Schmidt-Samoa, Carsten

[["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.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","178"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Neuroforum"],["dc.bibliographiccitation.lastpage","189"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Dechent, Peter"],["dc.contributor.author","Schmidt-Samoa, Carsten"],["dc.date.accessioned","2017-09-07T11:43:41Z"],["dc.date.available","2017-09-07T11:43:41Z"],["dc.date.issued","2012"],["dc.description.abstract","Räumlicher Neglect stellt eine schwerwiegende Konsequenz von Hirnläsionen dar und ist durch die perzeptuelle und motorische Vernachlässigung einer Raumhälfte gekennzeichnet. Die zu Neglect führenden Läsionen treten innerhalb verteilter Netzwerke auf, die sich sowohl aus kortikalen Arealen (z.B. fronto-parietalen) als auch aus subkortikalen Strukturen (z.B. dem thalamischen Pulvinar) zusammensetzen. Die Entwicklung effektiver therapeutischer Strategien setzt ein detailliertes Verständnis der wichtigen Knotenpunkte und ihrer Interaktionen voraus. Allerdings sind präzise Informationen dazu aus Patientenstudien, aufgrund der Größe und Variabilität der mit Neglect assoziierten Läsionen, oft nur schwer zu erhalten. Experimentelle Modelle, bei denen definierte Gehirnregionen systematisch inaktiviert werden können, stellen daher eine wichtige Ergänzung zu den klassischen Läsionsstudien dar. Neglect-Modelle wurden beispielsweise bei nicht-humanen Primaten mithilfe lokaler, reversibler pharmakologischer Inaktivierung entwickelt, sowie bei gesunden Probanden mithilfe nicht-invasiver Stimulations-/Inaktivierungsmethoden wie der transkraniellen Magnetstimulation. In diesem Artikel diskutieren wir Theorien zum räumlichen Neglect, insbesondere die des hemisphärischen Ungleichgewichtes, und ihre empirische Evidenz. Ein Fokus liegt dabei auf Ergebnissen aus funktionellen Bildgebungsstudien, welche die Auswirkungen lokaler Läsionen auf dynamische Netzwerkaktivität untersuchen."],["dc.identifier.doi","10.1515/nf-2012-0103"],["dc.identifier.gro","3151609"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8423"],["dc.language.iso","de"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","1868-856X"],["dc.title","Experimentelle Modelle für räumlichen Neglect (Studien in humanen und nicht-humanen Primaten)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","135"],["dc.bibliographiccitation.journal","Cortex"],["dc.bibliographiccitation.lastpage","149"],["dc.bibliographiccitation.volume","99"],["dc.contributor.author","Wilke, Melanie"],["dc.contributor.author","Schneider, Lukas"],["dc.contributor.author","Dominguez-Vargas, Adan-Ulises"],["dc.contributor.author","Schmidt-Samoa, Carsten"],["dc.contributor.author","Miloserdov, Kristina"],["dc.contributor.author","Nazzal, Ahmad"],["dc.contributor.author","Dechent, Peter"],["dc.contributor.author","Cabral-Calderin, Yuranny"],["dc.contributor.author","Scherberger, Hansjörg"],["dc.contributor.author","Kagan, Igor"],["dc.contributor.author","Bähr, Mathias"],["dc.date.accessioned","2018-02-08T10:49:56Z"],["dc.date.available","2018-02-08T10:49:56Z"],["dc.date.issued","2018-02"],["dc.description.abstract","Expansion of the dorsal pulvinar in humans and its anatomical connectivity suggests its involvement in higher-order cognitive and visuomotor functions. We investigated visuomotor performance in a 31 year old patient (M.B.) with a lesion centered on the medial portion of the dorsal pulvinar (left > right) due to an atypical Sarcoidosis manifestation. Unlike lesions with a vascular etiology, the lesion of M.B. did not include primary sensory or motor thalamic nuclei. Thus, this patient gave us the exceedingly rare opportunity to study the contribution of the dorsal pulvinar to visuomotor behavior in a human without confounding losses in primary sensory or motor domains. We investigated reaching, saccade and visual decision making performance. Patient data in each task was compared to at least seven age matched healthy controls. While saccades were hypometric towards both hemifields, the patient did not show any spatial choice bias or perceptual deficits. At the same time, he exhibited reach and grasp difficulties, which shared features with both, parietal and cerebellar damage. In particular, he had problems to form a precision grip and exhibited reach deficits expressed in decreased accuracy, delayed initiation and prolonged movement durations. Reach deficits were similar in foveal and extrafoveal viewing conditions and in both visual hemifields but were stronger with the right hand. These results suggest that dorsal pulvinar function in humans goes beyond its subscribed role in visual cognition and is critical for the programming of voluntary actions with the hands."],["dc.identifier.doi","10.1016/j.cortex.2017.10.011"],["dc.identifier.pmid","29216478"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/12057"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.doi","10.1016/j.cortex.2017.10.011"],["dc.relation.eissn","1973-8102"],["dc.relation.issn","1973-8102"],["dc.title","Reach and grasp deficits following damage to the dorsal pulvinar"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","102076"],["dc.bibliographiccitation.journal","NeuroImage: Clinical"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Miloserdov, Kristina"],["dc.contributor.author","Schmidt-Samoa, Carsten"],["dc.contributor.author","Williams, Kathleen"],["dc.contributor.author","Weinrich, Christiane Anne"],["dc.contributor.author","Kagan, Igor"],["dc.contributor.author","Bürk, Katrin"],["dc.contributor.author","Trenkwalder, Claudia"],["dc.contributor.author","Bähr, Mathias"],["dc.contributor.author","Wilke, Melanie"],["dc.date.accessioned","2020-12-10T15:20:31Z"],["dc.date.available","2020-12-10T15:20:31Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.1016/j.nicl.2019.102076"],["dc.identifier.issn","2213-1582"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16784"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/72695"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.intern","Merged from goescholar"],["dc.rights","CC BY-NC-ND 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by-nc-nd/4.0"],["dc.title","Aberrant functional connectivity of resting state networks related to misperceptions and intra-individual variability in Parkinson‘s disease"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","124"],["dc.bibliographiccitation.journal","Journal of Visualized Experiments"],["dc.contributor.author","Williams, Kathleen A."],["dc.contributor.author","Cabral-Calderin, Yuranny"],["dc.contributor.author","Schmidt-Samoa, Carsten"],["dc.contributor.author","Weinrich, Christiane Anne"],["dc.contributor.author","Dechent, Peter"],["dc.contributor.author","Wilke, Melanie"],["dc.date.accessioned","2018-10-10T09:02:41Z"],["dc.date.available","2018-10-10T09:02:41Z"],["dc.date.issued","2017"],["dc.description.abstract","Transcranial alternating current stimulation (tACS) is a promising tool for noninvasive investigation of brain oscillations. TACS employs frequency-specific stimulation of the human brain through current applied to the scalp with surface electrodes. Most current knowledge of the technique is based on behavioral studies; thus, combining the method with brain imaging holds potential to better understand the mechanisms of tACS. Because of electrical and susceptibility artifacts, combining tACS with brain imaging can be challenging, however, one brain imaging technique that is well suited to be applied simultaneously with tACS is functional magnetic resonance imaging (fMRI). In our lab, we have successfully combined tACS with simultaneous fMRI measurements to show that tACS effects are state, current, and frequency dependent, and that modulation of brain activity is not limited to the area directly below the electrodes. This article describes a safe and reliable setup for applying tACS simultaneously with visual task fMRI studies, which can lend to understanding oscillatory brain function as well as the effects of tACS on the brain."],["dc.fs.pkfprnr","60165"],["dc.identifier.doi","10.3791/55866"],["dc.identifier.fs","633451"],["dc.identifier.pmid","28605386"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15927"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1940-087X"],["dc.title","Simultaneous Transcranial Alternating Current Stimulation and Functional Magnetic Resonance Imaging"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]