Fiber-based lactate recordings with fluorescence resonance energy transfer sensors by applying an magnetic resonance-informed correction of hemodynamic artifacts

Lambers, Henriette; Wachsmuth, Lydia; Thomas, Dominik; Boumezbeur, Fawzi; Hoesker, Vanessa; Pradier, Bruno; Faber, Cornelius

doi:10.1117/1.nph.9.3.032212

Cited by 5 publications

(5 citation statements)

References 71 publications

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“…S5 , details in Methods), the DMN is presented in Fig.4d , including prelimbic cortex, cingulate cortex, auditory cortex, posterior parietal cortex, and retrosplenial cortex. These results provide strong evidence for highly reliable detection of BOLD fMRI signals under experimental conditions, which are highly consistent with reports from other researchers [37-42].…”

Section: Resultssupporting

confidence: 92%

Novel inductively-coupled ear-bars (ICEs) for fMRI signal enhancement in rat entorhinal cortex

Chen

Fernandez

Zhu

et al. 2022

Preprint

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Entorhinal cortex (EC) is a potential target of deep brain stimulation in Alzheimer's disease (AD) and fMRI can enable whole-brain dynamic mapping noninvasively. However, it remains challenging to study EC-based fMRI connectivity in rodents due to image signal loss and the lower sensitivity of the surface coil ring or array coil for deep brain areas. To reduce the magnetic susceptibility artifacts driven signal loss issue, we introduced baby cream into the middle ear. To improve detection sensitivity, we implemented novel inductively-coupled ear-bars (ICEs) in the 7 T Bruker scanner, which resulted in an approximately 2-fold signal-to-noise ratio (SNR) increase in EC over the conventional surface array. The ICE can be conveniently utilized as an add-on device, with no modulation to the scanner interface. To demonstrate the applicability of ICEs for both task and resting-state (rs) fMRI, whole-brain echo-planar imaging (EPI) was performed in anesthetized rats modeling AD mixed dementia. Seed-based rs-fMRI connectivity maps emanating from the left entorhinal cortex demonstrated its connectivity to the hippocampus, piriform cortex, septal nuclei, and prefrontal cortex. Hence, this work demonstrates an optimized procedure for ICE by acquiring large-scale networks emanating from a seed region that was not easily accessible by conventional MRI detectors, enabling better observation of EC-based brain fMRI connectivity studies with a higher signal-to-noise ratio in rodent models of dementia.

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Section: Resultssupporting

confidence: 92%

Novel inductively-coupled ear-bars (ICEs) for fMRI signal enhancement in rat entorhinal cortex

Chen

Fernandez

Zhu

et al. 2022

Preprint

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“…2021 ; Jung et al. 2022 ; Lambers et al. 2022 ), providing strong evidence for highly reliable detection of BOLD fMRI signals under experimental conditions without any modification or complication of the experimental procedure.…”

Section: Resultsmentioning

confidence: 97%

Novel inductively coupled ear-bars (ICEs) to enhance restored fMRI signal from susceptibility compensation in rats

Chen,

Fernandez,

Scheel

et al. 2023

Cerebral Cortex

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Functional magnetic resonance imaging faces inherent challenges when applied to deep-brain areas in rodents, e.g. entorhinal cortex, due to the signal loss near the ear cavities induced by susceptibility artifacts and reduced sensitivity induced by the long distance from the surface array coil. Given the pivotal roles of deep brain regions in various diseases, optimized imaging techniques are needed. To mitigate susceptibility-induced signal losses, we introduced baby cream into the middle ear. To enhance the detection sensitivity of deep brain regions, we implemented inductively coupled ear-bars, resulting in approximately a 2-fold increase in sensitivity in entorhinal cortex. Notably, the inductively coupled ear-bar can be seamlessly integrated as an add-on device, without necessitating modifications to the scanner interface. To underscore the versatility of inductively coupled ear-bars, we conducted echo-planner imaging-based task functional magnetic resonance imaging in rats modeling Alzheimer’s disease. As a proof of concept, we also demonstrated resting-state-functional magnetic resonance imaging connectivity maps originating from the left entorhinal cortex—a central hub for memory and navigation networks-to amygdala hippocampal area, Insular Cortex, Prelimbic Systems, Cingulate Cortex, Secondary Visual Cortex, and Motor Cortex. This work demonstrates an optimized procedure for acquiring large-scale networks emanating from a previously challenging seed region by conventional magnetic resonance imaging detectors, thereby facilitating improved observation of functional magnetic resonance imaging outcomes.

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“…(7) LFP recordings were conducted. A total of 10% of the data were included retrospectively from previous studies (Albers et al, 2019;van Alst et al, 2019;Lambers et al, 2022). Therefore, temporal resolution of MR measurements varied.…”

Section: Animal Handling and Data Overviewmentioning

confidence: 99%

“…This is not only relevant for fMRI, but for all techniques that are sensitive to hemodynamic changes. In addition to optical recordings of blood volume or flow and laser doppler flowmetry, this also applies to optical recordings of fluorescent dyes, as hemodynamic changes cause artifacts in these measurements (Kozberg et al, 2016;Ma et al, 2016;Lambers et al, 2022;Zhang et al, 2022).…”

Section: Hemodynamic Oscillations Occur In Both Small and Large Blood...mentioning

confidence: 99%

The impact of vasomotion on analysis of rodent fMRI data

et al. 2023

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IntroductionSmall animal fMRI is an essential part of translational research in the cognitive neurosciences. Due to small dimensions and animal physiology preclinical fMRI is prone to artifacts that may lead to misinterpretation of the data. To reach unbiased translational conclusions, it is, therefore, crucial to identify potential sources of experimental noise and to develop correction methods for contributions that cannot be avoided such as physiological noise. Aim of this study was to assess origin and prevalence of hemodynamic oscillations (HDO) in preclinical fMRI in rat, as well as their impact on data analysis.MethodsFollowing the development of algorithms for HDO detection and suppression, HDO prevalence in fMRI measurements was investigated for different anesthetic regimens, comprising isoflurane and medetomidine, and for both gradient echo and spin echo fMRI sequences. In addition to assessing the effect of vasodilation on HDO, it was studied if HDO have a direct neuronal correlate using local field potential (LFP) recordings. Finally, the impact of HDO on analysis of fMRI data was assessed, studying both the impact on calculation of activation maps as well as the impact on brain network analysis. Overall, 303 fMRI measurements and 32 LFP recordings were performed in 71 rats.ResultsIn total, 62% of the fMRI measurements showed HDO with a frequency of (0.20 ± 0.02) Hz. This frequent occurrence indicated that HDO cannot be generally neglected in fMRI experiments. Using the developed algorithms, HDO were detected with a specificity of 95%, and removed efficiently from the signal time courses. HDO occurred brain-wide under vasoconstrictive conditions in both small and large blood vessels. Vasodilation immediately interrupted HDO, which, however, returned within 1 h under vasoconstrictive conditions. No direct neuronal correlate of HDO was observed in LFP recordings. HDO significantly impacted analysis of fMRI data, leading to altered cluster sizes and F-values for activated voxels, as well as altered brain networks, when comparing data with and without HDO.DiscussionWe therefore conclude that HDO are caused by vasomotion under certain anesthetic conditions and should be corrected during fMRI data analysis to avoid bias.

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Fiber-based lactate recordings with fluorescence resonance energy transfer sensors by applying an magnetic resonance-informed correction of hemodynamic artifacts

Cited by 5 publications

References 71 publications

Novel inductively-coupled ear-bars (ICEs) for fMRI signal enhancement in rat entorhinal cortex

Novel inductively-coupled ear-bars (ICEs) for fMRI signal enhancement in rat entorhinal cortex

Novel inductively coupled ear-bars (ICEs) to enhance restored fMRI signal from susceptibility compensation in rats

The impact of vasomotion on analysis of rodent fMRI data

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