Spectral analysis of interictal background EEG activity recorded through foramen ovale (FO) electrodes during monitoring (mean 5.8 days per patient) was studied in 10 medically refractory complex partial seizure (CPS) patients who were candidates for epilepsy surgery. Data of the spectral analysis was plotted as compressed spectral array (CSA) with spectral edge frequency (SEF) markers. For each patient, time-varying fluctuations of the SEF markers were compared visually and by a computer-assisted method between two symmetrical FO electrode EEG channels recording from both mesiobasotemporal lobes (MTL). The amount of asymmetrical variations of the SEF markers ("rigidity" phenomenon) was first determined visually and then quantified by the computer-assisted method. These findings were correlated with the results of other clinical tests, including FO electrode-recorded seizure onset (FO ict), positron emission tomography with [18F]fluorodeoxyglucose (FDG-PET), and magnetic resonance imaging (MRI) to investigate whether the rigidity phenomenon could lateralize the primary epileptogenic zone. The rigid side had 80, 70, and 60% coincidence rates with the pathologic side indicated by FDG-PET, FO ict, and MRI, respectively, in a single test. We conclude that the rigidity phenomenon of FO electrode-recorded interictal background EEG activity is a valuable sign for lateralization of the primary epileptogenic zone in MTL epilepsy. The relative invariance of SEF may be caused by interictal deafferentation of epileptic neurons.

OBJECTIVE

Ketamine S(+) is important in pain modulation in surgical patients. The objective of the present study was to evaluate the relationship between the levels of sedation produced by low doses of ketamine S(+), as well as encephalographic variables: BIS, SEF 95%, pEMG, suppression rate, and presence of burst-suppression.

METHODS

Thirty patients of both sexes, aged 25-50 years, were randomized into three groups. Group G1 (10) received intravenous ketamine S(+) 0.050 mg,kg(-1); group G2 (10) intravenous ketamine S(+) 0.125 mg.kg(-1); and group G3 (10) intravenous ketamine S(+) 0.250 mg.kg(-1). All patients received 0.08 mg.kg(-1) of intravenous midazolam 10 minutes before administration of ketamine S(+). In each group, two moments were evaluated: M1, before ketamine S(+) administration; and M2, after ketamine S(+) administration. Sedation levels and encephalographic variables: BIS, SEF 95%, pEMG, suppression rate, and the presence of burst-suppression were evaluated in all patients before and after ketamine S(+) administration. ANOVA was used for repeated measurements and the p-value was adjusted for multiple comparisons by Tukey's test.

RESULTS

A decrease in alertness-sedation scale scores was observed in all three groups in moment M2. Electroencephalographic variables showed significant variation in all three groups when moments M1 and M2 were compared, both in pEMG and BIS (p < 0.05).

CONCLUSIONS

Sedation levels showed significant correlation with the increase in ketamine S(+) dosage. However, increased BIS levels may have reflected increased pEMG induced by ketamine S(+).

Precise localization of the current dipole by the magnetoencephalography (MEG) has enabled us to combine the functional information onto the anatomical landmarks. This merit can be best exhibited when the dipole is situated in the superficial cortex and directed parallel to the skull surface. However, before utilizing MEG extensively as a clinical tool, it is inevitable to confirm the precision of the source localization by comparing the estimation with the actual sources. Somatosensory evoked field (SEF) following the electric shock to the peripheral nerve and movement-related cortical field (MRCF) associated with self-paced movement can show us the estimated sources at the postcentral and precentral cortex, respectively, with somatotopic organization. These localizations were confirmed by the direct recordings from the human brain surface during the operation, even if the corresponding areas were anatomically distorted by some lesion occupying the central area. In addition, MEG can localize second somatosensory area (SII) over the superior bank of the Sylvian fissure as well as posterior parietal cortex (PPC), which are difficult to be detected by the EEG recording. These reliable estimation enables us to apply MEG to clarification of pathogenesis of various diseases and source localization for higher brain function.

Spectral edge frequency 90 (SEF 90) and relative power in four frequency bands (beta, alpha, theta, delta) of the processed electroencephalogram were recorded in 20 patients undergoing elective gynecological surgery under total intravenous anesthesia (propofol-ketamine-fentanyl) (group PKF, n = 10) or nitrous oxide-oxygen-isoflurane (group GOI, n = 10) anesthesia. During anesthesia, mean SEF 90 and relative beta power increased more significantly in group PKF than in group GOI. At emergence from anesthesia, SEF 90 was 21.8 Hz in group PKF and 20.5 Hz in group GOI. These results suggest that it is difficult to evaluate the depth of anesthesia using pEEG under PKF anesthesia.

SEPs and SEFs after air-puff stimulation of index and little fingers have been studied and compared to the responses following electrical stimulation of the same digits and of the median nerve at the wrist in 5 subjects. The differences in morphology of the evoked signals are described and the generator characteristics are analysed for SEFs by means of a moving dipole model inside a homogeneous sphere. In our measurements the magnetic fields following electrical finger stimulation show a 30 msec component, which was absent following air-puff stimulation. This could not be seen in the electric field activity. The generators of the first component of SEFs after air-puff finger stimulation proved to be deeper (8 mm on average across all subjects and for both fingers) than in the case of electrically evoked SEFs. A similar behaviour was also observed for the second component of SEFs for the 2 stimulus modalities.

Measurements of somatosensory evoked field (SEF) by median nerve stimulation and auditory evoked field (AEF) by tone burst to right ear were performed. MEG measurements of multiple sources, AEF and SEF overlapped in time, were carried out. In the mixed AEF and SEF, stimulation to the median nerve was delivered 80 and 200ms later than to the right ear, respectively. Dynamic singular value decomposition (DSVD) method, having a time window and shift time, was applied to each spatio-temporal magnetic data. It showed that the time course of the singular value corresponded to the change of magnetic field waveforms. Furthermore, in order to discuss hemispheric characteristics, the DSVD was also applied to the spatio-temporal magnetic data of bilateral hemisphere (contra and ipsilateral to the stimulation). It showed that the time course of the singular value of all magnetic data well matched to the results of the contralateral hemisphere. Correlation coefficient was calculated between the results of the DSVD in each hemisphere. The correlation coefficient of the contralateral (left) hemisphere showed a higher value than that of the ipsilateral (right, over 0.7). Finally, Time-frequency analysis was applied to the magnetic data of the contralateral hemisphere. We conclude that the DSVD, having time window and shift time, is useful for analyzing spatio-temporal activity of the human cortex.

We assessed whether subcortical structures can generate magnetic fields detectable outside the brain by first measuring the somatic evoked magnetic fields (SEFs) from a decorticated porcine preparation and then from an intact preparation. Strong SEFs were detected a few millimeters above the corpus callosum after electrical stimulations of the snout. The waveforms consisted of a large spike ( < or = 6 pT) with a peak latency of 11-18 ms depending on the age of the animal, followed by a slow wave. The waveform and latency of the SEF spike were virtually identical to those of the field potential within the brain. The SEF topography indicated that the underlying generator of the spike was in a region contralateral to the stimulation and inferior to the thalamus. The subcortical SEF was strong enough to be detectable even above the intact brain, after the cortically generated SEF was removed by ablation of the primary cortical area. The results indicate that a structure deep in the brain can produce remarkably strong magnetic fields detectable outside the brain.

Previous reports have shown that serum elastin fragments (SEFs) may be a useful biomarker for the diagnosis of an acute aortic dissection (AAD). However, because the reference interval of SEFs has not been established, it has not been determined whether SEFs are really useful for the diagnosis of AAD. The purpose of this study was to determine the usefulness of measuring SEFs for the diagnosis of AAD. A total of 42 consecutive patients aged 68 ± 18 years who were diagnosed with an AAD were studied. Patient background and SEF levels were examined on admission. SEF levels were also measured in patients undergoing a medical examination (n = 531, age 54 ± 17 years) to compare with those with an AAD. In the control group, SEF levels increased with age (R = 0.725, p <0.001). Then, we defined the upper limit of the reference interval of SEF levels as the 97.5th percentile of control SEF grouped by decade of life from the sixth to ninth decade. The overall risk of AAD exceeding the upper limit of the reference interval at each decade was 10% (4 of 42). For patients in their 60s and 70s, median SEF levels in the AAD group (89 [77 to 104], 93 [60 to 123] ng/ml, respectively) were not significantly higher than those in the control group (79 [68 to 92], 90 [79 to 106] ng/ml, respectively; p = 0.081 and 0.990, respectively). Our data suggest that measuring SEF levels may not be useful in the diagnosis of an AAD as the upper limit of the reference interval of the SEF level was unexpectedly higher.

Cortical activity related to the late component of the cutanomuscular reflex was studied by measuring somatosensory evoked magnetic fields (SEFs) during isometric contraction of the reflex-induced muscle. After electrical stimulation to the index finger with intensity of three times of the perception threshold, three peaks of the cortical activity were detected within the somato-sensory area contralaterally to the stimulation site. Three dimentional location and the amplitude of the equivalent current dipoles for each peak were compared to that of observed SEF without muscle contraction. Significantly increased third component of SEFs (the latency of about 50 ms) always preceeded ca 20 ms against the peak of the late component of the cutaneomusucular reflex observed in the first dorsal interosseous (1DI) muscle. The conduction delay from the primary somatomotor cortex to the 1DI was determined as also ca 20 ms according to the result of the transcranial magnetic stimulation. We conclude from these evidences that all or part of the ingredient of the third component of SEFs may contribute to inducement of the late excitatory component of the cutaneomuscular reflex.

Both subcutaneous echo-free space (SEFS) observed by ultrasonography and the ratio of intracellular fluid resistance to extracellular fluid resistance (Ri/Re) calculated from bioelectrical impedance analysis (BIA) represent extracellular edema status in the extremities. We tried to correlate these parameters.

In 70 legs with venous edema (VE) and 68 legs with lymphedema (LE), subcutaneous tissue ultrasonography to determine SEFS severity (range, 0-2) and BIA to calculate Ri/Re were performed. In the calf, SEFS severity showed good linear correlation with Ri/Re, particularly in the lower lateral calf where the mean Ri/Re for LE (SEFS grade 0: 3.2 ± 0.8; SEFS grade 1: 4.0 ± 0.9; SEFS grade 2: 6.3 ± 3.6) and VE (SEFS grade 0: 3.6 ± 0.6; SEFS grade 1: 4.4 ± 1.6; SEFS grade 2: 5.3 ± 2.0) was similar. In the thigh, a mild correlation was confirmed only in LE.

It may be concluded that SEFS in the lower calf area well represents the local fluid status regardless of the type of edema, but not so in the thigh.

Over the last ten years, monitors of depth of anesthesia have progressively been integrated in the clinical practice. Based on the analysis of the electroencephalogram (EEG), these monitors deliver an index that helps the anesthesiologist to determine the state of the patient during the surgery. Although they employ different kind of algorithms, spectral parameters are always taken into account to achieve the final indexes. In this work, a new spectral parameter based on the cumulative power spectrum is proposed. When compared to the Spectral Edge Frequency (SEF), a classic spectral parameter, the Cumulative Power Spectrum Index (CPSI) presents a higher correlation with reference indexes (AAI, BIS and CePROP) and a higher prediction probability of the state of the patient. Furthermore, when compared to the reference indexes, the CPSI shows similar performances in terms of correlation and presents a higher prediction probability than two of them (BIS and CePROP).

Tendon injuries are common to all ages. Injured tendons typically do not recover full functionality. The amount and organization of tendon constituents dictate their mechanical properties. The impact of changes in these constituents during (patho)physiologic processes (e.g., aging and healing) are not fully understood. Toward this end, microstructurally motivated strain energy functions (SEFs) offer insight into underlying mechanisms of age-dependent healing. Several SEFs have been adapted for tendon; however, most are phenomenological. Therefore, the aims of this study are: (1) evaluate the descriptive capability of SEFs in age-dependent murine patellar tendon healing and (2) identify a SEF for implementation in a growth and remodeling (G&R) model. To accomplish these aims, models were fitted to patellar tendon tensile data from multiple age groups and post-injury timepoints. Model sensitivity to parameters and the determinability of the parameters were assessed. A two-way analysis of variance was used to identify changes in parameters and the feasibility of implementing each model into a G&R model is discussed. The evaluated SEFs exhibited adequate descriptive capability. Parameter determinability and sensitivity analysis, however, highlighted the need for additional data to inform and validate the models to increase physiologic relevance and enable G&R model formulation to determine underlying mechanisms of age-dependent healing. This work, as a first, evaluated changes in tendon mechanical properties both as functions of age and injury in an age-dependent manner using microstructurally motivated models, highlights inherent dependencies between parameters of widely used hyperelastic models, and identified unique post-injury behavior by the aging group compared to the mature and aged groups.

Mechanical instability of soft tissues can either risk their normal function or alternatively trigger patterning mechanisms during growth and morphogenesis processes. Unlike standard stability analysis of linear elastic bodies, for soft tissues undergoing large deformations it is imperative to account for the nonlinearities induced by the coupling between load and surface changes at onset of instability. The related issue of boundary conditions, in context of soft tissues, has hardly been addressed in the literature, with most of available research employing dead-load conditions. This paper is concerned with the influence of imposed homogeneous rate (incremental) surface data on critical loads and associated modes in soft tissues, within the context of linear bifurcation analysis. Material behavior is modeled by compressible isotropic hyperelastic strain energy functions (SEFs), with experimentally validated material parameters for the Fung-Demiray SEF, over a range of constitutive response (including brain and liver tissues). For simplicity, we examine benchmark problems of basic spherical patterns: full sphere, spherical cavity, and thick spherical shell. Limiting the analysis to primary hydrostatic states we arrive at universal closed-form solutions, thus providing insight on the role of imposed boundary data. Influence of selected rate boundary conditions (RBCs) like dead-load and fluid-pressure (FP), coupled with constitutive parameters, on the existence and levels of bifurcation loads is compared and discussed. It is argued that the selection of the appropriate type of homogeneous RBC can have a critical effect on the level of bifurcation loads and even exclude the emergence of bifurcation instabilities.

Quantitative angiocardiographic examinations concerning the regional contraction of the left ventricle in 16 patients with acute myocardial infarction were performed. In comparison to a control group of 6 healthy male patients the determination of the speed of the medium regional shortening (MVRF) of 12 different ventricle segments resulted in typical findings deviating from the normal. On the second day after beginning of the infarction in the area of the myocardium affected by an acute infarction there existed as a rule severe hypokinetic and akinetic disturbances of the contraction (13 times), only in three cases slight paradoxical movements of the ventricular wall (dyskinesias) could be observed. The average speed of shortening of all segments together (MVRF) excellently represents the momentary global function of the ventricle. It comprises in the same way acutely and chronicly disturbed areas as well as also the function of regions of the myocardium which are not disturbed. MV/RF and systolic ejection fraction (SEF) show statistically a highly significant correlation of r = 0,797 (p less than 0.001). On the basis of the findings got considerations are performed concerning a proved differential therapy in the acute stage of the myocardial infarction.

The aim of the present study was to investigate the prognostic value of somatosensory evoked magnetic fields (SEFs) at an acute stage on recovery of an affected upper extremity (UE) function as practicality in hemiplegic patients after thalamic hemorrhage. Nine hemiplegic patients after thalamic hemorrhage were enrolled in this study. Median nerve SEFs, evoked by electrical stimulation at the wrist of the affected UE, were measured using a 204 channel whole-head magnetoencephalography system within 72 hours after the onset of thalamic hemorrhage (acute stage). Assessments on the affected UE, which included the motor palsies of the UE and fingers (Brunnstrom's motor recovery stage: BS), sensory disturbance (the thumb localizing test) and UE function (the UE ability test), were performed at both the acute stage and 3 months after the onset of thalamic hemorrhage (chronic stage). Almost all the patients showing any median nerve SEF components that originated from the somatosensory cortex in the affected hemisphere and occurred between about 20 ms and 100 ms post-stimulus at the acute stage demonstrated good outcomes in the motor palsies (BSV), sensory disturbance (normal) and affected UE function (practical hand) at the chronic stage. In contrast, majority of patients not showing them at all demonstrated poor outcomes in the motor palsies (BSIII or less), sensory disturbance (severely impaired) and affected UE function (disabled hand) at the chronic stage. These results suggest that the findings of the median nerve SEFs at the acute stage would contribute to the early outcome prediction on the affected UE function in hemiplegic patients after thalamic hemorrhage.

Based on an old paradigm that the extra-embryonic membranes develop semiautonomously from the embryo, it can also be postulated that subembryonic fluid (SEF) will be formed semiautonomously against embryonic growth, because the formation of SEF is mediated by the yolk sac membrane. In this study, we interfered in the development of SEF or the embryo. The acoustic resonance technique (which measures the resonant frequency of an excited egg) was used as a nondestructive tool to monitor the development of SEF. In the first experiment, in which the embryo was killed chemically with NaN3, it was proven that the formation of SEF continued, even when the embryo was killed after the initiation of the growth of the yolk sac membrane. In the second experiment, in which the development of SEF was inhibited chemically with amiloride, it was shown that the embryo developed further, although SEF formation was inhibited. In the last experiment, it was shown that the age of the flock affected the development of the embryo and the sudden decrease of the resonant frequency in a different way. However, some presetting conditions, such as storage, may affect both in a similar way. Our results further strengthen the idea that the formation of SEF develops semiautonomously against embryonic development by using the nondestructive acoustic resonance technique as an indirect method to monitor yolk sac membrane formation.

To clarify characteristics of each human somatosensory evoked field (SEF) component following passive movement (PM), PM1, PM2, and PM3, using high spatiotemporal resolution 306-channel magnetoencephalography and varying PM range and angular velocity. We recorded SEFs following PM under three conditions [normal range-normal velocity (NN), small range-normal velocity (SN), and small range-slow velocity (SS)] with changing movement range and angular velocity in 12 participants and calculated the amplitude, equivalent current dipole (ECD) location, and the ECD strength for each component. All components were observed in six participants, whereas only PM1 and PM3 in the other six. Clear response deflections at the ipsilateral hemisphere to PM side were observed in seven participants. PM1 amplitude was larger under NN and SN conditions, and mean ECD location for PM1 was at primary motor area. PM3 amplitude was larger under SN condition and mean ECD location for PM3 under SS condition was at primary somatosensory area. PM1 amplitude was dependent on the angular velocity of PM, suggesting that PM1 reflects afferent input from muscle spindle, whereas PM3 amplitude was dependent on the duration. The ECD for PM3 was located in the primary somatosensory cortex, suggesting that PM3 reflects cutaneous input. We confirmed the hypothesis for locally distinct generators and characteristics of each SEF component.

The cerebellum and the basal ganglia play an important role in the control of voluntary eye movement associated with complex behavior, but little is known about how cerebellar projections project to cortical eye movement areas. Here we used retrograde transneuronal transport of rabies virus to identify neurons in the cerebellar nuclei that project via the thalamus to supplementary eye field (SEF) of the frontal cortex of macaques. After rabies injections into the SEF, many neurons in the restricted region, the ventral aspects of the dentate nucleus (DN), the caudal pole of the DN, and the posterior interpositus nucleus (PIN) were labeled disynaptically via the thalamus, whereas no neuron labeling was found in the anterior interpositus nucleus (AIN). The distribution of the labeled neurons was dorsoventrally different from that of DN and PIN neurons labeled from the motor cortex. In the basal ganglia, a large number of labeled neurons were confined to the dorsomedial portion of the internal segment of the globus pallidus (GPi) as more neurons were labeled in the inner portion of the GPi (GPii) than in the outer portion of the GPi (GPio). This is the first evidence of a projection between cerebellum/basal ganglia and the SEF that could enable the cerebellum to modulate the cognitive control of voluntary eye movement.

UNASSIGNED

To examine the temporal stability and variability of neuronal synchronization among the contralateral primary somatosensory cortex (cSI) and contralateral (cSII) and ipsilateral secondary somatosensory cortex (iSII) in response to median nerve stimulation.

UNASSIGNED

Both the spontaneous magnetoencephalography (MEG) signals as the pre-stimulus condition and somatosensory evoked magnetic-fields (SEF) were recorded in eleven healthy subjects. We calculated a phase-locking value (PLV) between two areas among cSI, cSII, and iSII in five frequency bands (theta: 5-7 Hz, alpha: 8-12 Hz, beta: 15-29 Hz, gamma-1: 30-59 Hz, and gamma-2: 60-90 Hz), and compared the PLV among in pre-stimulus and stimulus conditions.

UNASSIGNED

The PLV between cSI and cSII for the theta band activity varied within 2 s from the stimulus onset. On the other hand, the PLV between cSI and iSII for the alpha band did not vary within 2 s.

UNASSIGNED

The fluctuation of neuronal synchrony among sensory-related cortices in response to median nerve stimulation depends on the induced frequency band and inter-region.

UNASSIGNED

This study is the first to report the temporal characteristic of stimulus-driven neural synchrony following somatosensory stimulation.

The recovery function of somatosensory evoked magnetic fields (SEFs) was recorded to investigate excitatory and inhibitory balance in the somatosensory cortex of patients with carpal tunnel syndrome.

SEFs were recorded in patients and controls. Recordings were taken following median nerve stimulation with single and double pulses with interstimulus intervals of 10-200ms. The root mean square for the N20m component following the second stimulation was analyzed. SEFs following stimulation of the first and middle digits were also recorded and the location for the equivalent current dipoles was estimated in three-dimensional planes.

Distances on the vertical axis between the equivalent current dipoles for the first and third digits were shorter in patients than in control participants. The root mean square for the N20m recovered earlier in patients compared to controls; this was statistically significant at an interstimulus interval of 10ms. There was no relationship between N20m recovery and the equivalent current dipole location in the primary somatosensory cortex.

Carpal tunnel syndrome was associated with functional disinhibition and destruction of the somatotopic organization in the primary somatosensory cortex.

Disinhibitory changes might induce a maladaptation of the central nervous system relating to pain.

A 49-year-old male worker developed persistent pain in his left wrist after work strain injuries. Clinical symptoms met with criteria for Complex Regional Pain Syndrome (CRPS) type I. In the present study, the effect of the experience of pain on the somatotopy of the primary cortical hand representation was investigated. Somatosensory evoked magnetic fields (SEF) elicited by non-painful tactile stimulation at the index finger of the affected and the unaffected hand were recorded when experiencing pain elicited by a moderate physical load condition (holding a 1.6 kg object in the hand). It was shown that MEG and subjective responses to innocuous tactile stimuli were reduced when simultaneous nociceptive stimulation was applied. These findings suggest a gating effect in the central nervous system elicited by concurrent simultaneous information from two different somatosensory modalities (pain and tactile). The results revealed the existence of nociceptive-induced plastic changes in the central nervous system associated with CRPS type I.

Evodiae Fructus (EF) is generally divided into three categories: small flower EF (SEF), medium flower EF (MEF) and big flower EF (BEF) in commodity circulation according to the size of the fruit. It is a well-known and frequently used herbal medicine for treating gastrointestinal disorder-related stomachache and headache, which has aroused wide attention for its hepatotoxicity. However, reports about hepatotoxicity is controversial and hepatotoxic components are inconclusive. The study aimed to explain the controversial hepatotoxicity of EF and screen the components associated with hepatotoxicity of EF based on the spectrum-toxicity relationship. UPLC fingerprints of 39 batches of EF collected from different regions were established. Combined with the results of L02 cell viability assays, the spectrum-toxicity relationship was investigated on the basic of orthogonal partial least squares (OPLS). The results of the research demonstrated that the toxicity of EF was obviously various among the different categories, in particularly, SEF was with less toxicity, MEF except for adulterants and BEF had mild toxicity and adulterants of MEF (A-MEF) produced more damage to L02 cell and no regions specificity in hepatotoxicity of EF. Thereinto, samples, the contents of which do not meet the requirements of Chinese Pharmacopoeia, were adulterants. It was worth noting that P11, P17, P20 and P25 were closely related to hepatotoxicity of EF and they were respectively identified as limonin (LIM), evodiamine (EVO), 1-methyl-2-nonyl-4(1H)-quinolone (MNQ), and 1-methyl-2-undecyl-4(1H)-quinolone (MUQ) by UPLC-Q-Exactive-MS. The hepatoprotection of P11 and hepatotoxicity of P17 were consistent with the results of spectrum-toxicity relationship. In summary, A-MEF was more toxic than other categories and SEF was less toxic than the others. It was noteworthy that EVO was the main hepatotoxic component of EF and LIM was the main hepatoprotective component of EF. The results provided worthy evidence for better utilization and development of EF.

Keywords: Evodiae Fructus; Spectrum-toxicity relationship; UPLC-Q-Exactive-MS.