Camchong Jazmin, Dyckman Kara A, Chapman Caroline E, Yanasak Nathan E, McDowell Jennifer E
Department of Psychology, University of Georgia, Athens, Georgia 30602, USA.
Biol Psychiatry. 2006 Aug 1;60(3):235-41. doi: 10.1016/j.biopsych.2005.11.014. Epub 2006 Feb 3.
Schizophrenia is characterized by executive functioning deficits, presumably mediated by prefrontal cortex dysfunction. For example, schizophrenia participants show performance deficits on ocular motor delayed response (ODR) tasks, which require both inhibition and spatial working memory for correct performance.
The present functional magnetic resonance imaging (fMRI) study compared neural activity of 14 schizophrenia and 14 normal participants while they performed ODR tasks.
Schizophrenia participants generated: 1) more trials with anticipatory saccades (saccades made during the delay period), 2) memory saccades with longer latencies, and 3) memory saccades of decreased accuracy. Increased blood oxygenation level-dependent (BOLD) signal changes were observed in both groups in ocular motor circuitry (e.g., supplementary eye fields [SEF], lateral frontal eye fields [FEF], inferior parietal lobule [IPL], cuneus, and precuneus). The normal, but not the schizophrenia, group demonstrated BOLD signal changes in dorsolateral prefrontal regions (right Brodmann area [BA] 9 and bilateral BA 10), medial FEF, insula, thalamus, and basal ganglia. Correlations between percentage of anticipatory saccade trials and BOLD signal changes were more similar between groups for subcortical regions and less similar for cortical regions.
These results suggest that executive functioning deficits in schizophrenia may be associated with dysfunction of the basal ganglia-thalamocortical circuitry, evidenced by decreased prefrontal cortex, basal ganglia, and thalamus activity in the schizophrenia group during ODR task performance.
精神分裂症的特征是执行功能缺陷，可能由前额叶皮质功能障碍介导。例如，精神分裂症患者在眼动延迟反应（ODR）任务中表现出性能缺陷，该任务需要抑制和空间工作记忆才能正确执行。
本功能磁共振成像（fMRI）研究比较了14名精神分裂症患者和14名正常参与者在执行ODR任务时的神经活动。
精神分裂症患者出现：1）更多伴有预期扫视（延迟期内的扫视）的试验，2）潜伏期更长的记忆性扫视，以及3）准确性降低的记忆性扫视。两组在眼动神经回路（如辅助眼区[SEF]、外侧额叶眼区[FEF]、顶下小叶[IPL]、楔叶和楔前叶）均观察到血氧水平依赖（BOLD）信号变化增加。正常组而非精神分裂症组在背外侧前额叶区域（右侧布罗德曼区[BA]9和双侧BA10）、内侧FEF、岛叶、丘脑和基底神经节表现出BOLD信号变化。预期扫视试验百分比与BOLD信号变化之间的相关性在皮质下区域两组之间更相似，而在皮质区域则不太相似。
这些结果表明，精神分裂症患者的执行功能缺陷可能与基底神经节-丘脑皮质神经回路功能障碍有关，精神分裂症组在ODR任务执行期间前额叶皮质、基底神经节和丘脑活动减少证明了这一点。
