- Long-term dynamics of mind wandering: ultradian rhythms in thought generation. [Journal Article]
- NCNeurosci Conscious 2019; 2019(1):niz007
- Using the method of experience sampling, we studied the fluctuations in thought generation and cognitive control strength during the wakeful hours of the day, centered around episodes of mind wanderi…
Using the method of experience sampling, we studied the fluctuations in thought generation and cognitive control strength during the wakeful hours of the day, centered around episodes of mind wandering. Thought generation, measured in terms of the number of thoughts that concurrently occupy the mind at sampling time, goes through regular 4-6 h cycles, suggesting the mind operates with an alternation of focused and multitasking modes. Cognitive control strength rises and falls in relative coordination with thought generation, implying that both are occasionally misaligned. This happens, in particular, when cognitive control suddenly drops after having been keeping up with a cycle of thought generation. When this drop occurs while the thought generation cycle is still up, mind wandering appears. As cognitive control quickly resumes before returning to intermediate values, the thought generation cycle begins to fall again, and the mind wandering episode comes to an end. Implications regarding the role of long-term regulation in mind-wandering processes are discussed.
- Neuroimaging Studies on Disorders of Consciousness: A Meta-Analytic Evaluation. [Journal Article]
- JCJ Clin Med 2019 Apr 16; 8(4)
- Neuroimaging tools could open a window on residual neurofunctional activity in the absence of detectable behavioural responses in patients with disorders of consciousness (DOC). Nevertheless, the lit…
Neuroimaging tools could open a window on residual neurofunctional activity in the absence of detectable behavioural responses in patients with disorders of consciousness (DOC). Nevertheless, the literature on this topic is characterised by a large heterogeneity of paradigms and methodological approaches that can undermine the reproducibility of the results. To explicitly test whether task-related functional magnetic resonance imaging (fMRI) can be used to systematically detect neurofunctional differences between different classes of DOC, and whether these differences are related with a specific category of cognitive tasks (either active or passive), we meta-analyzed 22 neuroimaging studies published between 2005 and 2017 using the Activation Likelihood Estimate method. The results showed that: (1) active and passive tasks rely on well-segregated patterns of activations; (2) both unresponsive wakeful syndrome and patients in minimally conscious state activated a large portion of the dorsal-attentional network; (3) shared activations between patients fell mainly in the passive activation map (7492 voxels), while only 48 voxels fell in a subcortical region of the active-map. Our results suggest that DOCs can be described along a continuum-rather than as separated clinical categories-and characterised by a widespread dysfunction of brain networks rather than by the impairment of a well functionally anatomically defined one.
- Benefit of wakeful resting on gist and peripheral memory retrieval in healthy younger and older adults. [Journal Article]
- NLNeurosci Lett 2019 07 13; 705:27-32
- Retrieval is greater if new learning is followed by a period of wakeful rest, minimising the likelihood of retroactive interference. It is not known if this benefit extends to recollection of both gi…
Retrieval is greater if new learning is followed by a period of wakeful rest, minimising the likelihood of retroactive interference. It is not known if this benefit extends to recollection of both gist and peripheral details, nor whether age affects the benefit of wakeful resting in either of these types of recollection. Forty-five younger and forty older adults were presented with prose passages for later recall followed by a period of either interference or wakeful resting. Younger participants outperformed older participants in remembering peripheral details, but not on gist memory. Wakeful resting led to higher overall recollection in both age groups, both for gist and for peripheral details. Also, wakeful resting was more beneficial for gist than peripheral memory in older but not younger adults. We discuss these novel findings and their theoretical implications for a memory consolidation account of the benefits of wakeful resting.
- Global music streaming data reveal diurnal and seasonal patterns of affective preference. [Journal Article]
- NHNat Hum Behav 2019; 3(3):230-236
- People manage emotions to cope with life's demands1,2. Previous research has identified affective patterns using self-reports3 and text analysis4,5, but these measures track the expression of affect,…
People manage emotions to cope with life's demands1,2. Previous research has identified affective patterns using self-reports3 and text analysis4,5, but these measures track the expression of affect, not affective preference for external stimuli such as music, which affects mood states and levels of emotional arousal1,6,7. We analysed a dataset of 765 million online music plays streamed by 1 million individuals in 51 countries to measure diurnal and seasonal patterns of affective preference. Findings reveal similar diurnal patterns across cultures and demographic groups. Individuals listen to more relaxing music late at night and more energetic music during normal business hours, including mid-afternoon when affective expression is lowest. However, there were differences in baselines: younger people listen to more intense music; compared with other regions, music played in Latin America is more arousing, while music in Asia is more relaxing; and compared with other chronotypes, 'night owls' (people who are habitually active or wakeful at night) listen to less-intense music. Seasonal patterns vary with distance from the equator and between Northern and Southern hemispheres and are more strongly correlated with absolute day length than with changes in day length. Taken together with previous findings on affective expression in text4, these results suggest that musical choice both shapes and reflects mood.
- Device-measured physical activity, sedentary behaviour and cardiometabolic health and fitness across occupational groups: a systematic review and meta-analysis. [Review]
- IJInt J Behav Nutr Phys Act 2019 04 02; 16(1):30
- CONCLUSIONS: This review identifies that occupational and wakeful time PA and ST differed between occupations. Future studies are needed to assess whether patterns differ by age and sex, describe leisure-time movement and movement patterns, and the relationship with cardiometabolic health.
- Escape From Oblivion: Neural Mechanisms of Emergence From General Anesthesia. [Journal Article]
- A&AAnesth Analg 2019; 128(4):726-736
- The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic underst…
The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic understanding of emergence. Once assumed to be a purely passive process, spontaneously occurring as residual levels of anesthetics dwindle below a critical value, emergence from general anesthesia has been reconsidered as an active and controllable process. Emergence is driven by mechanisms that can be distinct from entry to the anesthetized state. In this narrative review, we focus on the burgeoning scientific understanding of anesthetic emergence, summarizing current knowledge of the neurotransmitter, neuromodulators, and neuronal groups that prime the brain as it prepares for its journey back from oblivion. We also review evidence for possible strategies that may actively bias the brain back toward the wakeful state.
- Daytime Central Thalamic Deep Brain Stimulation Modulates Sleep Dynamics in the Severely Injured Brain: Mechanistic Insights and a Novel Framework for Alpha-Delta Sleep Generation. [Journal Article]
- FNFront Neurol 2019; 10:20
- Loss of organized sleep electrophysiology is a characteristic finding following severe brain injury. The return of structured elements of sleep architecture has been associated with positive prognosi…
Loss of organized sleep electrophysiology is a characteristic finding following severe brain injury. The return of structured elements of sleep architecture has been associated with positive prognosis across injury etiologies, suggesting a role for sleep dynamics as biomarkers of wakeful neuronal circuit function. In a continuing study of one minimally conscious state patient studied over the course of ~8½ years, we sought to investigate whether changes in daytime brain activation induced by central thalamic deep brain stimulation (CT-DBS) influenced sleep electrophysiology. In this patient subject, we previously reported significant improvements in sleep electrophysiology during 5½ years of CT-DBS treatment, including increased sleep spindle frequency and SWS delta power. We now present novel findings that many of these improvements in sleep electrophysiology regress following CT-DBS discontinuation; these regressions in sleep features correlate with a significant decrease in behavioral responsiveness. We also observe the re-emergence of alpha-delta sleep, which had been previously suppressed by daytime CT-DBS in this patient subject. Importantly, CT-DBS was only active during the daytime and has been proposed to mediate recovery of consciousness by driving synaptic activity across frontostriatal systems through the enhancement of thalamocortical output. Accordingly, the improvement of sleep dynamics during daytime CT-DBS and their subsequent regression following CT-DBS discontinuation implicates wakeful synaptic activity as a robust modulator of sleep electrophysiology. We interpret these findings in the context of the "synaptic homeostasis hypothesis," whereby we propose that daytime upregulation of thalamocortical output in the severely injured brain may facilitate organized frontocortical circuit activation and yield net synaptic potentiation during wakefulness, providing a homeostatic drive that reconstitutes sleep dynamics over time. Furthermore, we consider common large-scale network dynamics across several neuropsychiatric disorders in which alpha-delta sleep has been documented, allowing us to formulate a novel mechanistic framework for alpha-delta sleep generation. We conclude that the bi-directional modulation of sleep electrophysiology by daytime thalamocortical activity in the severely injured brain: (1) emphasizes the cyclical carry-over effects of state-dependent circuit activation on large-scale brain dynamics, and (2) further implicates sleep electrophysiology as a sensitive indicator of wakeful brain activation and covert functional recovery in the severely injured brain.
- Subthalamic and pallidal oscillatory activity in patients with Neurodegeneration with Brain Iron Accumulation type I (NBIA-I). [Journal Article]
- CNClin Neurophysiol 2019; 130(4):469-473
- CONCLUSIONS: Here we show for the first time the oscillatory activity pattern in the STN and the GPi in juvenile patients with dystonia plus syndrome due to NBIA-I. The low frequency peak we found is in line with previous studies in patients with isolated idiopathic dystonia. In our cohort, the pallidal beta band activity may be related to more severe motor slowing in dystonia plus syndrome such as NBIA-I.Our results further support the link between hyperkinetic motor symptoms such as dystonia and enhanced basal ganglia low frequency activity irrespective of the underlying etiology of dystonia.
- Impact of Paralytic Agent on Postintubation Sedation. [Journal Article]
- AMAir Med J 2019 Jan - Feb; 38(1):39-44
- CONCLUSIONS: This study suggests rocuronium's long duration of effect puts patients at risk for wakeful paralysis once the short effects of etomidate have subsided.
New Search Next
- Is using nanosilver mattresses/pillows safe? A review of potential health implications of silver nanoparticles on human health. [Review]
- EGEnviron Geochem Health 2019 Jan 22
- Human exposure to engineered nanoparticles has become inevitable in today's extensive commercial use and large-scale production of engineered nanoparticles. Even though several studies have character…
Human exposure to engineered nanoparticles has become inevitable in today's extensive commercial use and large-scale production of engineered nanoparticles. Even though several studies have characterised the exposure to nanomaterials during wakeful state (related to occupational exposures and exposures from commercially available particles), very few studies on human exposure during sleep exist. As the study of exposure to all possible nanomaterials during sleep is extensive, this study focuses on exposure to specifically silver nanoparticles which are present in beddings and mattresses. The reasoning behind the use of silver nanoparticles in bedding and related materials, possible routes of entry to various population groups in several sleep positions, exposure characterisation and toxicity potential of such silver nanoparticles are reviewed in this study. The toxicity potential of silver nanoparticles in vivo tests with relation to mammals and in vitro tests on human cells has been tabulated to understand the risks associated during oral, dermal and inhalation exposure to silver nanoparticles. The exposure to humans with regard to dermal absorption and oral intake has been summarised. Although potential inhalation exposure to silver nanoparticles is increasing, only a few studies address the possible toxic effect of inhaled silver particles. Determination of exposure to silver nanoparticles in beddings is a topic that has been less researched, and this review aims to provide background information for future research and help establish a comprehensive risk assessment during sleep in the times of increasing usage of nanoparticles in our daily activities. Despite the current limitations of our understanding, risk assessments must utilise the available data and apply extrapolation procedures in the face of uncertainty, in order to address the needs of regulatory programs. This would enable safe use of the antimicrobial properties of silver nanoparticles without negatively impacting human health. Until then, it would be better to adopt a conservative approach on the usage of silver nanoparticles in daily used commercial items.