Basic and Clinical Neuroscience
Volume:14 Issue: 6, Nov-Dec 2023

Neuropathic pain (NP) is caused by damage to the somatosensory system. Nerve damage often results in chronic pain states, including hyperalgesia and allodynia. This study aims to evaluate the anti-nociceptive effects of atorvastatin, vitamin C, and their combination on various laboratory tests in an experimental model NP in rats.

To assess the analgesic effects of atorvastatin (5 and 10 mg/kg), vitamin C (500 mg/kg), and their co-administration on chronic constriction injury (CCI) was induced in rats. Behavioral tests, motor nerve conduction velocity (MNCV), pro-inflammatory cytokines, and oxidative markers were measured. Furthermore, histopathological examination was performed.

In the present study, it was found that the CCI model can significantly cause hyperalgesia and allodynia on the 21st postoperative day. It was found that the co-administration of vitamin C and atorvastatin has attenuating effects on allodynia and hyperalgesia. Co-administration of vitamin C and atorvastatin also improved MNCV. In the treatment groups, the inflammatory reactions and oxidative markers decreased. Moreover, the co-administration of atorvastatin and vitamin C decreased the perineural inflammation around the sciatic nerve. 

The results of this study showed that vitamin C potentiates the analgesic effects of atorvastatin in this model of experimental pain, and simultaneous consumption of these medications may be considered as effective therapeutics for NP. The protective properties of atorvastatin, and vitamin C, and their combination on the NP that were assessed can be regarded as a novelty for this study.

Multiple sclerosis (MS) is an inflammatory demyelinating and neurodegenerative disorder of the central nervous system, which is associated with brain atrophy and volume changes in some brain structures. This study aimed to compare the volume of the basal ganglia, thalamus, cerebellum, and brainstem in patients with relapsing-remitting MS with that of the control group using magnetic resonance imaging (MRI).

In this cross-sectional study, MRI brain scans were obtained from 25 patients with relapsing-remitting MS and 25 healthy control subjects. Volumetric analyses were performed using Brain Suite software.

The mean age of the MS and the control groups was 33.96±8.75 and 40.40±8.72, respectively. No statistically significant difference was found in gender (P=0.747). The bilateral putamen and caudate nuclei volumes were significantly higher in the case group than in the control group (P<0.001). Moreover, lower the volume of the brainstem, cerebellum, bilateral thalamus, and globus pallidus were identified in the MS patients compared to the control group (P<0.001). There was an inverse correlation between the disease and treatment duration with the thalamus and cerebellum volume in MS patients (P=0.001). Treatment duration also had an inverse correlation with brainstem volume (P=0.047).

The volume of some structures of the brain, including globus pallidus, thalamus, cerebellum, and brainstem is lower in MS and can be one of the markers of disease progression and disability among MS patients.

Coronavirus-2019 (COVID-19) spreads rapidly worldwide and causes severe acute respiratory syndrome. The current study aims to evaluate the relationship between the whole-brain functional connections in a resting state and cognitive impairments in patients with COVID-19 compared to the healthy control group.

Resting-state functional magnetic resonance imaging (rs-fMRI) and Montreal cognitive assessment (MoCA) data were obtained from 29 patients of the acute stage of COVID-19 on the third day of admission and 20 healthy controls. Cross-correlation of the mean resting-state signals was determined in the voxels of 23 independent components (IC) of brain neural circuits. To assess cognitive function and neuropsychological status, MoCA was performed on all participants. The relationship between rs-fMRI information, neuropsychological status, and paraclinical data was analyzed.

The COVID-19 group got a lower mean MoCA score and showed a significant reduction in the functional connectivity of the IC14 (P<0.001) and IC38 (P<0.001) regions compared to the controls. The increase in functional connectivity was observed in the COVID-19 group compared to the controls at baseline in the default mode network (DMN) IC00 (P<0.001) and dorsal attention network (DAN) IC08 (P<0.001) regions. Furthermore, the alternation of functional connectivity in the mentioned ICs was significantly correlated with the mean MoCA scores and inflammatory parameters, i.e. erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).

Functional connectivity abnormalities in four brain neural circuits are associated with cognitive impairment and increased inflammatory markers in patients with COVID-19.

Delving into the prominent role of emotions and senses in language is not something new in the field. Thereupon, the newly developed notion of emotioncy has been introduced to foreign language education to underscore the role of sense-induced emotions in the language learning and teaching process.

The present study implemented event-related potentials (ERPs) to provide evidence of the significance of employing emosensory instructional strategies in teaching vocabulary items. Hence, 18 female participants were randomly instructed on six English nouns toward which they had no prior knowledge and received no instruction for the other three words. Then, while the participants’ electroencephalogram (EEG) was being recorded, they took a sentence comprehension task.

Behavioral results demonstrated significant differences among the avolved, the exvolved, and the involved nouns. However, ERP analyses of target words indicated the modulations of N100 and N480 components while no significant effect was observed at P200. Further, the analysis of sensory N100 for the critical words revealed no significant effect. 

In conclusion, emotioncy-based language instruction can affect neural correlates of emotional word comprehension from the early stages of EEG recording. The results of this study can clarify the importance of including senses and emotions in language teaching, learning, and testing, along with materials development.

Functional neuroimaging has developed a fundamental ground for understanding the physical basis of the brain. Recent studies have extracted invaluable information from the underlying substrate of the brain. However, cognitive deficiency has insufficiently been assessed by researchers in multiple sclerosis (MS). Therefore, extracting the brain network differences among relapsing-remitting MS (RRMS) patients and healthy controls as biomarkers of cognitive task functional magnetic resonance imaging (fMRI) data and evaluating such biomarkers using machine learning were the aims of this study. 

In order to activate cognitive functions of the brain, blood-oxygen-level-dependent (BOLD) data were collected throughout the application of a cognitive task. Accordingly, a nonlinear-based brain network was established using kernel mutual information based on the automated anatomical labeling atlas (AAL). Subsequently, a statistical test was carried out to determine the variation in brain network measures between the two groups on binary adjacency matrices. We also found the prominent graph features by merging the Wilcoxon rank-sum test with the Fisher score as a hybrid feature selection method. 

The results of the classification performance measures showed that the construction of a brain network using a new nonlinear connectivity measure in task-fMRI performs better than the linear connectivity measures in terms of classification. The Wilcoxon rank-sum test also demonstrated a superior result for clinical applications.

We believe that non-linear connectivity measures, like KMI, outperform linear connectivity measures, like correlation coefficient in finding the biomarkers of MS disease according to classification performance metrics.

This research aims to investigate the protective action of menthol dissolved in dimethyl sulfoxide (DMSO) on experimental epileptiform activity induced by the intraperitoneal (IP) injection of pentylenetetrazol (PTZ) in male rats.

Thirty adult male Wistar rats weighing 200-250 g were randomly assigned to five equal groups. The control animals received normal saline (200 µL) and the rest four cohorts were considered as treatment. Menthol was dissolved in DMSO and intraperitoneally injected at the doses of 100, 200, and 400 mg/kg into the first, second, and third groups (M100, M200, and M400 V=200 µL), respectively. The fourth treatment was injected with the solvent (200 µL). The animals were anesthetized, then underwent cranial surgery and a recording electrode was implanted in the stratum radiatum of the hippocampal carbonic anhydrase 1 (CA1) region (AP=-2.76 mm, ML=-1.4 mm and DV=3 mm). The seizure activity was induced by PTZ (IP) and assessed by counting and measuring amplitudes of the spikes for 10 minutes using the eTrace program.

Menthol was observed to significantly reduce the activity level of PTZ-induced epileptiform activity, as well as exert a protective and inhibitory action on proconvulsant effect of DMSO in a dose-dependent manner. 

Menthol can potentially be used as an adjuvant to prevent seizure activity.

Numerous physical and chemical agents can induce destructive effects on the brain tissue. Noise and toluene, which are some of these harmful agents, have significant adverse effects on the brain tissue. This work aimed to investigate the neurotoxic changes induced by co-exposure to toluene and noise. 

A total of 24 male white New Zealand rabbits were randomly segregated into four groups, including toluene exposure, noise exposure, co-exposure to noise and toluene, and control. This in vivo study tested the neurotoxic effects of exposure to 1000 ppm toluene and 100 dB noise during two weeks (8 h/day). The serum levels of brain-derived neurotrophic factor-α (BDNF-α), malondialdehyde (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase and total antioxidant capacity (TAC) values in the brain tissue were measured. Moreover, hematoxylin and eosin (H&E) staining was utilized for brain pathological analysis.

Exposure to noise increased TAC values in the cerebral cortex. Co-exposure to toluene and noise increased the serum levels of BDNF-α. Nevertheless, exposure to noise decreased the levels of BDNF-α in serum. On the other hand, histopathological examinations using H&E staining exhibited that different signs of inflammation, such as lymphocyte infiltration, pyknosis, vacuolization, and chromatolysis were induced by exposure to noise and toluene in the cerebellum, hippocampus, and frontal section in the brain tissue. In addition, simultaneous exposure to toluene and noise induced antagonistic and synergistic changes in some neurotoxic parameters.

Exposure to noise and toluene, which caused inflammation in the brain tissue cells, could be a noticeable risk factor for the neurological system.

Chronic low back pain (CLBP) is a global burden with an unknown etiology. Reorganization of the cortical representation of paraspinal muscles in the primary motor cortex (M1) may be related to the pathology. Single-pulse transcranial magnetic stimulation (TMS), commonly used to map the functional organization of M1, is not potent enough to stimulate the cortical maps of paraspinal muscles in M1 in CLBP patients with reduced corticospinal excitability (CSE) with intensities even as high as maximum stimulator output (100% MSO). This makes TMS mapping impractical for these patients. The aim of this study was to increase the practicality of TMS mapping for people with CLBP.

This study included eight men and ten women who had CLBP for over three months. A biphasic paired-pulse TMS paradigm, conjunct anticipatory postural adjustment (APA), and maximal voluntary activation of paraspinal muscles (MVC) were used to facilitate TMS mapping. 

TMS mapping was possible in all CLBP participants, with TMS intensities <50% of the MSO. Reorganization in terms of an anterior and lateral shift of the center of gravity (COG) of the cortical maps of paraspinal muscles was observed in all participants with CLBP, and a reduced number of discrete peaks was found in 33%.

The facilitation of the CSE to paraspinal muscles makes TMS mapping more practical and tolerable in people with CLBP, lowering the risk of seizure and discomfort associated with high-intensity TMS pulses.

Stem cells isolated from the amniotic membrane can produce and release substances that can regenerate damaged tissues and contain proteins and other factors that via numerous major and minor mechanisms lead to increasing angiogenesis and tissue survival. This research was conducted to prove the defensive characteristics of the secretome in the face of temporary focal cerebral ischemia in mouse stroke models.

Cerebral ischemia protocol in a specific area was implemented in rats with middle cerebral artery occlusion for 60 minutes and then reperfusion was given for 6, 20, and 30 minutes. Within 30 minutes after the start of reperfusion, conditioned medium derived from the human amniotic membrane (AMSC-CM) was poured into the right ventricle (ICV) at a dose of 0.5 µL. Finally, the volume of the injury, cerebral tissue water, sensorimotor activity, and the strength of the blood-brain barrier integrity were evaluated 24 hours after drug injection.

ICV injection of conditioned medium at the start of reperfusion phase considerably decreased the volume of the injury 6, 20, and 30 hours after reperfusion compared to the MCAO-operated group (P<0.01). Cerebral tissue water in the treatment group decreased considerably after the intervention in comparison with the MCAO group in the core and penumbral area not in the subcortical area (P<0.05). Also, the amount of Evans blue infiltration at all times in the core and half-foot area in the AMSC-CM group was significantly reduced in parallel with the MCAO group (P<0.05). 

Treatment with AMSC-CM during 6-30 h after ischemia-reperfusion insult exerts some beneficial effects against ischemia-reperfusion injury. These findings provide an important vision for more complementary research and treatment of stroke.

Hearing loss is the most common sensory-neurological defect in humans. The most common hearing impairment is sensorineural hearing loss (SNHL) caused by the inner ear and related nerves. Diffusion tensor imaging (DTI) is an advanced MRI technique that can provide valuable information about auditory neural pathways and their microstructural changes. The present study was designed to investigate the microstructural changes in auditory pathways-related fiber tracts in children with SNHL. 

Twenty-two children including 11 subjects with SNHL aged 1-4 years and 11 healthy children were examined as controls. Then, DTI-derived parameters, such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD), and radial diffusivity (RD), and volume of fiber tracts were extracted from the inferior longitudinal fasciculus, acoustic radiation, and uncinate fasciculus. 

The results showed an increase in MD, RD, and AxD as well as a decrease in FA, volume, and diameter of auditory-pathway-related fiber tracts. Interestingly, there was an increase in the FA of acoustic radiation.

White matter connections in the auditory canal decrease and AR integrity increases due to compensatory effects. These probably reflect atrophy or degradation as well as compensatory cross-modal reorganization in the absence of auditory input and the use of sign language.

Diabetic neuropathy is a well-known complication of diabetes. Recently, hyperglycemia-induced toxicity has been confirmed to participates in multiple cellular pathways typical for neural deterioration. Nicotinamide phosphoribosyltransferase/pre-b cell colony-enhancing factor (Nampt/PBEF)/visfatin is a novel endogenous ligand that some studies have shown its neuroprotective effects on neurodegenerative disease. Therefore, we hypothesized that visfatin may prevent high glucose (HG)-induced neurotoxicity by  inhibiting apoptosis, autophagy, and reactive oxygen species (ROS) responses properly.

In this study, pheochromocytoma cell line 12 (PC12) cells were exposed to both HG concentrations (50, 75, 100, 125, 150 mM) and visfatin (50, 100, 150 ng/mL) at different time -points to determine the optimum time and dose of glucose and visfatin. To investigate the effects of visfatin on HG-induced damage in the PC12 diabetic neuropathy model, we examined ROS response, apoptosis, and autophagy using ROS detection kit, flow cytometry, and real-time PCR/Western blot, respectively.

We determined that HG concentration significantly increased the ROS level and apoptosis of diabetic PC12 cells. However, visfatin treatment significantly decreased the ROS production (P<0.05) and apoptosis of diabetic PC12 cells (P<0.0001). Beclin-1 messenger ribonucleic acid (mRNA) level (P<0.05) and light chain 3 (Lc3)-II protein level (P<0.05) showed that the autophagy pathway is impaired by HG concentrations. 

We concluded that visfatin can sufficiently decrease neural damage caused by ROS production and apoptosis under HG-induced toxicity.

High frequency of adverse drug reactions (ADRs) challenges multiple sclerosis (MS) treatment. This study aims to assess the nature and frequency of ADRs induced by MS medications in an observational cross-sectional study. 

ADRs of all outpatients who had seen a neurologist and had received at least one disease-modifying therapy (DMT) for MS during the last three months were investigated.

A total of 484 ADRs were detected in these patients. The preventability rate was 5.9%, and 0.61% of reactions were serious.

The high frequency of adverse drug reactions in this study shows a strong need for strategy planning to increase patients’ adherence to treatment.