فهرست مطالب

Basic and Clinical Neuroscience
Volume:10 Issue: 3, May-Jun 2019

  • تاریخ انتشار: 1398/02/11
  • تعداد عناوین: 8
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  • Seifollah Gholampour*, Mehrnoush Bahmani, Azadeh Shariati Pages 185-197
    Introduction
    Hydrocephalus is one of the most common diseases in children, and its treatment requires brain operation. However, the pathophysiology of the disease is very complicated and still unknown. 
    Methods
    Endoscopic Third Ventriculostomy (ETV) and Ventriculoperitoneal Shunt (VPS) implantation are among the common treatments of hydrocephalus. In this study, Cerebrospinal Fluid (CSF) hydrodynamic parameters and efficiency of the treatment methods were compared with numerical simulation and clinical follow-up of the treated patients.
    Results
    Studies have shown that in patients under 19 years of age suffering from hydrocephalus related to a Posterior Fossa Brain Tumor (PFBT), the cumulative failure rate was 21% and 29% in ETV and VPS operation, respectively. At first, the ETV survival curve shows a sharp decrease and after two months it gets fixed while VPS curve makes a gradual decrease and reaches to a level lower than ETV curve after 5.7 months. Post-operative complications in ETV and VPS methods are 17% and 31%, respectively. In infants younger than 12 months with hydrocephalus due to congenital Aqueduct Stenosis (AS), and also in the elderly patients suffering from Normal Pressure Hydrocephalus (NPH), ETV is a better treatment option. Computer simulations show that the maximum CSF pressure is the most reliable hydrodynamic index for the evaluation of the treatment efficacy in these patients. After treatment by ETV and shunt methods, CSF pressure decreases about 9 and 5.3 times, respectively and 2.5 years after shunt implantation, this number returns to normal range.
    Conclusion
    In infants with hydrocephalus, initial treatment by ETV was more reasonable than implanting the shunt. In adult with hydrocephalus, the initial failure in ETV occurred sooner compared to shunt therapy; however, ETV was more efficient.
    Keywords: Cerebrospinal Fluid, Intracranial Pressure, Intracranial compliance, Survival curve, Reynolds number, CSF velocity
  • Amir Shiani*, Mohammad Taghi Joghataei, Hassan Ashayeri, Mohammad Kamali, Mohammad Reza Razavi, Fariba Yadegari Pages 199-208
    Introduction
    To study sentence comprehension in Persian-speaking Patients with Aphasia considering the factors of complexity.
    Methods
    In this cross-sectional study, the performance of 6 non-fluent aphasic patients were tested and their performance was compared to 15 matched control group. Comprehension of semantically reversible sentences was assessed using a binary sentence-picture matching task. The stimuli were as follows: clefts; subject clefts and object clefts, also relative clauses; subject relatives and object relatives. All of them were types of movement-derived structures and also simple declarative sentences as the control task.
    Results
    The best performance of aphasic patients were seen in the comprehension of subject clefts, although prior to this result we assumed that simple declarative sentences (in which there is no structural factor of complexity) can be understood easily. They showed the highest difficulty in the comprehension of object relatives. Furthermore, the performance of patients in the comprehension of relative clauses was significantly weaker than understanding the clefts.
    Conclusion
    The outcomes of this study suggest that the sentence comprehension deficits of aphasic patients, in contrast to the specific deficit models, may not be related to linguistic disabilities. Moreover, the problems in the comprehension of non-canonical sentences may be related to failure in the allocation of attention. Finally, our results support the claims that neural characterization of the cognitive resources (e.g. working memory) is disrupted in sentence comprehension deficits.
    Keywords: Sentence comprehension, Complex sentences, Syntax, Aphasia
  • Shabnam Khodayari, Firouz Ghaderi Pakdel*, Parviz Shahabi, Somayyeh Naderi Pages 209-223
    Introduction
    Ventral Tegmental Area (VTA) is a core region of the brainstem that contributes to different vital bio-responses such as pain and addiction. The Dopaminergic (DA) cellular content of VTA has major roles in different functions. This study aims to evaluate the cellular effect of tramadol on the putative VTA-DA neurons.
    Methods
    Wistar rats were assigned into three groups of control, sham, and tramadol-treated. The animals were anesthetized and their VTA-DA neuronal activity was obtained under controlled stereotaxic operation. The firing rate of the neurons was extracted according to principal component analysis by Igor Pro software and analyzed statistically considering P<0.05 as significant. Tramadol (20 mg/kg) was infused intraperitoneally. 
    Results
    Overall, 121 putative VTA-DA neurons were isolated from all groups. In tramadol-treated rats, the inhibition of the neuronal firing was proposed as tolerance and the excitation period as dependence or withdrawal. The Mean±SD inhibition time lasted up to 50.34±10.17 minutes and 31% of neurons stopped firing and silenced after 24±3 min on average but the remaining neurons lowered their firing up to 43% to 67% of their baseline firing. All neurons showed the excitation period, lasted about 56.12±15.30 min, and the firing of neurons increased from 176% to 244% of their baseline or pre-injection period.
    Conclusion
    The tolerance and dependence effects of tramadol are related to the changes in the neuronal firing rate at the putative VTA-DA neurons. The acute injection of tramadol can initiate neuroadaptation on the opioid and non-opioid neurotransmission to mediate these effects.
    Keywords: Tramadol, Dopamine, Ventral Tegmental Area, Firing rate, Tolerance, Dependence
  • Razieh Samandari, Majid Hassanpour, Ezatti, Sajad Fakhri, Fatemeh Abbaszadeh, Masoumeh Jorjani* Pages 225-234
    Introduction
    Sex differences in outcomes of Spinal Cord Injury (SCI) suggest a sex-hormone-mediated effect on post-SCI pathological events, including glutamate excitotoxicity. This study aimed to investigate the importance of gonadal hormones on glutamate release subsequent to SCI in rats.
    Methods
    After laminectomy at T8-T9, an electrolytic lesion was applied to the spinothalamic tracts of male and female rats. Using spinal microdialysis, we assessed glutamate levels at the site of lesion in both intact and gonadectomized rats for 4 hours. In this way, we examined the sex differences in the glutamate concentrations.
    Results
    The peak retention time of glutamate level was 10.6 min and spinal glutamate concentration reached a maximum level 40 min following SCI. In male SCI rats, gonadectomy caused a significant elevation of glutamate level (P<0.001) following injury which was maximum 40 min post-SCI as well. However, no significant alterations were seen in gonadectomized female rats.
    Conclusion
    The significant differences in glutamate levels between both intact and gonadectomized SCI male and female rats show the sex-hormone-related mechanisms underlying the molecular events in the second phase of SCI. It seems that the role of male gonadal hormones to prevent glutamate excitotoxicity is more prominent. The exact mechanisms of these hormones on the functional recovery after SCI should be clarified in further studies.
    Keywords: Spinal Cord Injury, Microdialysis, Glutamate, Sex hormones
  • Reza Mohebbati, Mahmoud Hosseini, Majid Khazaei, Abolfazl Khajavirad, Mohammad Naser Shafei* Pages 235-244
    Introduction
    Based on the evidence, the Pedunculopontine Tegmental nucleus (PPT) is involved in cardiovascular function regulation. In this study, the probable role of PPT on cardiovascular parameters in the hypotension induced by Hemorrhage (HEM) was evaluated. 
    Methods
    The study rats were divided up into 5 groups: 1. Control (Saline); 2. Cobalt(II) chloride (CoCl2); 3. HEM; 4. Saline+HEM; and 5. CoCl2+HEM. Their right and left femoral arteries were cannulated for recording the cardiovascular responses and blood withdrawal, respectively. Saline and CoCl2 were microinjected into the PPT using the stereotaxic apparatus. Maximum changes of Systolic Blood Pressure (SBP), Mean Arterial Pressure (MAP), and the Heart Rate (HR) after the microinjection of CoCl2 in normal and Hemorrhage conditions were recorded. Changes of SBP, MAP, and HR were calculated over time at 5-min intervals and compared with those of the control and HEM groups using repeated measures ANOVA. The Independent sample t-test was used to compare the changes in cardiovascular parameters between the control and HEM groups at 0 and 20 min after Hemorrhage. 
    Results
    The changes in SBP, MAP, and HR in the CoCl2 group were not significantly different from those in the control group. In the HEM group, the SBP and MAP changes significantly decreased (P<0.001) and HR changes significantly increased (P<0.001) compared to those parameters in the control group. In the CoCl2+HEM group, SBP and MAP changes were significantly attenuated compared to those in the HEM group (P<0.05) and HR changes induced by Hemorrhage decreased compared to that in the HEM group (P<0.01).
    Conclusion
    Our results indicate that the PPT has no effects on normal cardiovascular parameters. However, it could modulate cardiovascular responses induced by Hemorrhage.
    Keywords: Hemorrhage, Cobalt (II) chloride, Blood pressure, Heart rate, Pedunculopontine Tegmental nucleus (PPT)
  • Mehrnoosh Neghabi, Hamid Reza Marateb*, Amin Mahnam Pages 245-256
    Introduction
    Brain-Computer Interface (BCI) systems provide a communication pathway between users and systems. BCI systems based on Steady-State Visually Evoked Potentials (SSVEP) are widely used in recent decades. Different feature extraction methods have been introduced in the literature to estimate SSVEP responses to BCI applications.
    Methods
    In this study, the new algorithms, including Canonical Correlation Analysis (CCA), Least Absolute Shrinkage and Selection Operator (LASSO), L1-regularized Multi-way CCA (L1-MCCA), Multi-set CCA (MsetCCA), Common Feature Analysis (CFA), and Multiple Logistic Regression (MLR) are compared using proper statistical methods to determine which one has better performance with the least number of EEG electrodes.
    Results
    It was found that MLR, MsetCCA, and CFA algorithms provided the highest performances and significantly outperformed CCA, LASSO, and L1-MCCA algorithms when using 8 EEG channels. However, when using only 1 or 2 EEG channels d, CFA method provided the highest F-scores. This algorithm not only outperformed MLR and MsetCCA when applied on different electrode montages but also provided the fastest computation time on the test set.
    Conclusion
    Although MLR method has already demonstrated to have higher performance in comparison with other frequency recognition algorithms, this study showed that in a practical SSVEP-based BCI system with 1 or 2 EEG channels and short-time windows, CFA method outperforms other algorithms. Therefore, it is proposed that CFA algorithm is a promising choice for the expansion of practical SSVEP-based BCI systems.
    Keywords: Brain-Computer Interface (BCI), Electroencephalogram (EEG), Feature extraction, Steady-State Visually Evoked Potential (SSVEP)
  • Fateme Yousefzadeh, Gila Pirzad Jahromi, Ehsan Mokari Manshadi, Boshra Hatef* Pages 257-267
    Introduction
    “Sajdah”, a prostration position, is part of Muslim daily prayers. It seems to have several effects on the brain and heart function. This study aimed to investigate the prefrontal brain activity after 10 seconds of Sajdah in the direction of Qibla (the direction that a Muslim prays) while putting the forehead on the ground.
    Methods
    Three women and two men participated in this pilot study. Linear (absolute and relative power of θ (4-8Hz), α 1 (8-10 Hz), α 2 (10-12 Hz), β 1 (12-16 Hz), β 2 (16-20 Hz), β 3 (20-30 Hz), γ 1 (30-40 Hz), γ 2 (40-50 Hz) and non-linear features (approximate entropy, Katz fractal dimension, Petrosian fractal dimension, spectral entropy, and sample entropy) from Fps channel were calculated.
    Results
    The relative β to γ band, approximate and sample entropy, Petrosian fractal dimension and mean of amplitude decreased in open eye state in women. While θ to γ bands in the closed eye state decreased after Sajdah in women. The absolute γ bands in closed eye state and relative β band in open eye state increased after Sajdah in men.
    Conclusion
    The pilot study showed that 10 seconds of Sajdah has effects on brain activity and sometimes showed the opposite effect on genders.
    Keywords: Sajdah, EEG, Non-linear analysis, Brain activity, Gender
  • Yashar Sarbaz*, Hakimeh Pourakbari Pages 269-279
    Introduction
    Parkinson Disease (PD) is a degenerative and progressive disorder of the central nervous system. It results from degeneration of Substantia Nigra pars compacta (SNc) of the Basal Ganglia (BG). Gait disturbances in PD patients generally get worse over time. The underlying mechanism of gait disturbances in PD has not been elucidated yet.
    Methods
    In this study, we tried to analyze changes in walking performance under both single- and dual-task conditions in people with PD compared to healthy subjects. To this end, the participants’ trunk acceleration signals were recorded under dual-task (counting the stride number while walking) and single-task (walking without performing any other secondary tasks) conditions.
    Results
    The healthy subjects counted the number of their strides correctly; however, 85% of the patients made glaring errors in counting. Then variances of Stride Time Interval (STI) signals were calculated for each participant. STI signals of the patients had a higher variance than that of the healthy subjects in the dual-task condition. Separating the two groups in a dual-task condition is easier. Therefore, we think that the disease sate can be detected in early stages. It is thought that counting is performed independent of walking.
    Conclusion
    PD affects the function of BG that leads to motor timing dysfunction. So, it seems that timing in motor tasks is disrupted while timing in cognitive tasks is not. Therefore, perhaps inconsistency between the two clocks (motor-tasks and cognitive-tasks clocks) is the main cause of dual-task interference in patients’ gait.
    Keywords: Parkinson's Disease, Early diagnosis, Internal biological clock, Dual-task