scholarly journals Functional Connectivity of the Precuneus Reflects Effectiveness of Visual Restitution Training in Chronic Hemianopia

2020 ◽  
Author(s):  
Hinke N. Halbertsma ◽  
Joris A. Elshout ◽  
Douwe P. Bergsma ◽  
David G. Norris ◽  
Frans W. Cornelissen ◽  
...  
Keyword(s):  
Visual Field ◽  
Functional Connectivity ◽  
Spatial Attention ◽  
Resting State ◽  
Visual Field Defects ◽  
Resting State Functional Connectivity ◽  
Total Change ◽  
Potential Capacity ◽  
Sensitivity Change ◽  
Occipital Pole

AbstractVisual field defects in chronic hemianopia can improve through visual restitution training, yet not all patients benefit equally from this long and exhaustive process. Here, we asked if resting-state functional connectivity prior to visual restitution could predict training success. In two training sessions of eight weeks each, 20 patients with chronic hemianopia performed a visual discrimination task by directing spatial attention towards stimuli presented in either hemifield, while suppressing eye movements. We examined two effects: a sensitivity change in the attended (trained) minus the unattended (control) hemifield (i.e., a training-specific improvement), and an overall improvement (i.e., a total change in sensitivity after both sessions). We then identified five visual resting-state networks and evaluated their functional connectivity in relation to both training effects. We found that the functional connectivity strength between the anterior Precuneus and the Occipital Pole Network was positively related to the attention modulated (i.e., training-specific) improvement. No such relationship was found for the overall improvement or for the other visual networks of interest. Our finding suggests that the anterior Precuneus plays a role in training-induced visual field improvements. The resting-state functional connectivity between the anterior Precuneus and the Occipital Pole Network may thus serve as an imaging-based biomarker that quantifies a patient’s potential capacity to direct spatial attention. This may help to identify hemianopia patients that are most likely to benefit from visual restitution training.

scholarly journals Parietal Cortex Connectivity as a Marker of Shift in Spatial Attention Following Continuous Theta Burst Stimulation

2021 ◽  
Vol 15 ◽  
Author(s):  
Jessica Mariner ◽  
Tobias Loetscher ◽  
Brenton Hordacre
Keyword(s):  
Functional Connectivity ◽  
Spatial Attention ◽  
Brain Stimulation ◽  
Resting State ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Resting State Functional Connectivity ◽  
The Right ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation

Non-invasive brain stimulation is a useful tool to probe brain function and provide therapeutic treatments in disease. When applied to the right posterior parietal cortex (PPC) of healthy participants, it is possible to temporarily shift spatial attention and mimic symptoms of spatial neglect. However, the field of brain stimulation is plagued by issues of high response variability. The aim of this study was to investigate baseline functional connectivity as a predictor of response to an inhibitory brain stimulation paradigm applied to the right PPC. In fourteen healthy adults (9 female, aged 24.8 ± 4.0 years) we applied continuous theta burst stimulation (cTBS) to suppress activity in the right PPC. Resting state functional connectivity was quantified by recording electroencephalography and assessing phase consistency. Spatial attention was assessed before and after cTBS with the Landmark Task. Finally, known determinants of response to brain stimulation were controlled for to enable robust investigation of the influence of resting state connectivity on cTBS response. We observed significant inter-individual variability in the behavioral response to cTBS with 53.8% of participants demonstrating the expected rightward shift in spatial attention. Baseline high beta connectivity between the right PPC, dorsomedial pre-motor region and left temporal-parietal region was strongly associated with cTBS response (R2 = 0.51). Regression analysis combining known cTBS determinants (age, sex, motor threshold, physical activity, stress) found connectivity between the right PPC and left temporal-parietal region was the only significant variable (p = 0.011). These results suggest baseline resting state functional connectivity is a strong predictor of a shift in spatial attention following cTBS. Findings from this study help further understand the mechanism by which cTBS modifies cortical function and could be used to improve the reliability of brain stimulation protocols.

Resting-state Functional Connectivity After Occipital Stroke

2021 ◽  
pp. 154596832110628
Author(s):  
Silja Räty ◽  
Riikka Ruuth ◽  
Katri Silvennoinen ◽  
Bernhard A. Sabel ◽  
Turgut Tatlisumak ◽  
...  
Keyword(s):  
Visual Field ◽  
Functional Connectivity ◽  
Resting State ◽  
Prediction Accuracy ◽  
Chronic Phase ◽  
Visual Field Defects ◽  
Model Parameters ◽  
Healthy Population ◽  
Stroke Patients ◽  
Control Subjects

Background Resting-state functional magnetic resonance imaging (rsfMRI) reflects spontaneous activation of cortical networks. After stroke, these networks reorganize, both due to structural lesion and reorganization of functional connectivity (FC). Objective We studied FC in chronic phase occipital stroke patients with homonymous visual field defects before and after repetitive transorbital alternating current stimulation (rtACS). Methods This spin-off study, embedded in the randomized, sham-controlled REVIS trial, comprised 16 chronic occipital stroke patients with visual field defect and 12 healthy control subjects. The patients underwent rsfMRI at baseline, after two weeks of rtACS or sham treatment, and after two months of treatment-free follow-up, whereas the control subjects were measured once. We used a multivariate regression connectivity model to determine mutual prediction accuracy between 74 cortical regions of interest. Additionally, the model parameters were included into a graph to analyze average path length, centrality eigenvector, centrality degree, and clustering of the network. The patients and controls at baseline and the two treatment groups were compared with multilevel modeling. Results Before treatment, the patients and controls had similar whole-network prediction accuracy and network parameters, whereas centrality eigenvector differed in perilesional regions, indicating local modification in connectivity. In line with behavioral results, neither prediction accuracy nor any network parameter changed systematically as a result of rtACS rehabilitation compared to sham. Conclusions Whole-network FC showed no difference between occipital stroke patients and healthy population, congruent with the peripheral location of the visual network in relation to the high-density cortical core. rtACS treatment in the given setting did not affect FC.

Relating Disinhibited Eating Behaviors to Resting State Functional Connectivity in Young Children

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 1889-P
Author(s):  
ALLISON L.B. SHAPIRO ◽  
SUSAN L. JOHNSON ◽  
BRIANNE MOHL ◽  
GRETA WILKENING ◽  
KRISTINA T. LEGGET ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Young Children ◽  
Resting State ◽  
Eating Behaviors ◽  
Resting State Functional Connectivity ◽  
Disinhibited Eating

scholarly journals The effect of congenital blindness on resting-state functional connectivity revisited

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria J. S. Guerreiro ◽  
Madita Linke ◽  
Sunitha Lingareddy ◽  
Ramesh Kekunnaya ◽  
Brigitte Röder
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Visual Experience ◽  
Brain Regions ◽  
State Condition ◽  
Resting State Functional Connectivity ◽  
Congenital Blindness ◽  
Eyes Closed ◽  
Congenitally Blind ◽  
Eyes Open

AbstractLower resting-state functional connectivity (RSFC) between ‘visual’ and non-‘visual’ neural circuits has been reported as a hallmark of congenital blindness. In sighted individuals, RSFC between visual and non-visual brain regions has been shown to increase during rest with eyes closed relative to rest with eyes open. To determine the role of visual experience on the modulation of RSFC by resting state condition—as well as to evaluate the effect of resting state condition on group differences in RSFC—, we compared RSFC between visual and somatosensory/auditory regions in congenitally blind individuals (n = 9) and sighted participants (n = 9) during eyes open and eyes closed conditions. In the sighted group, we replicated the increase of RSFC between visual and non-visual areas during rest with eyes closed relative to rest with eyes open. This was not the case in the congenitally blind group, resulting in a lower RSFC between ‘visual’ and non-‘visual’ circuits relative to sighted controls only in the eyes closed condition. These results indicate that visual experience is necessary for the modulation of RSFC by resting state condition and highlight the importance of considering whether sighted controls should be tested with eyes open or closed in studies of functional brain reorganization as a consequence of blindness.

scholarly journals Prenatal stress dysregulates resting-state functional connectivity and sensory motifs

2021 ◽  
pp. 100345
Author(s):  
Zahra Rezaei ◽  
Zahra Jafari ◽  
Navvab Afrashteh ◽  
Reza Torabi ◽  
Surjeet Singh ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Prenatal Stress ◽  
Resting State ◽  
Resting State Functional Connectivity
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