Detection of neuronal current MRI in human without BOLD contamination

Luo, Qing; Jiang, Xia; Gao, Jia‐Hong

doi:10.1002/mrm.22842

Cited by 20 publications

(17 citation statements)

References 29 publications

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“…The literature contains several reports of positive results (Kamei et al, 1999; Xiong et al, 2003; Bianciardi et al, 2004; Liston et al, 2004; Konn et al, 2004; Petridou et al, 2006; Truong and Song, 2006; Chow et al, 2006a; Chow et al, 2006b; Chow et al, 2007; Chow et al, 2008; Xue et al, 2009) which conflict with reports of negative results (Chu et al, 2004; Parkes et al, 2007; Mandelkow et al, 2007; Tang et al, 2008; Luo et al, 2009; Rodionov et al, 2010; Luo, Jiang & Gao 2011; Huang, 2014). …”

Section: Introductionmentioning

confidence: 99%

Direct neural current imaging in an intact cerebellum with magnetic resonance imaging

et al. 2016

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The ability to detect neuronal currents with high spatiotemporal resolution using magnetic resonance imaging (MRI) is important for studying human brain function in both health and disease. While significant progress has been made, we still lack evidence showing that it is possible to measure an MR signal time-locked to neuronal currents with a temporal waveform matching concurrently recorded local field potentials (LFPs). Also lacking is evidence that such MR data can be used to image current distribution in active tissue. Since these two results are lacking even in vitro, we obtained these data in an intact isolated whole cerebellum of turtle during slow neuronal activity mediated by metabotropic glutamate receptors using a gradient-echo EPI sequence (TR = 100 ms) at 4.7 T. Our results show that it is possible (1) to reliably detect an MR phase shift time course matching that of the concurrently measured LFP evoked by stimulation of a cerebellar peduncle, (2) to detect the signal in single voxels of 0.1 mm3, (3) to determine the spatial phase map matching the magnetic field distribution predicted by the LFP map, (4) to estimate the distribution of neuronal current in the active tissue from a group-average phase map, and (5) to provide a quantitatively accurate theoretical account of the measured phase shifts. The peak values of the detected MR phase shifts were 0.27–0.37°, corresponding to local magnetic field changes of 0.67–0.93 nT (for TE = 26 ms). Our work provides an empirical basis for future extensions to in vivo imaging of neuronal currents.

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Section: Introductionmentioning

confidence: 99%

Direct neural current imaging in an intact cerebellum with magnetic resonance imaging

et al. 2016

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“…Early attempts at using MRI to detect a phase shift or signal loss caused by electrical currents were successful in phantom and in vitro experiments. However, in vivo studies in the brain using this approach have remained challenging and controversial, because the local magnetic fields induced by neuronal currents are not only extremely weak, but can also be oscillatory, resulting in temporal cancellation within the acquisition window, and because of challenging hemodynamic, respiratory, and cardiac‐related confounds. More recently, spin‐lock techniques based on the rotary saturation effect, which can be tuned to detect magnetic field oscillations within specific frequency bands, such as those induced by functional neuroelectric currents, have shown promising results in phantoms but have not yet been applied successfully in vivo, even in rats …”

Section: Introductionmentioning

confidence: 99%

Toward direct MRI of neuro‐electro‐magnetic oscillations in the human brain

Truong

Roberts

Woldorff

et al. 2019

Magnetic Resonance in Med

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Purpose Neuroimaging techniques are widely used to investigate the function of the human brain, but none are currently able to accurately localize neuronal activity with both high spatial and temporal specificity. Here, a new in vivo MRI acquisition and analysis technique based on the spin‐lock mechanism is developed to noninvasively image local magnetic field oscillations resulting from neuroelectric activity in specifiable frequency bands. Methods Simulations, phantom experiments, and in vivo experiments using an eyes‐open/eyes‐closed task in 8 healthy volunteers were performed to demonstrate its sensitivity and specificity for detecting oscillatory neuroelectric activity in the alpha‐band (8‐12 Hz). A comprehensive postprocessing procedure was designed to enhance the neuroelectric signal, while minimizing any residual hemodynamic and physiological confounds. Results The phantom results show that this technique can detect 0.06‐nT magnetic field oscillations, while the in vivo results demonstrate that it can image task‐based modulations of neuroelectric oscillatory activity in the alpha‐band. Multiple control experiments and a comparison with conventional BOLD functional MRI suggest that the activation was likely not due to any residual hemodynamic or physiological confounds. Conclusion These initial results provide evidence suggesting that this new technique has the potential to noninvasively and directly image neuroelectric activity in the human brain in vivo. With further development, this approach offers the promise of being able to do so with a combination of spatial and temporal specificity that is beyond what can be achieved with existing neuroimaging methods, which can advance our ability to study the functions and dysfunctions of the human brain.

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“…Phantom experiments on nc‐MRI have yielded promising results , but the conclusions from human experiments have been controversial. Detection of a nc‐MRI signal has been reported by several groups , but others have failed to find such effects with current MRI sensitivities . One important confounding factor in the in vivo nc‐MRI studies that yielded positive results is the inescapable presence of the BOLD effect.…”

Section: Introductionmentioning

confidence: 99%

Octopus visual system: A functional MRI model for detecting neuronal electric currents without a blood‐oxygen‐level‐dependent confound

Jiang

Shigeno

et al. 2013

Magnetic Resonance in Med

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Purpose Despite the efforts that have been devoted to detecting the transient magnetic fields generated by neuronal firing, the conclusion that a functionally relevant signal can be measured with magnetic resonance imaging (MRI) is still controversial. For human studies of neuronal current MRI (nc-MRI), the blood-oxygen-level-dependent (BOLD) effect remains an irresolvable confound. For tissue studies where hemoglobin is removed, natural sensory stimulation is not possible. This study investigates the feasibility of detecting a physiologically induced nc-MRI signal in vivo in a BOLD-free environment. Methods The cephalopod mollusc Octopus bimaculoides has vertebrate-like eyes, large optic lobes (OLs) and blood that does not contain hemoglobin. Visually evoked potentials were measured in the octopus retina and OL by electroretinogram and local field potential. nc-MRI scans were conducted at 9.4 Tesla to capture these activities. Results Electrophysiological recording detected strong responses in the retina and OL in vivo; however, nc-MRI failed to demonstrate any statistically significant signal change with a detection threshold of 0.2° for phase and 0.2% for magnitude. Experiments in a dissected eye-OL preparation yielded similar results. Conclusion These findings in a large hemoglobin-free nervous system suggest that sensory evoked neuronal magnetic fields are too weak for direct detection with current MRI technology.

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Detection of neuronal current MRI in human without BOLD contamination

Cited by 20 publications

References 29 publications

Direct neural current imaging in an intact cerebellum with magnetic resonance imaging

Direct neural current imaging in an intact cerebellum with magnetic resonance imaging

Toward direct MRI of neuro‐electro‐magnetic oscillations in the human brain

Octopus visual system: A functional MRI model for detecting neuronal electric currents without a blood‐oxygen‐level‐dependent confound

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