Visualization of electrophysiological activity at the carpal tunnel area using magnetoneurography

ObjectiveTo establish a noninvasive method to measure the neuromagnetic fields of the median nerve at the carpal tunnel after electrical digital nerve stimulation and evaluate peripheral nerve function.MethodsUsing a vector-type biomagnetometer system with a superconducting quantum interference device, neuromagnetic fields at the carpal tunnel were recorded after electrical stimulation of the index or middle digital nerve in five healthy volunteers. A novel technique for removing stimulus-induced artifacts was applied, and current distributions were calculated using a spatial filter algorithm and superimposed on X-ray.ResultsA neuromagnetic field propagating from the palm to the carpal tunnel was observed in all participants. Current distributions estimated from the magnetic fields had five components: leading and trailing components parallel to the conduction pathway, outward current preceding the leading component, inward currents between the leading and trailing components, and outward current following the trailing component. The conduction velocity and peak latency of the inward current agreed well with those of sensory nerve action potentials.ConclusionRemoving stimulus-induced artifacts enabled magnetoneurography to noninvasively visualize with high spatial resolution the electrophysiological neural activity from the palm to the carpal tunnel.SignificanceThis is the first report of using magnetoneurography to visualize electrophysiological nerve activity at the palm and carpal tunnel.     

Visualization of electrical activity in the cervical spinal cord and nerve roots after ulnar nerve stimulation using magnetospinography

ObjectiveTo establish a method for magnetospinography (MSG) measurement after ulnar nerve stimulation and to clarify its characteristics.MethodsUsing a 132-channel magnetoneurography system with a superconducting quantum interference device, cervical MSG measurements were obtained for 10 healthy volunteers after stimulation of the ulnar nerve at the elbow and the wrist, and neural current distribution was calculated and superimposed on the cervical X-ray images.ResultsNeuromagnetic signals were obtained in all participants after applying the stimulus artifact removal algorithm. The measured magnetic field intensity after elbow stimulation was about twice that after wrist stimulation. Calculated neural currents flowed into the intervertebral foramina at C6/7 to T1/2 and propagated cranially along the spinal canal. The conduction velocity from the peak latency of inward currents at C5-C7 was 73.4 ± 19.6 m/s.ConclusionsWe successfully obtained MSG measurements after ulnar nerve stimulation. The neural currents flowed into the spinal canal from more caudal segments after ulnar nerve stimulation compared with median nerve stimulation, and these MSG measurements were effective in examining the spinal tracts at C5/6/7.SignificanceThis is the first report on the use of MSG to visualize electrical activity in the cervical spinal cord and nerve root after ulnar nerve stimulation.     

EEG functional connectivity contributes to outcome prediction of postanoxic coma

ObjectiveTo investigate the additional value of EEG functional connectivity features, in addition to non-coupling EEG features, for outcome prediction of comatose patients after cardiac arrest.MethodsProspective, multicenter cohort study. Coherence, phase locking value, and mutual information were calculated in 19-channel EEGs at 12 h, 24 h and 48 h after cardiac arrest. Three sets of machine learning classification models were trained and validated with functional connectivity, EEG non-coupling features, and a combination of these. Neurological outcome was assessed at six months and categorized as “good” (Cerebral Performance Category [CPC] 1–2) or “poor” (CPC 3–5).ResultsWe included 594 patients (46% good outcome). A sensitivity of 51% (95% CI: 34–56%) at 100% specificity in predicting poor outcome was achieved by the best functional connectivity-based classifier at 12 h after cardiac arrest, while the best non-coupling-based model reached a sensitivity of 32% (0–54%) at 100% specificity using data at 12 h and 48 h. Combination of both sets of features achieved a sensitivity of 73% (50–77%) at 100% specificity.ConclusionFunctional connectivity measures improve EEG based prediction models for poor outcome of postanoxic coma.SignificanceFunctional connectivity features derived from early EEG hold potential to improve outcome prediction of coma after cardiac arrest.     

Dynamic functional connectivity of the EEG in relation to outcome of postanoxic coma

ObjectiveEarly EEG contains reliable information for outcome prediction of comatose patients after cardiac arrest. We introduce dynamic functional connectivity measures and estimate additional predictive values.MethodsWe performed a prospective multicenter cohort study on continuous EEG for outcome prediction of comatose patients after cardiac arrest. We calculated Link Rates (LR) and Link Durations (LD) in the α, δ, and θ band, based on similarity of instantaneous frequencies in five-minute EEG epochs, hourly, during 3 days after cardiac arrest. We studied associations of LR and LD with good (Cerebral Performance Category (CPC) 1–2) or poor outcome (CPC 3–5) with univariate analyses. With random forest classification, we established EEG-based predictive models. We used receiver operating characteristics to estimate additional values of dynamic connectivity measures for outcome prediction.ResultsOf 683 patients, 369 (54%) had poor outcome. Patients with poor outcome had significantly lower LR and longer LD, with largest differences 12 h after cardiac arrest (LR_θ 1.87 vs. 1.95 Hz and LD_α 91 vs. 82 ms). Adding these measures to a model with classical EEG features increased sensitivity for reliable prediction of poor outcome from 34% to 38% at 12 h after cardiac arrest.ConclusionPoor outcome is associated with lower dynamics of connectivity after cardiac arrest.SignificanceDynamic functional connectivity analysis may improve EEG based outcome prediction.     

Peripheral nerve imaging in amyotrophic lateral sclerosis

We systematically identified and reviewed 29 studies of peripheral nerve ultrasound or magnetic resonance imaging (MRN) in amyotrophic lateral sclerosis (ALS). The majority of the ultrasound studies reported smaller nerves and nerve roots in ALS compared to healthy controls, but there was a large overlap of the cross-sectional nerve area between ALS and controls. Most of the MRN studies confirmed nerve abnormalities demonstrating slight T2 hyperintensities and, sometimes, mild enlargement of more proximal nerve segments (plexus, roots) in ALS. The size of the proximal nerve segments, i.e. nerve roots, is thus somewhat incongruent between nerve ultrasound and MRN in ALS. Peripheral nerve ultrasound has the potential to differentiate between ALS and multifocal motor neuropathy (MMN) in that patients with MMN have significantly larger nerves. Conversely, there is an overlap of MRN abnormalities in ALS and MMN, restricting the techniques’ utility in the clinical setting. A subgroup of patients with ALS seems to reveal a sonographic nerve pattern suggesting peripheral nerve inflammation. In the future, combined imaging with nerve ultrasound and MRN assessing parameters such as blood flow or textural markers may aid in the understanding of the deep nerve microstructure down to the fascicle level, and thus, in the classification of the nerve state as more degenerative or more inflammatory in ALS. This systematic review provides evidence that nerve imaging abnormalities are common in ALS.     

Effects of propofol on cortico-cortical evoked potentials in the dorsal language white matter pathway

ObjectiveIn order to evaluate the clinical utility even under general anesthesia, the present study aimed to clarify the effect of anesthesia on the cortico–cortical evoked potentials (CCEPs).MethodsWe analyzed 14 patients’ data in monitoring the integrity of the dorsal language pathway by using CCEPs both under general anesthesia with propofol and remifentanil and awake condition, with the main aim of clarifying the effect of anesthesia on the distribution and waveform of CCEPs.ResultsThe distribution of larger CCEP response sites, including the locus of the maximum CCEP response site, was marginally affected by anesthesia. With regard to similarity of waveforms, the mean waveform correlation coefficient indicated a strong agreement. CCEP N1 amplitude increased by an average of 25.8% from general anesthesia to waking, except three patients. CCEP N1 latencies had no correlation in changes between the two conditions.ConclusionsWe demonstrated that the distribution of larger CCEP responses was marginally affected by anesthesia and that the CCEP N1 amplitude had tendency to increase from general anesthesia to the awake condition.SignificanceThe CCEP method provides the efficiency of intraoperative monitoring for dorsal language white matter pathway even under general anesthesia.     

Automated electrical source imaging with scalp EEG to define the insular irritative zone: Comparison with simultaneous intracranial EEG

Objective To evaluate the accuracy of automated interictal low-density electrical source imaging (LD-ESI) to define the insular irritative zone (IZ) by comparing the simultaneous interictal ESI localization with the SEEG interictal activity.Methods Long-term simultaneous scalp electroencephalography (EEG) and stereo-EEG (SEEG) with at least one depth electrode exploring the operculo-insular region(s) were analyzed. Automated interictal ESI was performed on the scalp EEG using standardized low-resolution brain electromagnetic tomography (sLORETA) and individual head models. A two-step analysis was performed: i) sublobar concordance between cluster-based ESI localization and SEEG-based IZ; ii) time-locked ESI-/SEEG analysis. Diagnostic accuracy values were calculated using SEEG as reference standard. Subgroup analysis was carried out, based on the involvement of insular contacts in the seizure onset and patterns of insular interictal activity.Results Thirty patients were included in the study. ESI showed an overall accuracy of 53% (C.I. 29–76%). Sensitivity and specificity were calculated as 53% (C.I. 29–76%), 55% (C.I. 23–83%) respectively. Higher accuracy was found in patients with frequent and dominant interictal insular spikes.Conclusions LD-ESI defines with good accuracy the insular implication in the IZ, which is not possible with classical interictal scalp EEG interpretation.SignificanceAutomated LD-ESI may be a valuable additional tool to characterize the epileptogenic zone in epilepsies with suspected insular involvement.     

In pursuit of a sensitive EEG functional connectivity outcome measure for clinical trials in Alzheimer’s disease

ObjectiveIn clinical trials in Alzheimer’s Disease (AD), an improvement of impaired functional connectivity (FC) could provide biological support for the potential efficacy of the drug. Electroencephalography (EEG) analysis of the SAPHIR-trial showed a treatment induced improvement of global relative theta power but not of FC measured by the phase lag index (PLI). We compared the PLI with the amplitude envelope correlation with leakage correction (AEC-c), a presumably more sensitive FC measure.MethodsPatients with early AD underwent 12 weeks of placebo or treatment with PQ912, a glutaminylcyclase inhibitor. Eyes-closed task free EEG was measured at baseline and follow-up (PQ912 n = 47, placebo n = 56). AEC-c and PLI were measured in multiple frequency bands. Change in FC was compared between treatment groups by using two models of covariates.ResultsA significant increase in global AEC-c in the alpha frequency band was found with PQ912 treatment compared to placebo (p = 0.004, Cohen’s d = 0.58). The effect remained significant when corrected for sex, country, ApoE ε4 carriage, age, baseline value (model 1; p = 0.006) and change in relative alpha power (model 2; p = 0.004).ConclusionsFunctional connectivity in early AD, measured with AEC-c in the alpha frequency band, improved after PQ912 treatment.SignificanceAEC-c may be a robust and sensitive FC measure for detecting treatment effects.     

Risks and benefits of timely screw removal after thoracolumbar spine fractures treated with non-fusion technique

BackgroundPercutaneous-short segment screw fixation (SSSF) without bone fusion has proven to be a safe and effective modality for thoracolumbar spine fractures (TLSFs). When fracture consolidation is confirmed, pedicle screws are no longer essential, but clear indications for screw removal following fracture consolidation have not been established.MethodsIn total, we enrolled 31 patients with TLSFs who underwent screw removal following treatment using percutaneous-SSSF without fusion. Plain radiographs, taken at different intervals, measured local kyphosis using Cobb’ angle (CA), vertebra body height (VBH), and the segmental motion angle (SMA). A visual analogue scale (VAS) and the Oswestry disability index (ODI) were applied pre-screw removal and at the last follow-up.ResultsThe overall mean CA deteriorated by 1.58° (p < 0.05) and the overall mean VBH decreased by 0.52 mm (p = 0.001). SMA preservation was achieved in 18 patients (58.1%) and kyphotic recurrence occurred in 4 patients (12.9%). SMA preservation was statistically significant in patients who underwent screw removal within 12 months following the primary operation (p = 0.002). Kyphotic recurrence occurred in patients with a CA ≥ 20° at injury (p < 0.001) with a median interval of 16.5 months after screw removal. No patients reported worsening pain or an increased ODI score after screw removal.ConclusionScrew removal within 12 months can be recommended for restoration of SMA with improvement in clinical outcomes. Although, TLSFs with CA ≥ 20° at the time of injury can help to predict kyphotic recurrence after screw removal, the clinical outcomes are less relevant.     

Real-time feedback on mobile application use for emergency management affects the door-to-needle time and functional outcomes in acute ischemic stroke

ObjectivesTime from onset to reperfusion affects mortality and favorable outcomes in patients with acute ischemic stroke (AIS). To evaluate effects of a real-time feedback mobile application on critical time intervals and functional outcomes in stroke emergency management.MethodsWe recruited patients with clinically suspected acute stroke from December 1st, 2020 until July 30st, 2022. All Patients had a non-contrast computed tomography (CT) and were included only if they had AIS. We divided the patients into two groups based on the date of availability on mobile application: pre-APP group and post-APP group. Onset to Door time (ODT), Door to Imaging Time (DIT), Door to Needle Time (DNT), Door to Puncture Time (DPT), Door to Recanalization Time (DRT), National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) were compared between two groups.ResultsWe retrospectively enrolled 312 AIS patients who were assigned into the pre-APP group (n = 159) and post-APP group (n = 153). The median ODT time and median admission NIHSS score were not significantly different between the two groups at baseline assessment. The median (IQR) DIT [44 (30-60) min vs 28 (20-36) min, P < 0.01] and DNT [44 (36.25-52) min vs 39 (29-45) min, P = 0.02] both decreased significantly in two groups. However, median DPT and DRT time showed no significant differences. The proportion of mRS score of 0 to 2 at day 90 was significantly higher in the post-App group than in the pre-App group, at 82.4% and 71.7%, respectively (dominance ratio OR=1.84, 95% CI: 1.07 to 3.16, P = 0.03).ConclusionThe present findings indicate that the real-time feedback of stroke emergency management used by a mobile application have potential for shortening the DIT and DNT time and improve the prognosis of stroke patients.     

Source imaging of seizure onset predicts surgical outcome in pediatric epilepsy

ObjectiveTo assess whether ictal electric source imaging (ESI) on low-density scalp EEG can approximate the seizure onset zone (SOZ) location and predict surgical outcome in children with refractory epilepsy undergoing surgery.MethodsWe examined 35 children with refractory epilepsy. We dichotomized surgical outcome into seizure- and non-seizure-free. We identified ictal onsets recorded with scalp and intracranial EEG and localized them using equivalent current dipoles and standardized low-resolution magnetic tomography (sLORETA). We estimated the localization accuracy of scalp EEG as distance of scalp dipoles from intracranial dipoles. We also calculated the distances of scalp dipoles from resection, as well as their resection percentage and compared between seizure-free and non-seizure-free patients. We built receiver operating characteristic curves to test whether resection percentage predicted outcome.ResultsResection distance was lower in seizure-free patients for both dipoles (p = 0.006) and sLORETA (p = 0.04). Resection percentage predicted outcome with a sensitivity of 57.1% (95% CI, 34–78.2%), a specificity of 85.7% (95% CI, 57.2–98.2%) and an accuracy of 68.6% (95% CI, 50.7–83.5%) (p = 0.01).ConclusionIctal ESI performed on low-density scalp EEG can delineate the SOZ and predict outcome.SignificanceSuch an application may increase the number of children who are referred for epilepsy surgery and improve their outcome.     

Parieto-premotor functional connectivity changes during parietal lobe seizures are associated with motor semiology

ObjectivesParietal lobe seizures (PLS) are characterized by multiple clinical manifestations including motor signs. The mechanisms underlying the occurrence of motor signs are poorly understood. The main objective of this work was to estimate the functional coupling of brain regions associated with this clinical presentation.MethodsWe retrospectively selected patients affected by drug-resistant epilepsy who underwent Stereoelectroencephalography (SEEG) for pre-surgical evaluation and in whom the seizure onset zone (SOZ) was located in the parietal cortex. The SOZ was defined visually and quantitatively by the epileptogenicity index (EI) method. Two groups of seizures were defined according to the presence (“motor seizures”) or the absence (“non-motor seizures”) of motor signs. Functional connectivity (FC) estimation was based on pairwise nonlinear regression analysis (h² coefficient). To study FC changes between parietal, frontal and temporal regions, for each patient, z-score values of 16 cortico-cortical interactions were obtained comparing h² coefficients of pre-ictal, seizure onset and seizure propagation periods.ResultsWe included 22 patients, 13 with “motor seizures” and 9 with “non-motor seizures”. Resective surgery was performed in 14 patients, 8 patients had a positive surgical outcome (Engel’s class I and II). During seizure onset period, a decrease of FC was observed and was significantly more important (in comparison with background period) in “motor” seizures. This was particularly observed between parietal operculum/post-central gyrus (OP/PoCg) and mesial temporal areas. During seizure propagation, a FC increase was significantly more important (in comparison with seizure onset) in “motor seizures”, in particular between lateral pre-motor (pmL) area and precuneus, pmL and superior parietal lobule (SPL) and between inferior parietal lobule (IPL) and supplementary motor area (SMA).ConclusionsOur study shows that motor semiology in PLS is accompanied by an increase of FC between parietal and premotor cortices, significantly different than what is observed in PLS without motor semiology.SignificanceOur results indicate that preferential routes of coupling between parietal and premotor cortices are responsible for the prominent motor presentation during PLS.     

Inflammation is associated with decreased functional connectivity of insula in unmedicated bipolar disorder

BackgroundSystemic inflammation and immune dysregulation have been considered as risk factors in the pathophysiology of mood disorders including bipolar disorder (BD). Previous neuroimaging studies have demonstrated metabolic, structural and functional abnormalities in the insula in BD, proposed that the insula played an important role in BD. We herein aimed to explore neural mechanisms underlying inflammation-induced in the insular subregions functional connectivity (FC) in patients with BD.MethodsBrain resting-state functional magnetic resonance imaging (rs-fMRI) data were acquired from 41 patients with unmedicated BD II (current episode depressed), 68 healthy controls (HCs). Three pairs of insular seed regions were selected: the bilateral anterior insula (AI), the bilateral middle insula (MI) and the bilateral posterior insula (PI), and calculated the whole-brain FC for each subregion. Additionally, the serum levels of pro-inflammatory cytokines in patients and HCs, including IL-6 and TNF-α, were detected. Then the partial correlation coefficients between the abnormal insular subregions FC values and pro-inflammatory cytokines levels in patients with BD II depression were calculated.ResultsThe BD II depression group exhibited decreased FC between the right PI and the left postcentral gyrus, and increased FC between the left AI and the bilateral insula (extended to the right putamen) when compared with the HC group. Moreover, the patients with BD II depression showed higher IL-6 and TNF-α levels than HCs, and IL-6 level was negatively correlated with FC of the right PI to the left postcentral gyrus.ConclusionsOur results demonstrated that abnormal FC between the bilateral insula, and between the insula and sensorimotor areas in BD. Moreover, disrupted FC between the insula and sensorimotor areas was associated with elevated pro-inflammatory cytokine levels of IL-6 in BD.     

Source-level EEG and graph theory reveal widespread functional network alterations in focal epilepsy

ObjectiveThe hypersynchronous neuronal activity associated with epilepsy causes widespread functional network disruptions extending beyond the epileptogenic zone. This altered network topology is considered a mediator for non-seizure symptoms, such as cognitive impairment. The aim of this study was to investigate functional network alterations in focal epilepsy patients with good seizure control and high quality of life.MethodsWe compared twenty-two focal epilepsy patients and sixteen healthy controls on graph metrics derived from functional connectivity of source-level resting-state EEG. Graph metrics were calculated over a range of network densities in five frequency bands.ResultsWe observed a significantly increased small world index in patients relative to controls. On the local level, two left-hemisphere regions displayed a shift towards greater alpha band “hubness”. The findings were not mediated by age, sex or education, nor by age of epilepsy onset, duration or focus lateralisation.ConclusionsWidespread functional network alterations are evident in focal epilepsy, even in a cohort characterised by successful anti-seizure medication therapy and high quality of life. These findings might support the position that functional network analysis could hold clinical relevance for epilepsy.SignificanceFocal epilepsy is accompanied by global and local functional network aberrancies which might be implied in the sustenance of non-seizure symptoms.     

Altered sensorimotor integration in multiple sclerosis: A combined neurophysiological and functional MRI study

ObjectiveTo explore whether abnormal thalamic resting-state functional connectivity (rsFC) contributes to altered sensorimotor integration and hand dexterity impairment in multiple sclerosis (MS).MethodsTo evaluate sensorimotor integration, we recorded kinematic features of index finger abductions during somatosensory temporal discrimination threshold (STDT) testing in 36 patients with relapsing-remitting MS and 39 healthy controls (HC). Participants underwent a multimodal 3T structural and functional MRI protocol.ResultsPatients had lower index finger abduction velocity during STDT testing compared to HC. Thalamic rsFC with the precentral and postcentral gyri, supplementary motor area (SMA), insula, and basal ganglia was higher in patients than HC. Intrathalamic rsFC and thalamic rsFC with caudate and insula bilaterally was lower in patients than HC. Finger movement velocity positively correlated with intrathalamic rsFC and negatively correlated with thalamic rsFC with the precentral and postcentral gyri, SMA, and putamen.ConclusionsAbnormal thalamic rsFC is a possible substrate for altered sensorimotor integration in MS, with high intrathalamic rsFC facilitating finger movements and increased thalamic rsFC with the basal ganglia and sensorimotor cortex contributing to motor performance deterioration.SignificanceThe combined study of thalamic functional connectivity and upper limb sensorimotor integration may be useful in identifying patients who can benefit from early rehabilitation to prevent upper limb motor impairment.     

Characterization of EEG-based functional brain networks in myotonic dystrophy type 1

ObjectiveIn the autosomal dominant, multisystem, chronic progressive disease myotonic dystrophy type 1 (DM1), cognitive deficits may originate from disrupted functional brain networks. We aimed to use network analysis of resting-state electro-encephalography (EEG) recordings of patients with DM1 and matched unaffected controls to investigate changes in network organization in large-scale functional brain networks and correlations with cognitive deficits.MethodsIn this cross-sectional study, 28 adult patients with genetically confirmed DM1 and 26 age-, sex- and education-matched unaffected controls underwent resting-state EEG and neuropsychological assessment. We calculated the Phase Lag Index (PLI) to determine EEG frequency-dependent functional connectivity between brain regions. Functional brain networks were characterized by applying concepts from graph theory and compared between-groups. Network topology was evaluated using the minimum spanning tree (MST). We evaluated correlations between network metrics and neuropsychological tests that showed statistically significant between-group differences.ResultsFunctional connectivity estimated as whole-brain median PLI for DM1 patients versus healthy controls was higher in theta band (0.141 [0.050] versus 0.125 [0.018], p = 0.029), and lower in the upper alpha band (0.154 [0.048] versus 0.182 [0.073], p = 0.038), respectively. Functional MST-constructed networks in DM1 patients were significantly dissimilar from healthy controls in the delta, (p = 0.009); theta, (p = 0.009); lower alpha, (p = 0.036); and upper alpha, (p = 0.008) bands. In evaluation of local MST network measures, trends toward networks with higher global integration in the theta band and lower global integration in the upper alpha band were observed. Compared to unaffected controls, DM1 patients performed worse on tests of attention, motor function, executive function and visuospatial memory. Visuospatial memory correlated with the global median PLI in the upper alpha band; the Stroop interference test correlated with betweenness centrality in this band.ConclusionThis study supports the hypothesis that brain changes in DM1 give rise to disrupted functional network organization, as modelled with EEG-based networks. Further study may help unravel the relations with clinical brain-related DM1 symptoms.SignificanceEEG network analysis has potential to help understand brain related DM1 phenotypes.FundingThis work was supported by the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 305697 (OPTIMISTIC) and the Marigold Foundation.     

Resolving the cellular specificity of TSPO imaging in a rat model of peripherally-induced neuroinflammation

The increased expression of 18 kDa Translocator protein (TSPO) is one of the few available biomarkers of neuroinflammation that can be assessed in humans in vivo by positron emission tomography (PET). TSPO PET imaging of the central nervous system (CNS) has been widely undertaken, but to date no clear consensus has been reached about its utility in brain disorders. One reason for this could be because the interpretation of TSPO PET signal remains challenging, given the cellular heterogeneity and ubiquity of TSPO in the brain.The aim of the current study was to ascertain if TSPO PET imaging can be used to detect neuroinflammation induced by a peripheral treatment with a low dose of the endotoxin, lipopolysaccharide (LPS), in a rat model (ip LPS), and investigate the origin of TSPO signal changes in terms of their cellular sources and regional distribution. An initial pilot study utilising both [¹⁸F]DPA-714 and [¹¹C]PK11195 TSPO radiotracers demonstrated [¹⁸F]DPA-714 to exhibit a significantly higher lesion-related signal in the intracerebral LPS rat model (ic LPS) than [¹¹C]PK11195. Subsequently, [¹⁸F]DPA-714 was selected for use in the ip LPS study.Twenty-four hours after ip LPS, there was an increased uptake of [¹⁸F]DPA-714 across the whole brain. Further analyses of regions of interest, using immunohistochemistry and RNAscope Multiplex fluorescence V2 in situ hybridization technology, showed TSPO expression in microglia, monocyte derived-macrophages, astrocytes, neurons and endothelial cells. The expression of TSPO was significantly increased after ip LPS in a region-dependent manner: with increased microglia, monocyte-derived macrophages and astrocytes in the substantia nigra, in contrast to the hippocampus where TSPO was mostly confined to microglia and astrocytes. In summary, our data demonstrate the robust detection of peripherally-induced neuroinflammation in the CNS utilising the TSPO PET radiotracer, [¹⁸F]DPA-714, and importantly, confirm that the resultant increase in TSPO signal increase arises mostly from a combination of microglia, astrocytes and monocyte-derived macrophages.     

Theta oscillation and functional connectivity alterations related to executive control in temporal lobe epilepsy with comorbid depression

ObjectiveDepression is widely acknowledged as the most common comorbidity of temporal lobe epilepsy (TLE), and executive control (EC) may be particularly impaired in patients with TLE with comorbid depression. The purpose of this study was to investigate brain network alterations in patients with TLE with or without depression using scalp electroencephalography (EEG), and to explore the potential mechanisms of TLE with comorbid depression.MethodsForty patients with TLE and 20 healthy controls (HC) were recruited for administered the BDI-II and HAMD-17 surveys. The patients with TLE were divided into those with depression (PDS, n = 20) and those without depression (nPDS, n = 20) according to the surveys. Neural oscillations and functional connectivity during performance of EC tasks were calculated during EEG.ResultsTheta oscillation and functional connectivity were significantly weakened in the PDS group compared to the nPDS and HC groups. Furthermore, the PDS group showed more serious EC dysfunction than nPDS group.ConclusionsOur results indicated that weakened theta oscillation and functional connectivity in the frontal lobe may be a mechanism of EC dysfunction in TLE with comorbid depression.SignificanceThe present results suggest that the alterations in frontal lobe connections may help predict the depression in patients with TLE.