Insomnia attenuates response inhibition: Evidence from Go/NoGo research

Highlights

• Under NoGo condition, insomnia participants have prolonged latency and higher amplitude.

• Insomnia attenuates executive function and response inhibition ability by Go/No research.

• Gender, anxiety-depression, BMI, education, and sleep structure had an impact on response inhibition ability.

Abstract

Objective

Varied cognitive dysfunctions including memory, attention, inputs, processing and filtration have been found in insomnia. Meanwhile, evidence from functional neuroimaging have revealed that the abnormal metabolism in prefrontal cortex was associated with probable deficit of executive function. And in our study, we have detected the response inhibition in insomnia patients by Go/NoGo,an Event-related potentials (ERPs) study, in order to explore the impaired executive function, because response inhibition is a hallmark of executive function.

Methods

We used polysomnography (PSG) to record such objective PSG parameters. Go/NoGo was performed in sequence, different ERP components have been analyzed such as latency or amplitude between insomnia group and control group. And we used Person correlation coefficient R to make analysis between different ERP components and gender, duration, education, BMI and sleep characteristics.

Results

On the behavioral level, we found a little poor performance insomnia participants. On the electrophysiological level, under Go condition, insomnia participants have prolonged latency and smaller amplitude of N2 or P3. While, under NoGo condition, insomnia participants also have longer latency, but higher amplitude of N2 or P3. another major finding was that different correlation was found between gender,anxiety-depression,duration, education,BMI,sleep characteristics and N2 or P3.

Discussion

Our study has revealed that sleep loss may influence the response inhibition ability in insomnia, not only on behavior level, but also on the electrophysiological level. Abnormal changes in inhibition process or inhibition supervision can be represented as N2/P3 components under Go/No-go condition. Additionally, correlation analysis has been found between gender, anxiety-depression, BMI, education, and sleep structure. Thus, sleep loss attenuates response inhibition and impairs executive function in insomnia participants.

Introduction

Insomnia is a sleep disorder, generated by an interplay of physiological, neurological and psychological factors. Epidemiological studies showed that the prevalence of insomnia in global population is 30%–48% [1]. Individuals with insomnia complain of poorly cognition in common. Research found that insomnia individuals show impaired cognitive functions, including working memory, episodic memory and executive function [2]. In our previous studies, varied cognitive dysfunctions including memory, attention, inputs, processing and filtration have been found in insomnia [3]. Evidence from functional neuroimaging have revealed that the abnormal metabolism in prefrontal cortex has been found in insomnia patients, and prefrontal dysfunction was associated with probable deficit of executive function [[4], [5], [6]]. Contrast to memory and attention, executive function has received even less attention in the insomnia literature [7]. They used different research methods and got different results. Some studies have reported significant group differences between patients with insomnia and controls [[8], [9], [10]], whereas some reports have indicated no group effects [[11], [12], [13]]. Response inhibition is a hallmark of executive function which is an important ability to resist temptations and acting impulsively [14]. Go/NoGo task.an Event-related potentials (ERPs) study, is a common paradigm for studying the ability to inhibition. Thus, in this study, we have designed a controlled pilot study with limited samples in order to explore the response inhibition and executive dysfunction in patients with insomnia.

ERPs, would provide a more direct measure of sensory and cognitive processing in insomnia, which can make a task-time related analysis and even can reveal the correlations between psychophysiology and poor performance. Among ERP studies, we employed the Go/NoGo task due to its wide application [15]. In this task, subjects should response quickly to “Go” targets but ignore to “NoGo” stimuli [16]. The performance in the Go/NoGo task will induce a typical response inhibition [17].

Two ERP components have been associated with response inhibition in the Go/NoGo task [18]. The first component is the frontal-midline N2, peaking from 200 ms to 400 ms post stimulus. The amplitudes of N2 in the NoGo condition were larger than Go conditions and would be negatively correlated with psychiatric symptoms [19]. The enhancement of NoGo-N2 has been interpreted as an inhibitory process that suppresses the incorrect response before reaction [20]. The latency of NoGo-N2 reflects the success or failure of inhibitory control [21].The second component is the parietal P3, peaking approximately from 300 ms to 600 ms post stimulus, with larger amplitudes in NoGo condition compared to Go condition [20].The enhanced NoGo-P3 has been considered as an extra cognitive control in order to monitor and evaluate inhibition process [22,23]. In addition, the latency of NoGo-P3 reflects speed of evaluation processing [21]. In a word, the perfect response inhibition was characterized as larger and shorter NoGo-N2 as well as smaller and shorter NoGo-P3 [24]. Table 1 shows the meaning of N2 and P3 under Go/NoGo task.

Overall, the aim of our study was to examine whether insomnia is associated with response inhibition (detected by Go/NoGo task). Meanwhile, the following questions are intended to be addressed: Firstly, whether different ERP parameters as amplitudes or latencies were distinguished differently between insomnia participants and controls; Secondly, whether differences can be found between Go condition and NoGo condition in insomnia participants; Then, whether the differences found in electrophysiological level can be demonstrated on the behavioral level, or electrophysiological changes are correlated with clinical variables; Finally, whether abnormal response inhibition is correlated with specific brain regions, such as prefrontal, temporal, or others.

Based on previous studies [8,25,26], we proposed our hypothesis: Insomnia attenuates response inhibition and impairs executive function. Such insomnia participants manifested with longer Go/NoGo reaction time in behavioral performance and the electrophysiological findings might correlated with abnormal N2 and P3.