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Förster, J., Koivisto, M. & Revonsuo, A. (2020). ERP and MEG correlates of visual consciousness: The second decade. Consciousness and Cognition, 80, Article ID 102917.
Open this publication in new window or tab >>ERP and MEG correlates of visual consciousness: The second decade
2020 (English)In: Consciousness and Cognition, ISSN 1053-8100, E-ISSN 1090-2376, Vol. 80, article id 102917Article in journal (Refereed) Published
Abstract [en]

The first decade of event-related potential (ERP) research had established that the most consistent correlates of the onset of visual consciousness are the early visual awareness negativity (VAN), a posterior negative component in the N2 time range, and the late positivity (LP), an anterior positive component in the P3 time range. Two earlier extensive reviews ten years ago had concluded that VAN is the earliest and most reliable correlate of visual phenomenal consciousness, whereas LP probably reflects later processes associated with reflective/access consciousness. This article provides an update to those earlier reviews. ERP and MEG studies that have appeared since 2010 and directly compared ERPs between aware and unaware conditions are reviewed, and important new developments in the field are discussed. The result corroborates VAN as the earliest and most consistent signature of visual phenomenal consciousness, and casts further doubt on LP as an ERP correlate of phenomenal consciousness. 

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Event-related fields, Event-related potentials, Global Neuronal Workspace theory, Late positivity, Neural correlates of consciousness, Recurrent processing theory, Visual awareness negativity, awareness, consciousness, controlled study, event related potential, evoked response, human, human experiment, review
National Category
Neurosciences Psychology (excluding Applied Psychology)
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-18342 (URN)10.1016/j.concog.2020.102917 (DOI)000527301900001 ()32193077 (PubMedID)2-s2.0-85081677017 (Scopus ID)
Available from: 2020-03-26 Created: 2020-03-26 Last updated: 2020-05-07Bibliographically approved
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
Salminen-Vaparanta, N., Koivisto, M., Vorobyev, V., Alakurtti, K. & Revonsuo, A. (2019). Does TMS on V3 block conscious visual perception?. Neuropsychologia, 128, 223-231
Open this publication in new window or tab >>Does TMS on V3 block conscious visual perception?
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2019 (English)In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 128, p. 223-231Article in journal (Refereed) Published
Abstract [en]

Primary visual cortex (V1) and extrastriate V2 are necessary for the emergence of visual consciousness, but the effects of involvement of extrastriate V3 on visual consciousness is unclear. The objective of this study was to examine the causal role of V3 in visual consciousness in humans. We combined neuronavigated transcranial magnetic stimulation (TMS) with a computational model of the TMS-induced electric field to test whether or not the intact processing of visual input in V3, like in V1 and V2, is necessary for conscious visual perception. We targeted the stimulation both to V2 and to V3. If TMS of V3 blocks conscious visual perception of stimuli, then activation in V3 is a causally necessary prerequisite for conscious perception of stimuli. According to the alternative hypothesis, TMS of V3 will not block the conscious visual perception of stimuli, because the pathways from V1 to the higher cortical areas that go around V3 provide sufficient visual input for the emergence of conscious visual perception. The results showed that TMS interfered with conscious perception of features, detection of stimulus presence and the ability to discriminate the letter stimuli both when TMS was targeted either to V3 or to V2. For the conscious detection of stimulus presence, the effect was significantly stronger when V2 was stimulated than when V3 was stimulated. The results of the present study suggest that in addition to the primary visual cortex and V2, also V3 causally contributes to the generation of the most basic form of visual consciousness. Importantly, the results also indicate that V3 is necessary for visual perception in general, not only for visual consciousness.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Behavioral Sciences Biology
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-15614 (URN)10.1016/j.neuropsychologia.2017.11.013 (DOI)000493910900026 ()29137989 (PubMedID)2-s2.0-85034618438 (Scopus ID)
Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2020-05-20Bibliographically approved
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
Grassini, S., Valli, K., Souchet, J., Aubret, F., Segurini, G. V., Revonsuo, A. & Koivisto, M. (2019). Pattern matters: Snakes exhibiting triangular and diamond-shaped skin patterns modulate electrophysiological activity in human visual cortex. Neuropsychologia, 131, 62-72
Open this publication in new window or tab >>Pattern matters: Snakes exhibiting triangular and diamond-shaped skin patterns modulate electrophysiological activity in human visual cortex
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2019 (English)In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 131, p. 62-72Article in journal (Refereed) Published
Abstract [en]

The neural and perceptual mechanisms that support the efficient visual detection of snakes in humans are still not fully understood. According to the Snake Detection Theory, selection pressures posed by snakes on early primates have shaped the development of the visual system. Previous studies in humans have investigated early visual electrophysiological activity in response to snake images vs. various alternative dangerous or non-dangerous stimuli. These studies have shown that the Early Posterior Negativity (EPN) component is selectively elicited by snake or snake-like images. Recent findings yielded the complementary/alternative hypothesis that early humans (and possibly other primates) evolved an aversion especially for potentially harmful triangular shapes, such as teeth, claws or spikes. In the present study we investigated the effect of triangular and diamond-shaped patterns in snake skins on the ERP correlates of visual processing in humans. In the first experiment, we employed pictures of snakes displaying either triangular/diamond-shaped patterns or no particular pattern on their skins, and pictures of frogs as control. Participants observed a random visual presentation of these pictures. Consistent with previous studies, snakes elicited an enhanced negativity between 225 and 300 ms (EPN) compared to frogs. However, snakes featuring triangular/diamond-shaped patterns on their skin produced an enhanced EPN compared to the snakes that did not display such patterns. In a second experiment we used pictures displaying only skin patterns of snakes and frogs. Results from the second experiment confirmed the results of the first experiment, suggesting that triangular snake-skin patterns modulate the activity in human visual cortex. Taken together, our results constitute an important contribution to the snake detection theory. 

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Snake detection hypothesis, Fear of snake, ERPs, EPN, EEG, Attention
National Category
Neurosciences
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-17238 (URN)10.1016/j.neuropsychologia.2019.05.024 (DOI)000493913900006 ()31153966 (PubMedID)2-s2.0-85066962862 (Scopus ID)
Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-12-19Bibliographically approved
Grassini, S., Revonsuo, A., Castellotti, S., Petrizzo, I., Benedetti, V. & Koivisto, M. (2019). Processing of natural scenery is associated with lower attentional and cognitive load compared with urban ones. Journal of Environmental Psychology, 62, 1-11
Open this publication in new window or tab >>Processing of natural scenery is associated with lower attentional and cognitive load compared with urban ones
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2019 (English)In: Journal of Environmental Psychology, ISSN 0272-4944, E-ISSN 1522-9610, Vol. 62, p. 1-11Article in journal (Refereed) Published
Abstract [en]

Environmental psychology has provided evidence for psychologically favorable effects of exposure to natural settings, by means of controlled laboratory experiments as well as outdoor field studies. Most of these studies have employed subjective rating scales to assess processes and outcomes of exposure to nature, while only few of them have used physiological measures to assess the neural correlates of these benefits. The present study used electroencephalography (EEG) to explore how the brain engages in processing of images of natural vs. urban scenery. During EEG recording, the participants (n = 32) were presented with a series of photos depicting urban or natural scenery. Participants rated the sceneries for their subjective relaxing value. Images of natural scenery were rated as more relaxing compared to the images of urban scenery. Event related potentials suggested a lower attentional demand for images of natural scenery compared to urban ones. Signal spectral analyses revealed differences in brain activity level and cognitive demand between natural and urban scenery. Our data suggest that the visual perception of natural environments calls for less attentional and cognitive processing, compared with urban ones. © 2019 Elsevier Ltd

Place, publisher, year, edition, pages
Academic Press, 2019
Keywords
Attention, Attention restoration theory (ART), Cognitive load, EEG, Perception, Environmental psychology
National Category
Psychology (excluding Applied Psychology) Neurosciences
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16653 (URN)10.1016/j.jenvp.2019.01.007 (DOI)000466252500001 ()2-s2.0-85061318570 (Scopus ID)
Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-11-18Bibliographically 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., 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
Hurme, M., Koivisto, M., Revonsuo, A. & Railo, H. (2019). V1 activity during feedforward and early feedback processing is necessary for both conscious and unconscious motion perception. NeuroImage, 185, 313-321
Open this publication in new window or tab >>V1 activity during feedforward and early feedback processing is necessary for both conscious and unconscious motion perception
2019 (English)In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 185, p. 313-321Article in journal (Refereed) Published
Abstract [en]

The study of blindsight has revealed a seminal dissociation between conscious vision and visually guided behavior: some patients who are blind due to V1 lesions seem to be able to employ unconscious visual information in their behavior. The standard assumption is that these findings generalize to the neurologically healthy. We tested whether unconscious processing of motion is possible without the contribution of V1 in neurologically healthy participants by disturbing activity in V1 using transcranial magnetic stimulation (TMS). Unconscious processing was measured with redundant target effect (RTE), a phenomenon where participants respond faster to two stimuli than to one stimulus, when the task is just to respond as fast as possible when one stimulus or two simultaneous stimuli are presented. We measured the RTE caused by a motion stimulus. V1 activity was interfered with different stimulus onset asynchronies (SOA) to test whether TMS delivered in a specific time window suppresses conscious perception (participant reports seeing only one of the two stimuli) but does not affect unconscious processing (RTE). We observed that at each SOA, when TMS suppressed conscious perception of the stimulus, the RTE was also eliminated. However, when visibility of the redundant target was suppressed with a visual mask, we found unconscious processing of motion. This suggests that unconscious processing of motion depends on V1 in neurologically healthy humans. We conclude that the neural mechanisms that enable motion processing in blindsight are modulated by neuroplastic changes in connectivity between subcortical areas and the visual cortex after the V1 lesion. Neurologically healthy observers cannot process motion unconsciously without functioning of V1. 

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
blindsight, motion perception, redundant target effect, TMS, unconscious vision, V1, adult, article, controlled study, ego development, female, human, human experiment, male, movement perception, stimulus, transcranial magnetic stimulation, visibility, visual cortex
National Category
Neurosciences Psychology Production Engineering, Human Work Science and Ergonomics
Research subject
Consciousness and Cognitive Neuroscience
Identifiers
urn:nbn:se:his:diva-16412 (URN)10.1016/j.neuroimage.2018.10.058 (DOI)000451628200029 ()30366074 (PubMedID)2-s2.0-85055542590 (Scopus ID)
Available from: 2018-11-21 Created: 2018-11-21 Last updated: 2019-02-11Bibliographically 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
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