Association of naturally occurring sleep loss with reduced amygdala resting-state functional connectivity following psychosocial stress.
- 作者列表："Nowak J","Dimitrov A","Oei NYL","Walter H","Adli M","Veer IM
:Enduring sleep loss is a risk factor for a variety of both somatic and mental health issues. When subjected to sleep loss, the brain becomes vulnerable to critical alterations in cognitive and emotional processing. In our study, we examined the effect of psychosocial stress on amygdala resting-state functional connectivity in participants with cumulative sleep loss calculated across the seven days preceding scanning. For this purpose, forty-five healthy male participants completed a one-week sleep diary and underwent resting-state scans before and after taking part in the ScanSTRESS paradigm, which allows social stress induction during functional magnetic resonance imaging. Sleep loss was negatively associated with seed-based functional connectivity of the left amygdala with the medial prefrontal cortex, dorsal anterior cingulate cortex, anterior insula, posterior cingulate cortex, and dorsolateral prefrontal cortex. That is, participants with higher amounts of sleep loss showed reduced left amygdala connectivity after social stress induction to cortical regions encompassing main nodes of the brain's default mode network and salience network. Our results shed more light on how brain functional connectivity may shape the brain's stress response in the context of naturally occurring sleep loss, revealing a potential neural mechanism for increased vulnerability to stress-related psychopathology.
: 持久的睡眠不足是各种躯体和精神卫生问题的危险因素。当睡眠不足时，大脑变得容易受到认知和情绪处理的关键改变。在我们的研究中，我们检测了心理社会应激对扫描前七天累积睡眠损失的参与者杏仁核静息态功能连接的影响。为此，45 名健康男性参与者完成了一周的睡眠日记，并在参加 ScanSTRESS 范式前后接受了静息态扫描,允许功能磁共振成像过程中社会压力诱导。睡眠缺失与左侧杏仁核与内侧前额叶皮质、背侧前扣带回皮质、前岛叶、后扣带回皮质和背外侧前额叶皮质的基于种子的功能连接呈负相关。也就是说，在社交压力诱导到包含大脑默认模式网络和突出网络主要节点的皮层区域后，睡眠失血量较高的参与者显示左侧杏仁核连接减少。我们的研究结果进一步揭示了在自然发生的睡眠丧失的背景下，大脑功能连接如何塑造大脑的应激反应，揭示了应激相关精神病理学脆弱性增加的潜在神经机制。
METHODS::In recent years, transcranial electrical stimulation (tES) has been used to improve cognitive and perceptual abilities and to boost learning. In the visual domain, transcranial random noise stimulation (tRNS), a type of tES in which electric current is randomly alternating in between two electrodes at high frequency, has shown potential in inducing long lasting perceptual improvements when coupled with tasks such as contrast detection. However, its cortical mechanisms and online effects have not been fully understood yet, and it is still unclear whether these long-term improvements are due to early-stage perceptual enhancements of contrast sensitivity or later stage mechanisms such as learning consolidation. Here we tested tRNS effects on multiple spatial frequencies and orientation, showing that tRNS enhances detection of a low contrast Gabor, but only for oblique orientation and high spatial frequency (12 cycles per degree of visual angle). No improvement was observed for low contrast and vertical stimuli. These results indicate that tRNS can enhance contrast sensitivity already after one training session, however this early onset is dependent on characteristics of the stimulus such as spatial frequency and orientation. In particular, the shallow depth of tRNS is likely to affect superficial layers of the visual cortex where neurons have higher preferred spatial frequencies than cells in further layers, while the lack of effect on vertical stimuli might reflect the optimization of the visual system to see cardinally oriented low contrast stimuli, leaving little room for short-term improvement. Taken together, these results suggest that online tRNS effects on visual perception are the result of a complex interaction between stimulus intensity and cortical anatomy, consistent with previous literature on brain stimulation.
METHODS:OBJECTIVE:There is growing interest in treating diseases by electrical stimulation and block of peripheral autonomic nerves, but a paucity of studies on excitation and block of small diameter autonomic axons. We conducted in vivo quantification of the strength-duration properties, activity-dependent slowing (ADS), and responses to kilohertz frequency (KHF) signals for the rat vagus nerve (VN). APPROACH:We conducted acute in vivo experiments in urethane-anesthetised rats. We placed two cuff electrodes on the left cervical VN and one cuff electrode on the anterior subdiaphragmatic VN. The rostral cervical cuff was used to deliver pulses to quantify recruitment and ADS. The caudal cervical cuff was used to deliver KHF signals. The subdiaphragmatic cuff was used to record compound action potentials (CAPs). MAIN RESULTS:We quantified the input-output recruitment and strength-duration curves. Fits to the data using standard strength-duration equations were qualitatively similar, but the resulting chronaxie and rheobase estimates varied substantially. We measured larger thresholds for the slowest fibres (0.5 to 1 m/s), especially at shorter pulse widths. Using a novel cross-correlation CAP-based analysis, we measured ADS of ~2.3% after 3 min of 2 Hz stimulation, which is comparable to ADS reported for sympathetic efferents in somatic nerves, but much smaller than ADS in cutaneous nociceptors. We found greater ADS with higher stimulation frequency and non-monotonic changes in CV in select cases. We found monotonically increasing block thresholds across frequencies from 10 to 80 kHz for both fast and slow fibres. Further, following 25 s of KHF signal, neural conduction could require tens of seconds to recover. SIGNIFICANCE:The quantification of mammalian autonomic nerve responses to conventional and KHF signals provides essential information for development of peripheral nerve stimulation therapies and for understanding their mechanisms of action.
METHODS:BACKGROUND:Early accounts of forced thought were reported at the onset of a focal seizure, and characterized as vague, repetitive, and involuntary intellectual auras distinct from perceptual or psychic hallucinations or illusions. Here, we examine the neural underpinnings involved in conceptual thought by presenting a series of 3 patients with epilepsy reporting intrusive thoughts during electrical stimulation of the left lateral prefrontal cortex (PFC) during invasive surgical evaluation. We illustrate the widespread networks involved through two independent brain imaging modalities: resting state functional magnetic resonance imaging (fMRI) (rs-fMRI) and task-based meta-analytic connectivity modeling (MACM). METHODS:We report the clinical and stimulation characteristics of three patients with left hemispheric language dominance who demonstrate forced thought with functional mapping. To examine the brain networks underlying this phenomenon, we used the regions of interest (ROI) centered at the active electrode pairs. We modeled functional networks using two approaches: (1) rs-fMRI functional connectivity analysis, representing 81 healthy controls and (2) meta-analytic connectivity modeling (MACM), representing 8260 healthy subjects. We also determined the overlapping regions between these three subjects' rs-fMRI and MACM networks through a conjunction analysis. RESULTS:We identified that left PFC was associated with a large-scale functional network including frontal, temporal, and parietal regions, a network that has been associated with multiple cognitive functions including semantics, speech, attention, working memory, and explicit memory. CONCLUSIONS:We illustrate the neural networks involved in conceptual thought through a unique patient population and argue that PFC supports this function through activation of a widespread network.