Cortical representation of different motor rhythms during bimanual movements

The cortical control of bimanual and unimanual movements involves complex facilitatory and inhibitory interhemispheric interactions. We analysed the part of the cortical network directly related to the motor output by corticomuscular (64 channel EEG–EMG) and cortico-cortical (EEG–EEG) coherence and delays at the frequency of a voluntarily maintained unimanual and bimanual rhythm and in the 15–30-Hz band during isometric contractions. Voluntary rhythms of each hand showed coherence with lateral cortical areas in both hemispheres and occasionally in the frontal midline region (60–80 % of the recordings and 10–30 %, respectively). They were always coherent between both hands, and this coherence was positively correlated with the interhemispheric coherence (p < 0.01). Unilateral movements were represented mainly in the contralateral cortex (60–80 vs. 10–30 % ipsilateral, p < 0.01). Ipsilateral coherence was more common in left-hand movements, paralleled by more left–right muscle coherence. Partial corticomuscular coherence most often disappeared (p < 0.05) when the contralateral cortex was the predictor, indicating a mainly indirect connection of ipsilateral/frontomesial representations with the muscle via contralateral cortex. Interhemispheric delays had a bimodal distribution (1–10 and 15–30 ms) indicating direct and subcortical routes. Corticomuscular delays (mainly 12–25 ms) indicated fast corticospinal projections and musculocortical feedback. The 15–30-Hz corticomuscular coherence during isometric contractions (60–70 % of recordings) was strictly contralaterally represented without any peripheral left–right coherence. Thus, bilateral cortical areas generate voluntary unimanual and bimanual rhythmic movements. Interhemispheric interactions as detected by EEG–EEG coherence contribute to bimanual synchronization. This is distinct from the unilateral cortical representation of the 15–30-Hz motor rhythm during isometric movements

A novel quantitative arousal-associated EEG-metric to predict severity of respiratory distress in obstructive sleep apnea patients

Respiratory arousals (RA) on polysomnography (PSG) are an important predictor of obstructive sleep apnea (OSA) disease severity. Additionally, recent reports suggest that more global indices of desaturation such as the hypoxic burden, namely the area under the curve (AUC) of the oxygen saturation (SaO2) PSG trace may better depict the desaturation burden in OSA. Here we investigated possible associations between a new metric, namely the AUC of the respiratory arousal electroencephalographic (EEG) recording, and already established parameters as the apnea/hypopnea index (AHI), arousal index and hypoxic burden in patients with OSA. In this data-driven study, polysomnographic data from 102 patients with OSAS were assessed (32 female; 70 male; mean value of age: 52 years; mean value of Body-Mass-Index-BMI: 31 kg/m2). The marked arousals from the pooled EEG signal (C3 and C4) were smoothed and the AUC was estimated. We used a support vector regressor (SVR) analysis to predict AHI, arousal index and hypoxic burden as captured by the PSG. The SVR with the arousal-AUC metric could quite reliably predict the AHI with a high correlation coefficient (0,58 in the training set, 0,65 in the testing set and 0,64 overall), as well as the hypoxic burden (0,62 in the training set, 0,58 in the testing set and 0,59 overall) and the arousal index (0,58 in the training set, 0,67 in the testing set and 0,66 overall). This novel arousal-AUC metric may predict AHI, hypoxic burden and arousal index with a quite high correlation coefficient and therefore could be used as an additional quantitative surrogate marker in the description of obstructive sleep apnea disease severity

Effects of ON and OFF subthalamic nucleus-DBS on prefrontal cortex activation during a cognitive task: an fNIRS study

Subthalamic nucleus (STN) deep brain stimulation (DBS) therapy is an effective treatment for the appendicular motor symptoms of Parkinson’s disease (PD). The STN contains multiple segregated circuits subserving motor, cognitive and mood functions through distinct connectivity to cortical regions. Therefore, we examined prefrontal cortical (PFC) effects of “ON” and “OFF” STN-DBS on executive function (Go/NoGo) using functional near-infrared spectroscopy (fNIRS). Methods Out of 8 PD STN-DBS patients, we present here preliminary analysis of a male (62y) PD patient with bilateral STN-DBS (unipolar, 180Hz, 3.5V). The patient was tested after 12h withdrawal of dopamine medications in both an “OFF” and “ON” DBS session separated by 30min. The subject performed a computerised GoNoGo task with 3 alternating Go/NoGo blocks of 30s duration (20 trials/block) interspersed with 30s rest. Reaction time (RT) and accuracy (omission-Om and commission-Cm errors) results were the average of the 3 Go/NoGo blocks. During performance of the Go/NoGo blocks, changes in oxygenated (O2Hb) and deoxygenated (HHb) haemoglobin concentrations were measured by a fNIRS system (Oxymon MkIII, Artinis Medical Systems) covering the bilateral PFC regions. Results/Discussion Clinical motor performance (UPDRSIII) improved from OFF (31) to ON (20). RT during Go and NoGo was ∼40ms faster in OFF (460 and 364ms) than ON (516 and 407ms). Furthermore, the NoGo condition increased misses (Om) in ON (7%) than OFF (0%); while false alarms (Cm) were similarly increased in ON (27%) and OFF (30%). The Go and NoGo conditions increased bilateral PFC activation (i.e., increase in O2Hb and decrease in HHb). However, there was a general decrease in PFC activation in OFF relative to ON, and this was more obvious in Go than NoGo (see Fig. 1) Conclusion These preliminary results indicate that STN-DBS modulates neurovascular responses in the bilateral PFC that are associated with response inhibition

Acute effect of gibberellic acid on serum enzymes and blood markers in male albino rats

This study was designed to evaluate the influence of a phytohormone, gibberellic acid (GA3) on marker enzymes and biomarkers of serum, and blood hemoglobin and its blood cells counts of rat. In order to evaluate the positive/negative effects, the rats were administered 75μg, 150μg and 300μg of GA3/kg body weight as a single dose. GA3 treatments produced differential effects on the different parameters at dose dependent manner after 4 hours.The down regulation in specific activities of ALT, ALP, GGT and amylase were noted against the control with significant up regulation of AST activity. GA3 also produced dose dependent effect on biomarkers. There is a substantial reduction in the quantity of glucose, urea, creatinine, calcium, phosphorus, sodium and potassium was recorded against the control. On the other hand, the insignificant increase in content of total protein, albumin and uric acid was observed at all dose of GA3 treatment against the control. GA3 increased the RBC, WBC and neutrophil by decreasing the lymphocyte total numbers. Platelets, monocytes and oesinophils count were not altered by any dose of GA3.In conclusion, GA3 produced dose dependent effect on different parameters of rat blood serum.Keywords: phytohormone; gibberellic acid; creatinine; neutrophi

Oscillating central motor networks in pathological tremors and voluntary movements: what makes the difference?

Parkinsonian tremor (PD), essential tremor (ET) and voluntarily mimicked tremor represent fundamentally different motor phenomena, yet, magnetoencephalographic and imaging data suggest their origin in the same motor centers of the brain. Using EEG–EMG coherence and coherent source analysis we found a different pattern of corticomuscular delays, time courses and central representations for the basic and double tremor frequencies typical for PD suggesting a wider range defective oscillatory activity. For the basic tremor frequency similar central representations in primary sensorimotor, prefrontal/premotor and diencephalic (e.g. thalamic) areas were reproduced for all three tremors. But renormalized partial directed coherence of the spatially filtered (source) signals revealed a mainly unidirectional flow of information from the diencephalon to cortex in voluntary tremor, e.g. a thalamocortical relay, as opposed to a bidirectional subcortico-cortical flow in PD and ET promoting uncontrollable, e.g. thalamocortical, loop oscillations. Our results help to understand why pathological tremors although originating from the physiological motor network are not under voluntary control and they may contribute to the solution of the puzzle why high frequency thalamic stimulation has a selective effect on pathological tremor leaving voluntary movement performance almost unaltered

Short term effect of 28-homobrassinolide on serum, liver and kidney marker enzymes and other biochemical parameters of male albino rats

Brassinosterols (BS) are ubiquitous pluripotent growth regulator present in plants. They exist in isoforms of epi and homobrassinolides (HB).  BS act as potent stimulators of root and shoot elongation, cell division, DNA and RNA polymerase activity, ethylene production and of stress tolerance to temperature, water scarcity and salinity in plants. It is also used to increase the yield of crop and to protect the plants against pesticides. Consumption of plant material as diet and used as growth regulator in animals, and application of BS in agriculture would increases its availability to the host tissues. In the present study, the effect of 28-HB, an isomer of brassinosterol on serum, liver and kidney marker enzymes, lipid peroxidation, tissue histology and the blood parameters of rat were investigated. The rats were given the compound by intradermal mode at the concentration of 75µg, 150µg and 300µg as single dose and the effects were observed after 4 hr to study the immediate response of the animal. The treatment of rats with 28-HB, caused different effects on the serum, liver and kidney parameters of this study. In conclusion, the present study showed that 28-HB affects the structure and function of rat tissues in a dose dependent manner.Keywords: Brassinosterols; homobrassinolides; 28-HB; lipid peroxidatio

Short term effect of 28-homobrassinolide on serum, liver and kidney marker enzymes and other biochemical parameters of male albino rats

Brassinosterols (BS) are ubiquitous pluripotent growth regulator present in plants. They exist in isoforms of epi and homobrassinolides (HB).  BS act as potent stimulators of root and shoot elongation, cell division, DNA and RNA polymerase activity, ethylene production and of stress tolerance to temperature, water scarcity and salinity in plants. It is also used to increase the yield of crop and to protect the plants against pesticides. Consumption of plant material as diet and used as growth regulator in animals, and application of BS in agriculture would increases its availability to the host tissues. In the present study, the effect of 28-HB, an isomer of brassinosterol on serum, liver and kidney marker enzymes, lipid peroxidation, tissue histology and the blood parameters of rat were investigated. The rats were given the compound by intradermal mode at the concentration of 75µg, 150µg and 300µg as single dose and the effects were observed after 4 hr to study the immediate response of the animal. The treatment of rats with 28-HB, caused different effects on the serum, liver and kidney parameters of this study. In conclusion, the present study showed that 28-HB affects the structure and function of rat tissues in a dose dependent manner.Keywords: Brassinosterols; homobrassinolides; 28-HB; lipid peroxidatio

Biochemical evaluation of low dose methyl 2-benzimidazole carbamate fungicide on male albino rats

Methyl 2-benzimidazole carbamate (carbendazim) is one of the synthetic fungicides that controlled organisms that caused plant diseases of different types. It is widely used as a preservative in leather, paint, textile, fruits and papermaking industry. It is also used as an anticancer drug in chemical medicine. In the present study low concentrations of carbendazim was administered at 5, 10, 25 and 50mM doses intradermally to male albino rats. At the end of 6 hr, 12hr and 24hr duration, blood samples were collected from the animal for the analysis of biochemical and haematological parameters. Carbendazim caused an increase of cholesterol, uric acid, glucose and creatinine while serum phosphorous content was decreased. However, mean hemoglobin, WBC, E, and platelet counts increased and total RBC, N and L counts decreased. These results indicated that low dose level carbendazim contributed to toxicological effects in the rat tissues.Keywords: Methyl 2-benzimidazole carbamate; Fungicide; Rat tissue

EEG-EMG-coherence in SDB patients with utilization of a support vector machine-algorithm [Poster Abstract]

Background We investigated whether the EEG-EMG-coherence allows a differentiation between patients with sleep-disordered breathing (SDB) without OSA and SDB-patients with mild, moderate or severe OSA. Methods Polysomnographic recordings of 102 patients with SDB (33 female; age: 53,± 12,4 years) were analyzed with the multitaper coherence method (MTM). Recordings contained 2 EEG-channels (C3 and C4) and a chin EMG-channel for one night. Four epochs (each 30 seconds, classified manually by AASM 2007 criteria) of each sleep stage were marked (1632 epochs in total), which were included in the classification analysis. The collected data sets were supplied to the support vector machine (SVM) algorithm to classify OSA severity. Twenty patients had a mild (RDI ≥10/h and < 15/h), 30 patients had a moderate (RDI ≥15/h and < 30/h) and 27 patients had a severe OSA (RDI ≥30/h). 25 patients had a RDI < 10/h. The AUC (area under the curve) value was calculated for each receiver operator curve (ROC) curve. Results EEG-EMG coherence was able to distinguish between the SDB-patients without OSA and SDB-patients with OSA in each of the 3 severity groups using an SVM algorithm. In mild OSA, the AUC was 0.616 (p = 0.024), in moderate OSA the AUC was 0.659 (p = 0.003), and in severe OSA the AUC was 0.823 (p < 0.001). Conclusions SDB patients with OSA can be differentiated from SDB patients without OSA on the basis of EEG-EMG coherence by using the Multitaper Coherence Method (MTM) and SVM algorithm

Sleep stage classification using spectral analyses and support vector machine algorithm on C3- and C4-EEG signals [Abstract]

Introduction Sleep stage classification currently relies largely on visual classification methods. We tested a new pipeline for automated offline classification based upon power spectrum at six different frequency bands. The pipeline allowed sleep stage classification and provided whole-night visualization of sleep stages. Materials and methods 102 subjects (69 male; 53.74 ± 12.4 years) underwent full-night polysomnography. The recording system included C3- and C4-EEG channels. All signals were measured at sampling rate of 200 Hz. Four epochs (30 seconds each) of each sleep stage (N1, N2, N3, REM, awake) were marked in the visually scored recordings of each one of the 102 patients. Scoring of sleep stages was performed according to AASM 2007-criteria. In total 408 epochs for each sleep stage were included in the sleep stage classification analyses. Recordings of all these epochs were fed into the pipeline to estimate the power spectrum at six different frequency bands, namely from very low frequency (VLF, 0.1-1 Hz) to gamma frequency (30-50 Hz). The power spectrum was measured with a method called multitaper method. In this method the spectrum is estimated by multiplying the data with K windows (i.e tapers).The estimated parameters were given as input to the support vector machine (SVM) algorithm to classify the five different sleep stages based on the mean power amplitude estimated from six different frequency bands. The SVM algorithm was trained with 51 subjects and the testing was done with the other 51 subjects. In order to avoid bias of the training dataset, a 10-fold cross validation was additionally done to check the performance of the SVM algorithm Results The estimated testing accuracy of prediction of the sleep stages was 84.1% for stage N1 using the mean power amplitude from the delta frequency band. Accuracy was 67.8% for stage N2 from the delta frequency band and 74.9% for stage N3 from the VLF. Accuracy was 79.7% for REM stage from the delta frequency band and 84,8% for the wake stage from the theta frequency band. Conclusions We were able to successfully classify the sleep stages using the mean power amplitude at six different frequency bands separately and achieved up to 85% accuracy using the electrophysiological EEG signals. The delta and theta frequency bands gave the best accuracy of classification among all sleep stages