NEUROPSYCHOLOGICAL AND COGNITIVE STUDIES IN EPILEPSY

方法：采用正电子发射断层扫描（PET）和功能磁共振成像（fMRI）对颞叶癫痫患者的语言和记忆神经成像进行无创评估，研究癫痫对儿童和成人癫痫发作患者认知解剖学的影响。这一信息对于顽固性癫痫患者的手术计划也是至关重要的。我们对正常志愿者和不受控制的癫痫发作患者的研究表明，成像评估比电刺激测绘和颈动脉内阿米妥钠试验等更具侵入性的方法要好。我们还评估了癫痫发作对功能性认知解剖学发展的影响。最近的发现：我们使用功能磁共振成像来比较儿童和成人在语言流畅性任务中的激活。两组左额下皮层和左额中回（背外侧前额皮质）均被激活。儿童的活跃度平均比成人高60%。在IFG和MFG中，儿童的偏侧程度小于成人。在儿童中发现的更大的激活可能反映了作为语言能力基础的神经网络正在组织的发育可塑性。我们还使用PET研究了单词押韵和假词押韵，它们激活了相同的大脑区域，表明单词和假词的语音处理是联合神经网络。然而，假词押韵也在左侧前额叶后皮质和左侧腹侧枕颞交界处调动了更多的皮质组织。此外，假词押韵激活了不积极参与押韵的左边缘上回。这些结果表明，押韵假词需要扩展的神经系统和网络，而押韵词不需要扩展神经系统和网络。目前的研究：我们正在使用几个新的任务来研究癫痫灶患者在语言处理区域的功能重组。-癫痫，认知功能，语言，记忆-人类受试者

Methods: We use positron emission tomography (PET) and functional magnetic resonance imaging (fMRI)to map language and memory neuroimaging in patients with temporal lobe epilepsy to perform non- invasive evaluation of functional cortex, and study the effect of epilepsy on cognitive anatomy in children and adults with seizures. This information is crucial as well for surgical planning in patients with intractable epilepsy.Our studies in both normal volunteers and patients with uncontrolled seizures have shown that imaging evaluation compares well with more invasive procdures such as electrostimulation mapping and the intracarotid sodium amytal test. We also evaluate the effect of seizures on the development of functional cognitive anatomy. Recent findings: We used fMRI to compare activation on a verbal fluency task in children and adults. In both groups, left inferior frontal cortex and left middle frontal gyrus (dorsolateral prefrontal cortex)were activated. Children had, on average, 60% more activation than adults. The degree of laterality was less in children than for adults in IFG and MFG. The greater activation found in children may reflect developmental plasticity for the ongoing organization of neural networks which underlie language capacity. We also used PET to study word rhyming and pseudoword rhyming, which activated the same brain regions, suggesting conjoint neural networks for phonological processing of words and pseudowords. However, pseudoword rhyming also recruited more cortical tissue in the left posterior prefrontal cortices and the left ventral occipital-temporal junction. In addition, pseudoword rhyming activated the left supramarginal gyrus which was not actively engaged in word rhyming. These results suggest that rhyming pseudowords requires extended neural systems and networks unnecessary for rhyming words. Current studies: We are using several new tasks to investigate functional reorganization in patients with epileptic foci in langauge processing regions. - Epilepsy, cognitive function, language, memory - Human Subjects