scholarly journals Simultaneous fMRI-EEG-Based Characterisation of NREM Parasomnia Disease: Methods and Limitations

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1087
Author(s):  
Marek Piorecky ◽  
Vlastimil Koudelka ◽  
Eva Miletinova ◽  
Jitka Buskova ◽  
Jan Strobl ◽  
...  
Keyword(s):  
Linear Models ◽  
Spectral Power ◽  
Blood Oxygen Level Dependent ◽  
Posterior Cingulate Cortex ◽  
Blood Oxygen Level ◽  
Sleep Studies ◽  
Power Fluctuations ◽  
Dependent Signal ◽  
Functional Areas ◽  
Disorders Of Arousal

Functional magnetic resonance imaging (fMRI) techniques and electroencephalography (EEG) were used to investigate sleep with a focus on impaired arousal mechanisms in disorders of arousal (DOAs). With a prevalence of 2–4% in adults, DOAs are significant disorders that are currently gaining attention among physicians. The paper describes a simultaneous EEG and fMRI experiment conducted in adult individuals with DOAs (n=10). Both EEG and fMRI data were validated by reproducing well established EEG and fMRI associations. A method for identification of both brain functional areas and EEG rhythms associated with DOAs in shallow sleep was designed. Significant differences between patients and controls were found in delta, theta, and alpha bands during awakening epochs. General linear models of the blood-oxygen-level-dependent signal have shown the secondary visual cortex and dorsal posterior cingulate cortex to be associated with alpha spectral power fluctuations, and the precuneus with delta spectral power fluctuations, specifically in patients and not in controls. Future EEG–fMRI sleep studies should also consider subject comfort as an important aspect in the experimental design.

Motor network recovery in patients with chronic spinal cord compression: a longitudinal study following decompression surgery

2018 ◽  
Vol 28 (4) ◽  
pp. 379-388 ◽  
Author(s):  
Kayla Ryan ◽  
Sandy Goncalves ◽  
Robert Bartha ◽  
Neil Duggal
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Compression ◽  
Surgical Intervention ◽  
Blood Oxygen Level Dependent ◽  
Cord Compression ◽  
Decompression Surgery ◽  
Blood Oxygen Level ◽  
Motor Network ◽  
Dependent Signal

OBJECTIVEThe authors used functional MRI to assess cortical reorganization of the motor network after chronic spinal cord compression and to characterize the plasticity that occurs following surgical intervention.METHODSA 3-T MRI scanner was used to acquire functional images of the brain in 22 patients with reversible cervical spinal cord compression and 10 control subjects. Controls performed a finger-tapping task on 3 different occasions (baseline, 6-week follow-up, and 6-month follow-up), whereas patients performed the identical task before surgery and again 6 weeks and 6 months after spinal decompression surgery.RESULTSAfter surgical intervention, an increased percentage blood oxygen level–dependent signal and volume of activation was observed within the contralateral and ipsilateral motor network. The volume of activation of the contralateral primary motor cortex was associated with functional measures both at baseline (r = 0.55, p < 0.01) and 6 months after surgery (r = 0.55, p < 0.01). The percentage blood oxygen level–dependent signal of the ipsilateral supplementary motor area 6 months after surgery was associated with increased function 6 months after surgery (r = 0.48, p < 0.01).CONCLUSIONSPlasticity of the contralateral and ipsilateral motor network plays complementary roles in maintaining neurological function in patients with spinal cord compression and may be critical in the recovery phase following surgery.

scholarly journals Aberrant blood-oxygen-level-dependent signal oscillations across frequency bands characterize the alcoholic brain

2017 ◽  
Vol 23 (2) ◽  
pp. 824-835 ◽  
Author(s):  
Jui-Yang Hong ◽  
Eva M. Müller-Oehring ◽  
Adolf Pfefferbaum ◽  
Edith V. Sullivan ◽  
Dongjin Kwon ◽  
...  
Keyword(s):  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Frequency Bands ◽  
Dependent Signal

scholarly journals fMRI of the rod scotoma elucidates cortical rod pathways and implications for lesion measurements

2015 ◽  
Vol 112 (16) ◽  
pp. 5201-5206 ◽  
Author(s):  
Brian Barton ◽  
Alyssa A. Brewer
Keyword(s):  
Blood Oxygen Level Dependent ◽  
Cortical Reorganization ◽  
Blood Oxygen Level ◽  
Short Term ◽  
Traumatic Lesion ◽  
Electrophysiological Studies ◽  
Short Term Adaptation ◽  
Early Visual Cortex ◽  
Dependent Signal

Are silencing, ectopic shifts, and receptive field (RF) scaling in cortical scotoma projection zones (SPZs) the result of long-term reorganization (plasticity) or short-term adaptation? Electrophysiological studies of SPZs after retinal lesions in animal models remain controversial, because they are unable to conclusively answer this question because of limitations of the methodology. Here, we used functional MRI (fMRI) visual field mapping through population RF (pRF) modeling with moving bar stimuli under photopic and scotopic conditions to measure the effects of the rod scotoma in human early visual cortex. As a naturally occurring central scotoma, it has a large cortical representation, is free of traumatic lesion complications, is completely reversible, and has not reorganized under normal conditions (but can as seen in rod monochromats). We found that the pRFs overlapping the SPZ in V1, V2, V3, hV4, and VO-1 generally (i) reduced their blood oxygen level-dependent signal coherence and (ii) shifted their pRFs more eccentric but (iii) scaled their pRF sizes in variable ways. Thus, silencing, ectopic shifts, and pRF scaling in SPZs are not unique identifiers of cortical reorganization; rather, they can be the expected result of short-term adaptation. However, are there differences between rod and cone signals in V1, V2, V3, hV4, and VO-1? We did not find differences for all five maps in more peripheral eccentricities outside of rod scotoma influence in coherence, eccentricity representation, or pRF size. Thus, rod and cone signals seem to be processed similarly in cortex.

scholarly journals Blood oxygen level-dependent signal responses in corticolimbic ‘emotions’ circuitry of lactating rats facing intruder threat to pups

2009 ◽  
Vol 30 (5) ◽  
pp. 934-945 ◽  
Author(s):  
Benjamin C. Nephew ◽  
Martha K. Caffrey ◽  
Ada C. Felix-Ortiz ◽  
Craig F. Ferris ◽  
Marcelo Febo
Keyword(s):  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Dependent Signal

scholarly journals Low Frequency Stimulation of the Perforant Pathway Generates Anesthesia-Specific Variations in Neural Activity and BOLD Responses in the Rat Dentate Gyrus

2011 ◽  
Vol 32 (2) ◽  
pp. 291-305 ◽  
Author(s):  
Karla Krautwald ◽  
Frank Angenstein
Keyword(s):  
Dentate Gyrus ◽  
Stimulus Frequency ◽  
Low Frequency ◽  
Blood Oxygen Level Dependent ◽  
Bold Response ◽  
Blood Oxygen Level ◽  
Perforant Pathway ◽  
Bold Responses ◽  
Dependent Signal ◽  
Frequency Stimulation

To study how various anesthetics affect the relationship between stimulus frequency and generated functional magnetic resonance imaging (fMRI) signals in the rat dentate gyrus, the perforant pathway was electrically stimulated with repetitive low frequency (i.e., 0.625, 1.25, 2.5, 5, and 10 Hz) stimulation trains under isoflurane/N2O, isoflurane, medetomidine, and α-chloralose. During stimulation, the blood oxygen level-dependent signal intensity (BOLD response) and local field potentials in the dentate gyrus were simultaneously recorded to prove whether the present anesthetic controls the generation of a BOLD response via targeting general hemodynamic parameters, by affecting mechanisms of neurovascular coupling, or by disrupting local signal processing. Using this combined electrophysiological/fMRI approach, we found that the threshold frequency (i.e., the minimal frequency required to trigger significant BOLD responses), the optimal frequency (i.e., the frequency that elicit the strongest BOLD response), and the spatial distribution of generated BOLD responses are specific for each anesthetic used. Concurrent with anesthetic-dependent characteristics of the BOLD response, we found the pattern of stimulus-induced neuronal activity in the dentate gyrus is also specific for each anesthetic. Consequently, the anesthetic-specific influence on local signaling processes is the underlying cause for the observation that an identical stimulus elicits different BOLD responses under various anesthetics.

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