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Noreika, V., Windt, J. M., Kern, M., Valli, K., Salonen, T., Parkkola, R., . . . Lenggenhager, B. (2020). Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement. Scientific Reports, 10(1), Article ID 6735.
Open this publication in new window or tab >>Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement
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2020 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 10, no 1, article id 6735Article in journal (Refereed) Published
Abstract [en]

Recently, cortical correlates of specific dream contents have been reported, such as the activation of the sensorimotor cortex during dreamed hand clenching. Yet, despite a close resemblance of such activation patterns to those seen during the corresponding wakeful behaviour, the causal mechanisms underlying specific dream contents remain largely elusive. Here, we aimed to investigate the causal role of the sensorimotor cortex in generating movement and bodily sensations during REM sleep dreaming. Following bihemispheric transcranial direct current stimulation (tDCS) or sham stimulation, guided by functional mapping of the primary motor cortex, naive participants were awakened from REM sleep and responded to a questionnaire on bodily sensations in dreams. Electromyographic (EMG) and electroencephalographic (EEG) recordings were used to quantify physiological changes during the preceding REM period. We found that tDCS, compared to sham stimulation, significantly decreased reports of dream movement, especially of repetitive actions. Other types of bodily experiences, such as tactile or vestibular sensations, were not affected by tDCS, confirming the specificity of stimulation effects to movement sensations. In addition, tDCS reduced EEG interhemispheric coherence in parietal areas and affected the phasic EMG correlation between both arms. These findings show that a complex temporal reorganization of the motor network co-occurred with the reduction of dream movement, revealing a link between central and peripheral motor processes and movement sensations of the dream self. tDCS over the sensorimotor cortex interferes with dream movement during REM sleep, which is consistent with a causal contribution to dream experience and has broader implications for understanding the neural basis of self-experience in dreams. © 2020, The Author(s).

Place, publisher, year, edition, pages
Springer, 2020
Keywords
adult, article, brain depth stimulation, controlled study, dreaming, female, human, human experiment, male, primary motor cortex, questionnaire, REM sleep, sensation, sensorimotor cortex, transcranial direct current stimulation
National Category
Neurosciences Psychology (excluding Applied Psychology)
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-18428 (URN)10.1038/s41598-020-63479-6 (DOI)32317714 (PubMedID)2-s2.0-85083765668 (Scopus ID)
Available from: 2020-05-07 Created: 2020-05-07 Last updated: 2020-05-08
Sikka, P., Revonsuo, A., Noreika, V. & Valli, K. (2019). EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations Over the Right Frontal Cortex During REM Sleep and Pre-Sleep Wakefulness Predict Anger in REM Sleep Dreams. Journal of Neuroscience, 39(24), 4775-4784, Article ID 2884-18.
Open this publication in new window or tab >>EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations Over the Right Frontal Cortex During REM Sleep and Pre-Sleep Wakefulness Predict Anger in REM Sleep Dreams
2019 (English)In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 39, no 24, p. 4775-4784, article id 2884-18Article in journal (Refereed) Published
Abstract [en]

Affective experiences are central not only to our waking life but also to rapid eye movement(REM) sleep dreams. Despite our increasing understanding of the neural correlates of dreaming, we know little about the neural correlates of dream affect. Frontal alpha asymmetry (FAA) is considered a marker of affective states and traits as well as affect regulation in the waking state. Here, we explored whether FAA during REM sleep and during evening resting wakefulness is related to affective experiences in REM sleep dreams. EEG recordings were obtained from 17humanparticipants (7men)whospent 2 nights in the sleep laboratory. Participants were awakened 5minafter the onset of everyREMstage after which they provided a dream report and rated their dream affect. Two-minute preawakening EEG segments were analyzed. Additionally, 8 min of evening presleep and morning postsleep EEG were recorded during resting wakefulness. Mean spectral power in the alpha band (8 –13 Hz and correspondingFAAwere calculated over the frontal (F4-F3) sites. Results showed that FAA during REM sleep, and during evening resting wakefulness, predicted ratings of dream anger. This suggests that individuals with greater alpha power in the right frontal hemisphere may be less able to regulate (i.e., inhibit) strong affective states, such as anger, in dreams. Additionally, FAA was positively correlated across wakefulness and REM sleep. Together, these findings imply that FAA may serve as a neural correlate of affect regulation not only in the waking but also in the dreaming state.

Place, publisher, year, edition, pages
Society for Neuroscience, 2019
Keywords
anger, dreaming, emotions, frontal alpha asymmetry, REM sleep
National Category
Natural Sciences Psychology
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16892 (URN)10.1523/JNEUROSCI.2884-18.2019 (DOI)000471130300011 ()30988168 (PubMedID)2-s2.0-85068196629 (Scopus ID)
Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2020-03-03Bibliographically approved
Kallionpää, R. E., Pesonen, H., Scheinin, A., Sandman, N., Laitio, R., Scheinin, H., . . . Valli, K. (2019). Single-subject analysis of N400 event-related potential component with five different methods. International Journal of Psychophysiology, 144, 14-24
Open this publication in new window or tab >>Single-subject analysis of N400 event-related potential component with five different methods
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2019 (English)In: International Journal of Psychophysiology, ISSN 0167-8760, E-ISSN 1872-7697, Vol. 144, p. 14-24Article in journal (Refereed) Published
Abstract [en]

There are several different approaches to analyze event-related potentials (ERPs) at single-subject level, and the aim of the current study is to provide information for choosing a method based on its ability to detect ERP effects and factors influencing the results. We used data from 79 healthy participants with EEG referenced to mastoid average and investigated the detection rate of auditory N400 effect in single-subject analysis using five methods: visual inspection of participant-wise averaged ERPs, analysis of variance (ANOVA) for amplitude averages in a time window, cluster-based non-parametric testing, a novel Bayesian approach and Studentized continuous wavelet transform (t-CWT). Visual inspection by three independent raters yielded N400 effect detection in 85% of the participants in at least one paradigm (active responding or passive listening), whereas ANOVA identified the effect in 68%, the cluster-method in 59%, the Bayesian method in 89%, and different versions of t-CWT in 22–59% of the participants. Thus, the Bayesian method was the most liberal and also showed the greatest concordance between the experimental paradigms (active/passive). ANOVA detected significant effect only in cases with converging evidence from other methods. The t-CWT and cluster-based method were the most conservative methods. As we show in the current study, different analysis methods provide results that do not completely overlap. The method of choice for determining the presence of an ERP component at single-subject level thus remains unresolved. Relying on a single statistical method may not be sufficient for drawing conclusions on single-subject ERPs. 

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Data analysis, Electroencephalography, Event-related potentials, N400 evoked potential, Statistical data interpretation, adult, analysis of variance, article, continuous wavelet transform, controlled study, drawing, electroencephalogram, event related potential, evoked response, female, human, human experiment, major clinical study, male, mastoid
National Category
Neurosciences
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-17539 (URN)10.1016/j.ijpsycho.2019.06.012 (DOI)000488144500003 ()31228496 (PubMedID)2-s2.0-85070079873 (Scopus ID)
Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-11-08Bibliographically approved
Tuominen, J., Peltola, K., Saaresranta, T. & Valli, K. (2019). Sleep Parameter Assessment Accuracy of a Consumer Home Sleep Monitoring Ballistocardiograph Beddit Sleep Tracker: A Validation Study. Journal of Clinical Sleep Medicine (JCSM), 15(3), 483-487, Article ID PII jc-18-00561.
Open this publication in new window or tab >>Sleep Parameter Assessment Accuracy of a Consumer Home Sleep Monitoring Ballistocardiograph Beddit Sleep Tracker: A Validation Study
2019 (English)In: Journal of Clinical Sleep Medicine (JCSM), ISSN 1550-9389, E-ISSN 1550-9397, Vol. 15, no 3, p. 483-487, article id PII jc-18-00561Article in journal (Refereed) Published
Abstract [en]

Study Objectives: Growing interest in monitoring sleep and well-being has created a market for consumer home sleep monitoring devices. Additionally, sleep disorder diagnostics, and sleep and dream research would benefit from reliable and valid home sleep monitoring devices. Yet, majority of currently available home sleep monitoring devices lack validation. In this study, the sleep parameter assessment accuracy of Beddit Sleep Tracker (BST), an unobtrusive and non-wearable sleep monitoring device based on ballistocardiography, was evaluated by comparing it with polysomnography (PSG) measures. We measured total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE). Additionally, we examined whether BST can differentiate sleep stages. Methods: We performed sleep studies simultaneously with PSG and BST in ten healthy young adults (5 female/5 male) during two non-consecutive nights in a sleep laboratory. Results: BST was able to distinguish SOL with some accuracy. However, it underestimated WASO and thus overestimated TST and SE. Also, it failed to discriminate between non-rapid eye movement sleep stages and did not detect the rapid eye movement sleep stage. Conclusions: These findings indicate that BST is not a valid device to monitor sleep. Consumers should be careful in interpreting the conclusions on sleep quality and efficiency provided by the device.

Place, publisher, year, edition, pages
American Academy of Sleep Medicine, 2019
Keywords
Beddit Sleep Tracker, validation, polysomnography, sleep parameter accuracy, sleep research methods
National Category
Psychology (excluding Applied Psychology)
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16730 (URN)10.5664/jcsm.7682 (DOI)000461417900016 ()30853052 (PubMedID)2-s2.0-85063615931 (Scopus ID)
Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2020-03-11Bibliographically approved
Tuominen, J., Stenberg, T., Revonsuo, A. & Valli, K. (2019). Social contents in dreams: An empirical test of the Social Simulation Theory. Consciousness and Cognition, 69, 133-145
Open this publication in new window or tab >>Social contents in dreams: An empirical test of the Social Simulation Theory
2019 (English)In: Consciousness and Cognition, ISSN 1053-8100, E-ISSN 1090-2376, Vol. 69, p. 133-145Article in journal (Refereed) Published
Abstract [en]

Social Simulation Theory (SST) considers the function of dreaming to be the simulation of social events. The Sociality Bias and the Strengthening hypotheses of SST were tested. Social Content Scale (SCS) was developed to quantify social events. Additionally, we attempted to replicate a previous finding (McNamara et al., 2005, Psychological Science) of REM dreams as predisposed to aggressive, and NREM dreams to prosocial interactions. Further, we investigated the frequency and quality of interactions in late vs early REM and NREM dreams. Data consisted of wake, REM and NREM home dream reports (N = 232, 116, 116, respectively) from 15 students. Dreams overrepresented social events compared to wake reports, supporting the Sociality Bias hypothesis. However, the Strengthening Hypothesis was not supported. We weren't able to replicate the McNamara et al. finding, and no time of night effect was found. While SST gained partial support, further research on social contents in dreams is required. © 2019 Elsevier Inc.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Continuity hypothesis, Dreaming, Functions of dreaming, NREM sleep, REM sleep, Social simulation theory, Sleep, Social Cognition
National Category
Psychology (excluding Applied Psychology)
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16654 (URN)10.1016/j.concog.2019.01.017 (DOI)000460197200011 ()30769273 (PubMedID)2-s2.0-85061351162 (Scopus ID)
Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2020-03-11Bibliographically approved
Blagrove, M., Hale, S., Lockheart, J., Carr, M., Jones, A. & Valli, K. (2019). Testing the Empathy Theory of Dreaming: The Relationships Between Dream Sharing and Trait and State Empathy. Frontiers in Psychology, 10, Article ID 1351.
Open this publication in new window or tab >>Testing the Empathy Theory of Dreaming: The Relationships Between Dream Sharing and Trait and State Empathy
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2019 (English)In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 10, article id 1351Article in journal (Refereed) Published
Abstract [en]

In general, dreams are a novel but realistic simulation of waking social life, with a mixture of characters, motivations, scenarios, and positive and negative emotions. We propose that the sharing of dreams has an empathic effect on the dreamer and on significant others who hear and engage with the telling of the dream. Study 1 tests three correlations that are predicted by the theory of dream sharing and empathy: that trait empathy will be correlated with frequency of telling dreams to others, with frequency of listening to others’ dreams, and with trait attitude toward dreams (ATD) (for which higher scores indicate positive attitude). 160 participants completed online the Toronto Empathy Questionnaire and the Mannheim Dream Questionnaire. Pearson partial correlations were conducted, with age and sex partialled out. Trait empathy was found to be significantly associated with the frequency of listening to the dreams of others, frequency of telling one’s own dreams to others, and attitude toward dreams. Study 2 tests the effects of discussing dreams on state empathy, using an adapted version of the Shen (2010) state empathy scale, for 27 pairs of dream sharers and discussers. Dream discussion followed the stages of the Ullman (1996) dream appreciation technique. State empathy of the dream discusser toward the dream sharer was found to increase significantly as a result of the dream discussion, with a medium effect size, whereas the dream sharer had a small decrease in empathy toward the discusser. A proposed mechanism for these associations and effects is taken from the robust findings in the literature that engagement with literary fiction can induce empathy toward others. We suggest that the dream acts as a piece of fiction that can be explored by the dreamer together with other people, and can thus induce empathy about the life circumstances of the dreamer. We discuss the speculation that the story-like characteristics of adult human dreams may have been selected for in human evolution, including in sexual selection, as part of the selection for emotional intelligence, empathy, and social bonding.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
dreaming, empathy, social simulation, dream sharing, human bonding, human evolution and behavior, human consciousness, consciousness
National Category
Psychology (excluding Applied Psychology)
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-17406 (URN)10.3389/fpsyg.2019.01351 (DOI)000472153100001 ()2-s2.0-85068710538 (Scopus ID)
Available from: 2019-07-08 Created: 2019-07-08 Last updated: 2019-11-08Bibliographically approved
Kallioinen, M., Scheinin, A., Maksimow, M., Långsjö, J., Kaisti, K., Takala, R., . . . Maksimow, A. (2019). The influence of dexmedetomidine and propofol on circulating cytokine levels in healthy subjects. BMC Anesthesiology, 19(1), 1-8, Article ID 222.
Open this publication in new window or tab >>The influence of dexmedetomidine and propofol on circulating cytokine levels in healthy subjects
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2019 (English)In: BMC Anesthesiology, ISSN 1471-2253, E-ISSN 1471-2253, Vol. 19, no 1, p. 1-8, article id 222Article in journal (Refereed) Published
Abstract [en]

Background: Surgery and diseases modify inflammatory responses and the immune system. Anesthetic agents also have effects on the human immune system but the responses they induce may be altered or masked by the surgical procedures or underlying illnesses. The aim of this study was to assess how single-drug dexmedetomidine and propofol anesthesia without any surgical intervention alter acute immunological biomarkers in healthy subjects. Methods: Thirty-five healthy, young male subjects were anesthetized using increasing concentrations of dexmedetomidine (n = 18) or propofol (n = 17) until loss of responsiveness (LOR) was detected. The treatment allocation was randomized. Multi-parametric immunoassays for the detection of 48 cytokines, chemokines and growth factors were used. Concentrations were determined at baseline and at the highest drug concentration for each subject. Results: The changes in the concentration of eotaxin (decrease after dexmedetomidine) and platelet-derived growth factor (PDGF, increase after propofol) were statistically significantly different between the groups. Significant changes were detected within both groups; the concentrations of monocyte chemotactic protein 1, chemokine ligand 27 and macrophage migration inhibitory factor were lower in both groups after the drug administration. Dexmedetomidine decreased the concentration of eotaxin, interleukin-18, interleukin-2Ra, stem cell factor, stem cell growth factor and vascular endothelial growth factor, and propofol decreased significantly the levels of hepatocyte growth factor, IFN-.-induced protein 10 and monokine induced by IFN-gamma, and increased the levels of interleukin-17, interleukin-5, interleukin-7 and PDGF. Conclusions: Dexmedetomidine seemed to have an immunosuppressive effect on the immune system whereas propofol seemed to induce mixed pro- and anti-inflammatory effects on the immune system. The choice of anesthetic agent could be relevant when treating patients with compromised immunological defense mechanisms. Trial registration: Before subject enrollment, the study was registered in the European Clinical Trials database (EudraCT number 2013-001496-21, The Neural Mechanisms of Anesthesia and Human Consciousness) and in ClinicalTrials.gov (Principal Investigator: Harry Scheinin, number NCT01889004, The Neural Mechanisms of Anesthesia and Human Consciousness, Part 2, on the 23rd of June 2013).

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Dexmedetomidine, Propofol, Immunology, Immunosuppression, Cytokines
National Category
Other Medical Sciences not elsewhere specified Anesthesiology and Intensive Care
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-18204 (URN)10.1186/s12871-019-0895-3 (DOI)000510509600002 ()31805854 (PubMedID)2-s2.0-85076141319 (Scopus ID)
Available from: 2020-02-17 Created: 2020-02-17 Last updated: 2020-04-22Bibliographically approved
Grassini, S., Railo, H., Valli, K., Revonsuo, A. & Koivisto, M. (2019). Visual features and perceptual context modulate attention towards evolutionarily relevant threatening stimuli: Electrophysiological evidence. Emotion, 19(2), 348-364
Open this publication in new window or tab >>Visual features and perceptual context modulate attention towards evolutionarily relevant threatening stimuli: Electrophysiological evidence
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2019 (English)In: Emotion, ISSN 1528-3542, E-ISSN 1931-1516, Vol. 19, no 2, p. 348-364Article in journal (Refereed) Published
Abstract [en]

The snake detection hypothesis claims that predatory pressure from snakes has shaped the primate visual system, but we still know very little about how the brain processes evolutionarily important visual cues, and which factors are crucial for quick detection of snakes. We investigated how visual features modulate the electrophysiological markers of early attentional processes. In Experiment 1, we compared snake, rope, gun, and bird images to isolate the effects due to curvilinearity of the stimuli. The results showed that both snake and rope images elicited enhanced P1 and N1 event-related potential components as well as early posterior negativity (EPN). In Experiment 2, we studied whether nonthreatening curvilinear images (i.e., ropes) still elicit the enhanced electrophysiological responses when snake images are not presented as stimuli, and therefore the context does not provoke top-down attention to curvilinear shapes. Rope images still evoked an enhanced EPN, suggesting that curvilinear shapes are preferably captured by attentional processes. However, this effect was smaller than in Experiment 1, in which snake images were present. Thus, our results hint to the possibility that the perceptual context may interact with processing of shape information, drawing attention to curvilinear shapes when the presence of snakes is expectable. Furthermore, we observed that spatial frequency of the visual stimuli modulated especially the early electrophysiological responses, and decreased the differences between stimulus categories in EPN without completely eliminating them. The findings suggest that low-level and high-level mechanisms interact to give an attentional priority to potentially threatening stimuli.

Place, publisher, year, edition, pages
American Psychological Association (APA), 2019
Keywords
Evolution psychology, ERP
National Category
Behavioral Sciences Biology
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-15100 (URN)10.1037/emo0000434 (DOI)000458951400014 ()29578746 (PubMedID)2-s2.0-85044303603 (Scopus ID)
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2019-03-07Bibliographically approved
Laaksonen, L., Kallioinen, M., Långsjö, J., Laitio, T., Scheinin, A., Scheinin, J., . . . Scheinin, H. (2018). Comparative effects of dexmedetomidine, propofol, sevoflurane, and S-ketamine on regional cerebral glucose metabolism in humans: a positron emission tomography study. Paper presented at 10th International Symposium on Memory and Awareness in Anesthesia (MAA), Helsinki, Finland, June 19-21, 2017. British Journal of Anaesthesia, 121(1), 281-290
Open this publication in new window or tab >>Comparative effects of dexmedetomidine, propofol, sevoflurane, and S-ketamine on regional cerebral glucose metabolism in humans: a positron emission tomography study
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2018 (English)In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 121, no 1, p. 281-290Article in journal (Refereed) Published
Abstract [en]

IntroductionThe highly selective α2-agonist dexmedetomidine has become a popular sedative for neurointensive care patients. However, earlier studies have raised concern that dexmedetomidine might reduce cerebral blood flow without a concomitant decrease in metabolism. Here, we compared the effects of dexmedetomidine on the regional cerebral metabolic rate of glucose (CMRglu) with three commonly used anaesthetic drugs at equi-sedative doses.

MethodsOne hundred and sixty healthy male subjects were randomised to EC50 for verbal command of dexmedetomidine (1.5 ng ml−1n=40), propofol (1.7 μg ml−1n=40), sevoflurane (0.9% end-tidal; n=40) or S-ketamine (0.75 μg ml−1n=20) or placebo (n=20). Anaesthetics were administered using target-controlled infusion or vapouriser with end-tidal monitoring. 18F-labelled fluorodeoxyglucose was administered 20 min after commencement of anaesthetic administration, and high-resolution positron emission tomography with arterial blood activity samples was used to quantify absolute CMRglu for whole brain and 15 brain regions.

ResultsAt the time of [F18]fluorodeoxyglucose injection, 55% of dexmedetomidine, 45% of propofol, 85% of sevoflurane, 45% of S-ketamine, and 0% of placebo subjects were unresponsive. Whole brain CMRglu was 63%, 71%, 71%, and 96% of placebo in the dexmedetomidine, propofol, sevoflurane, and S-ketamine groups, respectively (P<0.001 between the groups). The lowest CMRglu was observed in nearly all brain regions with dexmedetomidine (P<0.05 compared with all other groups). With S-ketamine, CMRgludid not differ from placebo.

ConclusionsAt equi-sedative doses in humans, potency in reducing CMRglu was dexmedetomidine>propofol>ketamine=placebo. These findings alleviate concerns for dexmedetomidine-induced vasoconstriction and cerebral ischaemia.

National Category
Other Medical Sciences not elsewhere specified
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-15615 (URN)10.1016/j.bja.2018.04.008 (DOI)000439025500072 ()29935583 (PubMedID)2-s2.0-85046622088 (Scopus ID)
Conference
10th International Symposium on Memory and Awareness in Anesthesia (MAA), Helsinki, Finland, June 19-21, 2017
Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2019-11-19Bibliographically approved
Scheinin, A., Kallionpää, R. E., Li, D., Kallioinen, M., Kaisti, K., Långsjö, J., . . . Scheinin, H. (2018). Differentiating Drug-related and State-related Effects of Dexmedetomidine and Propofol on the Electroencephalogram. Anesthesiology, 129(1), 22-36
Open this publication in new window or tab >>Differentiating Drug-related and State-related Effects of Dexmedetomidine and Propofol on the Electroencephalogram
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2018 (English)In: Anesthesiology, ISSN 0003-3022, E-ISSN 1528-1175, Vol. 129, no 1, p. 22-36Article in journal (Refereed) Published
Abstract [en]

BACKGROUND

Differentiating drug-related changes and state-related changes on the electroencephalogram during anesthetic-induced unconsciousness has remained a challenge. To distinguish these, we designed a rigorous experimental protocol with two drugs known to have distinct molecular mechanisms of action. We hypothesized that drug- and state-related changes can be separated.

METHODS: 

Forty-seven healthy participants were randomized to receive dexmedetomidine (n = 23) or propofol (n = 24) as target-controlled infusions until loss of responsiveness. Then, an attempt was made to arouse the participant to regain responsiveness while keeping the drug infusion constant. Finally, the concentration was increased 1.5-fold to achieve presumable loss of consciousness. We conducted statistical comparisons between the drugs and different states of consciousness for spectral bandwidths, and observed how drug-induced electroencephalogram patterns reversed upon awakening. Cross-frequency coupling was also analyzed between slow-wave phase and alpha power.

RESULTS: 

Eighteen (78%) and 10 (42%) subjects were arousable during the constant drug infusion in the dexmedetomidine and propofol groups, respectively (P = 0.011 between the drugs). Corresponding with deepening anesthetic level, slow-wave power increased, and a state-dependent alpha anteriorization was detected with both drugs, especially with propofol. Negative phase-amplitude coupling before and during loss of responsiveness frontally and positive coupling during the highest drug concentration posteriorly were observed in the propofol but not in the dexmedetomidine group.

CONCLUSIONS: 

Electroencephalogram effects of dexmedetomidine and propofol are strongly drug- and state-dependent. Changes in slow-wave and alpha activity seemed to best detect different states of consciousness.

Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2018
National Category
Biological Sciences
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-15616 (URN)10.1097/ALN.0000000000002192 (DOI)000435563800006 ()29642080 (PubMedID)2-s2.0-85048814054 (Scopus ID)
Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2019-11-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5133-8664

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