Dysregulation of visual motion inhibition in major depression.
Dysregulation of visual motion inhibition in major depression.
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DOI：
10.1016/j.psychres.2016.04.028
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发表时间：
2016-06-30
影响因子：
11.3
通讯作者：
Chen Y
中科院分区：
文献类型：
--
作者：
Norton DJ;McBain RK;Pizzagalli DA;Cronin-Golomb A;Chen Y
抑郁症患者枕叶(视觉)皮质中抑制性神经递质GABA的浓度降低，这预示着他们的视觉系统中抑制作用减弱。然而，抑郁症的视觉抑制在很大程度上仍未被研究。为了填补这一空白，我们研究了抑郁个体视觉运动的中心-环绕抑制(CSS)抑制过程。在抑郁症患者(n=27)和对照组(n=22)中，作为刺激呈现时间和对比度的函数来测量辨别运动方向的知觉操作。用大的(7.5度)和小的(1.5度)栅格刺激条件之间的精确度差异来操作css。在高对比度的小刺激下，抑郁症和对照组的受试者都表现出了预期的准确性优势。受试组、对比度水平和呈现时间之间存在显著的交互作用，表明抑郁症患者的条件反射变化受刺激条件的调节。在高对比度下，抑郁症患者在66毫秒的呈现时间(两组的效果都达到顶峰)表现出明显比对照组更大的css。结果的特异性和对对比度、大小和呈现时间等刺激特征的依赖表明，它们是由于早期视觉加工的变化而产生的，而不是普遍缺陷或认知偏差的结果。
Individuals with depression show depleted concentrations of the inhibitory neurotransmitter GABA in occipital (visual) cortex, predicting weakened inhibition within their visual systems. Yet, visual inhibition in depression remains largely unexplored. To fill this gap, we examined the inhibitory process of center-surround suppression (CSS) of visual motion in depressed individuals. Perceptual performance in discriminating the direction of motion was measured as a function of stimulus presentation time and contrast in depressed individuals (n=27) and controls (n=22). CSS was operationalized as the accuracy difference between conditions using large (7.5 degrees) and small (1.5 degrees) grating stimuli. Both depressed and control participants displayed the expected advantage in accuracy for small stimuli at high contrast. A significant interaction emerged between subject group, contrast level and presentation time, indicating that alterations of CSS in depression were modulated by stimulus conditions. At high contrast, depressed individuals showed significantly greater CSS than controls at the 66 msec presentation time (where the effect peaked in both groups). The results’ specificity and dependence on stimulus features such as contrast, size and presentation time suggest that they arise from changes in early visual processing, and are not the results of a generalized deficit or cognitive bias.