Neuroscience Journal of Shefaye Khatam
Year:2018 | Volume:6 | Issue:2 |Papers Count:10

Introduction: Cognitive control deficits are seen in many psychological and brain disorders. The dual mechanism of control (DMC) theory assumes two proactive (PC) and reactive control (RC) modes for cognitive control and uses the AX version of continuous performance test (AX-CPT) as the main research paradigm. This test determines deficits in cognitive control modes in various disorders. Midbrain dopamine signal plays an important role in the pathophysiology of various disorders with cognitive control deficits and plays a key role in DMC theory.Materials and Methods: The present study was a computer simulation to investigate the effect of midbrain dopamine signal manipulation on cognitive control deficits. Simulation is based on LEABRA cognitive architecture and using the PBWM model as a model of working memory and PVLV model as a model of midbrain dopaminergic system. This investigation has been implemented in the emergent computer simulation software where the AX-CPT is presented to the model and the model performance was measured. Simulation results are calculated in three proactive control behavioral index (PCB), PC, and RC indices.Results: With increasing gain of phasic dopamine signal from 0 to 100 percent, a 15 to 45 percent changes occurred in the trend of curves. Increasing up to 15 percent, the error indices sharply decreased, PC was reduced, RC is increased, and PCB tends from PC to RC. Increasing from 15 to 45 percent, PC was increased, RC was reduced, and PCB tends from RC to PC. These trends were damped between 45 to 100 percent enhancement. Indices related to the average reaction time showed a reversed pattern of error indices.Conclusion: The results of the error indices by decreasing phasic dopamine level indicate an increase in PC deficit and RC improvement as well as a greater tendency toward RC. These results are consistent with the hypodopaminergic pattern and DMC mechanism deficits in attention deficit hyperactivity disorder, depression, negative symptoms of schizophrenia as well as chronic addiction of cocaine and alcohol and Parkinson’s disease.

Introduction: One of the common complications of diabetic patients is peripheral neuropathy. The aim of the present study was to evaluation of the changes of parameters of peripheral nerves in patients with short- and long-term diabetes.Materials and Methods: 48 subjects were selected and classified into three groups: i) patients with diabetic peripheral neuropathy for 1-7 years (n=16), ii) patients with diabetic peripheral neuropathy for 10-17 years (n=16), and iii) 16 healthy subjects. All groups were evaluated by electroneurogram and electromyogram investigations.Results: Data analysis showed a significant difference between short-term diabetes and control groups in peroneal nerve and median nerve conductions. In addition, significant differences were observed between long-term diabetes and control groups in peroneal nerve and median nerve conductions as well as in biceps electrical activation and gastrocnemius electrical activation. Among these findings, the most important differences were observed between short and long-term diabetes groups in gas trocnemius and biceps electrical activation.Conclusion: Our data indicate that peripheral nerves deficits are early complications in patients with diabetes. A longer duration of diabetes leads to muscle functional changes and disorders of motor unit recruitment.

Introduction: Headache is one of the most common pain syndromes in humans, which can lead to social and occupational dysfunctions. The aim of this study was to investigate the prevalence of migraine and tension type headache (TTH) among the staffs of Sina Hospital, Tehran, Iran and its relationship with socio-demographic variables as well as psychological factors.Materials and Methods: This analytical observational study was conducted in 590 employees of Sina Hospital in Tehran, Iran using a randomized sampling method. The prevalence of migraine and TTH was evaluated in relation to psychological and sociodemographic variables. Required information was collected through a questionnaire and the diagnosis of the type of headache was confirmed by a neurologist.Results: The total prevalence of headaches within our study population was 129 cases among 590 subjects (21.8%), of which 58 (9.8%) subjects were migraineurs, 67 (11.3%) subjects had TTH, and 4 (0.67%) people had both TTH and migraine. These headaches were significantly higher in nurses, staffs with a bachelor’s degree or above, staffs with an average daily working hours of more than 8 hours, and staffs working in the morning shift. TTH had also a significant relationship with psychological characteristics, such as depression, fatigue, and job dissatisfaction. Job absenteeism, referral to physicians, and inability to do routine works during their headache periods were significantly higher in staffs with migraine headaches compared to TTH.Conclusion: TTH and migraine headaches had a significant relationship with the type of job, educational levels, and type of work shifts. In addition, migraine headaches had more negative effects on the quality of work compared to TTH.

Introduction: Exercise and physical activity have positive impacts on the physical and mental functions. However, their impact on cognitive functions needs to be elucidated in further details. Therefore, the present study was performed to determine the effect of aerobic exercise on neural network of attention and working memory.Materials and Methods: In this semi- experimental study, 20 inactive women with mean age of 22.65±2.03 years were selected by available sampling and equally divided into experimental and control groups. The experimental group participated in 16 sessions of aerobic exercise. Before and after the completion of training intervention, participant’s performance was assessed using attention network test and N-back task. Data were analyzed by the multivariable analysis of covariance method.Results: Our results showed that working memory in the experimental group was significantly increased compared to the control group. However, there were no significant differences in orienting network of attention.Conclusion: Our data are in line with the use of aerobic exercise to reinforce working memory. In addition, it seems that the impact of aerobic exercise on cognition is selective and depends on the nature of the targeted cognitive function as well as their brain substrates.

Introduction: Human visual system is able to recognize the objects relevant information in natural images rapidly and efficiently. In the recognition process, an object can belong to different levels of abstraction (superordinate, basic, and subordinate) in a hierarchical structure. However, it remains unclear whether different questions at levels of object categorization for identical stimulus create different activation responses in the brain or not.Materials and Methods: In order to investigate the relation between brain function and human behavior, three behavioral experimental studies have been designed with help of psychophysics’ tool box in MATLAB R2015a. During these experiments, the participants asked to record animate, face, and animal face images as target images respect to the superordinate, basic, and subordinate levels, respectively. The experiments include seven blocks of 96 trials in superordinate (four blocks), basic (two blocks), and subordinate (one block) levels. Totally each subject has done 672 trials.Results: We observed that subjects’ reaction time were task dependent for the same images in contrast to previous studies. That is, images in the superordinate level were observed in the early component of reaction time whereas basic and subordinate levels emerged relatively late. In all levels, only a set of 48 target images (animal face) was analyzed. These target images were randomly mixed with other ones.Conclusion: The results showed that superordinate level is well separated from the other two levels. In other words, this level needs more general information for object recognition process than other levels. These findings suggest that categorization of objects at different levels has done by three distinct neuronal circuits. Moreover, these results indicate that there are some top-down signals which change the information processing path respect to the questions.

Introduction: Studies have shown that borderline personality and alexithymia could affect the course of interpersonal problems. The aim of this study was to evaluate borderline personality characteristics and alexithymia among female college students with interpersonal problems.Materials and Methods: Research population included 150 female students in AL Zahra University who were received above cutoff scores in the inventory of interpersonal problems. The instruments used in this study were the inventory of interpersonal problems, the Toronto Alexithymia Scale (TAS-20), and the Personality Assessment Inventory Borderline Scale (PAI-BOR).Results: The results showed that difficulty identifying feelings and impulsive behaviors were predictors of interpersonal problems.Conclusion: These findings indicate the role of borderline personality and alexithymia in interpersonal problems. These results can be useful in intervention programs in treatments of interpersonal problems.

Introduction: Playing a musical instrument requires a high motor coordination, sensory integration, and cooperation among different areas of the brain, which affects the cognitive functions. The aims of this study were to evaluate the neurocognitive executive functioning in musicians and non-musician individuals.Materials and Methods: This is a descriptive and causal-comparative (ex post facto) study.120 people were selected through purposeful sampling method and were divided into two groups; musicians (n=60) and non-musicians (n=60). All subjects completed the Barkley Deficits in executive functioning scale test (BDEFS) and cognitive flexibility (CFI).Results: Our results revealed that non-musicians had poorer flexibility and executive functioning compared to musicians. In addition, the musicians who practiced for a longer period and began their training at early ages had higher scores in cognitive flexibility and executive functioning.Conclusion: These data suggest that music education and training can play an important role in promoting the levels of neurological functions.

Introduction: Spirituality and religion have an important role in human health and behavior. Referring to religious sources are one of the solutions that people seek during experience of life stress. Listening to the recitation of Quran has been suggested to alleviate the life stress. The aim of this study was to determine the effects of listening to the recitation of the holy Quran on the brain functions in healthy people.Materials and Methods: 52 healthy subjects were recruited based on convenience sampling and were randomly placed into two groups. Quantitative Electroencephalography (qEEG) was recorded while the experimental group were listening to surah Al-Insan (experimental group), control group were listening to an Arabic text (control group). Brain activities were recorded and analyzed.Results: There were differences between the brain waves of the experimental and control groups. In the experimental group, all EEG frequency bands were decreased and the most of frequency bands changes observed in fronto-temporal pathway. In the control group, decrease in beta, high beta, gamma, gamma 1, gamma 2 and high gamma was evident in the central regions. In comparison to the control group, beta and gamma frequency bands increased in the experimental group.Conclusion: Changes in the EEG frequency bands of fronto-temporal pathway of listening to the recitation of Quran suggest the potential use of that in alleviation of psychological disorders.

Introduction: Autism spectrum disorders (ASD) are neurodevelopmental disorders that are characterized by difficulties in social communication and social interaction as well as by restricted and repetitive behaviors, interests or activities. Researches within the field of social neuroscience demonstrate that social functioning deficits in ASD may arise from dysfunctions in the neural systems that implicate in social information processing. In this study, existing research related to the neural basis of three key neural systems underlying social information processing (social perception, action observation, and theory of mind and malfunction of neural systems) in ASD have been reviewed. The results indicate that there is atypical activation in brain regions involved in social perception (the posterior superior temporal sulcus (PSTS), the amygdala, the orbitofrontal cortex, and the fusiform gyrus), in regions associated with action observation consist of mirror neurons system and its three interconnected areas (PSTS, the inferior frontal gyrus, and the inferior parietal lobule), and in regions assign to theory of mind (the medial prefrontal cortex, the tempro-parietal junction, PSTS, the posterior cingulate cortex/precuneus, and the anterior temporal lobes).Conclusion: These results indicate aberrant social information processing in ASD and define it as deficits in the neural systems involved in social perception, action understanding, and theory of mind. These findings provide a foundation for understanding the neural mechanisms underlying social deficits in ASD and highlight the role of PSTS as a common region in all three systems.

Introduction: Multiple Sclerosis (MS) is a chronic progressive course of illness that leads to the widespread pathological processes of neurodegeneration, including neuroaxonal damage, apoptosis and gliosis. Due to complex mechanisms involve in the pathophysiology of MS, finding valid biomarkers is very difficult. However, finding the effective biomarkers that are more sensitive and be able to determine the level of activity and course of the disease is necessary. Today, several biomarkers with high efficacy have been introduced to design the initial therapy, to evaluate the response to drug treatments, and to identify early diagnosis and different stages of the disease. This study was aimed to review different known biomarkers to diagnose the MS.Conclusion: The complicity of MS and the important role of biomarkers in the diagnosis of MS focus lead to several studies to evaluate the most effective biomarkers. The findings indicate that the cerebrospinal fluid (CSF) biomarkers are more valid compared to plasma biomarkers. CSF biomarkers are not influenced by the circadian rhythm and circulate in the subarachnoid space, which is in close proximity to sites of neuroinflammatory lesions in MS. Among structural biomarkers, magnetic resonance imaging is the most practicable methods for MS diagnosis.