Category: Journal of Cognitive Neuroscience

Spectral Diversity in Default Mode Network Connectivity Reflects Behavioral State

Spectral Diversity in Default Mode Network Connectivity Reflects Behavioral State

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 526-539

Abstract
“Default mode network (DMN) functional connectivity is thought to occur primarily in low frequencies (<0.1 Hz), resulting in most studies removing high frequencies during data preprocessing. In contrast, subtractive task analyses include high frequencies, as these are thought to be task relevant. An emerging line of research explores resting fMRI data at higher-frequency bands, examining the possibility that functional connectivity is a multiband phenomenon. Furthermore, recent studies suggest DMN involvement in cognitive processing; however, without a systematic investigation of DMN connectivity during tasks, its functional contribution to cognition cannot be fully understood. We bridged these concurrent lines of research by examining the contribution of high frequencies in the relationship between DMN and dorsal attention network at rest and during task execution. Our findings revealed that the inclusion of high frequencies alters between network connectivity, resulting in reduced anticorrelation and increased positive connectivity between DMN and dorsal attention network. Critically, increased positive connectivity was observed only during tasks, suggesting an important role for high-frequency fluctuations in functional integration. Moreover, within-DMN connectivity during task execution correlated with RT only when high frequencies were included. These results show that DMN does not simply deactivate during task execution and suggest active recruitment while performing cognitively demanding paradigms.”

Written by: Michael M. Craig, Anne E. Manktelow, Barbara J. Sahakian, David K. Menon, Emmanuel A. Stamatakis
For full text: https://doi.org/10.1162/jocn_a_01213

The Neural Basis of Successful Word Reading in Aphasia

The Neural Basis of Successful Word Reading in Aphasia

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 514-525

Abstract
“Understanding the neural basis of recovery from stroke is a major research goal. Many functional neuroimaging studies have identified changes in brain activity in people with aphasia, but it is unclear whether these changes truly support successful performance or merely reflect increased task difficulty. We addressed this problem by examining differences in brain activity associated with correct and incorrect responses on an overt reading task. On the basis of previous proposals that semantic retrieval can assist pronunciation of written words, we hypothesized that recruitment of semantic areas would be greater on successful trials. Participants were 21 patients with left-hemisphere stroke with phonologic retrieval deficits. They read words aloud during an event-related fMRI paradigm. BOLD signals obtained during correct and incorrect trials were contrasted to highlight brain activity specific to successful trials. Successful word reading was associated with higher BOLD signal in the left angular gyrus. In contrast, BOLD signal in bilateral posterior inferior frontal cortex, SMA, and anterior cingulate cortex was greater on incorrect trials. These data show for the first time the brain regions where neural activity is correlated specifically with successful performance in people with aphasia. The angular gyrus is a key node in the semantic network, consistent with the hypothesis that additional recruitment of the semantic system contributes to successful word production when phonologic retrieval is impaired. Higher activity in other brain regions during incorrect trials likely reflects secondary engagement of attention, working memory, and error monitoring processes when phonologic retrieval is unsuccessful.”

Written by: Sara B. Pillay, William L. Gross, William W. Graves, Colin Humphries, Diane S. Book, Jeffrey R. Binder
For full text: https://doi.org/10.1162/jocn_a_01214

Hearing Shapes: Event-related Potentials Reveal the Time Course of Auditory–Visual Sensory Substitution

Hearing Shapes: Event-related Potentials Reveal the Time Course of Auditory–Visual Sensory Substitution

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 498-513

Abstract
“In auditory–visual sensory substitution, visual information (e.g., shape) can be extracted through strictly auditory input (e.g., soundscapes). Previous studies have shown that image-to-sound conversions that follow simple rules [such as the Meijer algorithm; Meijer, P. B. L. An experimental system for auditory image representation. Transactions on Biomedical Engineering, 39, 111–121, 1992] are highly intuitive and rapidly learned by both blind and sighted individuals. A number of recent fMRI studies have begun to explore the neuroplastic changes that result from sensory substitution training. However, the time course of cross-sensory information transfer in sensory substitution is largely unexplored and may offer insights into the underlying neural mechanisms. In this study, we recorded ERPs to soundscapes before and after sighted participants were trained with the Meijer algorithm. We compared these posttraining versus pretraining ERP differences with those of a control group who received the same set of 80 auditory/visual stimuli but with arbitrary pairings during training. Our behavioral results confirmed the rapid acquisition of cross-sensory mappings, and the group trained with the Meijer algorithm was able to generalize their learning to novel soundscapes at impressive levels of accuracy. The ERP results revealed an early cross-sensory learning effect (150–210 msec) that was significantly enhanced in the algorithm-trained group compared with the control group as well as a later difference (420–480 msec) that was unique to the algorithm-trained group. These ERP modulations are consistent with previous fMRI results and provide additional insight into the time course of cross-sensory information transfer in sensory substitution.”

Written by: Christian Graulty, Orestis Papaioannou, Phoebe Bauer, Michael A. Pitts, Enriqueta Canseco-Gonzalez
For full text: https://doi.org/10.1162/jocn_a_01210

Event-related Electroencephalographic Lateralizations Mark Individual Differences in Spatial and Nonspatial Visual Selection

Event-related Electroencephalographic Lateralizations Mark Individual Differences in Spatial and Nonspatial Visual Selection

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 482-497

Abstract
“Selective attention controls the distribution of our visual system’s limited processing resources to stimuli in the visual field. Two independent parameters of visual selection can be quantified by modeling an individual’s performance in a partial-report task based on the computational theory of visual attention (TVA): (i) top–down control α, the relative attentional weighting of relevant over irrelevant stimuli, and (ii) spatial bias wλ, the relative attentional weighting of stimuli in the left versus right hemifield. In this study, we found that visual event-related electroencephalographic lateralizations marked interindividual differences in these two functions. First, individuals with better top–down control showed higher amplitudes of the posterior contralateral negativity than individuals with poorer top–down control. Second, differences in spatial bias were reflected in asymmetries in earlier visual event-related lateralizations depending on the hemifield position of targets; specifically, individuals showed a positivity contralateral to targets presented in their prioritized hemifield and a negativity contralateral to targets presented in their nonprioritized hemifield. Thus, our findings demonstrate that two functionally different aspects of attentional weighting quantified in the respective TVA parameters are reflected in two different neurophysiological measures: The observer-dependent spatial bias influences selection by a bottom–up processing advantage of stimuli appearing in the prioritized hemifield. By contrast, task-related target selection governed by top–down control involves active enhancement of target, and/or suppression of distractor, processing. These results confirm basic assumptions of the TVA framework, complement the functional interpretation of event-related lateralization components in selective attention studies, and are of relevance for the development of neurocognitive attentional assessment procedures.”

Written by: Iris Wiegand, Natan Napiorkowski, Thomas Tollner, Anders Petersen, Thomas Habeskot, Hermann J. Müller, Kathrin Finke
For full text: https://doi.org/10.1162/jocn_a_01221

Oscillatory Mechanisms of Response Conflict Elicited by Color and Motion Direction: An Individual Differences Approach

Oscillatory Mechanisms of Response Conflict Elicited by Color and Motion Direction: An Individual Differences Approach

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, 468-481

Abstract
“Goal-directed behavior requires control over automatic behavior, for example, when goal-irrelevant information from the environment captures an inappropriate response and conflicts with the correct, goal-relevant action. Neural oscillations in the theta band (∼6 Hz) measured at midfrontal electrodes are thought to form an important substrate of the detection and subsequent resolution of response conflict. Here, we examined the extent to which response conflict and associated theta-band activity depend on the visual stimulus feature dimension that triggers the conflict. We used a feature-based Simon task to manipulate conflict by motion direction and stimulus color. Analyses were focused on individual differences in behavioral response conflict elicited across different stimulus dimensions and their relationship to conflict-related midfrontal theta. We first confirmed the presence of response conflict elicited by task-irrelevant motion and stimulus color, demonstrating the usefulness of our modified version of the Simon task to assess different sensory origins of response conflict. Despite titrating overall task performance, we observed large individual differences in the behavioral manifestations of response conflict elicited by the different visual dimensions. These behavioral conflict effects were mirrored in a dimension-specific relationship with conflict-related midfrontal theta power, such that, for each dimension, individual midfrontal theta power was generally higher when experienced response conflict was high. Finally, exploratory analyses of interregional functional connectivity suggested a role for phase synchronization between frontal and parietal scalp sites in modulating experienced conflict when color was the task-relevant visual dimension. Highlighting the importance of an individual differences approach in cognitive neuroscience, these results reveal large individual differences in experienced response conflict depending on the source of visual interference, which are predicted by conflict-related midfrontal theta power.”

Written by: Marlies E. Vissers, K. Richard Ridderinkhof, Michael X. Cohen, Heleen A. Slagter
For full text: https://doi.org/10.1162/jocn_a_01222

Does Extensive Training at Individuating Novel Objects in Adulthood Lead to Visual Expertise? The Role of Facelikeness

Does Extensive Training at Individuating Novel Objects in Adulthood Lead to Visual Expertise? The Role of Facelikeness

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 449-467

Abstract
“Human adults have a rich visual experience thanks to seeing human faces since birth, which may contribute to the acquisition of perceptual processes that rapidly and automatically individuate faces. According to a generic visual expertise hypothesis, extensive experience with nonface objects may similarly lead to efficient processing of objects at the individual level. However, whether extensive training in adulthood leads to visual expertise remains debated. One key issue is the extent to which the acquisition of visual expertise depends on the resemblance of objects to faces in terms of the spatial configuration of parts. We therefore trained naive human adults to individuate a large set of novel parametric multipart objects. Critically, one group of participants trained with the objects in a “facelike” stimulus orientation, whereas a second group trained with the same objects but with the objects rotated 180° in the picture plane into a “nonfacelike” orientation. We used a fast periodic visual stimulation EEG protocol to objectively quantify participants’ ability to discriminate untrained exemplars before and after training. EEG responses associated with the frequency of identity change in a fast stimulation sequence, which reflects rapid and automatic perceptual processes, were observed over lateral occipital sites for both groups before training. There was a significant, albeit small, increase in these responses after training but only for the facelike group and only to facelike stimuli. Our findings indicate that perceived facelikeness plays a role in visual expertise and highlight how the adult perceptual system exploits familiar spatial configurations when learning new object categories.”

Written by: Aliette Lochy, Friederike G.S. Zimmermann, Renaud Laguesse, Verena Willenbockel
For full text: https://doi.org/10.1162/jocn_a_01212

Control Changes the Way We Look at the World

Control Changes the Way We Look at the World

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 603-619

Abstract
“The feeling of control is a fundamental aspect of human experience and accompanies our voluntary actions all the time. However, how the sense of control interacts with wider perception, cognition, and behavior remains poorly understood. This study focused on how controlling an external object influences the allocation of attention. Experiment 1 examined attention to an object that is under a different level of control from the others. Participants searched for a target among multiple distractors on screen. All the distractors were partially under the participant’s control (50% control level), and the search target was either under more or less control than the distractors. The results showed that, against this background of partial control, visual attention was attracted to an object only if it was more controlled than other available objects and not if it was less controlled. Experiment 2 examined attention allocation in contexts of either perfect control or no control over most of the objects. Specifically, the distractors were under either perfect (100%) control or no (0%) control, and the search target had one of six levels of control varying from 0% to 100%. When differences in control between the distractors and the target were small, visual attention was now more strongly drawn to search targets that were less controlled than distractors, rather than more controlled, suggesting attention to objects over which one might be losing control. Experiment 3 studied the events of losing or gaining control as opposed to the states of having or not having control. ERP measures showed that P300 amplitude proportionally encoded the magnitude of both increases and decreases in degree of control. However, losing control had more marked effects on P170 and P300 than gaining an equivalent degree of control, indicating high priority for efficiently detecting failures of control. Overall, our results suggest that controlled objects preferentially attract attention in uncontrolled environments. However, once control has been registered, the brain becomes highly sensitive to subsequent loss of control. Our findings point toward careful perceptual monitoring of degree of one’s own agentic control over external objects. We suggest that control has intrinsic cognitive value because perceptual systems are organized to detect it and, once it has been acquired, to maintain it.”

Written by: Wen Wen, Patrick Haggard
For full text: https://doi.org/10.1162/jocn_a_01226

Cross-frequency Phase–Amplitude Coupling as a Mechanism for Temporal Orienting of Attention in Childhood

Cross-frequency Phase–Amplitude Coupling as a Mechanism for Temporal Orienting of Attention in Childhood

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 594-602

Abstract
“Temporal orienting of attention operates by biasing the allocation of cognitive and motor resources in specific moments in time, resulting in the improved processing of information from expected compared with unexpected targets. Recent findings have shown that temporal orienting operates relatively early across development, suggesting that this attentional mechanism plays a core role for human cognition. However, the exact neurophysiological mechanisms allowing children to attune their attention over time are not well understood. In this study, we presented 8- to 12-year-old children with a temporal cueing task designed to test (1) whether anticipatory oscillatory dynamics predict children’s behavioral performance on a trial-by-trial basis and (2) whether anticipatory oscillatory neural activity may be supported by cross-frequency phase–amplitude coupling as previously shown in adults. Crucially, we found that, similar to what has been reported in adults, children’s ongoing beta rhythm was strongly coupled with their theta rhythm and that the strength of this coupling distinguished validly cued temporal intervals, relative to neutral cued trials. In addition, in long trials, there was an inverse correlation between oscillatory beta power and children’s trial-by-trial reaction, consistent with oscillatory beta power reflecting better response preparation. These findings provide the first experimental evidence that temporal attention in children operates by exploiting oscillatory mechanism.”

Written by: Giovanni Mento, Duncan E. Astle, Gaia Scerif
For full text: https://doi.org/10.1162/jocn_a_01223

Memory Contextualization: The Role of Prefrontal Cortex in Functional Integration across Item and Context Representational Regions

Memory Contextualization: The Role of Prefrontal Cortex in Functional Integration across Item and Context Representational Regions

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 579-593

Abstract
“Memory recall is facilitated when retrieval occurs in the original encoding context. This context dependency effect likely results from the automatic binding of central elements of an experience with contextual features (i.e., memory “contextualization”) during encoding. However, despite a vast body of research investigating the neural correlates of explicit associative memory, the neural interactions during encoding that predict implicit context-dependent memory remain unknown. Twenty-six participants underwent fMRI during encoding of salient stimuli (faces), which were overlaid onto unique background images (contexts). To index subsequent context-dependent memory, face recognition was tested either in intact or rearranged contexts, after scanning. Enhanced face recognition in intact relative to rearranged contexts evidenced successful memory contextualization. Overall subsequent memory effects (brain activity predicting whether items were later remembered vs. forgotten) were found in the left inferior frontal gyrus (IFG) and right amygdala. Effective connectivity analyses showed that stronger context-dependent memory was associated with stronger coupling of the left IFG with face- and place-responsive areas, both within and between participants. Our findings indicate an important role for the IFG in integrating information across widespread regions involved in the representation of salient items and contextual features.”

Written by: Wei Zhang, Vanessa A. van Ast, Floris Klumpers, Karin Roelofs, Erno J. Hermans
For full text: https://doi.org/10.1162/jocn_a_01218

Sex, Sleep Deprivation, and the Anxious Brain

Sex, Sleep Deprivation, and the Anxious Brain

Published in: Journal of Cognitive Neuroscience, Volume 30, Issue 4, April 2018, 565-578

Abstract
“Insufficient sleep is a known trigger of anxiety. Nevertheless, not everyone experiences these effects to the same extent. One determining factor is sex, wherein women experience a greater anxiogenic impact in response to sleep loss than men. However, the underlying brain mechanism(s) governing this sleep-loss-induced anxiety increase, including the markedly different reaction in women and men, is unclear. Here, we tested the hypothesis that structural brain morphology in a discrete network of emotion-relevant regions represents one such explanatory factor. Healthy participants were assessed across sleep-rested and sleep-deprived conditions, with brain structure quantified using gray matter volume measures. Sleep loss triggered greater levels of anxiety in women compared with men. Reduced gray matter volume in the anterior insula and lateral orbitofrontal cortex predicted the anxiogenic impact of sleep loss in women, yet predicted resilience in men, and did so with high discrimination accuracy. In contrast, gray matter volume in ventromedial prefrontal cortex predicted the anxiogenic impact of sleep loss in both men and women. Structural human brain morphology therefore appears to represent one mechanistic pathway (and possible biomarker) determining anxiety vulnerability to sleep loss—a discovery that may help explain the higher prevalence of sleep disruption and anxiety in women.”

Written by: Andrea N. Goldstein-Piekarski, Stephanie M. Greer, Jared M. Saletin, Allison G. Harvey
For full text: https://doi.org/10.1162/jocn_a_01225

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