Wilke, Melanie

[["dc.bibliographiccitation.firstpage","1298"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Journal of Cognitive Neuroscience"],["dc.bibliographiccitation.lastpage","1307"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Cabral-Calderin, Yuranny"],["dc.contributor.author","Schmidt-Samoa, Carsten"],["dc.contributor.author","Wilke, Melanie"],["dc.date.accessioned","2018-11-07T09:55:29Z"],["dc.date.available","2018-11-07T09:55:29Z"],["dc.date.issued","2015"],["dc.description.abstract","When our brain is confronted with ambiguous visual stimuli, perception spontaneously alternates between different possible interpretations although the physical stimulus remains the same. Both alpha (8-12 Hz) and gamma (>30 Hz) oscillations have been reported to correlate with such spontaneous perceptual reversals. However, whether these oscillations play a causal role in triggering perceptual switches remains unknown. To address this question, we applied transcranial alternating current stimulation (tACS) over the posterior cortex of healthy human participants to boost alpha and gamma oscillations. At the same time, participants were reporting their percepts of an ambiguous structure-from-motion stimulus. We found that tACS in the gamma band (60 Hz) increased the number of spontaneous perceptual reversals, whereas no significant effect was found for tACS in alpha (10 Hz) and higher gamma (80 Hz) frequencies. Our results suggest a mechanistic role of gamma but not alpha oscillations in the resolution of perceptual ambiguity."],["dc.description.sponsorship","Herman and Lilly Schilling Foundation"],["dc.identifier.doi","10.1162/jocn_a_00781"],["dc.identifier.isi","000355418000003"],["dc.identifier.pmid","25603029"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36753"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Mit Press"],["dc.relation.issn","1530-8898"],["dc.relation.issn","0898-929X"],["dc.title","Rhythmic gamma stimulation affects bistable perception"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Frontiers in Neuroscience"],["dc.bibliographiccitation.volume","16"],["dc.contributor.affiliation","Steinmann, Iris; 1Department of Cognitive Neurology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.affiliation","Williams, Kathleen A.; 1Department of Cognitive Neurology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.affiliation","Wilke, Melanie; 1Department of Cognitive Neurology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.affiliation","Antal, Andrea; 4Department of Neurology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.author","Steinmann, Iris"],["dc.contributor.author","Williams, Kathleen A."],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Antal, Andrea"],["dc.date.accessioned","2022-07-11T15:00:32Z"],["dc.date.available","2022-07-11T15:00:32Z"],["dc.date.issued","2022-06-27"],["dc.date.updated","2022-07-11T13:34:32Z"],["dc.description.abstract","Non-invasive electrical stimulation methods, such as transcranial alternating current stimulation (tACS), are increasingly used in human neuroscience research and offer potential new avenues to treat neurological and psychiatric disorders. However, their often variable effects have also raised concerns in the scientific and clinical communities. This study aims to investigate the influence of subject-specific factors on the alpha tACS-induced aftereffect on the alpha amplitude (measured with electroencephalography, EEG) as well as on the connectivity strength between nodes of the default mode network (DMN) [measured with functional magnetic resonance imaging (fMRI)]. As subject-specific factors we considered the individual electrical field (EFIELD) strength at target regions in the brain, the frequency mismatch between applied stimulation and individual alpha frequency (IAF) and as a covariate, subject’s changes in mental state, i.e., sleepiness. Eighteen subjects participated in a tACS and a sham session conducted on different days. Each session consisted of three runs (pre/stimulation/). tACS was applied during the second run at each subject’s individual alpha frequency (IAF), applying 1 mA peak-to-peak intensity for 7 min, using an occipital bihemispheric montage. In every run, subjects watched a video designed to increase in-scanner compliance. To investigate the aftereffect of tACS on EEG alpha amplitude and on DMN connectivity strength, EEG data were recorded simultaneously with fMRI data. Self-rated sleepiness was documented using a questionnaire. Conventional statistics (ANOVA) did not show a significant aftereffect of tACS on the alpha amplitude compared to sham stimulation. Including individual EFIELD strengths and self-rated sleepiness scores in a multiple linear regression model, significant tACS-induced aftereffects were observed. However, the subject-wise mismatch between tACS frequency and IAF had no contribution to our model. Neither standard nor extended statistical methods confirmed a tACS-induced aftereffect on DMN functional connectivity. Our results show that it is possible and necessary to disentangle alpha amplitude changes due to intrinsic mechanisms and to external manipulation using tACS on the alpha amplitude that might otherwise be overlooked. Our results suggest that EFIELD is really the most significant factor that explains the alpha amplitude modulation during a tACS session. This knowledge helps to understand the variability of the tACS-induced aftereffects."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2022"],["dc.identifier.doi","10.3389/fnins.2022.870758"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/112460"],["dc.language.iso","en"],["dc.relation.eissn","1662-453X"],["dc.rights","CC BY 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by/4.0/"],["dc.title","Detection of Transcranial Alternating Current Stimulation Aftereffects Is Improved by Considering the Individual Electric Field Strength and Self-Rated Sleepiness"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Scientific Reports"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Poland, Eva"],["dc.contributor.author","Donner, Tobias H."],["dc.contributor.author","Müller, Kai-Markus"],["dc.contributor.author","Leopold, David. A."],["dc.contributor.author","Wilke, Melanie"],["dc.date.accessioned","2021-06-01T10:50:41Z"],["dc.date.available","2021-06-01T10:50:41Z"],["dc.date.issued","2020"],["dc.description.abstract","An amendment to this paper has been published and can be accessed via a link at the top of the paper."],["dc.identifier.doi","10.1038/s41598-020-59858-8"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/86752"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.relation.eissn","2045-2322"],["dc.title","Author Correction: Thalamus exhibits less sensory variability quenching than cortex"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","17507"],["dc.bibliographiccitation.issue","46"],["dc.bibliographiccitation.journal","Proceedings of the National Academy of Sciences"],["dc.bibliographiccitation.lastpage","17512"],["dc.bibliographiccitation.volume","103"],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Logothetis, Nikos K."],["dc.contributor.author","Leopold, David A."],["dc.date.accessioned","2017-09-07T11:43:46Z"],["dc.date.available","2017-09-07T11:43:46Z"],["dc.date.issued","2006"],["dc.description.abstract","Neurophysiological and functional imaging experiments remain in apparent disagreement on the role played by the earliest stages of the visual cortex in supporting a visual percept. Here, we report electrophysiological findings that shed light on this issue. We monitored neural activity in the visual cortex of monkeys as they reported their perception of a high-contrast visual stimulus that was induced to vanish completely from perception on a subset of trials. We found that the spiking of neurons in cortical areas V1 and V2 was uncorrelated with the perceptual visibility of the target, whereas that in area V4 showed significant perception-related changes. In contrast, power changes in the lower frequency bands (particularly 9–30 Hz) of the local field potential (LFP), collected on the same trials, showed consistent and sustained perceptual modulation in all three areas. In addition, for the gamma frequency range (30–50 Hz), the responses during perceptual suppression of the target were correlated significantly with the responses to its physical removal in all areas, although the modulation magnitude was considerably higher in area V4 than in V1 and V2. These results, taken together, suggest that low-frequency LFP power in early cortical processing is more closely related to the representation of stimulus visibility than is spiking or higher frequency LFP activity."],["dc.identifier.doi","10.1073/pnas.0604673103"],["dc.identifier.gro","3151630"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8444"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","0027-8424"],["dc.title","Local field potential reflects perceptual suppression in monkey visual cortex"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Frontiers in Psychology"],["dc.bibliographiccitation.volume","4"],["dc.contributor.author","Boly, Melanie"],["dc.contributor.author","Seth, Anil K."],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Ingmundson, Paul"],["dc.contributor.author","Baars, Bernard"],["dc.contributor.author","Laureys, Steven"],["dc.contributor.author","Edelman, David B."],["dc.contributor.author","Tsuchiya, Naotsugu"],["dc.date.accessioned","2017-09-07T11:43:41Z"],["dc.date.available","2017-09-07T11:43:41Z"],["dc.date.issued","2013"],["dc.description.abstract","This joint article reflects the authors' personal views regarding noteworthy advances in the neuroscience of consciousness in the last 10 years, and suggests what we feel may be promising future directions. It is based on a small conference at the Samoset Resort in Rockport, Maine, USA, in July of 2012, organized by the Mind Science Foundation of San Antonio, Texas. Here, we summarize recent advances in our understanding of subjectivity in humans and other animals, including empirical, applied, technical, and conceptual insights. These include the evidence for the importance of fronto-parietal connectivity and of “top-down” processes, both of which enable information to travel across distant cortical areas effectively, as well as numerous dissociations between consciousness and cognitive functions, such as attention, in humans. In addition, we describe the development of mental imagery paradigms, which made it possible to identify covert awareness in non-responsive subjects. Non-human animal consciousness research has also witnessed substantial advances on the specific role of cortical areas and higher order thalamus for consciousness, thanks to important technological enhancements. In addition, much progress has been made in the understanding of non-vertebrate cognition relevant to possible conscious states. Finally, major advances have been made in theories of consciousness, and also in their comparison with the available evidence. Along with reviewing these findings, each author suggests future avenues for research in their field of investigation."],["dc.identifier.doi","10.3389/fpsyg.2013.00625"],["dc.identifier.gro","3151613"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10704"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8426"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","1664-1078"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0"],["dc.title","Consciousness in humans and non-human animals: recent advances and future directions"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","94"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Human Brain Mapping"],["dc.bibliographiccitation.lastpage","121"],["dc.bibliographiccitation.volume","37"],["dc.contributor.author","Cabral-Calderin, Yuranny"],["dc.contributor.author","Weinrich, Christiane Anne"],["dc.contributor.author","Schmidt-Samoa, Carsten"],["dc.contributor.author","Poland, Eva"],["dc.contributor.author","Dechent, Peter"],["dc.contributor.author","Bähr, Mathias"],["dc.contributor.author","Wilke, Melanie"],["dc.date.accessioned","2017-09-07T11:54:45Z"],["dc.date.available","2017-09-07T11:54:45Z"],["dc.date.issued","2016"],["dc.description.abstract","Transcranial alternating current stimulation (tACS) has emerged as a promising tool for manipulating ongoing brain oscillations. While previous studies demonstrated frequency-specific effects of tACS on diverse cognitive functions, its effect on neural activity remains poorly understood. Here we asked how tACS modulates regional fMRI blood oxygenation level dependent (BOLD) signal as a function of frequency, current strength, and task condition. TACS was applied over the posterior cortex of healthy human subjects while the BOLD signal was measured during rest or task conditions (visual perception, passive video viewing and motor task). TACS was applied in a blockwise manner at different frequencies (10, 16, 60 and 80 Hz). The strongest tACS effects on BOLD activity were observed with stimulation at alpha (10 Hz) and beta (16 Hz) frequency bands, while effects of tACS at the gamma range were rather modest. Specifically, we found that tACS at 16 Hz induced BOLD activity increase in fronto-parietal areas. Overall, tACS effects varied as a function of frequency and task, and were predominantly seen in regions that were not activated by the task. Also, the modulated regions were poorly predicted by current density modeling studies. Taken together, our results suggest that tACS does not necessarily exert its strongest effects in regions below the electrodes and that region specificity might be achieved with tACS due to varying susceptibility of brain regions to entrain to a given frequency. (C) 2015 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc."],["dc.identifier.doi","10.1002/hbm.23016"],["dc.identifier.fs","618728"],["dc.identifier.gro","3141752"],["dc.identifier.isi","000369150500007"],["dc.identifier.pmid","26503692"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14044"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/680"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10 / Funder: Hermann and Lilly Schilling Foundation"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.eissn","1097-0193"],["dc.relation.issn","1065-9471"],["dc.rights","CC BY-NC-ND 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by-nc-nd/4.0"],["dc.title","Transcranial Alternating Current Stimulation Affects the BOLD Signal in a Frequency and Task-dependent Manner"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","40"],["dc.bibliographiccitation.journal","Cognition"],["dc.bibliographiccitation.lastpage","52"],["dc.bibliographiccitation.volume","176"],["dc.contributor.author","Moreira, Caio M."],["dc.contributor.author","Rollwage, Max"],["dc.contributor.author","Kaduk, Kristin"],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Kagan, Igor"],["dc.date.accessioned","2020-12-10T14:23:11Z"],["dc.date.available","2020-12-10T14:23:11Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1016/j.cognition.2018.02.026"],["dc.identifier.issn","0010-0277"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/71863"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Post-decision wagering after perceptual judgments reveals bi-directional certainty readouts"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","R766"],["dc.bibliographiccitation.issue","18"],["dc.bibliographiccitation.journal","Current Biology"],["dc.bibliographiccitation.lastpage","R768"],["dc.bibliographiccitation.volume","15"],["dc.contributor.author","Leopold, David A."],["dc.contributor.author","Wilke, Melanie"],["dc.date.accessioned","2017-09-07T11:43:47Z"],["dc.date.available","2017-09-07T11:43:47Z"],["dc.date.issued","2005"],["dc.description.abstract","New functional imaging studies demonstrate that it is possible todecode a sensory visual pattern, and even an internal perceptual state,by combining seemingly insignificant feature selective signal biasespresent in a large number of voxels."],["dc.identifier.doi","10.1016/j.cub.2005.08.055"],["dc.identifier.gro","3151628"],["dc.identifier.pmid","16169478"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8442"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0960-9822"],["dc.title","Neuroimaging: Seeing the Trees for the Forest"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1076"],["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Current Biology"],["dc.bibliographiccitation.lastpage","1085"],["dc.bibliographiccitation.volume","13"],["dc.contributor.author","Maier, Alexander"],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Logothetis, Nikos K."],["dc.contributor.author","Leopold, David A."],["dc.date.accessioned","2017-09-07T11:43:43Z"],["dc.date.available","2017-09-07T11:43:43Z"],["dc.date.issued","2003"],["dc.description.abstract","Continuous viewing of ambiguous patterns is characterized by wavering perception that alternates between two or more equally valid visual solutions. However, when such patterns are viewed intermittently, either by repetitive presentation or by periodic closing of the eyes, perception can become locked or “frozen” in one configuration for several minutes at a time. One aspect of this stabilization is the possible existence of a perceptual memory that persists during periods in which the ambiguous stimulus is absent. Here, we use a novel paradigm of temporally interleaved ambiguous stimuli to explore the nature of this memory, with particular regard to its potential impact on perceptual organization.Results: We found that the persistence of a perceptual configuration was robust to interposed visual patterns, and, further, that at least three ambiguous patterns, when interleaved in time, could undergo parallel, stable time courses. Then, using an interleaved presentation paradigm, we established that the occasional reversal in one pattern could be coupled with that of its interleaved counterpart, and that this coupling was a function of the structural similarity between the patterns.Conclusions: We postulate that the stabilization observed with repetitive presentation of ambiguous patterns can be at least partially accounted for by processes that retain a recent perceptual interpretation, and we speculate that such memory may be important in natural vision. We further propose that the interleaved paradigm introduced here may be of great value to gauge aspects of stimulus similarity that appeal to particular mechanisms of perceptual organization."],["dc.identifier.doi","10.1016/s0960-9822(03)00414-7"],["dc.identifier.gro","3151622"],["dc.identifier.pmid","12842006"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8435"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0960-9822"],["dc.title","Perception of Temporally Interleaved Ambiguous Patterns"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1270"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Journal of Cognitive Neuroscience"],["dc.bibliographiccitation.lastpage","1283"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Kagan, Igor"],["dc.contributor.author","Andersen, Richard A."],["dc.date.accessioned","2017-09-07T11:43:44Z"],["dc.date.available","2017-09-07T11:43:44Z"],["dc.date.issued","2013"],["dc.description.abstract","The ability to selectively process visual inputs and to decide between multiple movement options in an adaptive manner is critical for survival. Such decisions are known to be influenced by factors such as reward expectation and visual saliency. The dorsal pulvinar connects to a multitude of cortical areas that are involved in visuospatial memory and integrate information about upcoming eye movements with expected reward values. However, it is unclear whether the dorsal pulvinar is critically involved in spatial memory and reward-based oculomotor decision behavior. To examine this, we reversibly inactivated the dorsal portion of the pulvinar while monkeys performed a delayed memory saccade task that included choices between equally or unequally rewarded options. Pulvinar inactivation resulted in a delay of saccade initiation toward memorized contralesional targets but did not affect spatial memory. Furthermore, pulvinar inactivation caused a pronounced choice bias toward the ipsilesional hemifield when the reward value in the two hemifields was equal. However, this choice bias could be alleviated by placing a high reward target into the contralesional hemifield. The bias was less affected by the manipulation of relative visual saliency between the two competing targets. These results suggest that the dorsal pulvinar is involved in determining the behavioral desirability of movement goals while being less critical for spatial memory and reward processing."],["dc.identifier.doi","10.1162/jocn_a_00399"],["dc.identifier.gro","3151624"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8437"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","0898-929X"],["dc.title","Effects of Pulvinar Inactivation on Spatial Decision-making between Equal and Asymmetric Reward Options"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]