Alcohol and the dysregulation of cognitive control: Exploring the role of emotion

<p>Alcohol consumption attenuates both the behavioural adjustments and the heightened activity in the anterior cingulate cortex (ACC) which are normally observed following errors, leading to the hypothesis that alcohol disrupts the ability to effectively regulate the use of cognitive control. It has furthermore been theorized that these deficits may occur because alcohol reduces the negative affect elicited by unfavourable events, such as errors, thereby weakening the motivation to utilize cognitive control to improve performance. The aim of the current thesis was to provide an empirical test of this model. I carried out two studies in which I examined changes in two physiological indices of affective processing, skin conductance and heart rate, as well as behavioural and EEG responses, following errors on a flanker task. The first study was conducted on sober participants, in order to validate my experimental paradigm, while the second compared the physiological and behavioural effects of errors in participants given either alcohol or a placebo. In both experiments in both experiments, errors produced increased skin conductance responses and heart rate deceleration, and a typical error-related negativity in EEG. However, contrary to what would be expected if alcohol reduced the negative affect generated by errors, no difference in skin conductance or heart rate responses to errors were observed between alcohol and placebo participants in the second study. Furthermore, although intoxicated participants displayed an overall reduction in the use of cognitive control, based on both behavioural (flanker interference) and EEG (occipital alpha power) measures, groups did not differ in the degree to which this control was upregulated immediately after task errors. However, exploratory analyses of EEG indices (the feedback-related negativity and midfrontal theta power) of ACC activity following errors were significantly diminished in intoxicated participants. Overall, these findings suggest that alcohol does not reduce the immediate negative emotional consequences of errors but may instead disrupt brain networks needed for the sustained engagement of cognitive control and attention to task performance.</p>

Alcohol and the dysregulation of cognitive control: Exploring the role of emotion

<p>Alcohol consumption attenuates both the behavioural adjustments and the heightened activity in the anterior cingulate cortex (ACC) which are normally observed following errors, leading to the hypothesis that alcohol disrupts the ability to effectively regulate the use of cognitive control. It has furthermore been theorized that these deficits may occur because alcohol reduces the negative affect elicited by unfavourable events, such as errors, thereby weakening the motivation to utilize cognitive control to improve performance. The aim of the current thesis was to provide an empirical test of this model. I carried out two studies in which I examined changes in two physiological indices of affective processing, skin conductance and heart rate, as well as behavioural and EEG responses, following errors on a flanker task. The first study was conducted on sober participants, in order to validate my experimental paradigm, while the second compared the physiological and behavioural effects of errors in participants given either alcohol or a placebo. In both experiments in both experiments, errors produced increased skin conductance responses and heart rate deceleration, and a typical error-related negativity in EEG. However, contrary to what would be expected if alcohol reduced the negative affect generated by errors, no difference in skin conductance or heart rate responses to errors were observed between alcohol and placebo participants in the second study. Furthermore, although intoxicated participants displayed an overall reduction in the use of cognitive control, based on both behavioural (flanker interference) and EEG (occipital alpha power) measures, groups did not differ in the degree to which this control was upregulated immediately after task errors. However, exploratory analyses of EEG indices (the feedback-related negativity and midfrontal theta power) of ACC activity following errors were significantly diminished in intoxicated participants. Overall, these findings suggest that alcohol does not reduce the immediate negative emotional consequences of errors but may instead disrupt brain networks needed for the sustained engagement of cognitive control and attention to task performance.</p>

Human freezing responses to virtual characters in immersive virtual reality are impacted by body expression, group affiliation and threat proximity

Social threat requires fast adaptive reactions. One prominent threat-coping behavior present in humans is freezing, of which heart rate deceleration and reduced postural mobility are two key components. Previous studies focused mainly on freezing reactions in rodents, but now virtual reality offers unique possibilities for controlled and ecologically valid lab-based experiments. Using immersive virtual reality, this study examined how several understudied aspects of social threat, i.e., emotional body expressions, group affiliation, and distance from the potential threat, affect freezing behavior in humans. Reduced heart rate and postural mobility were observed in participants when they faced aggressive-looking and proximal avatars. Freezing was also observed for ingroup aggression when participants were embodied in a black-skinned virtual body and faced black-skinned aggressive and proximal avatars. Our results, based on a highly ecological virtual reality paradigm, provide novel evidence on the social factors that elicit freezing behavior in humans.

Site-Specific Evolutionary Rate Shifts in HIV-1 and SIV

Site-specific evolutionary rate shifts are defined as protein sites, where the rate of substitution has changed dramatically across the phylogeny. With respect to a given clade, sites may either undergo a rate acceleration or a rate deceleration, reflecting a site that was conserved and became variable, or vice-versa, respectively. Sites displaying such a dramatic evolutionary change may point to a loss or gain of function at the protein site, reflecting adaptation, or they may indicate epistatic interactions among sites. Here, we analyzed full genomes of HIV and SIV-1 and identified 271 rate-shifting sites along the HIV-1/SIV phylogeny. The majority of rate shifts occurred at long branches, often corresponding to cross-species transmission branches. We noted that in most proteins, the number of rate accelerations and decelerations was equal, and we suggest that this reflects epistatic interactions among sites. However, several accessory proteins were enriched for either accelerations or decelerations, and we suggest that this may be a signature of adaptation to new hosts. Interestingly, the non-pandemic HIV-1 group O clade exhibited a substantially higher number of rate-shift events than the pandemic group M clade. We propose that this may be a reflection of the height of the species barrier between gorillas and humans versus chimpanzees and humans. Our results provide a genome-wide view of the constraints operating on proteins of HIV-1 and SIV.

The optimal anesthesia mothod for external cephalic version (ECV): a randomized controlled trial

Background: The aim of the study is to investigate the success rate of ECV and relevant complications with intrathecal analgesia for singleton breech pregnancy.Methods: Sixty pregnant women received obstetrical regular prenatal care were randomly divided into EA group( epidural anesthesia, n = 30), CSEA group( combined spinal-epidural anesthesia, n = 30), control group(no analgesia, n = 30). The primary outcome of our study was the success rate of ECV confirmed by ultrasound. Visual analogue scale,, the rate of cesarean section and relevant side effect were recorded.Results: The success rate of spontaneous inversion to cephalic version was 76.7% in EA group, which was higher than that in CSEA group (53.3%) and control group (46.7%) (p = 0.058 and p = 0.017, respectively). The rate of cesarean section in EA group was 33.3%, which was also lower than that in CSEA group (53.3%) and control group (50.0%), however, the difference was not statistically significant between CSEA group and EA group(p = 0. 19). The VAS scores in the EA group and the spinal group were respectively 1.87 ± 2.94 and 1.73 ± 2.71 ,obviously better than that of the control group (6.84 ± 3.08) (p = 0.001 and p = 0.001).It was no significant difference between EA group and Control group ( p = 0. 118). The incidence of hypotension, nausea and vomiting, and fetal heart rate deceleration in CSEA group was significantly higher than that in control group (p = 0.000, p = 0.161, p = 0.129). The occurrence rate of spontaneous fetal heart rate deceleration in the EA, CSEA and control group were 6.7%, 20% and 6.7%, respectively, the differences were not statistically significant.Conclusions: EA can be more effective to enhance the success rate of spontaneous inversion to cephalic version than CSEA, and CSEA is accompanied with more side effects. Meanwhile, EA or CSEA don’t affect the rate of cesarean section of ECV for breech single pregnancy. (Registration number: ChiCTR1800017124)Trial registration: Name of the registry: Comparison of epidural analgesia with dexmedetomidine or sufentanil combined with ropivacaine: an observational study of multi-center ; Trial registration number: ChiCTR1800017124; Date of registration: 07-13-2018; URL of trial registry record: http://www.chictr.org.cn/edit.aspx?pid=29087&htm=4

Examining the Causal Effects of Sleep Deprivation on Emotion Regulation and Its Neural Mechanisms

Cognitive reappraisal (CR) is a strategy used to regulate emotions that is thought to be effective but effortful, relying on higher-order cognitive control systems to engage in active regulation. Sleep deprivation is believed to impair the functioning of these control systems, suggesting that it may impede the ability to implement CR effectively. This study tested the causal effects of sleep deprivation on emotional reactivity and the neurobiological systems underlying CR. We employed a within-subject crossover design in which participants underwent fMRI scanning twice, once when fully rested and once after a night of total sleep deprivation. During scans, participants passively viewed or used CR to down-regulate their emotional response to negative and neutral images. Contrary to hypotheses, both self-reported negative affect ratings and neural responses to the images indicated no difference in the way participants implemented CR when sleep deprived and when fully rested. Meanwhile, neural regions that showed distinct reactivity responses to negative relative to neutral images lost this specificity under deprived conditions. Negative affect ratings and heart rate deceleration, a physiological response typically evoked by aversive pictures, exhibited a similar blunting. Together, these results suggest that, although sleep deprivation may reduce the discrimination between emotional reactivity responses to negative and neutral stimuli, it does not impact CR the way it is presently studied.

Hysteresis in calcium rhythm patterns during electric field stimulation of cardiac tissue

Cardiac tissue subjected to fast pacing via electric field stimulation revealed hysteresis in calcium instability patterns (stimulus:response patterns) beyond departure and return to 1:1 response. The pacing frequency at which the first appearance of instabilities occurred (Fa) was higher than the frequency of ultimate disappearance (Fd) upon rate deceleration. Furthermore, hysteresis was observed in multiple pattern transitions. In the spatially extended system studied here, 2:2 alternans were the preferred starting point (Fa) in calcium instability development, while 2:1 blocks were more common in the return to Fa from higher pacing rates. Recovery of 1:1 patterns was preceded mostly by 2:2 alternans at Fd. In addition to previously reported hysteresis in action potential duration during 1:1 rhythm and alternans magnitude hysteresis (in 2:2 rhythm), our data reveal hysteresis in rhythm pattern transitions not just away from and return to 1:1, but also between different instability patterns, and thus provide insight into the rules of such transitions in electrically stimulated cardiac tissue.