Default network connectivity decodes brain states with simulated microgravity

Zeng, Ling‐Li; Yang, Lihong; Zhou, Zongtan; Shen, Hui; Liu, Yadong; Liu, Xufeng; Hu, Dewen

doi:10.1007/s11571-015-9359-8

Cited by 12 publications

(13 citation statements)

References 59 publications

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“…2.6 Subject-level analyses 2.6.1 Hypothesis-driven seed-to-voxel analyses We used a hypothesis-driven approach to examine resting-state functional connectivity (FC) between 14 regions of interest (ROIs) and the rest of the brain. Drawing upon the findings of previous HDBR studies in standard ambient air, we hypothesized that the two subgroups would exhibit differential patterns of FC involving brain areas related to multisensory integration, somatosensation, motor function, vestibular processing, and regions within the default mode network 5,24,25,[40][41][42][43] . The coordinates for the ROIs were the same as those used in our previous resting-state fMRI study using HDBR intervention in standard ambient air 5 .…”

Section: Image Denoisingmentioning

confidence: 99%

Ophthalmic Changes in a Spaceflight Analog Are Associated with Brain Functional Reorganization

McGregor

Lee

Mulder

et al. 2020

Preprint

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ImportanceFollowing long-duration missions onboard the International Space Station, some astronauts develop ophthalmic abnormalities collectively referred to as Spaceflight Associated Neuro-ocular Syndrome (SANS). Optic disc edema is a common sign of SANS. SANS presents significant potential risk to astronaut health and performance; however, the origin and effects of SANS are not understood as signs of SANS have not manifested in previous spaceflight analog studies.ObjectiveTo investigate whether development of optic disc edema during a spaceflight analog impacts resting-state functional connectivity.Design, Setting and ParticipantsEleven healthy volunteers participated in this 58-day longitudinal study conducted at the :envihab facility at the German Aerospace Center.Interventions or ExposuresBaseline data were collected during a 14-day ambulatory phase in standard ambient air. All participants then underwent a spaceflight analog intervention: 30 days of strict head-down tilt bed rest in elevated ambient carbon dioxide (HDBR+CO2). The elevated CO2 level (0.5%) was matched to the hypercapnic environment of the International Space Station. The intervention was followed by a 14-day ambulatory recovery phase in standard ambient air. During the HDBR+CO2 spaceflight analog, 5 participants developed optic disc edema (SANS subgroup) and 6 did not (NoSANS group).Main Outcomes and MeasuresUsing functional magnetic resonance imaging (fMRI), we acquired resting-state data at 6 time points throughout the study: before (2), during (2), and after (2) the HDBR+CO2 intervention. We assessed the time course of resting-state functional connectivity changes from before, during, to after the HDBR+CO2, and contrasted longitudinal changes between the SANS and NoSANS subgroups. We also assessed if the SANS and NoSANS subgroups exhibited differential patterns of resting-state functional connectivity prior to the HDBR+CO2 intervention.ResultsThe SANS and NoSANS subgroups exhibited differential patterns of resting-state connectivity changes during the HDBR+CO2 spaceflight analog within visual and vestibular-related brain networks. We further found that the SANS and NoSANS subgroups exhibited differential resting-state brain activity prior to the spaceflight analog within a visual cortical network and within a large-scale network of brain areas involved in multisensory integration.Conclusions and RelevanceSubgroup differences in resting-state functional connectivity changes may reflect differential patterns of visual and vestibular reweighting as optic disc edema develops during the HDBR+CO2 spaceflight analog. This finding suggests that SANS impacts not only neuro-ocular structures, but also brain function. Future prospective investigations incorporating sensory assessments are required to determine the functional significance of the observed connectivity differences.KEY POINTSQuestionDoes optic disc edema development during head-down tilt bed rest with elevated carbon dioxide impact brain resting-state functional connectivity?FindingsA subset of participants developed optic disc edema during the head-down tilt bed rest intervention with elevated ambient CO2. Participants who developed optic disc edema exhibited a distinct pattern of resting-state functional connectivity changes within visual and vestibular-related networks during the spaceflight analog compared to participants who did not. Participants who developed optic disc edema exhibited different resting-state brain activity prior to the spaceflight analog within a visual cortical network and within a large-scale network of brain areas involved in multisensory integration.MeaningDevelopment of optic disc edema was associated with distinct patterns of brain resting-state functional connectivity during and prior to the spaceflight analog.

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Section: Image Denoisingmentioning

confidence: 99%

Ophthalmic Changes in a Spaceflight Analog Are Associated with Brain Functional Reorganization

McGregor

Lee

Mulder

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…We used a hypothesis‐driven approach to examine resting‐state functional connectivity (FC) between 14 regions of interest (ROIs) and the rest of the brain. Drawing upon the findings of previous HDBR studies in standard ambient air, we hypothesized that the two subgroups would exhibit differential patterns of FC involving brain areas related to multisensory integration, somatosensation, motor function, vestibular processing, and regions within the default mode network (Cassady et al, 2016 ; Demertzi et al, 2016 ; Liao et al, 2014 ; Liao et al, 2015 ; Zeng et al, 2016 ; Zeng, Liao, Shen, Liu, & Hu, 2016 ; Zhou et al, 2014 ). The coordinates for the ROIs were the same as those used in our previous resting‐state fMRI study using HDBR intervention in standard ambient air (Cassady et al, 2016 ).…”

Section: Methodsmentioning

confidence: 99%

Ophthalmic changes in a spaceflight analog are associated with brain functional reorganization

McGregor

Lee

Mulder

et al. 2021

Human Brain Mapping

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Following long‐duration spaceflight, some astronauts exhibit ophthalmic structural changes referred to as Spaceflight Associated Neuro‐ocular Syndrome (SANS). Optic disc edema is a common sign of SANS. The origin and effects of SANS are not understood as signs of SANS have not manifested in previous spaceflight analog studies. In the current spaceflight analog study, 11 subjects underwent 30 days of strict head down‐tilt bed rest in elevated ambient carbon dioxide (HDBR+CO2). Using functional magnetic resonance imaging (fMRI), we acquired resting‐state fMRI data at 6 time points: before (2), during (2), and after (2) the HDBR+CO2 intervention. Five participants developed optic disc edema during the intervention (SANS subgroup) and 6 did not (NoSANS group). This occurrence allowed us to explore whether development of signs of SANS during the spaceflight analog impacted resting‐state functional connectivity during HDBR+CO2. In light of previous work identifying genetic and biochemical predictors of SANS, we further assessed whether the SANS and NoSANS subgroups exhibited differential patterns of resting‐state functional connectivity prior to the HDBR+CO2 intervention. We found that the SANS and NoSANS subgroups exhibited distinct patterns of resting‐state functional connectivity changes during HDBR+CO2 within visual and vestibular‐related brain networks. The SANS and NoSANS subgroups also exhibited different resting‐state functional connectivity prior to HDBR+CO2 within a visual cortical network and within a large‐scale network of brain areas involved in multisensory integration. We further present associations between functional connectivity within the identified networks and previously identified genetic and biochemical predictors of SANS. Subgroup differences in resting‐state functional connectivity changes may reflect differential patterns of visual and vestibular reweighting as optic disc edema develops during the spaceflight analog. This finding suggests that SANS impacts not only neuro‐ocular structures, but also functional brain organization. Future prospective investigations incorporating sensory assessments are required to determine the functional significance of the observed connectivity differences.

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“…The connectivity based models can produce behavior, which is an essential requirement for any neural model of cognition (van der Velde and de Kamps 2015). Estimation of effective connectivity supports the inference of causal relationships and directional information flow, and may provide insights into the interactive dynamics in normal (Astolfi et al 2005;Bitan et al 2005;Kundu et al 2013;Wang and Zhu 2016;Zeng et al 2016) or disordered (Baccala et al 2004;Behnam et al 2008;Cadotte et al 2009;Coben et al 2013Coben et al , 2014Gravier et al 2016;Kundu et al 2013;Liu et al 2012;Protopapa et al 2016) brain functions. Among many definitions of causality (Atmanspacher and Rotter 2008), there are two important aspects that are of practical relevance: (1) temporal precedence: causes precede their consequences; (2) physical influence: manipulation of the causes changes their consequences (Valdes-Sosa et al 2011).…”

Section: Introductionmentioning

confidence: 91%

Estimation of effective connectivity using multi-layer perceptron artificial neural network

2017

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Studies on interactions between brain regions estimate effective connectivity, (usually) based on the causality inferences made on the basis of temporal precedence. In this study, the causal relationship is modeled by a multi-layer perceptron feed-forward artificial neural network, because of the ANN's ability to generate appropriate input-output mapping and to learn from training examples without the need of detailed knowledge of the underlying system. At any time instant, the past samples of data are placed in the network input, and the subsequent values are predicted at its output. To estimate the strength of interactions, the measure of "" is defined based on the network structure, the connecting weights and the parameters of hidden layer activation function. Simulation analysis demonstrates that the method, called "CREANN" (Causal Relationship Estimation by Artificial Neural Network), can estimate time-invariant and time-varying effective connectivity in terms of MVAR coefficients. The method shows robustness with respect to noise level of data. Furthermore, the estimations are not significantly influenced by the model order (considered time-lag), and the different initial conditions (initial random weights and parameters of the network). CREANN is also applied to EEG data collected during a memory recognition task. The results implicate that it can show changes in the information flow between brain regions, involving in the episodic memory retrieval process. These convincing results emphasize that CREANN can be used as an appropriate method to estimate the causal relationship among brain signals.

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Default network connectivity decodes brain states with simulated microgravity

Cited by 12 publications

References 59 publications

Ophthalmic Changes in a Spaceflight Analog Are Associated with Brain Functional Reorganization

Ophthalmic Changes in a Spaceflight Analog Are Associated with Brain Functional Reorganization

Ophthalmic changes in a spaceflight analog are associated with brain functional reorganization

Estimation of effective connectivity using multi-layer perceptron artificial neural network

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