Taurine can Decrease Phosphorylated Tau Protein Levels in Alzheimer's Model Rats' Brains.

Background Microtubule formation is a dynamic process and Tau proteins promote the assembly of tubulin monomers into microtubules. Hyperphosphorylation of some amino acids in tau proteins causes neuron starvation and finally cell death. Taurine is found in the brain and has neuroprotective effects. Objective Since the protective and therapeutic effects of Taurine on phosphorylated tau proteins level in the cerebellum and prefrontal cortex of rats induced by scopolamine have not been studied, we examined these effects. Method Adult male Wistar rats were randomly distributed into nine groups. For two weeks, Taurine-treated rats received different doses of Taurine (25, 50, and 100 mg/kg/ day) before or after scopolamine injection. The phosphorylated tau protein level in the cerebellum and prefrontal cortex was determined by the enzyme-linked immunosorbent assay (ELISA) technique. Result Pretreatment with three doses of Taurine significantly decreased the phosphorylated tau protein level that increased by scopolamine in the prefrontal cortex (p < 0.001), as well as the cerebellum (p < 0.001). Moreover, high-dose administration of Taurine (100 mg/kg/day) after scopolamine injection significantly decreased phosphorylated tau protein level in the cerebellum (p < 0.01), as well as the prefrontal cortex (p < 0.05). However, there was not any significant change in the level of phosphorylated tau protein after Taurine treatment (25 and 50 mg/kg/day) in the cerebellum and prefrontal cortex. Conclusion It can be concluded that Taurine could attenuate the increase in phosphorylated tau protein induced by scopolamine in the brain of rats and usage of Taurine as a pretreatment complement could be more useful in the protection of neurons.

α2-Adrenoceptor-ir neurons' density changes after single dose of clonidine and yohimbine administration in the hippocampus of male rat.

OBJECTIVE: Despite the important role of α2-adrenoceptors in pain modulation processes, the impact of administration of α2-adrenoceptor agonist and antagonist on the density of hippocampal α2-adrenoceptor-immunoreactive neurons has not been investigated. Therefore, we aimed to determine the effect of single doses of clonidine and yohimbine on the density of α2-adrenoceptor-immunoreactive neurons in rat hippocampus. MATERIALS AND METHODS: Adult male Wistar rats received a single dose of clonidine (0.7 mg/kg) alone or 5 min after intraperitoneal (1 mg/kg) and/or intracerebroventricular (5 µg/kg) injection of yohimbine. After histological processing, neurons with α2-adrenoceptor immunoreactivity were identified and counted through immunohistochemical analysis of hippocampal regions. RESULTS: Clonidine slightly increased the number of α2-adrenoceptor-immunoreactive neurons in the hippocampal subregions compared with the normal saline group. Intraperitoneal injection of yohimbine followed by injection of clonidine significantly increased the number of α2-adrenoceptor-immunoreactive neurons in subregions cornu ammonis 1 (CA1) and cornu ammonis 3 (CA3). Intracerebroventricular injection of yohimbine after injection of clonidine significantly reduced the number of α2-adrenoceptor-immunoreactive neurons in all hippocampal subregions. CONCLUSION: The present study demonstrates that intraperitoneal administration of α2-adrenoceptor agonist clonidine increases the density of α2-adrenoceptor-immunoreactive neurons in rat hippocampus, while intracerebroventricular injection of yohimbine decreases the density of these neurons.

Computational studies on the interactions of glycine amino acid with graphene, h-BN and h-SiC monolayers.

In the present work, the adsorption of glycine amino acid and its zwitterionic form onto three different hexagonal sheets, namely graphene, boron-nitride (h-BN) and silicon carbide (h-SiC), has been investigated within the framework of Density Functional Theory (DFT) calculations. The energetics and geometrical parameters of the considered systems have been explored at the GGA-PBE level in combination with Grimme's empirical dispersion corrections with Becke-Johnson damping, the DFT-D3(BJ) method. Based on the obtained results, we found that both the glycine molecule and its zwitterionic conformation tend to be chemisorbed onto the surface of h-SiC (Eads ranges from -1.01 to -1.319 eV) while the types of interactions are recognized to be of non-covalent nature for the case of graphene (Eads ranges from -0.121 to -0.345 eV) and h-BN (Eads ranges from -0.103 eV to -0.325 eV) systems. Moreover, the empirical dispersion corrections applied in these calculations significantly improved the results and confirmed the crucial role of dispersion corrections in obtaining reliable geometries and adsorption energies. Our findings revealed that the electronic properties of the considered systems did not change during the adsorption process and these monolayers preserve their inherent electronic properties as they interact with the glycine molecule. Using the SMD implicit solvation model, the effect of solvation has also been evaluated by re-optimizing the structures within a medium with a dielectric constant of 78.39 (liquid water) and it has been shown that the strength of the interaction between the glycine conformers and hexagonal sheets has decreased. The accuracy of the obtained values has been evaluated by some benchmark calculations at the hybrid PW6B95 level of theory and reasonable consistency is found between the results of the PBE-D3 method and our benchmark system. In summary, h-SiC exhibited the highest affinity toward glycine conformers and gained an important edge over other monolayers. Our findings would actively encourage experimentalists to explore the potential applications of these materials in drug delivery, biofunctionalization of nanostructured monolayers as well as electronic and nanosensor devices.

Impaired probabilistic classification learning with feedback in patients with major depression.

BACKGROUND: The function of basal ganglia (BG) in the pathophysiology of major depression (MD) is still unclear. Recent research found changes in BG regarding size, structure and cerebral perfusion in patients with MD. Neuroimaging shows recruitment of the striatum during feedback (FB) based incidental learning of probabilistic classification learning, while the medial temporal lobe (MTL) is associated with paired associate (PA) based incidental learning. The purpose of this study was to evaluate whether FB-based incidental learning is affected in MD. METHODS: The FB and PA versions of the weather prediction task (WPT), a task of incidental probabilistic classification learning, were completed by patients with MD (n=44) and healthy controls (n=44). In FB-learning the participants received either a "thumbs-up" or "thumbs-down" message according to their right or wrong classification of cards to a certain kind of weather (either rainy or fine), while in PA learning no classification was required. Severity of MD was rated on the Beck Depression Inventory and Hamilton Rating Scale for depression. RESULTS: Patients with MD were selectively impaired on the FB task relative to controls (p<0.05), while no significant difference was found for PA learning between the two groups. Furthermore, there were no significant differences between FB and PA-learning within the patient and control groups. CONCLUSION: Our results indicate a distinct impairment on the FB-based version of the weather prediction task. These findings implicate disturbed reinforcement learning in this group of patients.

The effect of MDMA-induced anxiety on neuronal apoptosis in adult male rats' hippocampus.

Ecstasy or MDMA as a psychoactive drug and hallucinogen is considered one of the most commonly used drugs in the world. This psychotropic substance is discussed both as sexually stimulating and reducing fear and anxiety. Amphetamines also destroy neurons in some brain areas. The aim of this study was to investigate the effects of MDMA on anxiety and apoptosis of hippocampal neurons. Forty-two male Wistar rats of mean weight 200-220 g were used and distributed into six groups [control, control-saline, and experimental groups (1.25, 2.5, 5, 10 mg/kg)]. Rats in experimental groups received MDMA at different doses for seven days by intraperitoneal injection and the control-saline group received saline (1 ml/kg); anxiety was then investigated by plus-maze test. Forty-eight hours after behavioural testing brains were taken from animals and fixed, and after tissue processing, slices were stained with TUNEL kit for apoptotic cells. The area densities of apoptotic neurons were measured throughout the hippocampus and compared in all groups (P < 0.05). Physiological studies showed that 1.25 mg/kg and 2.5 mg/kg doses caused anti-anxiety behaviour and 5 and 10 mg/kg doses of MDMA caused anxietylike behaviour. Moreover, our histological study showed that ecstasy increased apoptotic cell numbers and the highest increase was observed with the 10 mg/kg dose of MDMA. We concluded that MDMA can cause different responses of anxiety-like behaviour in different doses. This phenomenon causes a different ratio of apoptosis in hippocampal formation. Reduction of anxiety-like behaviour induced by the 2.5 mg/kg dose of MDMA can control apoptosis.

Female rat hippocampal cell density after conditioned place preference.

The hippocampus is important for learning tasks, such as conditioned place preference (CPP), which is widely used as a model for studying the reinforcing effects of drugs with dependence liability. Long-term opiate use may produce maladaptive plasticity in the brain structures involved in learning and memory, such as the hippocampus. We investigated the phenomenon of conditioning with morphine on the cell density of female rat hippocampus. Forty-eight female Wistar rats weighing on average 200-250 g were used. Rats were distributed into eight groups. Experimental groups received morphine daily (three days) at different doses (2.5, 5, 7.5 mg/kg) and the control-saline group received normal saline (1 ml/kg), and then the CPP test was performed. Three sham groups received only different doses (2.5, 5, 7.5 mg/kg) of morphine without CPP test. Forty-eight hours after behavioural testing animals were decapitated under chloroform anaesthesia and their brains were fixed, and after tissue processing, slices were stained with cresyl violet for neurons and phosphotungstic acid haematoxylin for astrocytes. The maximum response was obtained with 5 mg/kg of morphine. The density of neurons in CA1 and CA3 areas of hippocampus after injection of morphine and CPP was decreased. The number of astrocytes in different areas of hippocampus was increased after injection of morphine and CPP. It seems that the effective dose was 5 mg/kg, as it led to the CPP. We concluded that both injection of mor phine and CPP can decrease the density of neurons and also increase the number of astrocytes in the rat hippocampus.

Gender differences in quality of life following subthalamic stimulation for Parkinson's disease.

OBJECTIVES: Surveys of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) have shown that this procedure is roughly twice more common in men than in women. Here, we investigate possible differences between women and men undergoing STN DBS, with respect to health-related quality of life. MATERIALS AND METHODS: Forty-nine consecutive patients (18 women) received STN DBS. The impact of PD and its surgical treatment was compared between women and men, before and at mean of 19 ± 11 months after surgery, using the Unified Parkinson Disease Rating Scale (UPDRS) and the Parkinson's Disease Questionnaire-39 (PDQ-39). RESULTS: Duration of disease at surgery and off-medication scores of the motor part of the UPDRS were similar in women and men. At baseline, women had lower doses of dopaminergic medication than men, experienced more disability due to dyskinesias, had more sensory symptoms and perceived more difficulties in mobility. Following DBS, both men and women showed equal and significant (P < 0.001) improvement in off-medication scores on the UPDRS III. On the PDQ-39, women expressed improvement in ADL to a greater extent than men. Moreover, women but not men showed a positive effect on mobility, stigma and cognition as well as on the summary score of PDQ-39. CONCLUSIONS: Although STN DBS results in equal degree of motor improvement between women and men, health-related quality of life seems to improve to a greater extent in women.

MRI-guided STN DBS in Parkinson's disease without microelectrode recording: efficacy and safety.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a commonly employed therapeutic procedure for patients with Parkinson's disease uncontrolled by medical therapies. This series describes the outcomes of 79 consecutive patients that underwent bilateral STN DBS at the National Hospital for Neurology and Neurosurgery between November 2002 and November 2008 using an MRI-guided surgical technique without microelectrode recording. Patients underwent immediate postoperative stereotactic MR imaging. The mean (SD) error in electrode placement was 1.3 (0.6) mm. There were no haemorrhagic complications. At a median follow-up period of 12 months, there was a mean improvement in the off-medication motor part of the Unified Parkinson's Disease Rating Scale (UPDRS III) of 27.7 points (SD 13.8) equivalent to a mean improvement of 52% (p<0.0001). In addition, there were significant improvements in dyskinesia duration, disability and pain, with a mean reduction in on-medication dyskinesia severity (sum of dyskinesia duration, disability and pain from UPDRS IV) from 3.15 (SD 2.33) pre-operatively, to 1.56 (SD 1.92) post-operatively (p=0.0001). Quality of life improved by a mean of 5.5 points (median 7.9 points, SD 17.3) on the Parkinson's disease Questionnaire 39 summary index. This series confirms that image-guided STN DBS without microelectrode recording can lead to substantial improvements in motor disability of well-selected PD patients with accompanying improvements in quality of life and most importantly, with very low morbidity.

Doxorubicin-loaded albumin nanoparticles: formulation and characterization.

The purpose of the present study was to develop Doxorubicin (Dox) loaded albumin nanoparticles for regional drug release in solid tumours. Bovine serum albumin nanoparticles were prepared by coacervation method. The nanoparticles were characterized using various techniques: Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS) technique and Laser Doppler Electrophoresis (LDE) method. The entrapment of Dox in albumin nanoparticles also found out and in vitro release of drug was studied. The results show that the size of albumin nanoparticles increases from Z average of 67 nm to 98 and 106 nm for two different methods; A and B of drug loading, respectively. The SEM results confirm the spherical shape of nanoparticles which made at 4 degrees C. The results show that the size of nanoparticles decreases by decreasing temperature in their production process.

Adsorption of hazardous atoms on the surface of TON zeolite and bilayer silica: a DFT study.

In the present study, the adsorption of two types of hazardous atoms including arsenic and lead with TON zeolite and bilayer silica (2D-SiO2) have been investigated by employing Ab initio-based density functional theory (DFT) calculations. To reach a full structural optimization and the most stable configuration, four sites were considered for TON zeolite as well as five sites for 2D-SiO2, and adsorption energy along with equilibrium geometry was determined. The adsorption energies of arsenic atom on the surface of 2D-SiO2 absorbents and TON zeolite have obtained equal to and - 1.25 eV and - 2.76 eV, respectively, which both of them are chemisorption type. We also found that the adsorption of lead on the surface of 2D-SiO2 was physisorption type with the adsorption energy accounting for - 0.13 eV, while the adsorption energy between lead and TON was calculated equal to - 2.32 eV which was chemisorption type. Furthermore, our results demonstrate that the TON zeolite was more capable of adsorbing hazardous atoms compared with 2D-SiO2 due to having greater adsorption energy. The adsorption of arsenic on the 2D-SiO2 and TON adsorbents is also stronger than those of lead atom. Furthermore, we modeled and considered graphene, as a common adsorbent nanostructure, to compare and validate the accuracy of our simulations and obtained results. Finally, the electronic density of states (DOS) calculations and charge analysis were done by the use of Mulliken method, and the results confirmed those results that had already been obtained from adsorption energies. Graphical abstract.

The effect of Urtica dioica extract on the number of astrocytes in the dentate gyrus of diabetic rats.

Diabetes mellitus is associated with cerebral alterations in both human and animal models of the disease. These alterations include abnormal expression of hypothalamic neuropeptides and hippocampal astrogliosis. Urtica dioica (Nettle) is among several species listed for their use against diabetes in folk medicine. The aim of this study was the evaluation of the astrocyte number in the dentate gyrus of diabetic rats after treatment with nettle. A total of 21 male albino Wistar rats were used in the present study. The animals were divided into three groups: control, nettle-untreated diabetic, and nettle treated diabetic. Hyperglycaemia was induced by streptozotocin (80 mg/kg) in the animals of the diabetic and treatment groups. One week after injection of the streptozotocin, the animals in the treatment group received a hydroalcoholic extract of Urtica dioica (100 mg/kg/day) for 4 weeks intraperitoneally. After a 5-week survival period, all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres. The area densities of the astrocytes were measured and compared between the three groups (p < 0.05). The number of astrocytes increased in the diabetic rats (24.06 +/- 9.57) compared with the controls (17.52 +/- 6.66). The densities in the treated rats (19.50 +/- 6.16) were lower than in the diabetic rats. Furthermore, the control and treated rats showed similar densities. We concluded that U. dioica extract helped compensate for astrocytes in the treatment rats dentate gyrus in comparison with diabetic rats.

Effects of hCG on reduced numbers of hCG receptors in the prefrontal cortex and cerebellum of rat models of Alzheimer's disease.

Age-associated changes in the levels of luteinizing hormone and human chorionic gonadotropin (hCG) are potential risk factors for Alzheimer's disease (AD); hCG concentration is related to the incidence of AD. The highest density of hCG receptors is in zones of the brain that are vulnerable to AD and streptozotocin (STZ) can decrease the density of this receptor. We investigated the effects of different doses of hCG on hCG receptor density in the prefrontal cortex and cerebellum in a rat model of STZ-induced AD. AD was induced by intracerebroventricular injection of 3 mg/kg STZ. The resulting AD rats were treated for 3 days with 50, 100 or 200 IU/200 µl hCG, or with saline as a control. Sections of prefrontal cortex and cerebellum were stained immunohistochemically and hCG receptor-immunoreactive (ir) neurons were counted. STZ injected into the lateral ventricles of rat brains reduced the density of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. hCG administration resulted in a significant dose-dependent increase in the number of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. The maximum increase in the number of receptors occurred following the 200 IU dose of hCG. Administration of hCG ameliorated the lowered density of hCG receptor-ir neurons in the cerebellum and prefrontal cortex in STZ-induced AD rats.

Depression in focal, segmental and generalized dystonia.

Dystonia causes body disfigurement in the majority of those affected. Our aim was to test the hypothesis that low self-esteem resulting from the sense of disfigurement is an important component of self-reported depression in focal, segmental and generalized dystonia. Questionnaires to assess self-reported depression, self-esteem, body concept, disfigurement, disability and quality of life were completed by 329 community based dystonia patients. Moderate to severe depression was reported by 30 %. Self-reported depression had a strong somatic component, but patients also showed a specific concern with self-image. Extent of dystonia, body parts affected and marital status influenced self-reported depression in dystonia. Self esteem, body concept, disfigurement and quality of life emerged as factors which accounted for the variance of self-reported depression in dystonia. These results suggest that in dystonia, disfigurement, negative body concept, low self-esteem, and the impact of the disease on quality of life make important contributions to depression. However, longitudinal followup is required to firmly establish the direction of causality between depression and these psychosocial variables in dystonia.

The factors that induce or overcome freezing of gait in Parkinson's disease.

Freezing of gait (FoG), a transient halt in walking, is a major mobility problem for patients with Parkinson's disease (PD). This study examined the factors that induce FoG, and identified the cues and strategies that help overcome it through a postal survey of 130 PD patients. 72% reported FoG. The factors that commonly induced FoG were turning, fatigue, confined spaces and stressful situations, in addition to emotional factors. FoG was also ameliorated by various attentional and external cueing strategies. The concept of paradoxical kinesis, the potential neural substrates of such external cueing effects, and their importance for rehabilitation in PD are discussed.

The granule cell density of the dentate gyrus following administration of Urtica dioica extract to young diabetic rats.

Urtica dioica L. Stinging nettle has long been known worldwide as a medicinal plant. To study the benefits of the nettle in diabetic encephalopathy, the granule cell density of the dentate gyrus of diabetic rats was studied following administration of Urtica dioica extract. A total of 24 male albino Wistar rats were allocated equally to normal, diabetic, preventive and treatment groups. Hyperglycaemia was induced by streptozotocin (80 mg/kg) in the animals of the diabetic and treatment groups. One week after injection of the streptozotocin the animals in the treatment group received a hydroalcoholic extract of Urtica dioica (100 mg/kg/day) for 4 weeks intraperitoneally. The rats of the preventive group received hydroalcoholic extract of U. dioica (100 mg/kg/day) IP for the first 5 days and an injection of streptozotocin (80 mg/kg) on the 6th day. After 5 weeks of study all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with cresyl violet. The area densities of the granule cells were measured and compared in the four groups. The density was lower in the diabetic rats compared with the controls (p > 0.05). The preventive group showed lower cell density than the controls (p > 0.05). The densities in the treated rats were higher than in the diabetic rats (p > 0.05). Furthermore, the control and treated rats showed similar densities (p > 0.05). It seems that U. dioica extract can help compensate for granule cell loss in the diabetic rat dentate gyrus, which can ameliorate cognitive impairment in diabetes. However, preventive use of the extract showed no significant benefit.

Stress among medical students of Gorgan (South East of Caspian Sea), Iran.

OBJECTIVE: This study aims to estimate the prevalence of psychological stress and association between the levels of stress and study variables among Gorgan medical students. MATERIALS AND METHODS: All three year medical students (129 basic sciences students) in Gorgan Faculty of Medicine, Golestan University of Medical Sciences, were asked to complete the Kessler 10 questionnaire. RESULTS: The findings showed mild, moderate and severe stress among 26.22%, 20.50% and 14.75% study subjects. 39.35% of medical students had no stress. There was statistically significant association between year of study and stress levels (p= 0.040). CONCLUSION: The results indicate that there is a decrease in the psychological health of first year medical students. Provided that stress management courses are organised by medical schools, when the students arrive, they will cope up with the stress in coming years. These courses may reduce the negative effects of stress on medical students. By providing such courses and reducing stress level, medical students may improve their medical education.

Design, fabrication and structural optimization of tubular carbon/Kevlar®/PMMA/graphene nanoplate composite for bone fixation prosthesis.

The present work investigates the mechanical properties of tubular carbon/Kevlar® composite coated with poly(methyl methacrylate)/graphene nanoplates as used in the internal fixation of bones. Carbon fibers are good candidates for developing high-strength biomaterials and due to better stress transfer and electrical properties, they can enhance tissue formation. In order to improve carbon brittleness, ductile Kevlar® was added to the composite. The tubular carbon/Kevlar® composites have been prepared with tailorable braiding technology by changing the fiber pattern and angle in the composite structure and the number of composite layers. Fuzzy analyses are used for optimizing the tailorable parameters of 80 prepared samples and then mechanical properties of selected samples are discussed from the viewpoint of mechanical properties required for a bone fixation device. Experimental results showed that with optimizing braiding parameters the desired composite structure with mechanical properties close to bone properties could be produced. Results showed that carbon/Kevlar® braid's physical properties, fiber composite distribution and diameter uniformity resulted in matrix uniformity, which enhanced strength and modulus due to better ability for distributing stress on the composite. Finally, as graphene nanoplates demonstrated their potential properties to improve wound healing intended for bone replacement, so reinforcing the PMMA matrix with graphene nanoplates enhanced the composite quality, for use as an implant.

Levodopa medication improves incidental sequence learning in Parkinson's disease.

Empirical evidence suggests that levodopa medication used to treat the motor symptoms of Parkinson's disease (PD) may either improve, impair or not affect specific cognitive processes. This evidence led to the 'dopamine overdose' hypothesis that levodopa medication impairs performance on cognitive tasks if they recruit fronto-striatal circuits which are not yet dopamine-depleted in early PD and as a result the medication leads to an excess of dopamine. This hypothesis has been supported for various learning tasks including conditional associative learning, reversal learning, classification learning and intentional deterministic sequence learning, on all of which PD patients demonstrated significantly worse performance when tested on relative to off dopamine medication. Incidental sequence learning is impaired in PD, but how such learning is affected by dopaminergic therapy remains undetermined. The aim of the current study was to investigate the effect of dopaminergic medication on incidental sequence learning in PD. We used a probabilistic serial reaction time task (SRTT), a sequence learning paradigm considered to make the sequence less apparent and more likely to be learned incidentally rather than intentionally. We compared learning by the same group of PD patients (n=15) on two separate occasions following oral administration of levodopa medication (on state) and after overnight withdrawal of medication (off state). Our results demonstrate for the first time that levodopa medication enhances incidental learning of a probabilistic sequence on the serial reaction time task in PD. However, neither group significantly differed from performance of a control group without a neurological disease, which indicates the importance of within group comparisons for identifying deficits. Levodopa medication enhanced incidental learning by patients with PD on a probabilistic sequence learning paradigm even though the patients were not aware of the existence of the sequence or their acquired knowledge. The results suggest a role in acquiring incidental motor sequence learning for dorsal striatal areas strongly affected by dopamine depletion in early PD.

In Parkinson's disease pallidal deep brain stimulation speeds up response initiation but has no effect on reactive inhibition.

The fronto-striatal circuits are considered to mediate inhibitory control over action. The aim of this study was to investigate the contribution of the internal segment of the pallidum (GPi), one of the final output pathways from the basal ganglia to the cortex, in inhibition. We examined the effect of deep brain stimulation (DBS) of the GPi (GPi-DBS) in patients with Parkinson's disease who performed a conditional stop signal task, with DBS on and off. Modulation of GPi activity was associated with significantly faster Go reaction times with DBS on than off, but stop signal reaction times were not altered. Application of the drift diffusion model indicated that GPi-DBS was associated with significantly lower response thresholds compared to GPi-DBS off. However, the drift rate was significantly lower than healthy controls with both GPi-DBS on and off. These results suggest that the GPi plays a crucial role in the 'Go' pathway, perhaps facilitating reaching the required threshold to initiate actions. However, GPi-DBS does not alter the functioning of the indirect 'NoGo' pathway, and other basal ganglia nuclei, such as the STN, may play a greater role in reactive response inhibition and conflict resolution.