Wong Ling M, Tassone Flora, Rivera Susan M, Simon Tony J
MIND Institute, University of California Davis School of Medicine Sacramento, CA, USA ; Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine Sacramento, CA, USA.
MIND Institute, University of California Davis School of Medicine Sacramento, CA, USA ; Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine Sacramento, CA, USA.
Front Hum Neurosci. 2015 Feb 5;9:37. doi: 10.3389/fnhum.2015.00037. eCollection 2015.
Carriers of the fragile X premutation allele (fXPCs) have an expanded CGG trinucleotide repeat size within the FMR1 gene and are at increased risk of developing fragile x-associated tremor/ataxia syndrome (FXTAS). Previous research has shown that male fXPCs with FXTAS exhibit cognitive decline, predominantly in executive functions such as inhibitory control and working memory. Recent evidence suggests fXPCs may also exhibit impairments in processing temporal information. The attentional blink (AB) task is often used to examine the dynamics of attentional selection, but disagreements exist as to whether the AB is due to excessive or insufficient attentional control. In this study, we used a variant of the AB task and neuropsychological testing to explore the dynamics of attentional selection, relate AB performance to attentional control, and determine whether fXPCs exhibited temporal and/or attentional control impairments. Participants were adult male fXPCs, aged 18-48 years and asymptomatic for FXTAS (n = 19) and age-matched male controls (n = 20). We found that fXPCs did not differ from controls in the AB task, indicating that the temporal dynamics of attentional selection were intact. However, they were impaired in the letter-number sequencing task, a test of executive working memory. In the combined fXPC and control group, letter-number sequencing performance correlated positively with AB magnitude. This finding supports models that posit the AB is due to excess attentional control. In our two-pronged analysis approach, in control participants we replicated a previously observed effect and demonstrated that it persists under more stringent theoretical constraints, and we enhance our understanding of fXPCs by demonstrating that at least some aspects of temporal processing may be spared.
脆性X前突变等位基因携带者（fXPCs）在FMR1基因内有一个扩展的CGG三核苷酸重复序列，患脆性X相关震颤/共济失调综合征（FXTAS）的风险增加。先前的研究表明，患有FXTAS的男性fXPCs表现出认知能力下降，主要体现在执行功能方面，如抑制控制和工作记忆。最近的证据表明，fXPCs在处理时间信息方面也可能存在缺陷。注意瞬脱（AB）任务常用于检查注意选择的动态过程，但对于AB是由于注意控制过度还是不足存在分歧。在本研究中，我们使用AB任务的一个变体和神经心理学测试来探索注意选择的动态过程，将AB表现与注意控制联系起来，并确定fXPCs是否存在时间和/或注意控制缺陷。参与者为18至48岁、无FXTAS症状的成年男性fXPCs（n = 19）和年龄匹配的男性对照组（n = 20）。我们发现，fXPCs在AB任务中的表现与对照组没有差异，这表明注意选择的时间动态是完整的。然而，他们在字母数字排序任务（一种执行工作记忆测试）中存在缺陷。在fXPCs和对照组的合并组中，字母数字排序表现与AB幅度呈正相关。这一发现支持了认为AB是由于注意控制过度的模型。在我们的双管齐下的分析方法中，在对照参与者中，我们重复了先前观察到的效应，并证明在更严格的理论限制下该效应仍然存在，并且通过证明至少某些时间处理方面可能未受影响，我们加深了对fXPCs的理解。
