a mathematical method for simulating the potential fields on the surface of the brain, was used to analyze the spatio-temporal progression of the AEP P300 component (as well as the preceding and subsequent N2a and N3 components) from thirty normal adult subjects recorded in a standard oddball paradigm. Comparisons were made between the progressions of the endogenous event-related cognitive potentials and the exogenous stimulus-dependent potentials (Nl component). Cortical imaging results suggest that different and multiple generator sites are involved in the production of exogenous and endogenous evoked responses. We particularly note the asymmetric development of the P300 component and the apparent anterior generator sites for the N2a component. This last result is interesting because the N2a precedes the P300 component and supports an earlier frontal contribution.     

Dynamic radionuclide imaging as a means of evaluating vascular perfusion of the upper extremity: a preliminary report

Vascular competence in the upper extremities of 44 patients was evaluated by three-phase bone scans consisting of rapid sequence dynamic radionuclide imaging (DRI), an immediate postinjection "blood pool" image, and a 3- to 4-hour delayed image. Findings were correlated with definitive anatomy determined by arteriography, operative findings, or both, in 50 extremities. DRI provided the correct diagnosis in all but four extremities (92%). Limited resolution precluded precise anatomic definition of aneurysms in three limbs and of digital artery occlusion, with adequate collateral circulation in the fourth limb. The greatest value of DRI was its provision of quantitative information about relative blood flow and preferential perfusion in every instance. We believe DRI to be a useful adjunct to preoperative and postoperative assessment of arterial perfusion.     

ALzheimer病认知功能与认识性诱发电位P_(300)的研究

目的 :研究 ALzheimer病 ( AD)患者神经心理学测验与认知性诱发电位的相关性。方法 :应用丹麦设备和两种短音刺激 ,对 3 1例 AD患者和 3 2例正常老年人 ( NC)做了心理学测试及 P3 0 0 检查。结果 :两组神经心理学测验指标经协方差分析均达到显著性水平。两组 P3 0 0 靶刺激潜伏期比较 AD组 (观察组 )明显慢于 NC组 (对照组 )。结论 :AD患者神经心理学测验与 P3 0 0 检查有相关性 ,且有助于鉴别 AD与正常衰老     

Visual event-related potentials in progressive supranuclear palsy, corticobasal degeneration, striatonigral degeneration, and Parkinson's disease

To determine whether there are characteristic changes in event-related potentials (ERPs) in parkinsonian syndromes we studied 8 patients with progressive supranuclear palsy (PSP), 10 patients with corticobasal degeneration (CBD), 9 patients with striatonigral degeneration (SND), and 16 patients with idiopathic Parkinson's disease (PD) with a mean duration of illness shorter than 5 years in each group. A visual oddball paradigm was employed to elicit P300. P300 to the rare target and rare nontarget stimuli and reaction time (RT) to rare target stimuli in each group were compared with those in the corresponding age-matched normal control group and to each other after age correction. The correlation of P300 and RT to motor disability score was also studied. In PSP P300 amplitude was markedly reduced while in CBD P300 latency was prolonged. P300 amplitude to rare nontargets in SND and PD was attenuated. The mean RT in the PSP and the CBD group was significantly longer than in the other two groups. The mean RT in PD and P300 amplitude to rare nontargets in both CBD and PD showed significant correlation with the severity of motor disability. Simultaneous measurement of P300 and RT may yield useful supplementary information in facilitating diagnosis of parkinsonian syndromes in addition to clinical criteria. Received: 6 April 1999, Received in revised form: 5 August 1999, Accepted: 12 January 2000     

奥拉西坦治疗轻中型脑伤的临床研究

目的：通过神经电生理监测来评价益智药奥拉西坦治疗轻中型脑伤的疗效。方法：采用随机双盲对照试验，对照药物为吡拉西坦。将连续收治的48例轻中型脑伤患者随机分入奥拉西坦组和吡拉西坦组，每组24例。分别于用药前、用药21天后进行定量脑电图和P300数据采样。统计分析各组用药前后定量脑电图和P300的差异；比较两种药物对定量脑电图和P300的影响。结果：两组患者用药后的定量脑电图和P300均有明显改善（P〈0．05）；奥拉西坦对脑电图和P300的影响较吡拉西坦更大（P〈0．05）。结论：奥拉西坦对轻中型脑伤患者脑功能的改善有明显促进作用，且功效较吡拉西坦更强。     

Transcranial direct current stimulation of prefrontal cortex: An auditory event-related potential and proton magnetic resonance spectroscopy study

Transcranial direct current stimulation (tDCS) is a non-invasive intervention altering neural plasticity by modulating neuronal excitability of pre- and postsynaptic neuron populations, which has been shown to improve depression symptoms and cognition. We investigated the effects of a single session of 20 min of 2 mA left-prefrontal anodal versus sham stimulation on auditory event-related potentials (ERPs) in 11 male and 5 female healthy subjects (mean age of 28.6 [SD 6.2] years) by employing a randomized single-blind crossover design. Stimulation effects on cortical glutamate (Glu) and glutamine (Glx) levels were subsequently measured in 12 of the 16 healthy subjects in a 3 T proton magnetic resonance spectroscopy scan. tDCS was associated with a significant increase of N1 amplitudes while smaller P3b amplitudes correlated with higher cortical Glu and Glx levels in the stimulated brain area when performing an auditory go/no-go discrimination task. tDCS did not change mismatch negativity, nor task performance or cortical Glu/Glx levels which, together with N1 amplitudes, depended on stimulation order (“sham” versus “active”). Increased N1 amplitudes are consistent with higher levels of cortical excitability following prefrontal anodal tDCS. The failure to replicate Glu/Glx changes with tDCS may have been masked by between-session carry-over effects while ceiling effects may have masked tDCS effects on task performance.