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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: 2018-09-03Bibliographically 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.

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)
Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2018-09-11Bibliographically approved
Sikka, P., Revonsuo, A., Sandman, N., Tuominen, J. & Valli, K. (2018). Dream emotions: a comparison of home dream reports with laboratory early and late REM dream reports. Journal of Sleep Research, 27(2), 206-214
Open this publication in new window or tab >>Dream emotions: a comparison of home dream reports with laboratory early and late REM dream reports
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2018 (English)In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 27, no 2, p. 206-214Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to compare the emotional content of dream reports collected at home upon morning awakenings with those collectedin the laboratory upon early and late rapid eye movement (REM) sleep awakenings. Eighteen adults (11 women, seven men; mean age = 25.89 ± 4.85) wrote down their home dreams every morning immediately upon awakening during a 7-day period. Participants also spent two non-consecutive nights in the sleep laboratory where they were awoken 5 min into each continuous REM sleep stage, upon which they gave a verbal dream report. The content of a total of 151 home and 120 laboratory dream reports was analysed by two blind judges using the modified Differential Emotions Scale. It was found that: (1) home dream reports were more emotional than laboratory early REM dream reports, but not more emotional than laboratory late REM dream reports; (2) home dream reports contained a higher density of emotions than laboratory (early or late REM) dream reports; and (3) home dream reports were more negative than laboratory dream reports, but differences between home and early REM reports were larger than those between home and late REM reports. The results suggest that differences between home and laboratory dream reports in overall emotionality may be due to the time of night effect. Whether differences in the density of emotions and negative emotionality are due to sleep environment or due to different reporting procedures and time spent in a sleep stage, respectively, remains to be determined in future studies.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
dreams, dreaming, emotions, content analysis, REM sleep, sleep stages
National Category
Psychology
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-13634 (URN)10.1111/jsr.12555 (DOI)000426866500008 ()28568911 (PubMedID)2-s2.0-85020126304 (Scopus ID)
Available from: 2017-06-06 Created: 2017-06-06 Last updated: 2018-05-17Bibliographically approved
Radek, L., Kallionpää, R. E., Karvonen, M., Scheinin, A., Maksimow, A., Långsjö, J., . . . Valli, K. (2018). Dreaming and awareness during dexmedetomidine- and propofol-induced unresponsiveness. 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), 260-269
Open this publication in new window or tab >>Dreaming and awareness during dexmedetomidine- and propofol-induced unresponsiveness
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2018 (English)In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 121, no 1, p. 260-269Article in journal (Refereed) Published
Abstract [en]

Background: Experiences during anaesthetic-induced unresponsiveness have previously been investigated by interviews after recovery. To explore whether experiences occur during drug administration, we interviewed participants during target-controlled infusion (TCI) of dexmedetomidine or propofol and after recovery. Methods: Healthy participants received dexmedetomidine (n = 23) or propofol (n = 24) in stepwise increments until loss of responsiveness (LOR1). During TCI we attempted to arouse them for interview (return of responsiveness, ROR1). After the interview, if unresponsiveness ensued with the same dose (LOR2), the procedure was repeated (ROR2). Finally, the concentration was increased 1.5-fold to achieve presumable loss of consciousness (LOC), infusion terminated, and the participants interviewed upon recovery (ROR3). An emotional sound stimulus was presented during LORs and LOC, and memory for stimuli was assessed with recognition task after recovery. Interview transcripts were content analysed. Results: Of participants receiving dexmedetomidine, 18/23 were arousable from LOR1 and LOR2. Of participants receiving propofol, 10/24 were arousable from LOR1 and two of four were arousable from LOR2. Of 93 interviews performed, 84% included experiences from periods of unresponsiveness (dexmedetomidine 90%, propofol 74%). Internally generated experiences (dreaming) were present in 86% of reports from unresponsive periods, while externally generated experiences (awareness) were rare and linked to brief arousals. No within drug differences in the prevalence or content of experiences during infusion vs after recovery were observed, but participants receiving dexmedetomidine reported dreaming and awareness more often. Participants receiving dexmedetomidine recognised the emotional sounds better than participants receiving propofol (42% vs 15%), but none reported references to sounds spontaneously. Conclusion: Anaesthetic-induced unresponsiveness does not induce unconsciousness or necessarily even disconnectedness.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
awareness, consciousness, dexmedetomidine, interview, propofol
National Category
Psychology
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16026 (URN)10.1016/j.bja.2018.03.014 (DOI)000439025500070 ()29935581 (PubMedID)2-s2.0-85046688138 (Scopus ID)
Conference
10th International Symposium on Memory and Awareness in Anesthesia (MAA), Helsinki, Finland, June 19-21, 2017
Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2018-10-22Bibliographically approved
Kallionpää, R. E., Scheinin, A., Kallionpää, R. A., Sandman, N., Kallioinen, M., Laitio, R., . . . Valli, K. (2018). Spoken words are processed during dexmedetomidine-induced unresponsiveness. 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), 270-280
Open this publication in new window or tab >>Spoken words are processed during dexmedetomidine-induced unresponsiveness
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2018 (English)In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 121, no 1, p. 270-280Article in journal (Refereed) Published
Abstract [en]

Background: Studying the effects of anaesthetic drugs on the processing of semantic stimuli could yield insights into how brain functions change in the transition from wakefulness to unresponsiveness. Here, we explored the N400 event-related potential during dexmedetomidine- and propofol-induced unresponsiveness. Methods: Forty-seven healthy subjects were randomised to receive either dexmedetomidine (n = 23) or propofol (n = 24) in this open-label parallel-group study. Loss of responsiveness was achieved by stepwise increments of pseudo-steady-state plasma concentrations, and presumed loss of consciousness was induced using 1.5 times the concentration required for loss of responsiveness. Pre-recorded spoken sentences ending either with an expected (congruous) or an unexpected (incongruous) word were presented during unresponsiveness. The resulting electroencephalogram data were analysed for the presence of the N400 component, and for the N400 effect defined as the difference between the N400 components elicited by congruous and incongruous stimuli, in the time window 300-600 ms post-stimulus. Recognition of the presented stimuli was tested after recovery of responsiveness. Results: The N400 effect was not observed during dexmedetomidine- or propofol-induced unresponsiveness. The N400 component, however, persisted during dexmedetomidine administration. The N400 component elicited by congruous stimuli during unresponsiveness in the dexmedetomidine group resembled the large component evoked by incongruous stimuli at the awake baseline. After recovery, no recognition of the stimuli heard during unresponsiveness occurred. Conclusions: Dexmedetomidine and propofol disrupt the discrimination of congruous and incongruous spoken sentences, and recognition memory at loss of responsiveness. However, the processing of words is partially preserved during dexmedetomidine-induced unresponsiveness.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
dexmedetomidine, event-related potentials, N400 evoked potential, propofol, semantics
National Category
Neurosciences
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16027 (URN)10.1016/j.bja.2018.04.032 (DOI)000439025500071 ()29935582 (PubMedID)2-s2.0-85047270309 (Scopus ID)
Conference
10th International Symposium on Memory and Awareness in Anesthesia (MAA), Helsinki, Finland, June 19-21, 2017
Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2018-10-22Bibliographically approved
Grassini, S., Railo, H., Valli, K., Revonsuo, A. & Koivisto, M. (2018). Visual features and perceptual context modulate attention towards evolutionarily relevant threatening stimuli: Electrophysiological evidence. Emotion, Article ID 10.1037/emo0000434.
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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2018 (English)In: Emotion, ISSN 1528-3542, E-ISSN 1931-1516, article id 10.1037/emo0000434Article in journal (Refereed) Epub ahead of print
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), 2018
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)29578746 (PubMedID)
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2018-11-12
Sikka, P., Feilhauer, D., Valli, K. & Revonsuo, A. (2017). How You Measure Is What You Get: Differences in Self- and External Ratings of Emotional Experiences in Home Dreams. American Journal of Psychology, 130(3), 367-384
Open this publication in new window or tab >>How You Measure Is What You Get: Differences in Self- and External Ratings of Emotional Experiences in Home Dreams
2017 (English)In: American Journal of Psychology, ISSN 0002-9556, E-ISSN 1939-8298, Vol. 130, no 3, p. 367-384Article in journal (Refereed) Published
Abstract [en]

This study demonstrates that different methods for measuring emotional experiences in dreams — self-ratings of dreams using emotion rating scales versus external ratings in the form of content analysis of narrative dream reports — can lead to strikingly different results and contradicting conclusions about the emotional content of home dreams. During 3 consecutive weeks, every morning upon awakening, 44 participants (16 men, 28 women, average age 26.9± 5.1 years) reported their dreams and rated their emotional experiences in those dreams using the modified Differential Emotions Scale. Two external judges rated emotional experiences inthe same 552 (M = 12.55 ± 5.72) home dream reports using the same scale. Comparison of the 2 methods showed that with self-ratings dreams were rated as more emotional and more positive than with external ratings. Moreover, whereas with self-ratings the majority of dreams was rated as positively valenced, with external ratings the majority of dream reports was rated as negatively valenced. Although self- and external ratings converge, at least partially, in the measurement of negative emotional experiences, they diverge greatly in the measurement of positive emotional experiences. On one hand, this discrepancy may result from different biases inherent in the 2 measurement methods highlighting the need to develop better methods for measuring emotional experiences. On the other hand, self- and external ratings may capture different phenomena and should thus be considered complementary and used concurrently. Nevertheless, results suggest that negative emotional experiences can be measured in a more valid and reliable manner than positive emotional experiences.

Place, publisher, year, edition, pages
Illinois, US: , 2017
Keywords
emotions, dreaming, dream emotions, content analysis, gender differences
National Category
Natural Sciences Psychology
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-14074 (URN)10.5406/amerjpsyc.130.3.0367 (DOI)000407872700010 ()2-s2.0-85027696254 (Scopus ID)
Note

Diana Feilhauer is now at the Department of Philosophy, Lund University, Sweden.

This research was supported by the Signe and Ane GyllenbergFoundation (P.S.), the Finnish Cultural Foundation (P.S.), and Academy of Finland (K.V., A.R.) (project 266434).

The authors thank Linnéa Stenström for assistance in the early phases of the study.

Available from: 2017-09-03 Created: 2017-09-03 Last updated: 2017-11-27Bibliographically approved
Sandman, N., Valli, K., Kronholm, E., Vartiainen, E., Laatikainen, T. & Paunio, T. (2017). Nightmares as predictors of suicide: an extension study including war veterans. Scientific Reports, 7, Article ID 44756.
Open this publication in new window or tab >>Nightmares as predictors of suicide: an extension study including war veterans
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2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 44756Article in journal (Refereed) Published
Abstract [en]

Nightmares are intensive dreams with negative emotional tone. Frequent nightmares can pose a serious clinical problem and in 2001, Tanskanen et al. found that nightmares increase the risk of suicide. However, the dataset used by these authors included war veterans in whom nightmare frequency -and possibly also suicide risk -is elevated. Therefore, re-examination of the association between nightmares and suicide in these data is warranted. We investigated the relationship between nightmares and suicide both in the general population and war veterans in Finnish National FINRISK Study from the years 1972 to 2012, a dataset overlapping with the one used in the study by Tanskanen et al. Our data comprise 71,068 participants of whom 3139 are war veterans. Participants were followed from their survey participation until the end of 2014 or death. Suicides (N = 398) were identified from the National Causes of Death Register. Frequent nightmares increase the risk of suicide: The result of Tanskanen et al. holds even when war experiences are controlled for. Actually nightmares are not significantly associated with suicides among war veterans. These results support the role of nightmares as an independent risk factor for suicide instead of just being proxy for history of traumatic experiences.

Place, publisher, year, edition, pages
Nature Publishing Group, 2017
Keywords
posttraumatic stress disorder, sleep disturbances, insomnia symptoms, major depression, risk factors, ideation, prevalence, adults, population, behavior
National Category
Social Sciences Psychology (excluding Applied Psychology) Medical and Health Sciences
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-13500 (URN)10.1038/srep44756 (DOI)000396661200001 ()28294195 (PubMedID)2-s2.0-85015327193 (Scopus ID)
Available from: 2017-04-18 Created: 2017-04-18 Last updated: 2017-11-27Bibliographically approved
Valli, K. (2016). Dreams. In: Harold L. Miller (Ed.), The SAGE Encyclopedia of Theory in Psychology: . Thousand Oaks: Sage Publications
Open this publication in new window or tab >>Dreams
2016 (English)In: The SAGE Encyclopedia of Theory in Psychology / [ed] Harold L. Miller, Thousand Oaks: Sage Publications, 2016Chapter in book (Other academic)
Place, publisher, year, edition, pages
Thousand Oaks: Sage Publications, 2016
Keywords
Dreams
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:his:diva-12919 (URN)10.4135/9781483346274.n81 (DOI)9781452256719 (ISBN)9781483346274 (ISBN)
Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2017-11-27Bibliographically approved
Sikka, P., Revonsuo, A. & Valli, K. (2016). Methodological Issues in Measuring Dream Emotions. In: : . Paper presented at The 33rd Annual International Dream Conference (organized by the International Association for the Study of Dreams), Kerkrade, the Netherlands, June 24-28, 2016.
Open this publication in new window or tab >>Methodological Issues in Measuring Dream Emotions
2016 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Emotions are central in dreams, specifically in rapid eye movement sleep dreams. Despite a wealth of research on the emotional content of dreams, there is little consensus about the overall emotionality and predominant valence of dreams or about the prevailing specific emotions in dreams. Previous contradictory findings are arguably due to unresolved methodological issues. However, studies that have directly investigated these methodological issues are scarce. In this presentation three studies that investigated the effect of study methodology on the frequency, valence and phenomenological content of dream emotions are discussed. The studies demonstrate that the use of different methods for rating dream emotions (participants who experience the dream vs external judges who analysed the respective dream report) and for collecting dream reports (home vs laboratory setting) leads to very different results and conclusions about the emotional content of dreams. As such, these studies highlight the importance of carefully considering study methodology when conducting and interpreting dream (emotional) content studies.

National Category
Natural Sciences Other Biological Topics Psychology (excluding Applied Psychology)
Research subject
Natural sciences; Humanities and Social sciences
Identifiers
urn:nbn:se:his:diva-12193 (URN)
Conference
The 33rd Annual International Dream Conference (organized by the International Association for the Study of Dreams), Kerkrade, the Netherlands, June 24-28, 2016
Available from: 2016-05-02 Created: 2016-05-02 Last updated: 2017-11-27Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5133-8664

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