scholarly journals Saccadic Adaptation Boosts Ongoing Gamma Activity in a Subsequent Visuoattentional Task

2018 ◽  
Vol 29 (9) ◽  
pp. 3606-3617 ◽  
Author(s):  
Judith Nicolas ◽  
Aline Bompas ◽  
Romain Bouet ◽  
Olivier Sillan ◽  
Eric Koun ◽  
...  
Keyword(s):  
Eye Movements ◽  
Right Hemisphere ◽  
Discrimination Performance ◽  
Gamma Oscillations ◽  
Gamma Activity ◽  
Functional Coupling ◽  
Saccadic Adaptation ◽  
Before And After ◽  
Critical Components ◽  
The Right

Abstract Attention and saccadic adaptation (SA) are critical components of visual perception, the former enhancing sensory processing of selected objects, the latter maintaining the eye movements accuracy toward them. Recent studies propelled the hypothesis of a tight functional coupling between these mechanisms, possibly due to shared neural substrates. Here, we used magnetoencephalography to investigate for the first time the neurophysiological bases of this coupling and of SA per se. We compared visual discrimination performance of 12 healthy subjects before and after SA. Eye movements and magnetic signals were recorded continuously. Analyses focused on gamma band activity (GBA) during the pretarget period of the discrimination and the saccadic tasks. We found that GBA increases after SA. This increase was found in the right hemisphere for both postadaptation saccadic and discrimination tasks. For the latter, GBA also increased in the left hemisphere. We conclude that oculomotor plasticity involves GBA modulation within an extended neural network which persists after SA, suggesting a possible role of gamma oscillations in the coupling between SA and attention.

scholarly journals Prefrontal High Gamma in ECoG tags periodicity of musical rhythms in perception and imagination

2019 ◽  
Author(s):  
S. A. Herff ◽  
C. Herff ◽  
A. J. Milne ◽  
G. D. Johnson ◽  
J. J. Shih ◽  
...  
Keyword(s):  
Auditory Processing ◽  
Right Hemisphere ◽  
Brain Activity ◽  
Activity Patterns ◽  
Superior Temporal Gyrus ◽  
Gamma Activity ◽  
Rhythm Perception ◽  
High Gamma ◽  
The Right ◽  
Musical Rhythms

AbstractRhythmic auditory stimuli are known to elicit matching activity patterns in neural populations. Furthermore, recent research has established the particular importance of high-gamma brain activity in auditory processing by showing its involvement in auditory phrase segmentation and envelope-tracking. Here, we use electrocorticographic (ECoG) recordings from eight human listeners, to see whether periodicities in high-gamma activity track the periodicities in the envelope of musical rhythms during rhythm perception and imagination. Rhythm imagination was elicited by instructing participants to imagine the rhythm to continue during pauses of several repetitions. To identify electrodes whose periodicities in high-gamma activity track the periodicities in the musical rhythms, we compute the correlation between the autocorrelations (ACC) of both the musical rhythms and the neural signals. A condition in which participants listened to white noise was used to establish a baseline. High-gamma autocorrelations in auditory areas in the superior temporal gyrus and in frontal areas on both hemispheres significantly matched the autocorrelation of the musical rhythms. Overall, numerous significant electrodes are observed on the right hemisphere. Of particular interest is a large cluster of electrodes in the right prefrontal cortex that is active during both rhythm perception and imagination. This indicates conscious processing of the rhythms’ structure as opposed to mere auditory phenomena. The ACC approach clearly highlights that high-gamma activity measured from cortical electrodes tracks both attended and imagined rhythms.

scholarly journals Virtual reality-based sensorimotor adaptation shapes subsequent spontaneous and naturalistic stimulus-driven brain activity

2021 ◽  
Author(s):  
Meytal Wilf ◽  
Celine Dupuis ◽  
Davide Nardo ◽  
Diana Huber ◽  
Sibilla Sander ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Large Scale ◽  
Right Hemisphere ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Visual Response ◽  
Spatial Shift ◽  
Before And After ◽  
Behavioural Tests ◽  
The Right

Our everyday life summons numerous novel sensorimotor experiences, to which our brain needs to adapt in order to function properly. However, tracking plasticity of naturalistic behaviour and associated brain modulations is challenging. Here we tackled this question implementing a prism adaptation training in virtual reality (VRPA) in combination with functional neuroimaging. Three groups of healthy participants (N=45) underwent VRPA (with a spatial shift either to the left/right side, or with no shift), and performed fMRI sessions before and after training. To capture modulations in free-flowing, task-free brain activity, the fMRI sessions included resting state and free viewing of naturalistic videos. We found significant decreases in spontaneous functional connectivity between large-scale cortical networks, namely attentional and default mode/fronto-parietal networks, only for adaptation groups. Additionally, VRPA was found to bias visual representations of naturalistic videos, as following rightward adaptation, we found upregulation of visual response in an area in the parieto-occipital sulcus (POS) in the right hemisphere. Notably, the extent of POS upregulation correlated with the size of the VRPA induced after-effect measured in behavioural tests. This study demonstrates that a brief VRPA exposure is able to change large-scale cortical connectivity and correspondingly bias the representation of naturalistic sensory inputs.

Transcranial Magnetic Stimulation of the Human Frontal Eye Field: Effects on Visual Perception and Attention

2002 ◽  
Vol 14 (7) ◽  
pp. 1109-1120 ◽  
Author(s):  
Marie-Hélène Grosbras ◽  
Tomáš Paus
Keyword(s):  
Eye Movements ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Visual Detection ◽  
Frontal Eye Field ◽  
Target Onset ◽  
Eye Field ◽  
The Right

When looking at one object, human subjects can shift their attention to another object in their visual field without moving the eyes. Such shifts of attention activate the same brain regions as those involved in the execution of eye movements. Here we investigate the role of one of the main cortical oculomotor area, namely, the frontal eye field (FEF), in shifts of attention. We used transcranial magnetic stimulation (TMS), a technique known to disrupt transiently eye-movements preparation. We hypothesized that if the FEF is a necessary element in the network involved in shifting attention without moving the eyes, then TMS should also disrupt visuospatial attention. For each volunteer, we positioned the TMS coil over the probabilistic anatomical location of the FEF, and we verified that single pulses delayed eye movements. We then applied TMS during a visuospatial attention task. In this task, a central arrow directed shifts of attention and the subject responded by a keypress to a subsequent visual peripheral target without moving the eyes from the central fixation point. In a few trials, the cue was invalid or uninformative, yielding slower responses than when the cue was valid. We delivered single pulses either 53 msec before or 70 msec after target onset. Contrary to our prediction, the main effect of the stimulation was a decrease in reaction time when it was applied 53 msec before target onset. TMS over the left hemisphere facilitated responses to targets in the right hemifield only and for all cueing conditions, whereas TMS over the right hemisphere had a bilateral effect for valid and neutral but not invalid cueing. Thus, TMS interfered with shift of attention only in the case of right hemisphere stimulation: it increased the cost of invalid cueing. Our results suggest that TMS over the FEF facilitates visual detection, and thereby reduces reaction time. This finding provides new insights into the role of the human FEF in processing visual information. The functional asymmetry observed for both facilitation of visual detection and interference with shifts of attention provides further evidence for the dominance of the right hemisphere for those processes. Our results also underline that the disruptive or facilitative effect of TMS over a given region depends upon the behavioral context.

scholarly journals Prism adaptation modulates connectivity of the intraparietal sulcus with multiple brain networks

2019 ◽  
Author(s):  
Selene Schintu ◽  
Michael Freedberg ◽  
Stephen J. Gotts ◽  
Catherine A. Cunningham ◽  
Zaynah M. Alam ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Prism Adaptation ◽  
Healthy Individuals ◽  
Resting State Functional Connectivity ◽  
Frontoparietal Network ◽  
Interhemispheric Competition ◽  
Before And After ◽  
And Shifts ◽  
The Right ◽  
Parietal Cortices

ABSTRACTPrism adaptation (PA) alters spatial cognition according to the direction of visual displacement by temporarily modifying sensorimotor mapping. Right-shifting prisms (right PA) improve neglect of left space in patients, possibly by decreasing activity in the left hemisphere and increasing it in the right. Left PA shifts attention to the right in healthy individuals by an opposite mechanism. However, functional imaging studies of PA are inconsistent, perhaps because of differing activation tasks. We measured resting-state functional connectivity (RSFC) in healthy individuals before and after PA. Right, vs. left, PA decreased RSFC in the navigation network defined by the right posterior parietal cortices (PPCs), hippocampus, and cerebellum. Right PA, relative to baseline, increased RSFC between regions within both PPCs and between the PPCs and the right middle frontal gyrus, whereas left PA decreased RSFC between these regions. These results show that right PA modulates connectivity within the right-hemisphere navigation network and shifts attention leftward by increasing connectivity in the right frontoparietal network and left PA produces essentially opposite effects, consistent with the interhemispheric competition model. These finding explain the action of PA on intact cognition and will help optimize interventions in neglect patients.

scholarly journals Perceptual effects of unequal saccadic adaptation produced by a dichoptic step

2020 ◽  
Author(s):  
Anna Kosovicheva ◽  
Peter J. Bex
Keyword(s):  
Eye Movements ◽  
Three Dimensional ◽  
Oculomotor System ◽  
Saccadic Adaptation ◽  
Localization Errors ◽  
The Face ◽  
Shift Experiment ◽  
The Right ◽  
And Control ◽  
Binocular Coordination

The binocular coordination of eye movements in a three-dimensional environment involves a combination of saccade and vergence movements. To maintain binocular accuracy and control in the face of sensory and motor changes (that occur with e.g. normal aging, surgery, corrective lenses), the oculomotor system must adapt in response to manifest visual errors. This may be achieved through a combination of binocular and monocular mechanisms, including the recalibration of saccade and vergence amplitudes in response to different visual errors induced in each eye (Maiello, Harrison, & Bex, 2016). This work has used a double-step paradigm to recalibrate eye movements in response to visual errors produced by dichoptic target steps (e.g., leftward in the left eye and rightward in the right eye). Here, we evaluated the immediate perceptual effects of this adaptation. Experiment 1 measured localization errors following adaptation, by comparing the apparent locations of pre- and post- saccadic probes. Consistent with previous work showing localization errors following saccadic adaptation, our results demonstrated that adaptation to a dichoptic step produces different localization errors in the two eyes. Furthermore, in Experiment 2, this effect was reduced for a vergence shift in the absence of a saccade, indicating that saccade programming is responsible for a large component of this illusory shift. Experiment 3 measured post-saccadic stereopsis thresholds and indicated that, unlike localization judgments, adaptation did not influence stereoacuity. Together, these results demonstrate novel dichoptic visual errors following oculomotor adaptation, and point to monocular and binocular mechanisms involved in the maintenance of binocular coordination.

scholarly journals Effects of a Phonological Intervention on EEG Connectivity Dynamics in Dyslexic Children

2021 ◽  
Author(s):  
Nicolas Bedo ◽  
Dikla Ender-Fox ◽  
Janet Chow ◽  
Linda Siegel ◽  
Urs Ribary ◽  
...  
Keyword(s):  
Language Processing ◽  
Right Hemisphere ◽  
Word Reading ◽  
Letter Recognition ◽  
Oscillatory Dynamics ◽  
Before And After ◽  
Eeg Connectivity ◽  
Eeg Recordings ◽  
The Right ◽  
Language Areas

We examined the brain networks and oscillatory dynamics, inferred from EEG recordings during a word-reading task, of a group of children in grades 4 and 5 (ages 9–11), some of whom were dyslexic. We did this in order to characterize the differences in these dynamics between typical and dyslexic readers, and to begin to characterize the effect of a phonological intervention on those differences. Dyslexic readers were recorded both before and after they participated in a FastForWord (FFW) reading training program for approximately six months and typical readers were recorded once during this period. Before FFW dyslexic readers showed (i) a bottleneck in letter recognition areas, (ii) expansion in activity and connectivity into the right hemisphere not seen in typical readers, and (iii) greater engagement of higher-level language areas, even for consonant string stimuli. After FFW, dyslexic readers evinced a significant reduction in the engagement of language processing areas, and more activity and connectivity expanding to frontal areas, more resembling typical readers. Reduction of connectivity was negatively correlated with gains in reading performance, suggesting an increase in communication efficiency. Training appeared to improve the efficiency of the alternative (bilateral) pathways already used by the dyslexic readers, rather than inducing them to create new pathways more similar to those employed by typical readers.

scholarly journals The Study of Face Processing in Social Anxiety Disorder Based on Face-Specific N170 Component

2022 ◽  
Vol 2022 ◽  
pp. 1-10
Author(s):  
Xuejing Bi ◽  
Min Guo ◽  
Jianqin Cao ◽  
Yanhua Hao
Keyword(s):  
Anxiety Disorder ◽  
Social Anxiety ◽  
Social Anxiety Disorder ◽  
Face Processing ◽  
Right Hemisphere ◽  
Asymmetry Index ◽  
Event Related Potential ◽  
N170 Component ◽  
Before And After ◽  
The Right

Although previous studies showed that social anxiety disorder (SAD) exhibits the attentional bias for angry faces, few studies investigated effective face recognition combined with event-related potential (ERP) technique in SAD patients, especially the treatment effect. This study examines the differences in face processing in SAD patients before and after treatment and healthy control people (H-group). High-density EEG scans were registered in response to emotional schematic faces, particularly interested in the face processing N170 component. Analysis of N170 amplitude revealed a larger N170 for P-group-pre in response to inverted and upright stimuli than H-group in the right hemisphere. The result of the intragroup t-test showed that N170 was delayed for inverted relative to upright faces only in P-group-post and H-group but not in P-group-pre. Remarkably, the results of ANOVAs manifested that emotional expression cannot modulate N170 for SAD patients. Besides, the N170-based asymmetry index (AI) was introduced to analyze the left- and right-hemisphere dominance of N170 for three groups. It was found that, with the improvement of patients’ treatment, the value of A I N 170 − b a s e     d presented a decreasing trend. These results together suggested that there was no inversion effect observed for patients with SAD. The change in the value of A I N 170 − b a s e     d can be used as potential electrophysiological markers for the diagnosis and treatment effects on patients with SAD.

scholarly journals Right-lateralized Brain Oscillations in Human Spatial Navigation

2010 ◽  
Vol 22 (5) ◽  
pp. 824-836 ◽  
Author(s):  
Joshua Jacobs ◽  
Igor O. Korolev ◽  
Jeremy B. Caplan ◽  
Arne D. Ekstrom ◽  
Brian Litt ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Spatial Navigation ◽  
Gamma Oscillations ◽  
Oscillatory Activity ◽  
Taxi Driver ◽  
Special Role ◽  
Brain Oscillations ◽  
Neurosurgical Patients ◽  
The Right ◽  
Log Linear

During spatial navigation, lesion and functional imaging studies suggest that the right hemisphere has a unique functional role. However, studies of direct human brain recordings have not reported interhemisphere differences in navigation-related oscillatory activity. We investigated this apparent discrepancy using intracranial electroencephalographic recordings from 24 neurosurgical patients playing a virtual taxi driver game. When patients were virtually moving in the game, brain oscillations at various frequencies increased in amplitude compared with periods of virtual stillness. Using log-linear analysis, we analyzed the region and frequency specificities of this pattern and found that neocortical movement-related gamma oscillations (34–54 Hz) were significantly lateralized to the right hemisphere, especially in posterior neocortex. We also observed a similar right lateralization of gamma oscillations related to searching for objects at unknown virtual locations. Thus, our results indicate that gamma oscillations in the right neocortex play a special role in human spatial navigation.

Differences in Task and Use of Language: A Study of Lateral Eye Movement

1981 ◽  
Vol 52 (3) ◽  
pp. 995-1002 ◽  
Author(s):  
Joan Katz ◽  
Patricia Salt
Keyword(s):  
Individual Differences ◽  
Eye Movements ◽  
Test Performance ◽  
Right Hemisphere ◽  
Scholastic Aptitude Test ◽  
Aptitude Test ◽  
College Majors ◽  
Scholastic Aptitude ◽  
Lateral Eye ◽  
The Right

The lateral eye movements of 25 right-handed, native-English speakers 18 to 30 yr. of age were recorded. Both task and individual differences in the utilization of cerebral hemispheres were found. Earlier findings of task differences in the direction of eye movements for verbal and spatial questions were confirmed, and previous evidence of the involvement of the right hemisphere with “unpleasant” emotion was supported. No differences in performance on the Scholastic Aptitude Test were found between consistent and inconsistent eye movers. Individual differences between right-eye movers and left-eye movers were found in their choice of college majors, Scholastic Aptitude Test performance, and in their course preferences. The current study also presents evidence of differences in language use by adults which seem related to cerebral hemispheric activity.

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