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Research field: Our laboratory “Translational Brain Function and Neuromodulation Lab” works in the field of understanding brain function in neuro-cognitive diseases and non-invasive brain stimulation as a method to prevent disease progression or treat disease. In this laboratory, translational studies from the laboratory to the bedside are carried out on animal models, healthy people and patients. These studies focus on learning and memory disorders, Alzheimer's disease, depression and anxiety.
Expert: Mehdi Salimi
Phone: 82884586
Address: Translational Brain Function and Neuromodulation Lab, Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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BackgroundMultiple Sclerosis (MS) is a demyelinating disease leading to long-term neurological deficit due to unsuccessful remyelination and axonal loss. Currently, there are no satisfactory treatments for progressive MS somewhat due to the lack of an adequate animal model for studying the mechanisms of disease progression and screening new drugs.New methodLysolecithin (LPC) or agarose-gel loaded LPC (AL-LPC) were applied to mouse optic nerve behind the globe via a minor surgery. Agarose loading was used to achieve longer time of LPC exposure and subsequently long-lasting demyelination.ResultsThe lesion sites characterized by luxol fast blue (LFB), FluoroMyelin, Bielschowsky’s staining, and immunostaining showed extensive demyelination an
Mechanical ventilation (MV) can result in long-term brain impairments that are resistant to treatment. The mechanisms underlying MV-induced brain function impairment remain unclear. Since nasal airflow modulates brain activity, here we evaluated whether reinstating airflow during MV could influence the memory performance of rats after recovery. Rats were allocated into two study groups: one group received rhythmic air-puff into the nasal cavity during MV and a control group that underwent ventilation without air-puff. During MV, air-puffs induced time-locked event potentials in OB, mPFC and vHPC and significantly increased the oscillatory activity at the air-puff frequency. Furthermore, in mPFC and vHPC, (but not in OB), delta and theta osc
Allergic rhinitis (AR) is a chronic inflammatory disease frequently associated with a deficit in learning and memory. Working memory is an important system for decision making and guidance, which depends on interactions between the ventral hippocampus (vHipp) and the prelimbic prefrontal cortex (plPFC). It is still unclear whether AR influences the activity and coupling of these brain areas, which consequently may impair working memory. The current study aimed to examine alterations of the vHipp-plPFC circuit in a rat model of AR. Our results show decreased working memory performance in AR animals, accompanied by a reduction of theta and gamma oscillations in plPFC. Also, AR reduces coherence between vHipp and plPFC in both theta and gamma
Alzheimer’s disease (AD) is a progressive disorder associated with cognitive dysfunction that alters the brain’s functional connectivity. Assessing these alterations has become a topic of increasing interest. However, a few studies have examined different stages of AD from a complex network perspective that cover different topological scales. This study analyzed the trend of functional connectivity alterations from a cognitively normal (CN) state through early and late mild cognitive impairment (EMCI and LMCI) and to Alzheimer’s disease. The analyses had been done at the local (hubs and activated links and areas), meso (clustering, assortativity, and rich-club), and global (small-world, small-worldness, and efficiency) topological sca
Objective (s): Seizure detection during online recording of electrophysiological parameters is very important in epileptic patients. In the present study, online analysis of field potential recordings was used for detecting spontaneous seizures in epileptic animals.Materials and Methods: Epilepsy was induced in rats by pilocarpine injection. During the chronic period of the pilocarpine model, local field potential (LFP) recording was run for at least 24 hr. At the same time, video monitoring of the animals was done to determine the real time of seizure occurrence. Both power and sample entropy of LFP were used for online analysis.Results: Obtained results showed that changes in LFP power are a better index for seizure detection. In addition
The mechanisms involved in the anti-seizure effects of low-frequency stimulation (LFS) have not been completely determined. However, Gi-protein-coupled receptors, including D2-like receptors, may have a role in mediating these effects. In the present study, the role of D2-like receptors in LFS’ anti-seizure action was investigated. Rats were kindled with semi-rapid (6 stimulations per day), electrical stimulation of the hippocampal CA1 area. In LFS-treated groups, subjects received four trials of LFS at 5 min, 6 h, 24 h, and 30 h following the last kindling stimulation. Each LFS set occurred at 5 minute intervals, and consisted of 4 trains. Each train contained 200, 0/1 ms long, monophasic square wave pulses at 1 Hz. Haloperidol (D2-like
AimsThere is much controversy regarding whether cardiovascular events increase in women with polycystic ovary syndrome (PCOS) with aging. Considering the lack of possibility of certain investigations in humans, animal models of PCOS may be suitable resources to obtain the useful data needed. In this study; we aimed to investigate whether cardiac function and tolerance to ischemia/reperfusion (I/R) injury worsen in postmenopausal rats, who had PCOS at younger ages, compared to controls.Main methodsThe hearts of aged rats with a history of PCOS and their controls were isolated and perfused in a Langendorff apparatus. Values of hemodynamic parameters, including left ventricular systolic pressure (LVSP), left ventricular developed pressure (LVD
Objective (s):The modulatory effect of deep inspiration (DI) on airway constriction is impaired in asthma. However, mechanisms underlying this impairment are not clear. Since there is evidence indicating that Rho-kinase activation mediates force maintenance under oscillatory strain, we investigated the impact of Rho-kinase inhibition on the bronchodilatory effect of DI in ovalbumin (OVA) sensitized guinea pigs.Materials and Methods:forty-eight male Dunkin Hartley guinea pigs were divided into 8 groups including saline/constant, saline/DI, OVA/constant, OVA/DI, Rho-I/OVA/constant, Rho-I/OVA/DI, OVA-Rho-I/MCh/constant, and OVA-Rho-I/MCh/DI. Animals were subjected to 12 inhalations of OVA or saline aerosol. Guinea pigs in Rho-I/OVA/constant or
Background: The Electrocardiogram (ECG) is an important measure for diagnosing the presence or absence of heart arrhythmias. Premature ventricular contractions (PVC) is a relatively large arrhythmia occurring outside the normal tract and being triggered outside the Sino atrial (SA) node of heart. Objective: This study has focused on tunable Q-factor wavelet transform (TQWT) algorithm and statistical methods to detect PVC.Material and Methods: In this analytical and statistical study, 22 ECGs records were selected from the MIT/BIH arrhythmia database. In the first stage the noise of signal remove and then five sub-bands create by TQWT. In the second stage nine features (minimum, maximum, root mean square, mean, interquartile range, standard
Background:The clinical characteristics of the novel coronavirus disease (COVID-19) were diverse and unspecific. Here, we identified the associated factors with surviving of COVID-19 ICU patients based on the clinical characteristics of patients admitted to one of the Corona Centre Hospitals of Iran.Materials and Methods:This cohort study was performed retrospectively from February to June 2020 on 133 COVID-19 patients admitted to 4 intensive care units of Masih Daneshvari Hospital in Tehran, Iran. Demographic, medical, clinical manifestation at admission, laboratory parameters and outcome data were obtained from medical records. Also the SOFA and APACHE II scores were calculated. All data were analyzed using SPSS (version 23, IBM Corp.) so
AimsCardiovascular diseases may originate from suboptimal intrauterine environments. We aimed to examine the effects of prenatal androgen exposure (PAE) on heart basal hemodynamic parameters and tolerance to ischemia/reperfusion (I/R) injury, in PAE adult females and males.Main methodsPregnant Wistar rats in the experimental group (n = 8) received 5 mg of testosterone (s.c. injection) on the 20th day of pregnancy, while controls received solvent. The hearts of adult female and male offspring were isolated and perfused in a Langendorff apparatus, values of left ventricular systolic pressure(LVSP), left ventricular developed pressure(LVDP), rate pressure product(RPP) and peak rates of positive and negative changes in left ventricular pr
Multiple sclerosis (MS) is an autoimmune disease characterized by myelin and axonal damage in the central nervous system (CNS). Glial scar which is a hallmark of MS contains repair inhibitory molecules including chondroitin sulfate proteoglycans (CSPGs). CSPGs inhibit repair of damaged area through various receptors including protein tyrosine phosphatase sigma (PTPσ). In the current study we use intracellular sigma peptide (ISP), an inhibitor of PTPσ signaling, in LPC-induced focal demyelination of mouse optic chiasm. ISP treatment resulted in decreased demyelination, reduced astrogliosis, and increased newly generated oligodendrocytes which subsequently led to enhanced remyelination. Analyzing of electrophysiological (as performed by vis
Cognitive impairment (CI) is a common morbidity after cardio-pulmonary resuscitation (CPR) with long time persistence. Brain hypoxia is believed to be the main but not the single etiology of post CPR cognitive impairment. Theta and lower theta waves of the EEG have essential role in proper functioning of the memory performance. Both endotracheal intubation and atropine administration in CPR process can abolish these waves. We hypothesize that CI in CPR survivors can be caused by disturbance in aforementioned waves due to endotracheal intubation and atropine administration.
Psychological stress can provoke airway constriction in asthmatic patients, which may be because of autonomic nervous system dysfunction in asthma. We investigated the effect of enhancing respiratory sinus arrhythmia using heart rate variability biofeedback (HRV-BF) on spirometry performance and HRV indices during stress induced by Stroop Color-Word interference test in asthmatic patients and healthy volunteers. Stress caused decrease in FEV1%, FVC%, and PEF% compared to baseline in asthmatic patients, but not in healthy subjects. A single short duration episode of HRV-BF not only had a protective effect on stress-induced airway constriction, but also significantly augmented the level of FEV1% and FVC% as compared with their own baseline. A
Low frequency stimulation (LFS) has inhibitory effect on hyperexcitability during epileptic states. However, knowledge is lacking about LFS patterns that can exert an optimal antiepileptic effect. In this study, the effect of different numbers of pulses and current intensities of 1 Hz LFS applied at various time points of epileptiform activity was evaluated in high-K+ model of epileptiform activity (EA). LFS was applied to the Schaffer collaterals, and changes in the excitability of CA1 pyramidal neurons were measured using whole-cell patch-clamp recording. Six hundred and 900 pulses of LFS at two current intensities (equal to and 1.5 times greater than the current intensity sufficient to elicit a 5 mV EPSP) administered at the beginnin
The Poincar? plot is a geometrical technique used to visualise and quantify the correlation between two consecutive data points in a time-series. Since the dynamics of fluctuations in physiological rhythms exhibit long-term correlation and memory, this study aimed to extend the Poincar? plot by calculating the correlation between sequential data points in a time-series, rather than between two consecutive points. By incorporating this so-called lag, we hope to integrate a temporal aspect into quantifying the correlation, to depict whether a physiological system holds prolonged association between events separated by time. In doing so, it attempts to instantaneously characterise the intrinsic behaviour of a complex system. We tested this hyp