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  • 1
    Online Resource
    Online Resource
    Society for Neuroscience ; 2018
    In:  The Journal of Neuroscience Vol. 38, No. 20 ( 2018-05-16), p. 4738-4748
    In: The Journal of Neuroscience, Society for Neuroscience, Vol. 38, No. 20 ( 2018-05-16), p. 4738-4748
    Abstract: In visual search, the more one knows about a target, the faster one can find it. Surprisingly, target identification is also faster with knowledge about distractor-features. The latter is paradoxical, as it implies that to avoid the selection of an item, the item must somehow be selected to some degree. This conundrum has been termed the “ignoring paradox”, and, to date, little is known about how the brain resolves it. Here, in data from four experiments using neuromagnetic brain recordings in male and female humans, we provide evidence that this paradox is resolved by giving distracting information priority in cortical processing. This attentional priority to distractors manifests as an enhanced early neuromagnetic index, which occurs before target-related processing, and regardless of distractor predictability. It is most pronounced on trials for which a response rapidly occurred, and is followed by a suppression of the distracting information. These observations together suggest that in visual search items cannot be ignored without first being selected. SIGNIFICANCE STATEMENT How can we ignore distracting stimuli in our environment? To do this successfully, a logical hypothesis is that as few neural resources as possible should be devoted to distractor processing. Yet, to avoid devoting resources to a distractor, the brain must somehow mark what to avoid; this is a philosophical problem, which has been termed the “ignoring paradox” or “white bear phenomenon”. Here, we use MEG recordings to determine how the human brain resolves this paradox. Our data show that distractors are not only processed, they are given temporal priority, with the brain building a robust representation of the to-be-ignored items. Thus, successful suppression of distractors can only be achieved if distractors are first strongly neurally represented.
    Type of Medium: Online Resource
    ISSN: 0270-6474 , 1529-2401
    Language: English
    Publisher: Society for Neuroscience
    Publication Date: 2018
    detail.hit.zdb_id: 1475274-8
    SSG: 12
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  • 2
    In: Carbohydrate Polymers, Elsevier BV, Vol. 229 ( 2020-02), p. 115452-
    Type of Medium: Online Resource
    ISSN: 0144-8617
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
    detail.hit.zdb_id: 1501516-6
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  • 3
    In: Carbohydrate Polymers, Elsevier BV, Vol. 246 ( 2020-10), p. 116652-
    Type of Medium: Online Resource
    ISSN: 0144-8617
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
    detail.hit.zdb_id: 1501516-6
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  • 4
    In: The Journal of Neuroscience, Society for Neuroscience, Vol. 37, No. 43 ( 2017-10-25), p. 10346-10357
    Abstract: Attention can facilitate the selection of elementary object features such as color, orientation, or motion. This is referred to as feature-based attention and it is commonly attributed to a modulation of the gain and tuning of feature-selective units in visual cortex. Although gain mechanisms are well characterized, little is known about the cortical processes underlying the sharpening of feature selectivity. Here, we show with high-resolution magnetoencephalography in human observers (men and women) that sharpened selectivity for a particular color arises from feedback processing in the human visual cortex hierarchy. To assess color selectivity, we analyze the response to a color probe that varies in color distance from an attended color target. We find that attention causes an initial gain enhancement in anterior ventral extrastriate cortex that is coarsely selective for the target color and transitions within ∼100 ms into a sharper tuned profile in more posterior ventral occipital cortex. We conclude that attention sharpens selectivity over time by attenuating the response at lower levels of the cortical hierarchy to color values neighboring the target in color space. These observations support computational models proposing that attention tunes feature selectivity in visual cortex through backward-propagating attenuation of units less tuned to the target. SIGNIFICANCE STATEMENT Whether searching for your car, a particular item of clothing, or just obeying traffic lights, in everyday life, we must select items based on color. But how does attention allow us to select a specific color? Here, we use high spatiotemporal resolution neuromagnetic recordings to examine how color selectivity emerges in the human brain. We find that color selectivity evolves as a coarse to fine process from higher to lower levels within the visual cortex hierarchy. Our observations support computational models proposing that feature selectivity increases over time by attenuating the responses of less-selective cells in lower-level brain areas. These data emphasize that color perception involves multiple areas across a hierarchy of regions, interacting with each other in a complex, recursive manner.
    Type of Medium: Online Resource
    ISSN: 0270-6474 , 1529-2401
    Language: English
    Publisher: Society for Neuroscience
    Publication Date: 2017
    detail.hit.zdb_id: 1475274-8
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 2015
    In:  Cerebral Cortex Vol. 25, No. 9 ( 2015-09), p. 2828-2841
    In: Cerebral Cortex, Oxford University Press (OUP), Vol. 25, No. 9 ( 2015-09), p. 2828-2841
    Type of Medium: Online Resource
    ISSN: 1047-3211 , 1460-2199
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2015
    detail.hit.zdb_id: 1483485-6
    SSG: 12
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  • 6
    In: Journal of Neural Engineering, IOP Publishing, Vol. 17, No. 5 ( 2020-10-01), p. 056012-
    Abstract: Objective. One of the main goals of brain-computer interfaces (BCI) is to restore communication abilities in patients. BCIs often use event-related potentials (ERPs) like the P300 which signals the presence of a target in a stream of stimuli. The P300 and related approaches, however, are inherently limited, as they require many stimulus presentations to obtain a usable control signal. Many approaches depend on gaze direction to focus the target, which is also not a viable approach in many cases, because eye movements might be impaired in potential users. Here we report on a BCI that avoids both shortcomings by decoding spatial target information, independent of gaze shifts. Approach. We present a new method to decode from the electroencephalogram (EEG) covert shifts of attention to one out of four targets simultaneously presented in the left and right visual field. The task is designed to evoke the N2pc component—a hemisphere lateralized response, elicited over the occipital scalp contralateral to the attended target. The decoding approach involves decoding of the N2pc based on data-driven estimation of spatial filters and a correlation measure. Main results. Despite variability of decoding performance across subjects, 22 out of 24 subjects performed well above chance level. Six subjects even exceeded 80% (cross-validated: 89%) correct predictions in a four-class discrimination task. Hence, the single-trial N2pc proves to be a component that allows for reliable BCI control. An offline analysis of the EEG data with respect to their dependence on stimulation time and number of classes demonstrates that the present method is also a workable approach for two-class tasks. Significance. Our method extends the range of strategies for gaze-independent BCI control. The proposed decoding approach has the potential to be efficient in similar applications intended to decode ERPs.
    Type of Medium: Online Resource
    ISSN: 1741-2560 , 1741-2552
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 2135187-9
    SSG: 12
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  • 7
    In: Journal of Agricultural and Food Chemistry, American Chemical Society (ACS), Vol. 66, No. 7 ( 2018-02-21), p. 1678-1692
    Type of Medium: Online Resource
    ISSN: 0021-8561 , 1520-5118
    Language: English
    Publisher: American Chemical Society (ACS)
    Publication Date: 2018
    detail.hit.zdb_id: 1483109-0
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  • 8
    Online Resource
    Online Resource
    MIT Press ; 2016
    In:  Journal of Cognitive Neuroscience Vol. 28, No. 4 ( 2016-04-01), p. 529-541
    In: Journal of Cognitive Neuroscience, MIT Press, Vol. 28, No. 4 ( 2016-04-01), p. 529-541
    Abstract: When a stimulus is associated with a reward, it becomes prioritized, and the allocation of attention to that stimulus increases. For low-level features, such as color, this reward-based allocation of attention can manifest early in time and as a faster and stronger shift of attention to targets with that color, as reflected by the N2pc (a parieto-occipital electrophysiological component peaking at ∼250 msec). It is unknown, however, if reward associations can similarly modulate attentional shifts to complex objects or object categories, or if reward-related modulation of attentional allocation to such stimuli would occur later in time or through a different mechanism. Here, we used magnetoencephalographic recordings in 24 participants to investigate how object categories with a reward association would modulate the shift of attention. On each trial, two colored squares were presented, one in a target color and the other in a distractor color, each with an embedded object. Participants searched for the target-colored square and performed a corner discrimination task. The embedded objects were from either a rewarded or non-rewarded category, and if a rewarded-category object were present within the target-colored square, participants could earn extra money for correct performance. We observed that when the target color contained an object from a rewarded versus a non-rewarded category, the neural shift of attention to the target was faster and of greater magnitude, although the rewarded objects were not relevant for correct task performance. These results suggest that reward associations of complex objects can rapidly modulate attentional allocation to a target.
    Type of Medium: Online Resource
    ISSN: 0898-929X , 1530-8898
    Language: English
    Publisher: MIT Press
    Publication Date: 2016
    SSG: 5,2
    SSG: 7,11
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  • 9
    In: Cerebral Cortex Communications, Oxford University Press (OUP), Vol. 2, No. 1 ( 2021-01-01)
    Abstract: Mind-wandering (MW) is a subjective, cognitive phenomenon, in which thoughts move away from the task toward an internal train of thoughts, possibly during phases of neuronal sleep-like activity (local sleep, LS). MW decreases cortical processing of external stimuli and is assumed to decouple attention from the external world. Here, we directly tested how indicators of LS, cortical processing, and attentional selection change in a pop-out visual search task during phases of MW. Participants’ brain activity was recorded using magnetoencephalography, MW was assessed via self-report using randomly interspersed probes. As expected, the performance decreased under MW. Consistent with the occurrence of LS, MW was accompanied by a decrease in high-frequency activity (HFA, 80–150 Hz) and an increase in slow wave activity (SWA, 1–6 Hz). In contrast, visual attentional selection as indexed by the N2pc component was enhanced during MW with the N2pc amplitude being directly linked to participants’ performance. This observation clearly contradicts accounts of attentional decoupling that would predict a decrease in attention-related responses to external stimuli during MW. Together, our results suggest that MW occurs during phases of LS with processes of attentional target selection being upregulated, potentially to compensate for the mental distraction during MW.
    Type of Medium: Online Resource
    ISSN: 2632-7376
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 3040464-2
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