Department of Psychiatry and Psychotherapy, University of Jena, Jena, Germany.
Psychol Med. 2009 Nov;39(11):1809-19. doi: 10.1017/S0033291709005820. Epub 2009 Apr 20.
There is increasing evidence that the frequently reported working memory impairments in schizophrenia might be partly due to an alteration in the functional connectivity between task-relevant areas. However, little is known about the functional connectivity patterns in schizophrenia patients during learning processes. In a previous study, Koch et al. [Neuroscience (2007) 146, 1474-1483] have demonstrated stronger exponential activation decreases in schizophrenia patients during overlearning of short-term memory material. The question arises whether these differential temporal patterns of activation in schizophrenia patients and controls are going along with changes in task-related functional connectivity.
Therefore, in the current study, 13 patients with schizophrenia and 13 controls were studied while performing a short-term memory task associated with increasing overlearning of verbal stimulus material. Functional connectivity was investigated by analyses of psychophysiological interactions (PPI).
Results revealed significant task-related modulation of functional connectivity between the left dorsolateral prefrontal cortex (DLPFC) and a network including the right DLPFC, left ventrolateral prefrontal cortex, premotor cortex, right inferior parietal cortex, left and right cerebellum as well as the left occipital lobe in patients during the course of overlearning and practice. No significant PPI results were detectable in controls.
Activation changes with practice were associated with high functional connectivity between task-relevant areas in schizophrenia patients. This could be interpreted as a compensatory resource allocation and network integration in the context of cortical inefficiency and may be a specific neurophysiological signature underlying the pathophysiology of schizophrenia.
越来越多的证据表明，精神分裂症患者经常报告的工作记忆损伤部分可能是由于与任务相关区域之间的功能连接改变所致。然而，对于精神分裂症患者在学习过程中的功能连接模式知之甚少。在之前的一项研究中，Koch 等人[神经科学（2007）146，1474-1483]已经证明，精神分裂症患者在过度学习短期记忆材料时，指数激活的减少更为明显。问题是，精神分裂症患者和对照组的这些不同的激活时间模式是否伴随着与任务相关的功能连接的变化。
因此，在当前的研究中，13 名精神分裂症患者和 13 名对照者在进行与言语刺激材料的过度学习相关的短期记忆任务时接受了研究。通过心理生理交互作用（PPI）分析研究了功能连接。
结果表明，在过度学习和练习过程中，患者的左背外侧前额叶皮层（DLPFC）与包括右 DLPFC、左腹外侧前额叶皮层、运动前皮层、右下顶叶皮层、左和右小脑以及左枕叶在内的网络之间的功能连接存在显著的任务相关调节。在对照组中未检测到显著的 PPI 结果。
与实践相关的激活变化与精神分裂症患者相关区域之间的高功能连接有关。这可以解释为皮质效率低下背景下的补偿性资源分配和网络整合，并且可能是精神分裂症病理生理学的特定神经生理特征。
