Schwiedrzik, Caspar

[["dc.bibliographiccitation.firstpage","2960-6"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","The Journal of Neuroscience"],["dc.bibliographiccitation.lastpage","2966"],["dc.bibliographiccitation.volume","30"],["dc.contributor.author","Alink, Arjen"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Kohler, Axel"],["dc.contributor.author","Singer, Wolf"],["dc.contributor.author","Muckli, Lars"],["dc.date.accessioned","2020-09-14T07:24:30Z"],["dc.date.available","2020-09-14T07:24:30Z"],["dc.date.issued","2010-02-24"],["dc.description.abstract","In this functional magnetic resonance imaging study we tested whether the predictability of stimuli affects responses in primary visual cortex (V1). The results of this study indicate that visual stimuli evoke smaller responses in V1 when their onset or motion direction can be predicted from the dynamics of surrounding illusory motion. We conclude from this finding that the human brain anticipates forthcoming sensory input that allows predictable visual stimuli to be processed with less neural activation at early stages of cortical processing."],["dc.identifier.doi","10.1523/JNEUROSCI.3730-10.2010"],["dc.identifier.pmid","20181593"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67673"],["dc.language.iso","en"],["dc.relation.eissn","1529-2401"],["dc.relation.issn","0270-6474"],["dc.relation.issn","1529-2401"],["dc.title","Stimulus predictability reduces responses in primary visual cortex"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1152-64"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Cerebral Cortex"],["dc.bibliographiccitation.lastpage","1164"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Ruff, Christian C"],["dc.contributor.author","Lazar, Andreea"],["dc.contributor.author","Leitner, Frauke C"],["dc.contributor.author","Singer, Wolf"],["dc.contributor.author","Melloni, Lucia"],["dc.date.accessioned","2020-09-14T07:24:59Z"],["dc.date.available","2020-09-14T07:24:59Z"],["dc.date.issued","2014-05"],["dc.description.abstract","Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain \"decide\" what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function)."],["dc.identifier.doi","10.1093/cercor/bhs396"],["dc.identifier.pmid","23236204"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67676"],["dc.language.iso","en"],["dc.relation.eissn","1460-2199"],["dc.relation.issn","1460-2199"],["dc.relation.issn","1047-3211"],["dc.title","Untangling perceptual memory: hysteresis and adaptation map into separate cortical networks"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","18.1-18"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Journal of Vision"],["dc.bibliographiccitation.lastpage","18"],["dc.bibliographiccitation.volume","9"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Singer, Wolf"],["dc.contributor.author","Melloni, Lucia"],["dc.date.accessioned","2020-09-14T07:24:18Z"],["dc.date.available","2020-09-14T07:24:18Z"],["dc.date.issued","2009-09-25"],["dc.description.abstract","Can practice effects on unconscious stimuli lead to awareness? Can we \"learn to see\"? Recent evidence suggests that blindsight patients trained for an extensive period of time can learn to discriminate and consciously perceive stimuli that they were previously unaware of. So far, it is unknown whether these effects generalize to normal observers. Here we investigated practice effects in metacontrast masking. Subjects were trained for five consecutive days on the stimulus onset asynchrony (SOA) that resulted in chance performance. Our results show a linear increase in sensitivity (d') but no change in bias (c) for the trained SOA. This practice effect on sensitivity spreads to all tested SOAs. Additionally, we show that subjects rate their perceptual awareness of the target stimuli differently before and after training, exhibiting not only an increase in sensitivity, but also in the subjective awareness of the percept. Thus, subjects can indeed \"learn to see.\""],["dc.identifier.doi","10.1167/9.10.18"],["dc.identifier.pmid","19810799"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67672"],["dc.language.iso","en"],["dc.relation.eissn","1534-7362"],["dc.relation.issn","1534-7362"],["dc.title","Sensitivity and perceptual awareness increase with practice in metacontrast masking"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3424-33"],["dc.bibliographiccitation.issue","28"],["dc.bibliographiccitation.journal","Vision Research"],["dc.bibliographiccitation.lastpage","3433"],["dc.bibliographiccitation.volume","47"],["dc.contributor.author","Schwiedrzik, Caspar M."],["dc.contributor.author","Alink, Arjen"],["dc.contributor.author","Kohler, Axel"],["dc.contributor.author","Singer, Wolf"],["dc.contributor.author","Muckli, Lars"],["dc.date.accessioned","2020-09-14T07:24:07Z"],["dc.date.available","2020-09-14T07:24:07Z"],["dc.date.issued","2007-12"],["dc.description.abstract","During the perception of apparent motion, activity along the apparent motion trace has been found in the primary visual cortex. It has been hypothesized that this activity interferes with stimuli presented on the apparent motion trace (\"motion masking\"). We investigated whether this perceptual interference varies with regard to the trajectory of a moving object token in a detection task. We found a general decrease of detectability of targets presented on the trace. Surprisingly, targets presented in time with the trajectory were detected significantly more often than targets which appeared out of time. We relate this finding to a spatio-temporally specific prediction of visual events along the apparent motion trace."],["dc.identifier.doi","10.1016/j.visres.2007.10.004"],["dc.identifier.pmid","18053847"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67671"],["dc.language.iso","en"],["dc.relation.issn","0042-6989"],["dc.title","A spatio-temporal interaction on the apparent motion trace"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","8-10; author reply 10-12"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Neuron"],["dc.bibliographiccitation.lastpage","10"],["dc.bibliographiccitation.volume","62"],["dc.contributor.author","Melloni, Lucia"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Wibral, Michael"],["dc.contributor.author","Rodriguez, Eugenio"],["dc.contributor.author","Singer, Wolf"],["dc.date.accessioned","2020-09-14T07:25:53Z"],["dc.date.available","2020-09-14T07:25:53Z"],["dc.date.issued","2009-04-16"],["dc.identifier.doi","10.1016/j.neuron.2009.04.002"],["dc.identifier.pmid","19376062"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67684"],["dc.language.iso","en"],["dc.relation.eissn","1097-4199"],["dc.relation.issn","0896-6273"],["dc.title","Response to: Yuval-Greenberg et al., \"Transient Induced Gamma-Band Response in EEG as a Manifestation of Miniature Saccades.\" Neuron 58, 429-441"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4506-11"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Proceedings of the National Academy of Sciences of the United States of America"],["dc.bibliographiccitation.lastpage","4511"],["dc.bibliographiccitation.volume","108"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Singer, Wolf"],["dc.contributor.author","Melloni, Lucia"],["dc.date.accessioned","2020-09-14T07:24:49Z"],["dc.date.available","2020-09-14T07:24:49Z"],["dc.date.issued","2011-03-15"],["dc.description.abstract","Perceptual learning not only improves sensitivity, but it also changes our subjective experience. However, the question of how these two learning effects relate is largely unexplored. Here we investigate how subjects learn to see initially indiscriminable metacontrast-masked shapes. We find that sensitivity and subjective awareness increase with training. However, sensitivity and subjective awareness dissociate in space: Learning effects on performance are lost when the task is performed at an untrained location in another quadrant, whereas learning effects on subjective awareness are maintained. This finding indicates that improvements in shape sensitivity involve visual areas up to V4, whereas changes in subjective awareness involve other brain regions. Furthermore, subjective awareness dissociates from sensitivity in time: In an early phase of perceptual learning, subjects perform above chance on trials that they rate as subjectively invisible. Later, this phenomenon disappears. Subjective awareness is thus neither necessary nor sufficient for achieving above-chance objective performance."],["dc.identifier.doi","10.1073/pnas.1009147108"],["dc.identifier.pmid","21368168"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67675"],["dc.language.iso","en"],["dc.relation.eissn","1091-6490"],["dc.relation.issn","0027-8424"],["dc.relation.issn","1091-6490"],["dc.title","Subjective and objective learning effects dissociate in space and in time"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1386-96"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","The Journal of Neuroscience"],["dc.bibliographiccitation.lastpage","1396"],["dc.bibliographiccitation.volume","31"],["dc.contributor.author","Melloni, Lucia"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Müller, Notger"],["dc.contributor.author","Rodriguez, Eugenio"],["dc.contributor.author","Singer, Wolf"],["dc.date.accessioned","2020-09-14T07:24:42Z"],["dc.date.available","2020-09-14T07:24:42Z"],["dc.date.issued","2011-01-26"],["dc.description.abstract","Previous experience allows the brain to predict what comes next. How these expectations affect conscious experience is poorly understood. In particular, it is unknown whether and when expectations interact with sensory evidence in granting access to conscious perception, and how this is reflected electrophysiologically. Here, we parametrically manipulate sensory evidence and expectations while measuring event-related potentials in human subjects to assess the time course of evoked responses that correlate with subjective visibility, the properties of the stimuli, and/or perceptual expectations. We found that expectations lower the threshold of conscious perception and reduce the latency of neuronal signatures differentiating seen and unseen stimuli. Without expectations, this differentiation occurs ∼300 ms and with expectations ∼200 ms after stimulus in occipitoparietal sensors. The amplitude of this differentiating response component (P2) decreases as visibility increases, regardless of whether this increase is attributable to enhanced sensory evidence and/or the gradual buildup of perceptual expectations. Importantly, at matched performance levels, responses to seen and unseen stimuli differed regardless of the physical stimulus properties. These findings indicate that the latency of the neuronal correlates of access to consciousness depend on whether access is driven by stimulus saliency or by a combination of expectations and sensory evidence."],["dc.identifier.doi","10.1523/JNEUROSCI.4570-10.2011"],["dc.identifier.pmid","21273423"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67674"],["dc.language.iso","en"],["dc.relation.eissn","1529-2401"],["dc.relation.issn","0270-6474"],["dc.relation.issn","1529-2401"],["dc.title","Expectations change the signatures and timing of electrophysiological correlates of perceptual awareness"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","239-45"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Trends in Cognitive Sciences"],["dc.bibliographiccitation.lastpage","245"],["dc.bibliographiccitation.volume","13"],["dc.contributor.author","Melloni, Lucia"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Rodriguez, Eugenio"],["dc.contributor.author","Singer, Wolf"],["dc.date.accessioned","2020-09-14T07:25:30Z"],["dc.date.available","2020-09-14T07:25:30Z"],["dc.date.issued","2009-06"],["dc.description.abstract","In natural vision, attention and eye movements are linked. Furthermore, eye movements structure the inflow of information into the visual system. Saccades, where little vision occurs, alternate with fixations, when most vision occurs. A mechanism must be in place to maximize information intake during fixations. Oscillatory synchrony has been proposed as a mechanism for rapid and reliable communication of signals, subserving cognitive functions such as attention and object identification. We propose that saccade-related corollary activity has a crucial role in anticipatory preparation of visual centers, which interacts with ongoing oscillation, favoring the processing of postfixational signals. During prolonged fixations, microsaccades could be generated to exploit this mechanism. Studying this interplay between the sensory and the motor system will provide novel insight into the dynamics of natural vision."],["dc.identifier.doi","10.1016/j.tics.2009.03.007"],["dc.identifier.pmid","19428286"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67681"],["dc.language.iso","en"],["dc.relation.issn","1364-6613"],["dc.title","(Micro)Saccades, corollary activity and cortical oscillations"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3146-60"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Cerebral Cortex"],["dc.bibliographiccitation.lastpage","3160"],["dc.bibliographiccitation.volume","26"],["dc.contributor.author","Mayer, Anna"],["dc.contributor.author","Schwiedrzik, Caspar M"],["dc.contributor.author","Wibral, Michael"],["dc.contributor.author","Singer, Wolf"],["dc.contributor.author","Melloni, Lucia"],["dc.date.accessioned","2020-09-14T07:25:05Z"],["dc.date.available","2020-09-14T07:25:05Z"],["dc.date.issued","2016"],["dc.description.abstract","Predictions strongly influence perception. However, the neurophysiological processes that implement predictions remain underexplored. It has been proposed that high- and low-frequency neuronal oscillations act as carriers of sensory evidence and top-down predictions, respectively (von Stein and Sarnthein 2000; Bastos et al. 2012). However, evidence for the latter hypothesis remains scarce. In particular, it remains to be shown whether slow prestimulus alpha oscillations in task-relevant brain regions are stronger in the presence of predictions, whether they influence early categorization processes, and whether this interplay indeed boosts perception. Here, we directly address these questions by manipulating subjects' prior expectations about the identity of visually presented letters while collecting magnetoencephalographic recordings. We find that predictions lead to increased prestimulus alpha oscillations in a multisensory network representing grapheme/phoneme associations. Furthermore, alpha power interacts with stimulus degradation and top-down expectations to predict visibility ratings, and correlates with the amplitude of early sensory components (P1/N1m complex), suggesting a role in the selective amplification of predicted information. Our results thus indicate that low-frequency alpha oscillations can serve as a mechanism to carry and test sensory predictions about letters."],["dc.identifier.doi","10.1093/cercor/bhv146"],["dc.identifier.pmid","26142463"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67677"],["dc.language.iso","en"],["dc.relation.eissn","1460-2199"],["dc.relation.issn","1047-3211"],["dc.relation.issn","1460-2199"],["dc.title","Expecting to See a Letter: Alpha Oscillations as Carriers of Top-Down Sensory Predictions"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]