Ragland J Daniel, Gur Ruben C, Valdez Jeffrey N, Loughead James, Elliott Mark, Kohler Christian, Kanes Stephen, Siegel Steven J, Moelter Stephen T, Gur Raquel E
Department of Psychiatry, 10th Floor Gates Bldg./HUP, University of Pennsylvania, Philadelphia, PA 19104, USA.
Am J Psychiatry. 2005 Oct;162(10):1840-8. doi: 10.1176/appi.ajp.162.10.1840.
Patients with schizophrenia improve episodic memory accuracy when given organizational strategies through levels-of-processing paradigms. This study tested if improvement is accompanied by normalized frontotemporal function.
Event-related blood-oxygen-level-dependent functional magnetic resonance imaging (fMRI) was used to measure activation during shallow (perceptual) and deep (semantic) word encoding and recognition in 14 patients with schizophrenia and 14 healthy comparison subjects.
Despite slower and less accurate overall word classification, the patients showed normal levels-of-processing effects, with faster and more accurate recognition of deeply processed words. These effects were accompanied by left ventrolateral prefrontal activation during encoding in both groups, although the thalamus, hippocampus, and lingual gyrus were overactivated in the patients. During word recognition, the patients showed overactivation in the left frontal pole and had a less robust right prefrontal response.
Evidence of normal levels-of-processing effects and left prefrontal activation suggests that patients with schizophrenia can form and maintain semantic representations when they are provided with organizational cues and can improve their word encoding and retrieval. Areas of overactivation suggest residual inefficiencies. Nevertheless, the effect of teaching organizational strategies on episodic memory and brain function is a worthwhile topic for future interventional studies.
精神分裂症患者通过加工水平范式接受组织策略时，情景记忆准确性会提高。本研究测试了这种改善是否伴随着额颞叶功能的正常化。
采用事件相关血氧水平依赖性功能磁共振成像（fMRI）来测量14例精神分裂症患者和14名健康对照者在浅层（知觉）和深层（语义）单词编码及识别过程中的激活情况。
尽管总体单词分类较慢且准确性较低，但患者表现出正常的加工水平效应，对深度加工单词的识别更快且更准确。两组在编码过程中，这些效应都伴随着左侧腹外侧前额叶的激活，不过患者的丘脑、海马和舌回过度激活。在单词识别过程中，患者左侧额极过度激活，右侧前额叶反应较弱。
正常加工水平效应和左侧前额叶激活的证据表明，精神分裂症患者在获得组织线索时能够形成并维持语义表征，且能改善其单词编码和检索。过度激活区域表明存在残留的低效情况。尽管如此，教授组织策略对情景记忆和脑功能的影响是未来干预研究的一个有价值的课题。
