Basic and Clinical Neuroscience
Volume:4 Issue: 3, Summer 2013

Transcranial current stimulation (TCS) is a neuromodulation method in which the patient is exposed to a mild electric current (direct or alternating) at 1-2 mA, resulting in an increase or a decrease in the brain excitability. This modi.cation in neural activities can be used as a method for functional human brain mapping with causal inferences. This method might also facilitate the treatments of many neuropsychiatric disorders based on its inexpensive, simple, safe, noninvasive, painless, semi-focal excitatory and inhibitory effects. Given this, a comparison amongst different brain stimulation modalities has been made to determine the potential advantages of the TCS method. In addition, considerable methodological details on using TCS in basic and clinical neuroscience studies in human subjects have been introduced. Technical characteristics of TCS devices and their related accessories with regard to safety concerns have also been well articulated. Finally, some TCS application opportunities have been emphasized, including its potential use in the near future

In this study we compared transcranial magnetic stimulation (TMS) elicited motor evoked potentials (MEPs) in a postural (bilateral low back extension: BLBE) and a respiratory (forced expiration during breath holding: FEBH) task. Using TMS of the left motor cortex, simultaneous patterns of corticospinal facilitation of the contralateral erector spinae (ES) and rectus abdominis (RA) muscles during graded voluntary activation were compared in seven healthy subjects. The facilitation pattern demonstrated task dependency by showing that MEP amplitudes in the ES muscle tended to be smaller at any given contraction level in the FEBH task than in the BLBE task. The results suggested a linear-type relationship between the size of MEPs with increasing background contraction of ES and RA in the BLBE task. However, both muscles showed a plateau effect with higher background contractions (>50% of maximum) during the FEBH task. The varied response of ES and RA across these two tasks reinforces the importance of task speci.c training in clinical settings.

Parkinson’s disease is one of the most disabling diseases which by electrode implantation and stimulation of subthalamic nucleus (STN), much progress has been made in the treatment of drug resistant patient. This new method of neurosurgery may have some neuropsychological side effects on the patients. The main aim of this study is to evaluate the effects of this kind of treatment on the different neuropsychological aspect of patients. The case-control study designed for comparing two groups of patients with Parkinson’s disease. Thirty patients, who underwent electrode implantation and Deep Brain Stimulation (DBS), compare with 60 patients treated with antiparkinson’s drugs. These two groups matched in age, sex, Parkinson’s disease duration and Parkinson’s severity scores. Measurements: the UPDR scale was used to assess the severity of the Parkinson’s severity. Beck Depression Inventory questionnaire (BDI) and Hamilton Anxiety Rating Scale questionnaire (HARS) were used to evaluate the depression and anxiety consequences of DBS.Mini Mental Status Examination (MMSE) and Clock Drawing Test (CDT) were used to evaluate the cognitive and executive function of the study subjects. patients with STN stimulation showed lower level of anxiety and depression, however, the cognitive status were more deteriorated in study subjects than control group. Patient with DBS surgery have to be followed up for neuropsychiatric symptoms particularly for the cognitive deterioration in long term period.

Working memory plays a critical role in cognitive processes which are central to our daily life. Neuroimaging studies have shown that one of the most important areas corresponding to the working memory is the dorsolateral prefrontal cortex (DLFPC). This study was aimed to assess whether bilateral modulation of the DLPFC using a noninvasive brain stimulation, namely transcranial direct current stimulation (tDCS), modi.es the working memory function in healthy adults. In a randomized sham-controlled cross-over study, 60 subjects (30 Males) received sham and active tDCS in two subgroups (anode left/cathode right and anode right/cathode left) of the DLPFC. Subjects were presented working memory n-back task while the reaction time and accuracy were recorded. A repeated measures, mixed design ANOVA indicated a signi.cant difference between the type of stimulation (sham vs. active) in anodal stimulation of the left DLPFC with cathodal stimulation of the right DLPFC [F(1,55)= 5.29, P=0.019], but not the inverse polarity worsened accuracy in the 2-back working memory task. There were also no statistically signi.cant changes in speed of working memory [F(1,55)= 0.458, P=0.502] related to type or order of stimulation.. The results would imply to a polarity dependence of bilateral tDCS of working memory. Left anodal/ right cathodal stimulation of DLPFC could impair working memory, while the reverser stimulation had no effect. Meaning that bilateral stimulation of DLFC would not be a useful procedure to improve working memory. Further studies are required to understand subtle effects of different tDCS stimulation/inhibition electrode positioning on the working memory.

In this paper, a control strategy is proposed for control of ankle movement on animals using intraspinal microstimulation (ISMS). The proposed method is based on fuzzy logic control. Fuzzy logic control is a methodology of intelligent control that mimics human decision-making process. This type of control method can be very useful for the complex uncertain systems that their mathematical model is unknown. To increase the stability and speed of the system’s response and reduce the steady-state error, we combine the FLC with a lead (lag) compensator. The experiments are conducted on. ve rats. Microelectrodes are implanted into the spinal cord to provide selective stimulation of plantar.exor and dorsi.exor. The results show that motor functions can be restored using ISMS. Despite the complexity of the spinal neuronal networks and simplicity of the proposed control strategy, our results show that the proposed strategy can provide acceptable tracking control with fast convergence.

Serum Anti endothelial Cell Antibodies (AECAs) play a prominent role in idiopathic Sensorineural Hearing Loss (SNHL) in that they induce vascular damage (immune mediated).The of the current study is To compare AECAs in serum and perilymphatic. uid of idiopathic SNHL children (<15y) undergoing cochlear implant surgery. This was a cross sectional study performed in the cochlear implant ward in Rasoul Akram hospital, Tehran, Iran (2008 -2010) on 99 SNHL children undergoing cochlear implant surgery. The data collected from47 idiopathic and 52 non-idiopathic SNHL cases. AECAs were measured by indirect immuno. uorescence assay and compared in sera and perilymphatic. uids between the two groups. P-value<0.05 was considered signi.cant. Idiopathic SNHL was diagnosed in 47.5% of cases. Positive AECA results in serum and perilymphatic. uid were 10% and 12%, respectively. Although AECA results in perilymphatic. uids were different between idiopathic and non-Idiopathic SNHL patients (PV<0.05), AECAs in serum showed no signi.cant difference between the two (PV=0.1).No signi.cant difference was detected between the mean age of idiopathic and non-idiopathic SNHL patients with positive AECAs in serum and perilymphatic. uids (PV=0.2; PV=0.2). Idiopathic SNHL was diagnosed in 47.5 % of studied cases. Idiopathic SNHL has a poor out come in children. In cases with idiopathic SNHL,. nding AECAs in perilymphatic. uids are more valuable than in the serum. We suggest that serum and perilymphatic. uids testing for AECAs would be helpful in management of idiopathic SNHL cases. Speci.c immunosuppressive treatments for selected cases suffering from Idiopathic SNHL (only in those older than 5) might be successful in disease management. However, this theory should. rst be validated by randomized clinical trials.

Low frequency stimulation (LFS) is a potential alternative therapy for epilepsy. However, it seems that the anticonvulsant effects of LFS depend on its target sites in the brain. Thus, the present study was designed to compare the anticonvulsant effects of LFS administered to amygdala, piriform cortex and substantia nigra on amygdala kindling acquisition. In control group, rats were kindled in a chronic manner (one stimulation per 24 h). In other experimental groups, animals received low-frequency stimulation (8 packages at 100 s intervals, each package contained 200 monophasic square-wave pulses, 0.1 ms pulse duration at 1 Hz andAD threshold intensity) in amygdala, piriform cortex or substantia nigra 60 seconds after the kindling stimulation, the AD duration and daily seizure stages were recorded. The obtained results showed that administration of LFS in all three regions reduced electrical and behavioral parameters of the kindling procedure. However LFS has a stronger inhibitory effect on kindling development when applied in substantia nigra compared to the amygdala and piriform cortex which reinforce the view that the substantia nigra mediates a crucial role in amygdala-kindled seizures. LFS had also greater inhibitory effects when applied to the amygdala compared to piriform cortex. Thus, it may be suggested that antiepileptogenic effect of LFS depends on its target site and different brain areas exert different inhibitory effects on kindling acquisition according to the seizure focus.

During the past. . years, non-invasive. rain stimulation has. ecome an emerging. eld in clinical neuroscience due to its capability to transiently modulate corticospinal excitability, motor and cognitive functions.. hereas transcranial magnetic stimulation has. een used e.tensively since more than t.o decades ago as a potential. neuromodulator., transcranial current stimulation. tCS. has more recently gathered increased scienti.c interests. The primary aim of this narrative revie. is to descri.e characteristics of different tCS paradigms. tCS is an umbrella term for a number of brain modulating paradigms such as transcranial direct current stimulation. tDCS., transcranial alternative current stimulation. tACS., and transcranial random noise stimulation. tR.S.. Their ef.cacy is dependent on t.o current parameters: intensity and length of application.. nlike tACS and tR.S, tDCS is polarity dependent.These techniques could be used as stand-alone techniques or can be used to prime the effects of other movement trainingsThe review also summarises safety issues, the mechanisms of tDCS-induced neuroplasticity, limitations of current state of knowledge in the literature, tool that could be used to understand brain plasticity effects in motor regions and tool that could be used to understand motor learning effects.

The technology of Neural Stimulation in recent years has become the focus of the research and treatment, although it has been around for many years. The potential use of stimulating the brain and nerves ranges from the spinal cord stimulation to the implantations of cochlear and bionic eyes with a large discrepancy between the clinical readiness for these various uses. Electrical high-frequency Deep Brain Stimulation (DBS) was developed as an alternative option to treat a few neurological disorders. However, with advancing in surgical procedures, technologies and safeties, the applications of DBS are expanding not only for therapeutic purposes but also for research. Although the exact mechanisms of action/s are not fully understood, the outcome of the ongoing research and clinical trials are promising. DBS has been used to treat the essential tremor since 1997, Parkinson’s disease (PD) since 2002 and dystonia since 2003. It has also been used to treat various disorders, including major depression. The therapeutic effect of DBS in PD is well established but for other diseases such as epilepsy the outcomes are unclear and ambiguous. This article is a succinct review of the literature, focusing on PD, epilepsy and Obsessive Compulsive Disorder (OCD).

Repetitive transcranial magnetic stimulation (rTMS) has been used widely in various psychiatric disorders like depression and schizophrenia. There have been some reports of its usefulness in alcohol dependence and substance use disorders. The present paper reviews the studies done using rTMS in substance use disorders including alcohol and nicotine dependence. Various studies done have been reviewed including the proposed mechanisms of action are outlined with the future research needs and need for further clinical data