Ghorashi Shahab, Spencer Kevin M
Research Service, Veterans Affairs Boston Healthcare System , Boston, MA , USA ; Department of Psychiatry, Harvard Medical School , Boston, MA , USA.
Front Psychiatry. 2015 Oct 19;6:149. doi: 10.3389/fpsyt.2015.00149. eCollection 2015.
Attentional deficits are prominent among the cognitive disturbances found in schizophrenia. Given that schizophrenia is also characterized by abnormalities in high-frequency oscillations, we investigated whether attentional function in schizophrenia is related to abnormalities in high-frequency oscillations in a visual discrimination task in which attentional load was manipulated. Sixteen healthy control subjects (HC) and 23 chronic schizophrenia patients (SZ) discriminated between target discs (p = 0.2) and standard discs (p = 0.8). Attentional load was manipulated by varying the size difference between the target and standard discs across blocks: large (Easy condition), medium (Medium), and small (Difficult). The electroencephalogram was recorded and the oscillations evoked by the standard stimuli were analyzed using the Morlet wavelet transform. Subjects' performance decreased as attentional load increased, but HC and SZ did not differ. Attentional load increased β phase-locking factor at frontal, parietal, and occipital electrode sites in HC but not SZ. In SZ, however, there was a correlation between the β attentional load effect and overall d', indicating that high-performing SZ had relatively normal β attentional load effects. These results show that variations in attentional load are associated with β oscillations and provide a link between attentional dysfunction and β-generating neural circuitry in schizophrenia.
注意缺陷在精神分裂症患者的认知障碍中较为突出。鉴于精神分裂症还具有高频振荡异常的特征，我们在一项操纵了注意负荷的视觉辨别任务中，研究了精神分裂症患者的注意功能是否与高频振荡异常有关。16名健康对照者（HC）和23名慢性精神分裂症患者（SZ）对目标圆盘（p = 0.2）和标准圆盘（p = 0.8）进行辨别。通过在不同组块中改变目标圆盘和标准圆盘之间的大小差异来操纵注意负荷：大（容易条件）、中（中等）和小（困难）。记录脑电图，并使用Morlet小波变换分析标准刺激诱发的振荡。随着注意负荷增加，受试者的表现下降，但HC组和SZ组之间没有差异。注意负荷增加了HC组额叶、顶叶和枕叶电极部位的β相位锁定因子，但SZ组没有。然而，在SZ组中，β注意负荷效应与总体d'之间存在相关性，这表明表现良好的SZ患者具有相对正常的β注意负荷效应。这些结果表明，注意负荷的变化与β振荡有关，并为精神分裂症患者的注意功能障碍和β产生神经回路之间提供了联系。
