Significant Increase In Amplitude Research Articles

Changes in late-latency auditory evoked potentials after tinnitus suppression using auditory stimulation

ObjectiveTinnitus can result from auditory system reorganization due to neural activity dysfunctions. Auditory stimulation can cause temporary or persistent tinnitus alleviation by altering the neural generators. The present study investigated the changes in Late-Latency Auditory Evoked Potentials (LLAEPs) after tinnitus suppression using auditory stimulation with short-term Residual Inhibition (RI) and long-term Tinnitus Masker (TM). MethodsThe study included 40 participates with equal numbers in the Tinnitus Group (TG), including the chronic tinnitus subjects, and the Control Group (CG), including matched volunteers. The participants had normal hearing in conventional audiometry. All the participants underwent LLAEP recording pre-intervention and after a one-minute auditory stimulation (RI), as well as a pre-intervention Dichotic Digit Test (DDT) as a behavioral assessment of the selective attention. Moreover, TG underwent a 3-month course of TM, a third LLAEP recording post-TM, a second DDT post-TM, and the Tinnitus Handicap Inventory (THI) before and after the TM. ResultsIn the baseline LLAEP recording, the TG had significantly later N1, P3a, and P3b latencies, as well as significantly lower P3a and P3b amplitudes. The second LLAEP recording showed a significant intragroup increase in P3a amplitude and a significant decrease in P3a latency in the TG, while no significant intragroup difference was observed in the CG. In the third LLAEP recording performed on TG, the P3a amplitude and latency had significant changes compared to the second recording, while the N1 latency was significantly decreased. Moreover, the DDT and THI scores had significant improvement after the TM in TG. ConclusionsThe present study showed the neurophysiological changes after short-term (RI) and long-term (TM) auditory stimulations in tinnitus subjects. The LLAEP changes suggest that these interventions lead to tinnitus suppression through common mechanisms. The electrophysiological observation was also confirmed using behavioral assessments. Level of evidenceThis study type is a “comparative study” with the level of evidence “3”.

Photoacoustic non-human primate brain imaging

Non-human primates (NHPs) play significant roles in brain research because of the physiological similarities between humans and NHPs. Current functional brain imaging techniques for NHPs are difficult to meet the required high spatiotemporal resolution for behavior active NHPs. In this presentation, we review our initial study on evaluating the feasibility of photoacoustic imaging (PAI) for monitoring hemodynamic responses in the NHP brains due to various functional activities. PAI systems, including array-based photoacoustic computed tomography (PACT) system and photoacoustic microscopy (PAM), were used to detect hemodynamic responses in the NHP brains through a cranial window. The NHPs were subjected to different functional stimulations or actively performing behavioral tasks. Strong increases in PA signal amplitude during functional activities can be detected with single-blood-vessel spatial resolution in the cortex and subcortical regions of the NHP brains. Realtime-temporal-resolution hemodynamic response can also be obtained for the detected blood vessels in the brain. Our results demonstrate that PAI can reliably detect brain activations in NHPs with high spatiotemporal resolution.

Short-Term HRV Detection and Human Fatigue State Analysis Based on Optical Fiber Sensing Technology.

Mental fatigue is a key cause of chronic diseases and traffic accidents, which is difficult to be quantitatively evaluated. In order to non-intrusively detect fatigue state, an optical fiber sensing system is proposed, which is non-invasive and does not require direct contact with skin. The fiber sensor was fabricated through phase mask exposure method and packaged by sensitivity-enhanced structure, which can suppress transverse force and increase signal amplitude by 5%. A fatigue-inducing experiment was carried out, and the heartbeat signals of 20 subjects under different fatigue states were collected by the proposed sensing system. A series of heart rate variability indicators were calculated from the sensing signals, and their statistical significance for fatigue was analyzed. The experiment results showed that the values of SDNN and LF/HF increased significantly with subjects’ fatigue level. This study shows that the proposed fiber optic sensing system has practical value in fatigue state monitoring.

Temporal effects of two interferential current applications on peripheral circulation in children with hemiplegic cerebral palsy

ObjectivesTo determine the short-term effects of sympathetic and peripheral stimulation of interferential current (IFC) on blood flow (BF) in children with hemiplegic cerebral palsy (CP). MethodsThirty children with hemiplegic CP, ranging from 8 to 12 years old, were randomly divided into three groups (10 children/group). The first group received sympathetic stimulation of IFC, the second group received peripheral stimulation of IFC, and the third group (control) received placebo peripheral stimulation of IFC. A frequency of 80–100 Hz at an intensity of 10–20 mA was applied for 20 min. Blood volume pulse (BVP) amplitude was measured before IFC application using a plethysmography sensor at the big toe immediately after and 15 min poststimulation. The data were statistically analyzed and compared. ResultsThere were statistically significant differences in BVP amplitude among the three time intervals in both the sympathetic and peripheral groups (P < 0.05) with no difference in the control group (P = 0.995). There was a significant increase in BVP amplitude immediately after stimulation compared with before stimulation in both the sympathetic and peripheral groups (P = 0.0001). However, differences between the sympathetic and peripheral groups at the three measured periods were statistically nonsignificant (P > 0.05). ConclusionBoth IFC applications had a proper effect on improving BF in children with hemiplegic CP with no difference in efficacy between sympathetic and peripheral stimulation.

The protective effects of escitalopram on synaptic plasticity in the CA1 region of chronically stressed and non-stressed male rats.

Stress impairs cognitive processes and escitalopram affects them in various ways. The present study has compared the protective effects of two escitalopram doses on neural excitability and synaptic plasticity in the CA1 region of chronically stressed and non-stressed male rats. Forty-nine rats were randomly allocated into seven groups: Control (Co), stress (St), sham (Sh), escitalopram 10 and 20 mg/kg (Esc10 and Esc20), and stress-escitalopram 10 and 20 mg/kg (St-Esc10 and St-Esc20). Induction of restraint stress (6h/day) and escitalopram injections were performed for 14 days. The fEPSP slope and amplitude were measured according to input-output functions and after the LTP induction in the hippocampal CA1 region. Also, serum corticosterone levels were evaluated in all experimental groups. The fEPSP slope and amplitude decreased significantly in the St group and increased significantly in the Esc10 group compared with the Co group. In non-stressed states, significant increases in slope and amplitude occurred in the Esc10 group compared with the Esc20 group. Notably, these values were also significantly enhanced by both escitalopram doses under stressed conditions. Moreover, serum corticosterone levels significantly elevated in the St group although its levels decreased in both St-Esc groups compared with the St. Stress significantly attenuated neural excitability and long-term plasticity in the CA1 area. Only escitalopram 10mg/kg improved synaptic excitability, as well as LTP induction and maintenance in non-stressed subjects even more than normal levels. However, under stress conditions, both escitalopram doses enhanced neural excitability and memory probably due to reduced serum corticosterone levels.

Forced changes in El Niño–Southern Oscillation due to global warming and the associated uncertainties in ACCESS-ESM1.5 large ensembles

Understanding the forced response of El Niño–Southern Oscillation (ENSO) to future global warming (GW) is important for reliable climate projections; however, many important aspects of this response are yet to be fully understood. Here, we use two large ensembles of CMIP6 historical and SSP3-7.0 experiments (each with 40 ensemble members), performed with ACCESS-ESM1.5, to investigate the combined greenhouse gas (GHG) and aerosol forced changes in selected ENSO properties. We document the forced changes in ENSO's amplitude, power spectrum, skewness, and feedbacks and quantify the internal variability associated with these forced changes. There is a modest but statistically significant GW-induced increase in the ensemble-mean ENSO amplitude and a sizable ensemble variation (due to internal variability) with both increases (in 80% of the members) and decreases. To understand the mechanism of this variation, we examine the role of changes in the mean state and atmosphere-ocean coupling processes in the Pacific. We find that the ensemble variation of GW-induced ENSO amplitude change is most sensitive to the zonal wind forcing change. A change in the zonal gradient of mean sea surface temperatures (SSTs) also plays an important role in the ENSO amplitude change, with the changes in the atmospheric Bjerknes feedback and thermocline feedback playing a minor role. The implications and some caveats of these findings are discussed.

Long-term Average Spectrum and Nasal Accelerometry in Sentences of Differing Nasality and Forward-Focused Vowel Productions Under Altered Auditory Feedback

To investigate whether voice focus adjustments can alter the audio-vocal feedback and consequently modulate speech/voice motor control. Speaking with a forward-focused voice was expected to enhance audio-vocal feedback and thus decrease the variability of vocal fundamental frequency (F0). Twenty-two healthy, untrained adults (10 males and 12 females) were requested to sustain vowel /a/ with their natural focus and a forward focus and to naturally read the nasal, oral, and mixed oral-nasal sentences in normal noise-masked auditory conditions. Meanwhile, a miniature accelerometer was externally attached on the noise to detect the nasal vibrations during vocalization. Audio recordings were made and analyzed using the long-term average spectrum (LTAS) and power spectral analysis of F0. Compared with naturally-focused vowel production and oral sentences, forward-focused vowel productions and nasal sentences both showed significant increases in nasal accelerometric amplitude and the spectral power within the range of 200∼300 Hz, and significantly decreased the F0 variability below 3 Hz, which has been reported to be associated with enhanced auditory feedback in our previous research. The auditory masking not only significantly increased the low-frequency F0 variability, but also significantly decreased the ratio of the spectral power within 200∼300 Hz to the power within 300∼1000 Hz for the vowel and sentence productions. Gender differences were found in the correlations between the degree of nasal coupling and F0 stability as well as in the LTAS characteristics in response to noise. Variations in nasal-oral acoustic coupling not only change the formant features of speech signals, but involuntarily influence the auditory feedback control of vocal fold vibrations. Speakers tend to show improved F0 stability in response to a forward-focused voice adjustment.

Theoretical and Numerical Analyses and Application of Novel Underdamped Tri-Stable Stochastic Resonances under Symmetric Trichotomous Noise

In this paper, a novel underdamped tri-stable stochastic resonance (NUTSR) is presented in order to overcome the low out-performance of weak signal reinforcement in the classical tri-stable stochastic resonance (CTSR). The two systems are compared using the input and output amplitude as a measure when noiseless. NUTSR improves the output saturation characteristics and has more outstanding signal enhancement capability. In the background of Gaussian noise, the expressions of mean first-pass time (MFPT), steady-state probability density (SPD) and signal-to-noise ratio (SNR) are derived. The fourth-order Runge–Kutta algorithm and genetic algorithm (GA) is used for numerical simulations. Then the numerical simulation results of the two systems are compared comprehensively, and the theoretical deduction and numerical simulation results of NUTSR are also compared. Moreover, the two systems are applied in two bearing fault types of 6205-2RS JEM SKF and HRB 6205-2Z. Finally, the feasibility of NUTSR is verified under different noise, which is simulated numerically under symmetric trichotomous that NUTSR has better noise immunity and the increase in signal amplitude is more pronounced.

A meta-analysis on the evolution of the Lombard effect reveals that amplitude adjustments are a widespread vertebrate mechanism

Animal communication is central to many animal societies, and effective signal transmission is crucial for individuals to survive and reproduce successfully. One environmental factor that exerts selection pressure on acoustic signals is ambient noise. To maintain signal efficiency, species can adjust signals through phenotypic plasticity or microevolutionary response to natural selection. One of these signal adjustments is the increase in signal amplitude, called the Lombard effect, which has been frequently found in birds and mammals. However, the evolutionary origin of the Lombard effect is largely unresolved. Using a phylogenetically controlled meta-analysis, we show that the Lombard effect is also present in fish and amphibians, and contradictory results in the literature can be explained by differences in signal-to-noise ratios among studies. Our analysis also demonstrates that subcortical processes are sufficient to elicit the Lombard effect and that amplitude adjustments do not require vocal learning. We conclude that the Lombard effect is a widespread mechanism based on phenotypic plasticity in vertebrates for coping with changes in ambient noise levels.

Sodium Benzoate (NaB) Induced Impairment of the Functions of Duodenal Visceral Smooth Muscle (VSM) ex vivo in Rat

Sodium benzoate (NaB) is a versatile food additive used to preserve packaged foods and beverages. Thus, people are unknowingly consuming it above the WHO recommended daily intake limit which draws our attention to experimenting with the effects of NaB on contractile functions of visceral smooth muscle (VSM) of the small intestine, the primary target organ exposed to NaB during digestion and absorption of food, in the albino rat model. We have observed a significant (p&lt;0.05) increase in amplitude and decrease in the frequency of the contraction of the duodenum, the initial part of the small intestine, in dose and duration response manner in NaB exposed groups of rats compared to control contractions. This result indicates that NaB probably impairs the contraction of duodenal VSM by promoting the activity of myenteric cholinergic and/or the activity of adrenergic and/or nitrergic efferents. We have also found, a significant (p&lt;0.05) decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) and an increase in the level of malondialdehyde (MDA) in duodenal VSM homogenate of groups of exposed rats compared to control. These results suggest that NaB probably impairs the contractile function of VSM by altering the functions of myenteric intrinsic efferents by producing oxidative stress in VSM and/or in intrinsic neurons. Further, we have found significant degenerative lesions and altered tissue architecture in the muscularis externa layer of the wall of the duodenum in NaB exposed hematoxylin and eosin stained duodenal tissue sections. These findings reveal that NaB might impair the contractile function of duodenal VSM by inducing the oxidative stress induced degenerations of the architecture of muscle at tissue and cellular levels. Hence, it is concluded that NaB impairs the contraction of duodenal VSM probably by inducing the cytoarchitectural degenerations of VSM structure and/or altering the functions of myenteric intrinsic efferent through oxidative stress.

Arterial Pulse Localization with Varying Electrode Sizes and Spacings in Wrist-Worn Bioimpedance Sensing.

Bioimpedance has emerged as a promising modality to continuously monitor hemodynamic and respiratory physiological parameters through a non-invasive skin-contact approach. Bioimpedance sensors placed at the radial zone of the volar wrist provide sensitive operation to the blood flow of the underlying radial artery. The translation of bioimpedance systems into medical-grade settings for continuous hemodynamic monitoring, however, presents challenges when constraining the necessary sensing components to a minimal form factor while maintaining sufficient accuracy and precision of measurements. Thus, it is important to understand the effects of electrode configuration on bioimpedance signals when reducing them to a wearable form factor. Previous work regarding electrode configurations in bioimpedance does not address wearable constraints, nor do they focus on electrodes viable for wearable applications. In this study, we present empirical evidence of the effects of dry silver electrode sizes and spacings on the specificity and sensitivity of a wrist-worn bioimpedance sensor array. We found that wrist-worn bioimpedance systems for hemodynamic monitoring would benefit from reduced injection electrode spacings (up to a 392% increase in signal amplitude with a 50% decrease in spacing), increased sensing electrode spacings, and decreased electrode surface areas. Clinical Relevance - The work directly contributes towards the development of cuffless continuous blood pressure monitors with applications in clinical and ambulatory settings.

Forced sliding mode control for chaotic systems synchronization

Synchronization of chaotic systems is considered to be a common engineering problem. However, the proposed laws of synchronization control do not always provide robustness toward the parametric perturbations. The purpose of this article is to show the use of synergy-cybernetic approach for the construction of robust law for Arneodo chaotic systems synchronization. As the main method of design of robust control, the method of design of control with forced sliding mode of the synergetic control theory is considered. To illustrate the effectiveness of the proposed law, in this article it is compared with the classical sliding mode control and adaptive backstepping. The distinctive features of suggested robust control law are the more good compensation of parametric perturbations (better performance indexes—the root-mean-square error (RMSE), average absolute value (AVG) of error) without designing perturbation observers, the ability to exclude the chattering effect, less energy consuming and a simpler analysis of the stability of a closed-loop system. The study of the proposed control law and the change of its parameters and the place of parametric perturbation’s application is carried out. It is possible to significantly reduce the synchronization error and RMSE, as well as AVG of error by reducing some parameters, but that leads to an increase in control signal amplitude. The place of application of parametric disturbances (slave or master system) has no effect on the RMSE and AVG of error. Offered approach will allow a new consideration for the design of robust control laws for chaotic systems, taking into account the ideas of directed self-organization and robust control. It can be used for synchronization other chaotic systems.

Imbibition Retention in the Process of Fluid Replacement in Tight Sandstone Reservoir

“Fracture network stimulation and oil-water infiltration and replacement” are recent attempts to effectively produce oil from tight reservoirs. On the one hand, the formation can be fractured by the fracturing fluid, which can carry proppant into fractures. On the other hand, the fracturing fluid can spontaneously infiltrate into the pores under the action of capillary pressure to displace the oil phase, thereby enhancing the oil recovery. To distinguish imbibition and displacement processes during fluid replacement in tight reservoirs is difficult, and the effect of these two processes is also vaguely defined. In this study, an experimental method that can visualize the imbibition and displacement process is proposed by combining the core slice displacement experiment. Based on this method, the process of imbibition and displacement can be effectively distinguished, and imbibition retention rate can be quantitatively characterized. The effectiveness of this method is proved by taking the core of Chang 7 tight sandstone reservoir in the Ordos Basin as the research object. The results show that the force direction of the fluid under imbibition is related to the wettability, and it is always from the wetting phase to the nonwetting phase, while the force direction of fluid under displacement is mainly related to the directivity of displacement pressure difference. Based on the difference of force action, imbibition and displacement can be quantitatively characterized, respectively. During the imbibition process, the peak value of the NMR curve corresponding to the small pore throat shifts to the left, and the signal amplitude increases. During the displacement process, the peak value of the NMR curve corresponding to the small pore throat has no obvious shift, nor signal amplitude change, but the peak value of the curve corresponding to the large pore throat shifts to the right. The results also indicate that there is an exponential negative correlation between imbibition retention rate and gas permeability. The greater the gas permeability is, the smaller the imbibition retention rate is.

Intrinsic excitability mechanisms of neuronal ensemble formation.

Neuronal ensembles are coactive groups of cortical neurons, found in spontaneous and evoked activity, that can mediate perception and behavior. To understand the mechanisms that lead to the formation of ensembles, we co-activated layer 2/3 pyramidal neurons in brain slices from mouse visual cortex, in animals of both sexes, replicating in vitro an optogenetic protocol to generate ensembles in vivo. Using whole-cell and perforated patch-clamp pair recordings we found that, after optogenetic or electrical stimulation, coactivated neurons increased their correlated activity, a hallmark of ensemble formation. Coactivated neurons showed small biphasic changes in presynaptic plasticity, with an initial depression followed by a potentiation after a recovery period. Optogenetic and electrical stimulation also induced significant increases in frequency and amplitude of spontaneous EPSPs, even after single-cell stimulation. In addition, we observed unexpected strong and persistent increases in neuronal excitability after stimulation, with increases in membrane resistance and reductions in spike threshold. A pharmacological agent that blocks changes in membrane resistance reverted this effect. These significant increases in excitability can explain the observed biphasic synaptic plasticity. We conclude that cell-intrinsic changes in excitability are involved in the formation of neuronal ensembles. We propose an 'iceberg' model, by which increased neuronal excitability makes subthreshold connections suprathreshold, enhancing the effect of already existing synapses, and generating a new neuronal ensemble.

Ampakine‐Hypoxia Induced Phrenic Motor Facilitation is Not Prevented by Intrathecal Methysergide

Hypoxia‐induced sustained increases in phrenic nerve burst amplitude lasting beyond the hypoxic stimulus are generally accepted to require repeated bouts of hypoxia (i.e., acute intermittent hypoxia, AIH). However, our laboratory recently reported that pretreatment with a drug (ampakine) which acts as a positive allosteric modulator of AMPA receptors lowered the number of hypoxic exposures required to trigger sustained phrenic motor facilitation. Our working hypothesis for the current study was that the combination of ampakine and hypoxia activates the same serotonin (5‐HT) dependent cellular mechanisms that are well established for AIH‐induced phrenic long‐term facilitation following repeated bouts of moderate hypoxia. Phrenic nerve output was recorded from vagotomized, mechanically ventilated, adult male Sprague‐Dawley rats under urethane‐anesthesia. A broad‐spectrum 5‐HT receptor antagonist (methysergide, 20mM, dissolved in DMSO) was delivered intrathecally over the C4 spinal dorsal surface. At least 15 min of stable phrenic burst amplitude was recorded post methysergide delivery. After a stable baseline (BL) was established, intravenous (i.v.) ampakine (CX717, 15mg/kg) was followed by a single episode of hypoxia (arterial partial pressure of O2 = 42±9mmHg). Phrenic nerve bursting was recorded for 60 min after hypoxia. Initial results indicate that intrathecal methysergide does not prevent the ampakine‐hypoxia induced phrenic motor facilitation as evidenced by a significant increase in burst amplitude at 60 min (89±54% BL, n=7). To verify the efficacy of intrathecal drug delivery method, additional experiments were conducted. Specifically, we determined if intrathecal methysergide prevented the phrenic long‐term facilitation induced by AIH, as has been shown by several prior investigations. These experiments used the same preparation, and AIH consisted of three‐5 min episodes of hypoxia with 5‐min intervals of baseline O2conditions. Intrathecal methysergide blocked pLTF (60 min post‐AIH, phrenic burst amplitude = ‐2±31% BL, n=3), but intrathecal delivery of the DMSO vehicle did not (60 min: 94±28% BL, n=3). Collectively, these results do not support our hypothesis that phrenic motor facilitation induced by the pairing of ampakine with a single bout of hypoxia is dependent on serotonin receptor activation.

Basal and Hypoxic Respiratory Behaviors in Aged 6‐OHDA‐Induced SN Lesion PD Rat Model: Effects of the 5‐HT1A Receptor Agonist Buspirone

Parkinson’s disease (PD) is progressive neurodegenerative disease, with the diagnosis of idiopathic PD occurring in humans at ~60 years of age. Most studies, however, use young adult (≤3 month old) rats to investigate PD‐related abnormalities in various physiological systems, with the most commonly used experimental rat PD model being generated by unilateral injection of the neurotoxin 6‐hydroxydopamine (6‐OHDA) into specific regions of the nigrostriatal pathway. While this model results in the loss of dopaminergic neurons and the subsequent changes in downstream neurotransmitter signaling that are characteristic of PD, it does not consider potential contributions of physical changes to the brain and neurotransmitter signaling that are part of normal aging on the progression of PD. To better understand age‐related influences and potential contributions of PD‐related abnormalities in serotonergic (5‐HT) neurotransmission on respiratory dysfunction (which is a common non‐motor symptom) in PD, we investigated basal and hypoxic (12% O2; 90s) respiratory behaviors before and after acute administration of the frequently prescribed anxiolytic 5‐HT1A receptor agonist buspirone (BUS; 0.5 mg/kg, iv) in an aged (~9 month old) female Sprague‐Dawley PD rat model produced by unilateral 6‐OHDA injection into the substantia nigra (SN). For these experiments, diaphragm EMG activity was recorded and quantified from spontaneously breathing urethane‐anesthetized rats at 2‐weeks after SN 6‐OHDA or vehicle (control) injections. We found that 6‐OHDA‐injected rats have a lower basal breathing frequency (P&lt;0.05) due to shorter expiratory duration (TE; P&lt;0.05) than vehicle‐injected rats, but both 6‐OHDA‐ and vehicle‐injected rats exhibit significant increases in breathing frequency (P≤0.001) and EMG amplitude (P≤0.023) during hypoxia; the magnitude of the peak frequency increase in 6‐OHDA‐injected rats was slightly greater (P=0.083). Both 6‐OHDA‐ and vehicle‐injected rats also showed similar post‐hypoxic frequency decline (P≤0.003), but only vehicle‐injected rats displayed a slight and sustained post‐hypoxic amplitude depression (P&lt;0.1). In vehicle‐injected rats, acute BUS injection produced a progressive decrease in basal EMG amplitude (P=0.066) and a persistent increase in breathing frequency (P=0.064) by decreasing inspiratory duration (TI; P&lt;0.001) while in 6‐OHDA‐injected rats, a transient initial increase in EMG amplitude (P=0.043) and a persistent decrease in TI (P=0.005) and TE (P=0.089) were noted. In both 6‐OHDA‐ and vehicle‐injected rats, BUS injection also slightly exaggerated the initial hypoxic frequency increase, but blunted the amplitude increase with amplitude progressively declining to near pre‐hypoxic levels before the end of the hypoxic exposure. BUS injection also shortened the duration of post‐hypoxic EMG amplitude depression in vehicle‐injected rats. These data demonstrate that some differences in basal and hypoxic respiratory behaviors exist between older 6‐OHDA‐ and vehicle‐injected rats, and that some respiratory behaviors of these rat models are differentially impacted by BUS‐induced effects on respiratory control. We suggest that this older PD rat model be further evaluated.

Gait analysis and knee joint kinematics before a and 6month after of corrective valgus osteotomy at patients with medial knee arthritis.

A varus deformity (VD) of the lower limbs results in greater loading of the medial compartment of the knee joint (KJ), leading to its degenerative changes and, eventually, to progressive osteoarthritis (OA) of the joint. The aim of the study was to investigate the mid-term changes in gait biomechanics and clinical symptoms in patients with VD of KJ and OA before and sixmonths after surgical correction. The study enrolled 25 patients with medial OA of grade 2-3 according to Kellgren-Lawrence and a VD of > 3°, who underwent arthroscopic lavage and debridement of the knee joint followed by corrective osteotomy. The control group included 20 healthy adults. Clinical and biomechanical assessments were done twice: immediately prior to and sixmonths after the surgical treatment. Biomechanical parameters of gait were recorded using an inertial sensor system. According to our findings, there was a statistically significant post-operative increase in the knee extension amplitude by 1.4° in female patients and an insignificant extension increase in male patients. The mean postoperative KOOS score was 66.7 points (46 to 91) in the patient group, 67.1 points (54 to 91) in males, and 59.5 points (46 to 64) in females. As early as sixmonths after a valgus osteotomy, we already observed improved biomechanics of the KJ motions compared to pre-operative data. By that time, the swing flexion amplitude of the affected KJ had increased and became symmetrical, which had not been the case before surgery. We observed a total of three changes in the KJ kinematics after surgery: increased swing flexion amplitudes in both KJs, a decreased extension amplitude in the affected KJ, and increased first flexion amplitudes in both KJs. According to our study, the midterm outcomes after a valgus osteotomy showed clinical improvements based on the VAS and KOOS scores, which were however less pronounced than in similar studies with a longer assessment term after surgery. We also found a significant increase in the amplitude of joint extension, but only in females. As the function of the operated joint is concerned, valgus osteotomy restored the kinematics of walking movements to a nearly normal gait with increased first and second flexion amplitudes. The function of KJ becomes symmetric though the non-operative side. Thus, the healthy and functionally more capable side is copying the movement pattern of the affected side. Hence, the non-operative leg is functioning less efficiently than it is required by the walking pace.

Increase in b-wave amplitude after light stimulation of the blind spot is positively correlated with the axial length of myopic individuals

Altered retinal dopamine and ON-pathway activity may underlie myopia development. It has been shown that the stimulation of the blind spot with short-wavelength light increases the electroretinogram (ERG) b-wave amplitude of myopic eyes and may engage the retinal dopaminergic system. This study evaluated the impact of various durations of blind spot stimulation on the electrophysiological response of the myopic retina and their relationship to axial length. Six myopic individuals underwent three short-wavelength blue light blind spot stimulation protocols (10 s, 1 min, 10 min) using a virtual reality headset. As a control condition, no stimulation was shown for 1 min. The b-wave amplitude of the photopic full-field ERG was measured at baseline and 10, 20, 30, 40, 50, and 60 min after each condition. A significant increase in b-wave amplitude was observed for all stimulation protocols compared to the control. The peak b-wave amplitude was observed 20 min after the 1-min stimulation protocol and 60 min after the 10-min stimulation protocol. A significant positive correlation was found between axial length of the eye and percent change in b-wave amplitude for the 10-min stimulation protocol. A rapid and a delayed b-wave time course responses were observed following 1 min and 10 min of blind spot stimulation, respectively. Overall, these results indicate that light stimulation of the blind spot for various durations elevates ON-bipolar cell activity in the retina and as such is assumed to reduce the myopic response. These findings could have implications for future myopia treatment.

The Influence of Motoric Maneuvers on Cervical Vestibular Evoked Myogenic Potentials (cVEMPs).

The cervical vestibular evoked myogenic potential (cVEMP) is a vestibular response that is produced by the saccule in response to intense, often low-frequency, short-duration auditory stimuli, and is typically recorded from a contracted sternocleidomastoid (SCM) muscle. Previous research has shown that the amplitude of the cVEMP is related to the amount of SCM electromyographic (EMG) activity. The aim of this study was to determine the influence of various remote motoric maneuvers on the amplitude of the cVEMP, as well as whether they influence the level of SCM EMG activity. The cVEMP was recorded from the left SCM muscle to left ear stimulation, in response to the SCM condition, as well as three different motoric maneuvers (jaw clench, eye closure, and the Jendrassik maneuver). EMG activity was also varied between 50, 75, and 100% of maximal EMG activity. Data from 14 healthy subjects, with a mean age of 25.57 years (standard deviation = 5.93 years), was included in the present study. Mean latency and amplitude of the cVEMP were compared across the four conditions and varying magnitudes of EMG contraction. SPSS 26 was used to statistically analyze the results. cVEMP latency did not vary across condition. cVEMP amplitude decreased with decreasing EMG magnitude. SCM contraction with jaw clench produced the largest increase in cVEMP amplitude; however, this condition was not significantly different from the SCM condition alone. SCM contraction with the Jendrassik maneuver produced a cVEMP amplitude that was similar and not statistically different from SCM contraction alone, and the addition of the eye closure maneuver to SCM contraction resulted in the lowest cVEMP amplitude, which was found to be statistically different from the standard SCM condition at 100 and 75% EMG activity. The amplitude relationship across the conditions was not found to vary with changes in EMG activity; however, a significant increase in EMG amplitude was found during the 50% muscle contraction condition when subjects performed the Jendrassik maneuver in addition to the standard SCM contraction. The addition of the eye closure maneuver to SCM contraction resulted in a significant decrease in cVEMP amplitude, while the addition of the Jendrassik maneuver resulted in a significant increase in EMG activity at the lowest level of SCM activation (i.e., 50%). Additional research is necessary to determine how motoric maneuvers influence the cVEMP amplitude, and whether the results are also dependent on how SCM contraction is being produced (e.g., while supine vs. sitting).

The Investigation of Ameliorating Effect of Methylene Blue on Cisplatin-Induced Neurotoxicity in Female Rats

Objective: Cisplatin is indispensable in many solid tumors, and peripheral neurotoxicity is an essential dose-limiting side effect. The study aims to investigate the ameliorating effect of methylene blue, which has anti-oxidant properties, in rats with neurotoxicity due to cisplatin treatment. Materials and methods: Twenty-four adult female rats were included in the study and divided into 3 groups. The first group (n=8), the control group, did not receive any treatment. The second (n=8) and the third (n=8) group received 2.5 mg/kg/day of cisplatin and 1 ml/kg/day of 0.9% NaCl (saline) twice a week for 4 weeks. Also, the third group received 20 mg/kg/day of methylene blue every day for 4 weeks. Blood samples were collected from rats for malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor- α (TNF-α), and interleukin-6 (IL-6) levels, and electromyography (EMG) and motor function were evaluated. Results: In non-treated cisplatin injected rats, a significant increase in the lipid peroxidation product MDA and pro-inflammatory cytokines compared to the control group (p<0.001). Electromyography measurements also resulted in a significant decrease in cisplatin injected rats’ compound muscle action potential (CMAP) amplitude and prolongation in CMAP latency compared to the control group (p<0.05). A statistically significant decrease in MDA, TNF-α, and IL-6 levels and a statistically significant increase in GSH levels and CMAP amplitude was observed in the methylene blue-treated group compared to the group injected with cisplatin alone. Conclusions: We concluded that methylene blue has ameliorating effects against cisplatin-induced neurotoxicity (CIN) by enhancing anti-oxidative capacity, energy metabolism and suppressing inflammatory parameters and oxidative stress.