Papers by Venkata Chaitanya Chirumamilla
<p>Demographic description of groups.</p
<p>Clinical scores from both groups.</p
<p>Statistical significant clusters for the group comparison between patients with BEB and ... more <p>Statistical significant clusters for the group comparison between patients with BEB and HC.</p
<p>Statistical significant clusters for the group comparison between patients with HFS and ... more <p>Statistical significant clusters for the group comparison between patients with HFS and HC.</p
Clinical neurophysiology, Apr 1, 2024
Neural Regeneration Research, Dec 20, 2023
Journal of Perinatology, Aug 20, 2023
Clinical Neurophysiology, Aug 1, 2022
Clinical Neurophysiology, Jun 1, 2017
In the present study we investigated brain network connectivity differences between patients with... more In the present study we investigated brain network connectivity differences between patients with relapsing-remitting multiple sclerosis (RRMS) and healthy controls (HC) as derived from functional resonance magnetic imaging (fMRI) using graph theory. Resting state fMRI data of 18 RRMS patients (12 female, mean age ± SD: 42 ± 12.06 years) and 25 HC (8 female, 29.2 ± 5.38 years) were analyzed. In order to obtain information of differences in entire brain network, we focused on both, local and global network connectivity parameters. And the regional connectivity differences were assessed using regional network parameters. RRMS patients presented a significant increase of modularity in comparison to HC, pointing towards a network structure with densely interconnected nodes within one module, while the number of connections with other modules outside decreases. This higher decomposable network favours cost-efficient local information processing and promotes long-range disconnection. In addition, at the regional anatomical level, the network parameters clustering coefficient and local efficiency were increased in the insula, the superior parietal gyrus and the temporal pole. Our study indicates that modularity as derived from fMRI can be seen as a characteristic connectivity feature that is increased in MS patients compared to HC. Furthermore, specific anatomical regions linked to perception, motor function and cognition were mainly involved in the enhanced local information processing.
Frontiers in Human Neuroscience, Apr 6, 2018
Frontiers in Neuroscience, Jan 9, 2023
Journal of Neuroinflammation, May 24, 2022
bioRxiv (Cold Spring Harbor Laboratory), Mar 6, 2018
Childs Nervous System, Aug 29, 2021
Objective Recent evidence favors a network concept in tuberous sclerosis (TSC) with seizure gener... more Objective Recent evidence favors a network concept in tuberous sclerosis (TSC) with seizure generation and propagation related to changes in global and regional connectivity between multiple, anatomically distant tubers. Direct exploration of network dynamics in TSC has been made possible through intracranial sampling with stereoelectroencephalography (sEEG). The objective of this study is to define epileptic networks in TSC using quantitative analysis of sEEG recordings. We also discuss the impact of the definition of these epileptic networks on surgical decision-making. Methods Intracranial sEEG recordings were obtained from four pediatric patients who presented with medically refractory epilepsy secondary to TSC and subjected to quantitative signal analysis methods. Cortical connectivity was quantified by calculating pairwise coherence between all contacts and constructing an association matrix. The global coherence, defined as the ratio of the largest eigenvalue to the sum of all the eigenvalues, was calculated for each frequency band (delta, theta, alpha, beta, gamma). Spatial distribution of the connectivity was identified by plotting the leading principal component (product of the largest eigenvalue and its corresponding eigenvector). Results Four pediatric subjects with TSC underwent invasive intracranial monitoring with sEEG, comprising 31 depth electrodes and 250 contacts, for localization of the epileptogenic focus and guidance of subsequent surgical intervention. Quantitative connectivity analysis revealed a change in global coherence during the ictal period in the beta/low gamma (14–30 Hz) and high gamma (31–80 Hz) bands. Our results corroborate findings from existing literature, which implicate higher frequencies as a driver of synchrony and desynchrony. Conclusions Coordinated high-frequency activity in the beta/low gamma and high gamma bands among spatially distant sEEG define the ictal period in TSC. This time-dependent change in global coherence demonstrates evidence for intra-tuberal and inter-tuberal connectivity in TSC. This observation has surgical implications. It suggests that targeting multiple tubers has a higher chance of seizure control as there is a higher chance of disrupting the epileptic network. The use of laser interstitial thermal therapy (LITT) allowed us to target multiple disparately located tubers in a minimally invasive manner with good seizure control outcomes.
Brain Communications
Physiological responses to threat and stress stimuli entrain synchronized neural oscillations amo... more Physiological responses to threat and stress stimuli entrain synchronized neural oscillations among cerebral networks. Network architecture and adaptation may play a critical role in achieving optimal physiological responses, while alteration can lead to mental dysfunction. We reconstructed cortical and sub-cortical source time series from high-density electroencephalography, which were then fed into community architecture analysis. Dynamic alterations were evaluated in terms of flexibility, clustering coefficient and global and local efficiency, as parameters of community allegiance. Transcranial magnetic stimulation was applied over the dorsomedial prefrontal cortex during the time window relevant for physiological threat processing and effective connectivity was computed to test the causality of network dynamics. A theta band-driven community re-organization was evident in key anatomical regions conforming the central executive, salience network and default mode networks during i...
Clinical Neurophysiology
Objective: Identifying the functional brain network properties of term low-risk newborns using hi... more Objective: Identifying the functional brain network properties of term low-risk newborns using high-density EEG (HD-EEG) and comparing these properties with those of established functional magnetic resonance image (fMRI)-based networks. Methods: HD-EEG was collected from 113 low-risk term newborns before delivery hospital discharge and within 72 hours of birth. Functional brain networks were reconstructed using coherence at the scalp and source levels in delta, theta, alpha, beta, and gamma frequency bands. These networks were characterized for the global and local network architecture.
<p>(A) cross-sectional analysis between BEB and HFS at baseline; (B) cross-sectional analys... more <p>(A) cross-sectional analysis between BEB and HFS at baseline; (B) cross-sectional analysis between BEB and HFS after the treatment; (C) longitudinal rate of change of cortical thickness over time in BEB compared to HFS. Only clusters that survived the <i>P<</i>0.001 threshold are included. Images are presented at <i>P</i> = 0.05 to better show the extent of cortical changes.</p
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Papers by Venkata Chaitanya Chirumamilla