Institute of Psychology, Jagiellonian University, Ingardena 6, 30-060, Kraków, Poland.
Department of Psychiatry, Faculty of Medicine, Masaryk University and University Hospital Brno, Brno, Czech Republic.
Brain Topogr. 2021 Jul;34(4):537-554. doi: 10.1007/s10548-021-00849-x. Epub 2021 May 10.
Figurative language processing (e.g. metaphors) is commonly impaired in schizophrenia. In the present study, we investigated the neural activity and propagation of information within neural circuits related to the figurative speech, as a neural substrate of impaired conventional metaphor processing in schizophrenia. The study included 30 schizophrenia outpatients and 30 healthy controls, all of whom were assessed with a functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) punchline-based metaphor comprehension task including literal (neutral), figurative (metaphorical) and nonsense (absurd) endings. The blood oxygenation level-dependent signal was recorded with 3T MRI scanner and direction and strength of cortical information flow in the time course of task processing was estimated with a 64-channel EEG input for directed transfer function. The presented results revealed that the behavioral manifestation of impaired figurative language in schizophrenia is related to the hypofunction in the bilateral fronto-temporo-parietal brain regions (fMRI) and various differences in effective connectivity in the fronto-temporo-parietal circuit (EEG). Schizophrenia outpatients showed an abnormal pattern of connectivity during metaphor processing which was related to bilateral (but more pronounced at the left hemisphere) hypoactivation of the brain. Moreover, we found reversed lateralization patterns, i.e. a rightward-shifted pattern during metaphor processing in schizophrenia compared to the control group. In conclusion, the presented findings revealed that the impairment of the conventional metaphor processing in schizophrenia is related to the bilateral brain hypofunction, which supports the evidence on reversed lateralization of the language neural network and the existence of compensatory recruitment of alternative neural circuits in schizophrenia.
隐喻等修辞手法的加工在精神分裂症中普遍受损。在本研究中，我们通过功能性磁共振成像（fMRI）和脑电图（EEG），考察了与隐喻言语相关的神经回路中的神经活动和信息传递，以作为精神分裂症患者常规隐喻处理受损的神经基础。该研究纳入了 30 名精神分裂症患者和 30 名健康对照者，所有参与者均接受 fMRI 及基于一语双关语的隐喻理解任务（包括字面、隐喻和荒谬结尾）的 EEG 检测。使用 3T MRI 扫描仪记录血氧水平依赖信号（BOLD），通过 64 通道 EEG 输入估计在任务处理过程中的时间进程中皮质信息流的方向和强度，以获得定向传递函数。结果表明，精神分裂症患者隐喻语言受损的行为表现与双侧额颞顶叶大脑区域功能减退（fMRI）和额颞顶叶回路中有效连接的各种差异（EEG）有关。精神分裂症患者在隐喻处理过程中表现出异常的连接模式，这与大脑双侧（但左半球更明显）活动减退有关。此外，我们还发现了反转的侧化模式，即在精神分裂症患者中，隐喻处理过程中存在右移模式，而在对照组中则没有。总之，本研究结果表明，精神分裂症患者常规隐喻处理受损与双侧大脑功能减退有关，这支持了语言神经网络反转侧化的证据，以及精神分裂症中替代神经回路代偿性招募的存在。
