Vigilant Attention, Cerebral Blood Flow and Grey Matter Volume Change after 36 h of Acute Sleep Deprivation in Healthy Male Adults: A Pilot Study.

It is commonly believed that alertness and attention decrease after sleep deprivation (SD). However, there are not enough studies on the changes in psychomotor vigilance testing (PVT) during SD and the corresponding changes in brain function and brain structure after SD. Therefore, we recruited 30 healthy adult men to perform a 36 h acute SD experiment, including the measurement of five indicators of PVT every 2 h, and analysis of cerebral blood flow (CBF) and grey matter volume (GMV) changes, before and after SD by magnetic resonance imaging (MRI). The PVT measurement found that the mean reaction time (RT), fastest 10% RT, minor lapses, and false starts all increased progressively within 20 h of SD, except for major lapses. Subsequently, all indexes showed a significant lengthening or increasing trend, and the peak value was in the range of 24 h-32 h and decreased at 36 h, in which the number of major lapses returned to normal. MRI showed that CBF decreased in the left orbital part of the superior frontal gyrus, the left of the rolandic operculum, the left triangular part, and the right opercular part of the inferior frontal gyrus, and CBF increased in the left lingual gyrus and the right superior gyrus after 36 h SD. The left lingual gyrus was negatively correlated with the major lapses, and both the inferior frontal gyrus and the superior frontal gyrus were positively correlated with the false starts. Still, there was no significant change in GMV. Therefore, we believe that 36 h of acute SD causes alterations in brain function and reduces alert attention, whereas short-term acute SD does not cause changes in brain structure.

Altered Hypothalamic Functional Connectivity Following Total Sleep Deprivation in Young Adult Males.

Background: Sleep deprivation can markedly influence vigilant attention that is essential to complex cognitive processes. The hypothalamus plays a critical role in arousal and attention regulation. However, the functional involvement of the hypothalamus in attentional impairments after total sleep deprivation (TSD) remains unclear. The purpose of this study is to investigate the alterations in hypothalamic functional connectivity and its association with the attentional performance following TSD. Methods: Thirty healthy adult males were recruited in the study. Participants underwent two resting-state functional magnetic resonance imaging (rs-fMRI) scans, once in rested wakefulness (RW) and once after 36 h of TSD. Seed-based functional connectivity analysis was performed using rs-fMRI for the left and right hypothalamus. Vigilant attention was measured using a psychomotor vigilance test (PVT). Furthermore, Pearson correlation analysis was conducted to investigate the relationship between altered hypothalamic functional connectivity and PVT performance after TSD. Results: After TSD, enhanced functional connectivity was observed between the left hypothalamus and bilateral thalamus, bilateral anterior cingulate cortex, right amygdala, and right insula, while reduced functional connectivity was observed between the left hypothalamus and bilateral middle frontal gyrus (AlphaSim corrected, P < 0.01). However, significant correlation between altered hypothalamic functional connectivity and PVT performance was not observed after Bonferroni correction (P > 0.05). Conclusion: Our results suggest that TSD can lead to disrupted hypothalamic circuits, which may provide new insight into neural mechanisms of attention impairments following sleep deprivation.

Disrupted Small-world Networks are Associated with Decreased Vigilant Attention after Total Sleep Deprivation.

Sleep deprivation critically affects vigilant attention. Previous neuroimaging studies have revealed altered inter-regional functional connectivity after sleep deprivation, which may disrupt topological properties of brain functional networks. However, little is known about alterations in the topology of intrinsic connectivity and its involvement in attention performance after sleep deprivation. In the current study, we investigated the topological properties of brain networks derived from resting-state functional magnetic resonance imaging of 26 healthy men in rested wakefulness (RW) state and after 36 h of total sleep deprivation (TSD). In the predefined sparsity threshold range, both global and nodal network properties were evaluated based on graph theory analysis. Vigilant attention was assessed using the psychomotor vigilance test (PVT) before and after TSD. Furthermore, Pearson's correlation analyses were conducted to explore the association between altered network properties and changed PVT performance after TSD. At the global level, the brain functional networks in the TSD state showed a significantly lower small-world coefficient than RW, with decreased global efficiency. At the nodal level, the altered regions were selectively distributed in frontoparietal networks, sensorimotor networks, temporal regions, and salience networks. More specifically, the altered clustering coefficient in the posterior superior temporal sulcus (pSTS) and insula, and altered local efficiency in pSTS were further associated with PVT performance after TSD. Our results suggest that the topological properties of brain functional networks are disrupted, and aberrant topology of temporal networks and salience networks may act as neural signatures underlying the vigilant attention impairments after TSD.

Altered insula-prefrontal functional connectivity correlates to decreased vigilant attention after total sleep deprivation.

BACKGROUND: Sleep deprivation can robustly affect vigilant attention. The insula is a key hub of the salience network that mediates shifting attention between endogenous and exogenous states. However, little is known regarding the involvement of insular functional connectivity in impaired vigilant attention after total sleep deprivation (TSD). The purpose of this study is to explore the alterations in insular functional connectivity and its association with vigilant attention performance following TSD. METHODS: Twenty-six adult men were enrolled in the study. Participants underwent two counterbalanced resting-state functional magnetic resonance imaging (rs-fMRI) scans, once in rested wakefulness (RW) and once after 36 h of TSD. Seed-based functional connectivity analysis was performed using rs-fMRI data for the left and right insula. The vigilant attention was measured using a psychomotor vigilance test (PVT). Furthermore, Pearson correlation analysis was conducted to investigate the relationship between altered insular functional connectivity and PVT performance. RESULTS: Compared to RW, enhanced functional connectivity was observed between the insula and prefrontal cortex and anterior cingulate cortex, while reduced functional connectivity was observed between the insula and temporal, parietal, and occipital regions following TSD. Moreover, altered insular functional connectivity with the prefrontal cortex, ie superior frontal gyrus and middle frontal gyrus, and inferior temporal gyrus was correlated with PVT performance after TSD. CONCLUSION: Our results suggest that insular coupling with the prefrontal cortex and inferior temporal gyrus may act as neural indicators for vigilant attention impairment, which further reveals the critical role of the salience network in cognitive decline following TSD.

Altered functional connectivity between the nucleus basalis of Meynert and anterior cingulate cortex is associated with declined attentional performance after total sleep deprivation.

BACKGROUND: Sleep deprivation can markedly influence vigilant attention. The nucleus basalis of Meynert (NBM), the main source of cholinergic projections to the cortex, plays an important role in wakefulness maintenance and attention control. However, the involvement of NBM in attentional impairments after total sleep deprivation (TSD) has yet to be established. The purpose of this study is to investigate the alterations in NBM functional connectivity and its association with the attentional performance following TSD. METHODS: Thirty healthy adult males were recruited in the study. Participants underwent two resting-state functional magnetic resonance imaging (rs-fMRI) scans, once in rested wakefulness (RW) and once after 36 h of TSD. Seed-based functional connectivity analysis was performed using rs-fMRI data for the left and right NBM. The vigilant attention was measured using a psychomotor vigilance test (PVT). Furthermore, Pearson correlation analysis was conducted to investigate the relationship between altered NBM functional connectivity and changed PVT performance after TSD. RESULTS: Compared to RW, enhanced functional connectivity was observed between right NBM and bilateral thalamus and cingulate cortex, while reduced functional connectivity was observed between left NBM and right superior parietal lobule following TSD. Moreover, altered NBM functional connectivity with the left anterior cingulate cortex was negatively correlated with PVT performance after TSD. CONCLUSION: Our results suggest that the disrupted NBM-related cholinergic circuit highlights an important role in attentional performance after TSD. The enhanced NBM functional connectivity with the anterior cingulate cortex may act as neural signatures for attentional deficits induced by sleep deprivation.

Relation of Decreased Functional Connectivity Between Left Thalamus and Left Inferior Frontal Gyrus to Emotion Changes Following Acute Sleep Deprivation.

Objective: The thalamus is a key node for sleep-wake pathway gate switching during acute sleep deprivation (ASD), and studies have shown that it plays a certain role in emotion changes. However, there are no studies on the association between the thalamus and emotion changes in ASD. In this study, we used resting-state functional magnetic resonance imaging (R-fMRI) to explore whether changes in the functional connections between the thalamus and other brain regions are related to emotion changes and further explored the function of the thalamus under total ASD conditions. Method: Thirty healthy, right-handed adult men underwent emotional assessment according to the Profile of Mood States Scale and R-fMRI scans before and after ASD. The correlations between changes in functional connectivity between the thalamus and other brain regions and emotion changes were then studied. Results: Positive emotions and psychomotor performance were reduced, and negative emotions were increased following ASD. The functional connections between the left thalamus and left middle temporal gyrus, left inferior frontal gyrus, right thalamus, right inferior temporal gyrus, left middle temporal pole gyrus, right calcarine, left cuneus, left rectus and left medial superior frontal gyrus were significantly altered. Decreased functional connectivity between left thalamus and left inferior frontal gyrus related to emotion changes following ASD. Conclusion: This study finds that functional changes in the thalamus are associated with emotion changes during ASD, suggesting that the left thalamus probably plays an essential role in emotion changes under ASD conditions.

Circadian misalignment on submarines and other non-24-h environments - from research to application.

Circadian clocks have important physiological and behavioral functions in humans and other organisms, which enable organisms to anticipate and respond to periodic environmental changes. Disturbances in circadian rhythms impair sleep, metabolism, and behavior. People with jet lag, night workers and shift workers are vulnerable to circadian misalignment. In addition, non-24-h cycles influence circadian rhythms and cause misalignment and disorders in different species, since these periods are beyond the entrainment ranges. In certain special conditions, e.g., on submarines and commercial ships, non-24-h watch schedules are often employed, which have also been demonstrated to be deleterious to circadian rhythms. Personnel working under such conditions suffer from circadian misalignment with their on-watch hours, leading to increased health risks and decreased cognitive performance. In this review, we summarize the research progress and knowledge concerning circadian rhythms on submarines and other environments in which non-24-h watch schedules are employed.

[The effect of transcranial direct current stimulation on dysfunction of bilateral posterior cingulate cortex after sleep deprivation: a preliminary study].

Objective: To investigate the effects of transcranial direct current stimulation (tDCS) on the disturbance of brain network dysfunction after sleep deprivation (SD). Methods: The experimental design of self-control was used in the study. All 16 subjects received 2 times of 24 h SD with an interval of 3 weeks. After the first normal sleep, 24 h SD and transcranial electrical stimulation (true or false stimulation) intervention (the current magnitude of true and false stimulation was 1 mA, and the action time was 20 min and 2 s, respectively. The intervention experiment lasted for 20 min. ) and the resting magnetic resonance imaging data were collected after the second transcranial electrical stimulation (sham or true stimulation). The resting fMRI data were collected as baseline before SD, the bilateral posterior cingulate cortex in the default mode network was selected as the seed point, and the functional connectivity between the seed points and the whole brain was calculated. Results: Compared with the rest wakefulness, the functional connectivity among bilateral posterior cingulate cortex, bilateral thalamus and hippocampus was increased (P＜0. 01), but connected with the right precuneus, bilateral insula was decreased after 24 h SD (P＜0. 01). Compared with the sham tDCS group, the functional connectivity between left posterior cingulate cortex seed point and right precuneus of tDCS group was increased (P＜0. 01); but decreased with the bilateral thalamus, insula and right cerebral cortex (P＜0. 01). There was a decrease in the functional connectivity among the right posterior cingulate cortex and the bilateral thalamus, right insula, and cerebral cortex(P＜0. 01). Conclusion: 24-hours sleep deprivation can cause functional connection disorder of bilateral posterior cingulate gyrus, and transcranial electrical stimulation can improve the functional connection disorder after sleep deprivation to some extent.

[Effect of 36h total sleep deprivation on the object working memory: an ERP study].

Objective: To investigate the effects of 36 h total sleep deprivation (TSD) on object working memory by event related potential(ERP). Methods: We used a pre-post-design, sixteen healthy college students (age range: 21-28 years, mean age: 23 years) received object working memory tasks while awake and after 36 hours of TSD and simultaneously recording electroencephalograph (EEG) data while completing 2-back object working memory tasks. ERP data were statistically analyzed using repeated measurements analysis of variance to observe the changes in the working memory-related P2, N2 and P3 components. Results: After 36 h TSD, the latency of N2 waves related to object working memory significantly was prolonged (P＜0.05), and the amplitude was decreased, but difference did not reach statistical significance (P＞0.05). The latency of P2 was significantly prolonged after TSD (P＜0.05). There was no significant difference in the change of latency and amplitude of P3 waves (P＞0.05). Conclusion: 36 h of total sleep deprivation affected working memory-related components and impaired object working memory capacity.

Altered intrinsic hippocmapus declarative memory network and its association with impulsivity in abstinent heroin dependent subjects.

Converging evidence suggests that addiction can be considered a disease of aberrant learning and memory with impulsive decision-making. In the past decades, numerous studies have demonstrated that drug addiction is involved in multiple memory systems such as classical conditioned drug memory, instrumental learning memory and the habitual learning memory. However, most of these studies have focused on the contributions of non-declarative memory, and declarative memory has largely been neglected in the research of addiction. Based on a recent finding that hippocampus, as a core functioning region of declarative memory, was proved biased the decision-making process based on past experiences by spreading associated reward values throughout memory. Our present study focused on the hippocampus. By utilizing seed-based network analysis on the resting-state functional MRI datasets with the seed hippocampus we tested how the intrinsic hippocampal memory network altered toward drug addiction, and examined how the functional connectivity strength within the altered hippocampal network correlated with behavioral index 'impulsivity'. Our results demonstrated that HD group showed enhanced coherence between hippocampus which represents declarative memory system and non-declarative reward-guided learning memory system, and also showed attenuated intrinsic functional link between hippocampus and top-down control system, compared to the CN group. This alteration was furthered found to have behavioral significance over the behavioral index 'impulsivity' measured with Barratt Impulsiveness Scale (BIS). These results provide insights into the mechanism of declarative memory underlying the impulsive behavior in drug addiction.

Dynamic neural responses to cue-reactivity paradigms in heroin-dependent users: an fMRI study.

Neuroimaging methods have been employed to study cue-reactivity-induced neural correlates in the human brain. However, very few studies have focused on characterizing the dynamic neural responses to the factorial interactions between the cues and the subjects. Fifteen right-handed heroin-dependent subjects and 12 age-matched nondrug using subjects participated in this study. Cue-reactivity paradigms were employed, while changes in blood oxygenation level-dependent (BOLD) signals were acquired by functional MRI (fMRI). The fMRI datasets were analyzed with AFNI software and repeated two-way ANOVA was employed for factorial analyses. Neural correlates of factorial interactions between cue-factor and subject-factor were identified in the regions of the ventral tegmental area (VTA), the left and right amygdala, the left and right fusiform cortex, and the precuneus in the mesocorticolimbic system, and in the superior frontal, dorsal lateral prefrontal, and orbitofrontal cortices in the prefrontal cortex system. The neural response patterns in the prefrontal systems are dynamic: decreased response to neutral-cues and increased response to heroin-cues. Further, heroin-cue-induced neural responses within the subregions in the PFC system are significantly intercorrelated. In conclusion, the cue-reactivity paradigms significantly activated the dynamic neural activations in the prefrontal system. It is suggested that the dynamic response patterns in the PFC system characterize the impaired brain control functions in heroin-dependent subjects.

Medication of l-tetrahydropalmatine significantly ameliorates opiate craving and increases the abstinence rate in heroin users: a pilot study.

AIM: Drug addiction is a chronic brain disease with constant relapse requiring long-term treatment. New pharmacological strategies focus on the development of an effective antirelapse drug. This study examines the effects of levotetrahydropalmatine (l-THP) on reducing heroin craving and increasing the abstinence rate among heroin-dependent patients. METHODS: In total, 120 heroin-dependent patients participated in the randomized, double-blinded, and placebocontrolled study using l-THP treatment. The participants remained in a ward during a 4-week period of l-THP treatment, followed by 4 weeks of observation after treatment. The patients were followed for 3 months after discharge. Outcome measures are the measured severity of the protracted abstinence withdrawal syndrome (PAWS) and the abstinence rate. RESULTS: Four weeks of l-THP treatment significantly ameliorated the severity of PAWS, specifically, somatic syndrome, mood states, insomnia, and drug craving, in comparison to the placebo group. Based on the 3 month follow-up observation, participants who survived the initial 2 weeks of l-THP medication and remained in the trial program had a significantly higher abstinence rate of 47.8% (95% confidence interval [CI]: 33%- 67%) than the 15.2% in the placebo group (95% CI: 7%-25%), according to a log- rank test (P<0.0005). CONCLUSION: l-THP significantly ameliorated PAWS, especially reducing drug craving. Furthermore, it increased the abstinence rate among heroin users. These results support the potential use of l-THP for the treatment of heroin addiction.