Improving electrotactile communication with a multi-pad electrode under cognitive load.

BACKGROUND: Electrotactile systems are compact interfaces that can be used to convey information through the skin by producing a range of haptic sensations. In many applications, however, the user needs to perceive and interpret haptic stimulation while being engaged in parallel activities. Developing methods that ensure reliable recognition of electrotactile messages despite additional cognitive load is, therefore, an important step for the practical application of electrotactile displays. METHODS: This study investigated if a simple strategy of repeating electrotactile messages can improve message identification during multitasking. Ten participants identified 36 spatiotemporal electrotactile messages delivered through a 3 × 2 pad-matrix electrode placed on the torso while performing a concomitant cognitive task in three conditions: the messages were presented once (No-REP), and each message was repeated three (REP3) and five (REP5) times. The main outcome measure was the success rate (SR) of message identification. RESULTS: During multitasking, in the No-REP condition, the SR (median (IQR)) dropped to 56.25% (22.62%), demonstrating that the cognitive task decreased performance. However, the SR significantly improved with message repetitions, reaching 72.92% (21.87%) and 81.25% (18.66%) in REP3 and REP5 conditions respectively, without a statistically significant difference between REP3 and REP5. CONCLUSIONS: Multitasking affected the efficacy of haptic communication, but message repetition was shown to be an effective strategy for improving performance. Additionally, only three repetitions were enough, as an additional increase in the duration of message transmission (5 repetitions) did not lead to further improvement. This study is an important step toward delivering electrotactile communication that can cope with the demands of real-world applications.

Patient Brain Organoids Identify a Link between the 16p11.2 Copy Number Variant and the RBFOX1 Gene.

Copy number variants (CNVs) that delete or duplicate 30 genes within the 16p11.2 genomic region give rise to a range of neurodevelopmental phenotypes with high penetrance in humans. Despite the identification of this small region, the mechanisms by which 16p11.2 CNVs lead to disease are unclear. Relevant models, such as human cortical organoids (hCOs), are needed to understand the human-specific mechanisms of neurodevelopmental disease. We generated hCOs from 17 patients and controls, profiling 167,958 cells with single-cell RNA-sequencing analysis, which revealed neuronal-specific differential expression of genes outside the 16p11.2 region that are related to cell-cell adhesion, neuronal projection growth, and neurodevelopmental disorders. Furthermore, 16p11.2 deletion syndrome organoids exhibited reduced mRNA and protein levels of RBFOX1, a gene that can also harbor CNVs linked to neurodevelopmental phenotypes. We found that the genes previously shown to be regulated by RBFOX1 are also perturbed in organoids from patients with the 16p11.2 deletion syndrome and thus identified a novel link between independent CNVs associated with neuronal development and autism. Overall, this work suggests convergent signaling, which indicates the possibility of a common therapeutic mechanism across multiple rare neuronal diseases.

How do different bile acid derivatives affect rat macrophage function - Friends or foes?

Due to an increased need for new immunomodulatory agents, many previously known molecules have been structurally modified in order to obtain new drugs, preserving at the same time some of the benevolent characteristics of the parent molecule. This study aimed to evaluate the immunomodulatory potential of a selected library of bile acid derivatives (BAD) using a broad spectrum of assays, evaluating rat peritoneal macrophages viability, cell membrane damage, lysosomal and adhesion function, and nitric oxide and cytokine production as a response to lipopolysaccharide stimulation. Also, in silico studies on two bile acid-activated receptors were conducted and the results were related to the observed in vitro effects. All tested BAD exerted significant toxicity in concentrations higher than 10 µM, which was determined based on mitochondria and cell membrane damage in a panel of assays. On the other hand, at lower concentrations, the tested BAD proved to be immunomodulatory since they affected lysosomal function, cell adhesion capacities and the ability to produce inflammatory cytokines in response to a stimulus. One of the compounds proved to exhibit significant toxicity toward macrophages, but also caused a concentration-dependent decrease in nitric oxide levels and was identified as a potential farnesoid X receptor agonist.

Electrotactile Communication via Matrix Electrode Placed on the Torso Using Fast Calibration, and Static vs. Dynamic Encoding.

Electrotactile stimulation is a technology that reproducibly elicits tactile sensations and can be used as an alternative channel to communicate information to the user. The presented work is a part of an effort to develop this technology into an unobtrusive communication tool for first responders. In this study, the aim was to compare the success rate (SR) between discriminating stimulation at six spatial locations (static encoding) and recognizing six spatio-temporal patterns where pads are activated sequentially in a predetermined order (dynamic encoding). Additionally, a procedure for a fast amplitude calibration, that includes a semi-automated initialization and an optional manual adjustment, was employed and evaluated. Twenty subjects, including twelve first responders, participated in the study. The electrode comprising the 3 × 2 matrix of pads was placed on the lateral torso. The results showed that high SRs could be achieved for both types of message encoding after a short learning phase; however, the dynamic approach led to a statistically significant improvement in messages recognition (SR of 93.3%), compared to static stimulation (SR of 83.3%). The proposed calibration procedure was also effective since in 83.8% of the cases the subjects did not need to adjust the stimulation amplitude manually.

Encoding of spatial patterns using electrotactile stimulation via a multi-pad electrode placed on the torso.

BACKGROUND: Tactile stimulation can be used to convey information to a user in different scenarios while avoiding overloading other senses. Tactile messages can be transmitted as spatial patterns, potentially allowing for a high information throughput. The aim of the present study was to design and test different encoding schemes to determine the best approach for conveying spatial patterns. METHODS: Encoding schemes with simultaneous (SIM) and sequential pad activation (SEQ) were evaluated, including four SEQ variants designed to potentially facilitate the recognition. In SEQ-col and SEQ-row, the column and row of the activated pad were signified using different frequencies, while SEQ-all and SEQ-all-fast included the activation of all pads where those belonging to the pattern were indicated by changes in frequency (ON pads). The success rate (SR) of the pattern identification and the response time were quantified in 15 participants who recognized 20 patterns delivered through a 3 × 2 pad matrix placed on the lateral torso. RESULTS: SIM was not a feasible method to present the patterns (median, 15%; IQR, 5%). The SR improved with SEQ (median, 60%; IQR, 20%) and further increased with additional cues, particularly with SEQ-row (median, 78.3%; IQR, 23.3%) and SEQ-all (median, 96.7%; IQR, 5%). Importantly, the stimulation time of SEQ-all could be decreased without a substantial drop in accuracy (SEQ-all-fast: median, 89.2%; IQR, 19.2%). CONCLUSIONS: The spatiotemporal stimulation with sequential activation of all pads (SEQ-all) seems to be the method of choice when conveying tactile messages as spatial patterns. This is an important outcome for increasing the information bandwidth of communication through the tactile channel.

The Impact of Size and Position of Reference Electrode on the Localization of Biphasic Electrotactile Stimulation on the Fingertips.

Development of haptic interfaces to enrich augmented and virtual reality with the sense of touch is the next frontier for technological advancement of these systems. Among available technologies, electrotactile stimulation enables design of high-density interfaces that can provide natural-like sensation of touch in interaction with virtual objects. The present study investigates the human perception of electrotactile sensations on fingertips, focusing on the sensation localization in function of the size and position of reference electrode. Ten healthy subjects participated in the study, with the task to mark the sensations elicited by stimulating the index fingertip using an 8-pad electrode. The test systematically explored several configurations of the active (position) and reference (position and size) electrode pads. The results indicated that there was a spreading of perceived sensations across the fingertip, but that they were mostly localized below the active pad. The position and size of the reference electrode were shown to affect the location of the perceived sensations, which can potentially be exploited as an additional parameter to modulate the feedback. The present study demonstrates that the fingertip is a promising target for the delivery of high-resolution feedback.

BEAGLE-A Kinematic Sensory System for Objective Hand Function Assessment in Technology-Mediated Rehabilitation.

We present a hand functions assessment system (BEAGLE) for kinematic tracking of hand and finger movements, envisioned as a technology-mediated rehabilitation tool. The system is custom-designed for fast and easy placement on an impaired hand (spastic or flaccid), featuring inertial sensors integrated into simple finger caps and a hand strap. An algorithm for a range of motion (ROM) estimation was implemented to provide an objective assessment of hand functions. The efficacy and feasibility of the BEAGLE system were examined in a pilot clinical study performed with ten stroke survivors in the subacute phase. Participants received therapy within two consecutive intensity-matched rehabilitation cycles. The first consisted of conventional therapy, while the second involved a combination of conventional therapy and advanced functional electrical stimulation. Assessments were performed before and after each phase. These included BEAGLE estimates of active voluntary ROM for wrist and various digits, as well as two referent clinical measures for hand functions assessment, Fugl-Meyer and Action Research Arm Test. The results indicate that the ROM assessments can detect change with sensitivity comparable to the standardized clinical scales. Statistically significant changes between the beginning and the end of the second cycle existed in all observed measures, whereas none of these measurements showed a statistically significant improvement in the first therapy cycle. The noted usability metrics indicate that the BEAGLE could be integrated into the rehabilitation workflow in a clinical environment.

Immunomodulatory effects of galectin-1 in patients with chronic lymphocytic leukemia.

Galectin-1 (Gal-1) has been implicated in the progression of chronic lymphocytic leukemia (CLL) but also the development of immunodeficiency, which commonly accompany this malignancy. In this in vitro study, we investigated the effects of Gal-1 inhibition in the sera of immunocompromised CLL patients on immunomodulating properties of dendritic cells (DCs). DCs derived from peripheral blood mononuclear cells were treated with a healthy serum, CLL serum as well as the combination of CLL serum and Gal-1 inhibitor (OTX008). Following the treatment, the expression levels of DC maturation markers (CD80, CD83, CD86 and IDO-1) were determined as well as their cytokine profile and the ability to polarize the immune response in co-cultures with CD4+ T cells. After treatment with CLL serum, an increase in interleukin (IL)-10 production was observed in both DC cultures and co-cultures with CD4+ T cells. OTX008 caused a reduction in IL-10 production as well as IL-2, but no significant alteration in the expression of DC maturation markers or T regulatory cell (Treg) frequency was observed. The results of our study suggest that Gal-1 from CLL serum give rise to a specific IL-10+ CD4+ T cell phenotype, other than Treg, that could mediate immunodeficiency development in CLL patients.

Can Salivary Biomarkers Be Used as Predictors of Dental Caries in Young Adolescents?

BACKGROUND Identifying caries predictors in the subpopulation at risk is one of the preconditions for developing effective caries prevention measures. The present exploratory study aimed to examine the significance of socio-demographic characteristics, dietary-hygiene habits, salivary pH, and salivary antimicrobial HNP-1, hBD-2, and LL-37 peptides as potential caries risk predictors in children ages 11-13 years. MATERIAL AND METHODS This prospective 1-year study enrolled 213 children ages 11-13 years. The subjects underwent a dental examination and their mothers were interviewed. Unstimulated saliva was collected from the subjects to determine its pH value, as well as the salivary levels of HNP-1, hBD-2, and LL-37 peptides in 85 of the subjects. After 12 months, the 1-year caries incidence rate was recorded. Logistic regression analysis was used to estimate the ability of selected variables to predict caries risk. RESULTS The univariable logistic regression analysis determined that the most significant independent caries risk predictors were: sex (female) (OR=2.132, p=0.007), mothers' education (OR=1.986, p=0.020), salivary pH (OR=0.270, p=0.043), oral hygiene index (OR=1.886, p=0.015), and daily tooth brushing frequency (OR=0.565, p=0.042). The multivariable model showed that sex and oral hygiene-related variables were the most important caries predictors. CONCLUSIONS Salivary HNP-1, hBD-2, and LL-37 peptides were not found to have a significant predictive value. Therefore, socio-demographic and oral hygiene variables remain important caries predictors in early adolescents, suggesting the importance of the mechanical control of biofilm as the key measure for preventing caries. However, there is still a need for effective caries risk biomarkers, and additional research is needed in this area of caries risk prediction.

CD4+ T cell phenotypes in the pathogenesis of immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by low platelet counts due to enhanced platelet clearance and compromised production. Traditionally, ITP was regarded a B cell mediated disorder as anti-platelet antibodies are detected in most patients. The very nature of self-antigens, evident processes of isotype switching and the affinity maturation of anti-platelet antibodies indicate that B cells in order to mount anti-platelet immune response require assistance of auto-reactive CD4+ T cells. For a long time, ITP pathogenesis has been exclusively reviewed through the prism of the disturbed balance between Th1 and Th2 subsets of CD4+ T cells, however, more recently new subsets of these cells have been described including Th17, Th9, Th22, T follicular helper and regulatory T cells. In this paper, we review the current understanding of the role and immunological mechanisms by which CD4+ T cells contribute to the pathogenesis of ITP.

Effects of galectin-1 on immunomodulatory properties of human monocyte-derived dendritic cells.

Our study aimed to evaluate the effects of Gal-1 in dose depending manner on maturation and immunomodulatory properties of monocyte-derived (Mo) DCs in-vitro. The effects were analyzed by monitoring their phenotypic characteristics, cytokine profile, and the ability to direct the immune response in the co-culture with allogeneic CD4+T cells. Gal-1 reduced the expression of CD80 and CD86 molecules on MoDCs compared to untreated MoDCs. Gal-1 at concentrations of 1 and 6 µg/mL significantly reduced IL-12 production, while the concentration of 3 µg/mL led to its significant increase. Gal-1 in all concentrations induced a significant increase in the production of IL-10. Treatment of MoDCs with 3 and 6 µg/mL of Gal-1 stimulated the production of IL-2 and IFN-γ in the co-culture with CD4+T lymphocytes. This study demonstrated a dual immunomodulatory effect of Gal-1 on MoDCs in terms of immune stimulation and immune suppression, depending on the applied concentration.

Do we really know how to overcome trastuzumab resistance in hormone sensitive metastatic breast cancer?

PURPOSE: This article focuses on how the status of hormone receptors (HR) influences the efficacy of trastuzumab in patients with metastatic HER2-positive breast cancer treated with first-line trastuzumab in combination with taxane-based chemotherapy. METHODS: A prospective study was carried out at the Clinic for Oncology, Clinical Centre in Nis, from January 2015 to until June 2018. A total of 121 patients were treated with first-line trastuzumab in combination with taxane-based chemotherapy. None of the patients from the HR-positive group received hormonotherapy after completion of chemotherapy with trastuzumab. RESULTS: Clinical benefit rate was present in 76% of the patients, including partial response (PR) in 37%, stable disease (SD) in 38%, and complete response (CR) in almost 8% of the patients. Progressive disease (PD) occurred in almost a quarter of the patients, i.e. 24%. Progression-free survival (PFS) in the entire group of patients amounted to 9 months, whereas overall survival (OS) was 30 months. PFS in the HR-negative tumor group was significantly longer (13 months) compared to 8 months in the HR-positive tumor group (p<0.0001; HR 0.49;95% CI 0.31-0.69). Furthermore, OS was significantly longer in the HR-negative tumor group (34 months), compared to 26 months in the HR-positive tumor group (p=0.0073, HR 0.57; 95% CI 0.36-0.90). CONCLUSIONS: These data indicate a different response to anti-HER2 therapy in patients with HER2+ metastatic breast cancer (MBC) according to HR status, thus emphasizing that ER most likely represents an escape pathway for the response to anti-HER2 target therapy and vice versa. Combining hormonotherapy with anti-HER2 therapy surely represents a promising strategy which could help overcome resistance to trastuzumab and other anti-HER2 agents.

Optimization of Semiautomated Calibration Algorithm of Multichannel Electrotactile Feedback for Myoelectric Hand Prosthesis.

The main drawback of the commercially available myoelectric hand prostheses is the absence of somatosensory feedback. We recently developed a feedback interface for multiple degrees of freedom myoelectric prosthesis that allows proprioceptive and sensory information (i.e., grasping force) to be transmitted to the wearer instantaneously. High information bandwidth is achieved through intelligent control of spatiotemporal distribution of electrical pulses over a custom-designed electrode array. As electrotactile sensations are location-dependent and the developed interface requires that electrical stimuli are perceived to be of the same intensity on all locations, a calibration procedure is of high importance. The aim of this study was to gain more insight into the calibration procedure and optimize this process by leveraging a priori knowledge. For this purpose, we conducted a study with 9 able-bodied subjects performing 10 sessions of the array electrode calibration. Based on the collected data, we optimized and simplified the calibration procedure by adapting the initial (baseline) amplitude values in the calibration algorithm. The results suggest there is an individual pattern of stimulation amplitudes across 16 electrode pads for each subject, which is not affected by the initial amplitudes. Moreover, the number of user actions performed and the time needed for the calibration procedure are significantly reduced by the proposed methodology.

YAP Activity Is Necessary and Sufficient for Basal Progenitor Abundance and Proliferation in the Developing Neocortex.

Neocortex expansion during mammalian evolution has been linked to an increase in proliferation of basal progenitors in the subventricular zone. Here, we explored a potential role of YAP, the major downstream effector of the Hippo pathway, in proliferation of basal progenitors. YAP expression and activity are high in ferret and human basal progenitors, which exhibit high proliferative capacity, but low in mouse basal progenitors, which lack such capacity. Conditional expression of a constitutively active YAP in mouse basal progenitors resulted in increased proliferation of basal progenitor and promoted production of upper-layer neurons. Pharmacological and genetic interference with YAP function in ferret and human developing neocortex resulted in decreased abundance of cycling basal progenitors. Together, our data indicate that YAP is necessary and sufficient to promote the proliferation of basal progenitors and suggest that increases in YAP levels and presumably activity contributed to the evolutionary expansion of the neocortex.

Human-specific ARHGAP11B induces hallmarks of neocortical expansion in developing ferret neocortex.

The evolutionary increase in size and complexity of the primate neocortex is thought to underlie the higher cognitive abilities of humans. ARHGAP11B is a human-specific gene that, based on its expression pattern in fetal human neocortex and progenitor effects in embryonic mouse neocortex, has been proposed to have a key function in the evolutionary expansion of the neocortex. Here, we study the effects of ARHGAP11B expression in the developing neocortex of the gyrencephalic ferret. In contrast to its effects in mouse, ARHGAP11B markedly increases proliferative basal radial glia, a progenitor cell type thought to be instrumental for neocortical expansion, and results in extension of the neurogenic period and an increase in upper-layer neurons. Consequently, the postnatal ferret neocortex exhibits increased neuron density in the upper cortical layers and expands in both the radial and tangential dimensions. Thus, human-specific ARHGAP11B can elicit hallmarks of neocortical expansion in the developing ferret neocortex.

Granulocyte-macrophage colony-stimulating factor as a mediator of autoimmunity in multiple sclerosis.

Autoreactive, myelin-specific, CD4+ T cells have a central role in multiple sclerosis (MS) pathogenesis; however the exact phenotype characteristics of these cells remain elusive. Recently, granulocyte-macrophage colony-stimulating factor (GM-CSF) expression has emerged as the main pathological signature of the encephalogenicity in both T and B cell compartment. In this review we have summarized the current data supporting GM-CSF relevance in MS pathophysiology, in the context of both immunomodulatory and neuroinflammatory processes; as well as the potential cellular sources of this stimulating factor, including different T and B cell subsets.

Synthesis of mesoporous triple-metal nanosorbent from layered double hydroxide as an efficient new sorbent for removal of dye from water and wastewater.

In this study, co-precipitation synthesis of the mesoporous triple-metal nanosorbent from Fe, Cu, Ni layered double hydroxide (FeCuNi-LDH), on the basis of the data obtained from the TG analysis was carried out. The FTIR spectroscopy and XRD results confirm the formation of CuO, NiO and Fe2O3 nanoparticles, while the EDX analysis does not show significant variations on the surface in elemental composition. BET analysis shows that FeCuNi-280 (FeCuNi-LDH calcinated at 280 °C) with mesoporous structure, has larger surface area compared to FeCuNi-LDH and FeCuNi-550 (FeCuNi-LDH calcinated at 550 °C). The value of pHPZC of FeCuNi-280 is found to be 8.66. Obtained FeCuNi-280 material showed the ability for efficient removal of dye Reactive Blue 19 (RB19) from water, with a very high sorption capacity of 480.79 mg/g at optimal conditions: the sorbent dose of 0.6 g/dm3, stirring speed of 280 rpm and pH 2. The kinetics results of the sorption process were well fitted by pseudo-second order and Chrastil model, and the sorption isotherm was well described by Sips, Langmuir and Brouers-Sotolongo model. FeCuNi-280 was easily regenerated with aqueous solution of NaOH, and reutilization was successfully done in five sorption cycles. The present study show that easy-to-prepare, relatively inexpensive nanosorbent FeCuNi-280 is among the best sorbents for the removal of RB19 dye from water solution and wastewater from textile industry in wide range of pH.

Ten years of using adjuvant trastuzumab in breast cancer in Serbia - Single institution experience.

PURPOSE: The purpose of this study was to determinate disease-free interval (DFI) and overall survival (OS) in HER2-positive breast cancer patients who received adjuvant trastuzumab at the University Clinic of Nis, Serbia, and to investigate the influence of clinicopathological and biological characteristics of the tumor on prognosis. The second aim was to determinate the most frequent cause for the treatment discontinuation, recurrence rate, as well as the site of most common localization of the first recurrence of disease. METHODS: This research was conducted as a retrospective study at the University Oncology Clinic, Clinical Centre in Nis. The study included 238 patients who were operated and treated for HER2-positive breast cancer between January 1st, 2007 to September 30th, 2012 and followed up until December 31st, 2016. Trastuzumab was administered concurrently with taxanes, if administered, or after the completed anthracycline-based chemotherapy. RESULTS: After a median follow up of 69 months the 5-year DFI was 65.9% and 5-year OS was 81.8% and, as expected, significantly longer in the group of patients with smaller tumors, a smaller number of positive axillary lymph nodes, as well as a lower stage of disease (p<0.0001). Patients older than 65 years had a longer DFI compared to the 45-65 and under 45 age groups of patients (p=0.01). No statistical significance was found in the length of DFI in relation to the histological tumor subtype, tumor grade, or the status of hormone receptors. Unlike DFI, a longer OS was recorded in the group of patients with lower tumor grade (p=0.03) and there was no statistically significant difference in survival regarding the age of patients (p=0.07). Recurrence occurred in approximately one third of the patients (38.23%), mostly in the form of local recurrence. Adjuvant therapy with trastuzumab was not completely carried out in 18.49% of the patients, the most common reason being the progression of disease. CONCLUSIONS: A long median follow up period of 69 months indicated that anti-HER2 monoclonal antibody trastuzumab, after anthracycline-based chemotherapy or concurrently with taxanes, is efficient and safe in treating early breast cancer.

A New Photocatalyst Bismuth Oxo Citrate: Synthesis, Characterization, and Photocatalytic Performance.

A new photocatalyst bismuth oxo citrate was synthesized by facile precipitation process with calcination at 200 °C. The photocatalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N2 sorptometry, and elemental analysis. Morphologically, it is composed of polyhedral particles with different, irregular shapes and sizes. The specific surface area (SSA) of the photocatalyst was 8.92 m2 g-1. It showed very good photocatalytic performance and reusability. Total decolorization of Reactive Blue 19 (RB19) was achieved in less than 10 minutes, which is much faster in comparison with TiO2 P25. Also, bismuth oxo citrate showed higher photocatalytic activity than other photocatalysts based on bismuth compounds reported by other authors. Optimal photocatalysis parameters were pH 2 and photocatalyst dose of 250 mg dm-3. The decolorization rate was found to decrease as initial dye concentration increased. The photocatalytic data best fitted to L-H kinetic model with pseudo-first order reaction rate. Chrastil diffusion model showed that diffusion has not influence on the process.

Temporal and Spatial Variability of Surface Motor Activation Zones in Hemiplegic Patients During Functional Electrical Stimulation Therapy Sessions.

The goal of this study was to investigate surface motor activation zones and their temporal variability using an advanced multi-pad functional electrical stimulation system. With this system motor responses are elicited through concurrent activation of electrode matrix pads collectively termed "virtual electrodes" (VEs) with appropriate stimulation parameters. We observed VEs used to produce selective wrist, finger, and thumb extension movements in 20 therapy sessions of 12 hemiplegic stroke patients. The VEs which produce these three selective movements were created manually on the ergonomic multi-pad electrode by experienced clinicians based on visual inspection of the muscle responses. Individual results indicated that changes in VE configuration were required each session for all patients and that overlap in joint movements was evident between some VEs. However, by analyzing group data, we defined the probability distribution over the electrode surface for the three VEs of interest. Furthermore, through Bayesian logic we obtained preferred stimulation zones that are in accordance with our previously reported heuristically obtained results. We have also analyzed the number of active pads and stimulation amplitudes for these three VEs. Presented results provide a basis for an automated electrode calibration algorithm built on a priori knowledge or the starting point for manual selection of stimulation points.