Intact subliminal processing and delayed conscious access in multiple sclerosis
Intact subliminal processing and delayed conscious access in multiple sclerosis
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多发性硬化症中完整的阈下处理和延迟的意识访问
DOI：
10.1016/j.neuropsychologia.2007.04.010
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发表时间：
2007
期刊：
影响因子：
2.6
通讯作者：
J. Pelletier
中科院分区：
文献类型：
--
作者：
F. Reuter;A. D. Cul;B. Audoin;I. Malikova;L. Naccache;J. Ranjeva;O. Lyon‐Caen;A. Chérif;L. Cohen;S. Dehaene;J. Pelletier
室周白色物质损害影响连接远端皮质区的大束，可能构成早期多发性硬化症（MS）患者控制信息处理缺陷的主要神经机制。视觉后向掩蔽已被证明会影响意识感知的后期阶段，涉及视觉感知区域和高级整合皮层之间的长距离相互作用，同时保留完整的早期前馈视觉处理，甚至复杂的处理，如物体识别或语义处理。因此，我们假设早期MS患者的掩蔽阈值会升高，因为有意识的知觉受损，而掩蔽刺激的阈下处理将被保留。22例早期MS患者和22名正常对照进行了两次后向掩蔽实验。我们使用阿拉伯数字作为刺激和变化准连续的时间间隔与随后的面具，从而使我们能够逐步“揭露”的刺激。我们使用客观和主观的措施精细地量化了掩蔽刺激的可见性，从而获得了对进入意识的阈值持续时间的准确估计。我们还研究了启动效应所造成的掩蔽的数字上进行的比较任务，随后提出的和高度可见的目标数字。与对照组相比，MS患者获得掩蔽刺激的意识的阈值升高，而这些刺激的无意识处理，如通过引发所测量的，被保留。这些发现表明，对掩蔽刺激的有意识获取依赖于大规模皮质整合过程的完整性，这涉及长距离白色物质投射，并且由于早期MS患者的弥漫性脱髓鞘损伤而受损。
Periventricular white matter damage affecting large bundles connecting distant cortical areas may constitute the main neuronal mechanism for the deficit of controlled information processing observed in patients with early multiple sclerosis (MS). Visual backward masking has been demonstrated to affect late stages of conscious perception involving long-range interactions between visual perceptual areas and higher level integrative cortices while leaving intact early feed-forward visual processing and even complex processing such as object recognition or semantic processing. We therefore hypothesized that patients with early MS would have an elevated masking threshold, because of an impairment of conscious perception whereas subliminal processing of masked stimuli would be preserved. Twenty-two patients with early MS and 22 normal controls performed two backward-masking experiments. We used Arabic digits as stimuli and varied quasi-continuously the temporal interval with a subsequent mask, thus allowing us to progressively “unmask” the stimuli. We finely quantified the visibility of the masked stimuli using both objective and subjective measures, thus obtaining accurate estimates of the threshold duration for access to consciousness. We also studied the priming effect caused by the variably masked numbers on a comparison task performed on a subsequently presented and highly visible target number. The threshold for access to consciousness of masked stimuli was elevated in MS patients compared to controls, whereas non-conscious processing of these stimuli, as measured by priming, was preserved. These findings suggest that conscious access to masked stimuli depends on the integrity of large-scale cortical integrative processes, which involve long-distance white matter projections, and are impaired due to diffuse demyelinating injury in patients with early MS.