Dorsal Contacts Research Articles

Differential Responses to Low- and High-Frequency Subthalamic Nucleus Deep Brain Stimulation on Sensor-Measured Components of Bradykinesia in Parkinson's Disease.

The current approach to assessing bradykinesia in Parkinson's Disease relies on the Unified Parkinson's Disease Rating Scale (UPDRS), which is a numeric scale. Inertial sensors offer the ability to probe subcomponents of bradykinesia: motor speed, amplitude, and rhythm. Thus, we sought to investigate the differential effects of high-frequency compared to low-frequency subthalamic nucleus (STN) deep brain stimulation (DBS) on these quantified facets of bradykinesia. We recruited advanced Parkinson's Disease subjects with a chronic bilateral subthalamic nucleus (STN) DBS implantation to a single-blind stimulation trial where each combination of medication state (OFF/ON), electrode contacts, and stimulation frequency (60 Hz/180 Hz) was assessed. The Kinesia One sensor system was used to measure upper limb bradykinesia. For each stimulation trial, subjects performed extremity motor tasks. Sensor data were recorded continuously. We identified STN DBS parameters that were associated with improved upper extremity bradykinesia symptoms using a mixed linear regression model. We recruited 22 subjects (6 females) for this study. The 180 Hz STN DBS (compared to the 60 Hz STN DBS) and dopaminergic medications improved all subcomponents of upper extremity bradykinesia (motor speed, amplitude, and rhythm). For the motor rhythm subcomponent of bradykinesia, ventral contacts yielded improved symptom improvement compared to dorsal contacts. The differential impact of high- and low-frequency STN DBS on the symptoms of bradykinesia may advise programming for these patients but warrants further investigation. Wearable sensors represent a valuable addition to the armamentarium that furthers our ability to conduct objective, quantitative clinical assessments.

A multicenter double-blind randomized crossover study comparing the impact of dorsal subthalamic nucleus deep brain stimulation versus standard care on apathy in Parkinson’s disease: a study protocol

BackgroundNeuroimaging studies suggest an association between apathy after deep brain stimulation (DBS) and stimulation of the ventral part of the subthalamic nucleus (STN) due to the associative fibers connected to the non-motor limbic circuits that are involved in emotion regulation and motivation. We have previously described three patients with severe apathy that could be fully treated after switching stimulation from a ventral electrode contact point to a more dorsal contact point.ObjectivesTo determine whether more dorsal stimulation of the STN decreases apathy compared to standard care in a multicenter randomized controlled trial with a crossover design.MethodsWe will include 26 patients with a Starkstein Apathy Scale (SAS) score of 14 or more after subthalamic nucleus (STN) deep brain stimulation (DBS) for refractory Parkinson’s disease. This is a multicenter trial conducted in two teaching hospitals and one university medical center in the Netherlands after at least 3 months of STN DBS. Our intervention will consist of 1 month of unilateral dorsal STN stimulation compared to treatment as usual. The primary outcome is a change in SAS score following 1 month of DBS on the original contact compared to the SAS score following 1 month of DBS on the more dorsal contact. Secondary outcomes are symptom changes on the Movement Disorders Society-Unified Parkinson’s Disease Rating Scale motor part III, Montgomery-Åsberg Depression Rating Scale, 39-item Parkinson’s disease questionnaire, Parkinson’s disease impulsive-compulsive disorders questionnaire, changes in levodopa-equivalent daily dosage, apathy rated by the caregiver, and burden and quality of life of the caregiver.Trial registrationClinicalTrials.gov NL8279. Registered on January 10, 2020.

Behavioral responses to natural rewards in developing male and female rats.

Reward deficits are a hallmark feature of multiple psychiatric disorders and often recapitulated in rodent models useful for the study of psychiatric disorders, including those employing early life stress. Moreover, rodent studies have shown sex differences during adulthood in response to natural and drug rewards under normative conditions and in stress-based rodent models. Yet, little is known about the development of reward-related responses under normative conditions, including how these may differ in rats of both sexes during early development. Comparing reward-related behavioral responses between developing male and female rats may be useful for understanding how these processes may be affected in rodent models relevant to psychiatric disorders. To this end, we tested behavioral responses to natural rewards in male and female rats using sucrose consumption, sweet palatable food intake and social play tests at two timepoints (peripuberty, adolescence).Our results suggest comparable responses to consummatory and social rewards in male and female rats during peripuberty and adolescence as no sex differences were found for sucrose preference, chocolate candy intake or a subset of play behaviors (dorsal contacts, pins). These findings suggest that sex differences in response to these natural rewards emerge and may be more robust during adulthood.

Mapping Subchondral Bone Density Distribution in the Canine C6-C7 Vertebral Endplates: A CT-OAM Study.

Intervertebral cage subsidence is a common complication in treating disc-associated cervical spondylomyelopathy in dogs. The mechanical stability of the vertebral endplate in contact with the cage is crucial to preventing subsidence. This study aims to assess subchondral bone mineral density (sBMD) in the canine vertebral endplate (specifically, the C6-C7 vertebral motion unit) as a measure of its mechanical stability. The sBMD distribution was mapped for the C6 caudal and C7 cranial vertebral endplates in 15 middle- to large-breed dogs using computed tomography osteoabsorptiometry. The sBMD distribution in the canine C6 and C7 vertebral endplates exhibited a heterogeneous pattern, with lower density observed in the central and dorsal contact areas of the nucleus pulposus, where common subsidence occurs. Our results suggest a potential need to redesign intervertebral cages to ensure that contact areas align with regions of higher bone density. A broad-based design extending toward the lateral and dorsal aspects of the annulus fibrosus contact area may enhance stability.

Mandibular anatomy of the paracryptodire Glyptops ornatus supports active hunting behavior in a Jurassic turtle.

The mandible of turtles is rich in osteological characters that are relevant for systematic purposes. Shape variation additionally reflects upon various feeding strategies and are thus informative for the palaeoecological interpretation of extinct species based on fossils. The mandibular anatomy of non-baenid paracryptodires has so far been undescribed. Based on digital segmentation of a computed tomography scan, I herein describe the mandible of the pleurosternid paracryptodire Glyptops ornatus. This taxon has a slender and gracile jaw, with weakly developed muscle attachment sites for adductor muscles (i.e., adductor fossa, coronoid process, and retroarticular process) and strongly reduced triturating ridges. These features are typical for suction-feeding aquatic hunters, thereby contrasting with the robust, durophagous-adapted mandibles of many baenid or compsemydid paracryptodires. In addition, the mandible of G. ornatus is characterized by the presence of a large splenial with a dorsal splenial-dentary contact, the presence of a splenial foramen, and the strong reduction of the foramen dentofaciale majus and the absence of a posterior intermandibular foramen.

Dorsal subthalamic deep brain stimulation improves pain in Parkinson's disease.

Inconsistent effects of subthalamic deep brain stimulation (STN DBS) on pain, a common non-motor symptom of Parkinson's disease (PD), may be due to variations in active contact location relative to some pain-reducing locus of stimulation. This study models and compares the loci of maximal effect for pain reduction and motor improvement in STN DBS. We measured Movement Disorder Society Unified PD Rating Scale (MDS-UPDRS) Part I pain score (item-9), and MDS-UPDRS Part III motor score, preoperatively and 6-12 months after STN DBS. An ordinary least-squares regression model was used to examine active contact location as a predictor of follow-up pain score while controlling for baseline pain, age, dopaminergic medication, and motor improvement. An atlas-independent isotropic electric field model was applied to distinguish sites of maximally effective stimulation for pain and motor improvement. In 74 PD patients, mean pain score significantly improved after STN DBS (p = 0.01). In a regression model, more dorsal active contact location was the only significant predictor of pain improvement (R2 = 0.17, p = 0.03). The stimulation locus for maximal pain improvement was lateral, anterior, and dorsal to that for maximal motor improvement. STN stimulation, dorsal to the site of optimal motor improvement, improves pain. This region contains the zona incerta, which is known to modulate pain in humans, and may explain this observation.

Case series investigating the differences between stimulation of rostral zona incerta region in isolation or in conjunction with the subthalamic nucleus on acute clinical effects for Parkinson’s disease

BackgroundSubthalamic nucleus (STN) deep brain stimulation (DBS) is a highly effective therapy for movement disorders including Parkinson’s disease (PD). One focus of research has been to explore whether stimulation of the rostral zona incerta (rZI) region contributes to the efficacy observed in STN DBS therapy. ObjectiveIn this study, we conducted a case series to evaluate the clinical efficacy and adverse effects of stimulation to the rZI region in isolation and in conjunction with STN stimulation. MethodsVolunteers with PD (N = 5), treated with STN DBS, and determined to have a dorsal contact within the region of rZI were recruited to participate. Following evaluation of tolerability, each volunteer underwent routine motor assessments during three stimulation parameter conditions: STN, rZI, and co-stimulation STN + rZI. Both participant and clinical examiner were blinded to the condition. Efficacy was measured with the Movement Disorders Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) and the Unified Dyskinesia Rating Scale (UDysRS). Volumes of tissue activation for all conditions were assessed for STN and rZI coverage. ResultsNo significant differences between measures of MDS-UPDRS and UDysRS were observed for the three stimulation settings. Although not statistically significant, results showed that 2 participants preferred STN + rZI co– stimulation, 2 participants preferred STN stimulation, and 1 participant preferred rZI stimulation and 4/5 participant preferences were consistent with clinician preference. ConclusionsFindings from this case series support further investigation into co-stimulation of the rZI region and STN for PD motor symptoms.

Effects of Socks on the Dorsal Foot Contact Pressure during Gait with Shoes

Effects of Socks on the Dorsal Foot Contact Pressure during Gait with Shoes

Effects of socks on dorsal foot contact pressure during gait

Effects of socks on dorsal foot contact pressure during gait

Acute low frequency dorsal subthalamic nucleus stimulation improves verbal fluency in Parkinson's disease

BackgroundParkinson's disease (PD) is a common neurodegenerative disorder that results in movement-related dysfunction and has variable cognitive impairment. Deep brain stimulation (DBS) of the dorsal subthalamic nucleus (STN) has been shown to be effective in improving motor symptoms; however, cognitive impairment is often unchanged, and in some cases, worsened particularly on tasks of verbal fluency. Traditional DBS strategies use high frequency gamma stimulation for motor symptoms (∼130 Hz), but there is evidence that low frequency theta oscillations (5–12 Hz) are important in cognition. MethodsWe tested the effects of stimulation frequency and location on verbal fluency among patients who underwent STN DBS implantation with externalized leads. During baseline cognitive testing, STN field potentials were recorded and the individual patients’ peak theta frequency power was identified during each cognitive task. Patients repeated cognitive testing at five different stimulation settings: no stimulation, dorsal contact gamma (130 Hz), ventral contact gamma, dorsal theta (peak baseline theta) and ventral theta (peak baseline theta) frequency stimulation. ResultsAcute left dorsal peak theta frequency STN stimulation improves overall verbal fluency compared to no stimulation and to either dorsal or ventral gamma stimulation. Stratifying by type of verbal fluency probes, verbal fluency in episodic categories was improved with dorsal theta stimulation compared to all other conditions, while there were no differences between stimulation conditions in non-episodic probe conditions. ConclusionHere, we provide evidence that dorsal STN theta stimulation may improve verbal fluency, suggesting a potential possibility of integrating theta stimulation into current DBS paradigms to improve cognitive outcomes.

Effects of Shoe Type on Dorsal Foot Contact Pressure during Gait:

Effects of Shoe Type on Dorsal Foot Contact Pressure during Gait:

Trans-vocalic coronal consonant coarticulation in Central Arrernte: An electro-palatographic study

This study examines trans-vocalic CVC coarticulation of the coronal (dental, alveolar, retroflex and (alveo-)palatal) stop, nasal and lateral consonants of Arrernte, an Aboriginal language of Central Australia, using electro-palatographic (EPG) recordings of continuous speech. Coronal consonants are known to be more coarticulatorily resistant than peripheral consonants such as bilabials and velars, and this study teases out the coarticulatory differences between these four coronal places of articulation. Results confirm findings from previous studies that laminal consonants (dental and alveo-palatal) are broadly more coarticulatorily aggressive than apical consonants (alveolars and retroflexes), with the alveolars the least resistant to coarticulation. Dental consonants exert fronting effects on both preceding and following consonants, a result consistent with previous acoustic results for these sounds. Similarly, alveo-palatal consonants show both anticipatory and carryover effects, though their exact coarticulatory effect depends on the affected consonant place and manner. The retroflex consonants exert strong fronting effects on the following consonant, and it is suggested that this is due to the anterior release of retroflexes following ballistic forward movement during closure. There is also some evidence of a retraction effect of retroflexes on preceding consonants. Despite this evidence of coarticulatory aggression, retroflexes are particularly affected by preceding and following palatals: in these cases, the retroflex articulation becomes more forward, and dorsal contact for the retroflex is increased. In sum, by examining speech in an understudied language, we learn that there are still greater complexities in the co-ordination of consonants produced using the tongue tip and blade.

A novel local field potential-based functional approach for targeting the centromedian-parafascicular complex for deep brain stimulation

BackgroundThe centromedian-parafascicular (Cm-Pf) complex of the thalamus is a common deep brain stimulation (DBS) target for treatment of Tourette syndrome (TS). Currently, there are no standardized functional intraoperative neurosurgical targeting approaches. Collectively, these issues have led to variability in DBS lead placement. Therefore, more defined methods are needed to improve targeting accuracy. ObjectiveThe objective of this observational study was to develop and to verify a functional mapping task capable of differentiating the Cm-Pf region from the nearby ventral intermediate (Vim) nucleus region of the thalamus. The overarching goal was to improve the reproducibility of DBS targeting in the Cm-Pf region. MethodsSeven TS patients completed a modified Go/NoGo task (five in the post-operative setting and two in the intra-operative setting). Post-operative neural signals from Cm-Pf region were collected using sensing-enabled implanted neural stimulators, and intraoperative neural signals from the Cm-Pf region were collected using an external amplifier. Event-related potential (ERP) features were identified by using the grand-average of stimulus onset signals derived from the postoperative participants. These features were correlated with anatomical locations for the specific electrode recordings. The same features were extracted from the intraoperative patients in order to verify electrode positions in the operating room environment. ResultsTwo features – a positive and a negative deflection – were identified in the average ERP from the post-operative participants. The peak amplitudes of both features were significantly correlated with the electrode depth position (p = 0.025 for positive deflection and p = 0.039 for negative deflection). The same result was reproduced intra-operatively in the two most recent patients, where more ventral electrode contacts revealed stronger peak amplitudes in comparison to the dorsal electrode contacts. ConclusionThis process was used to physiologically confirm accurate lead placement in the operating room setting. The modified Go/NoGo task elicited robust neural responses in the Cm-Pf region however the signal was not present in the Vim nucleus region of thalamus along the DBS electrode trajectory. We conclude that the differences in ERP responses may be a potentially novel LFP based functional approach for future targeting of the Cm-Pf complex for TS DBS.

Hand-to-mouth and other hand-to-face touching behavior in a quasi-naturalistic study under controlled conditions

ABSTRACT Data gaps exist in our understanding of hand-to-mouth touching behavior among adults, despite its relevance for accurately characterizing inadvertent ingestion exposures to chemical and pathogenic microbial agents and consequent associated health risks. The present study describes detailed observations of the frequency and nature of hand-to-mouth and other hand-to-face touching behavior among 14 male and female volunteers in a controlled, quasi-naturalistic setting. Participants performed four 15-min tasks: 1) installation of a brass object as part of a short home improvement project, 2) completion of a pen-and-paper survey, 3) engagement in a telephone conversation, and 4) use of headphones to listen to music. Video recordings of the participants performing each task were reviewed and coded for touches to the face with emphasis on specific regions of the face and palmar versus dorsal contacts. During the installation task, only one of the 14 participants was observed touching his face; this was to the nose, on two separate occasions. Summed across the three non-installation tasks, including palmar and dorsal contacts, participants touched their lips, their mouth, and anywhere on their face on average (range) 5.1 (0–19), 0.4 (0–3), and 27.7 (6–49) times, respectively. Facial contacts during these three non-installation tasks were predominantly with the palmar surface of the hand. The implications of these data are contextually specific, as the potential health impacts of face touching behavior among adults might differ based upon toxicity or virulence of hand contaminants of interest.

Subthalamic Nucleus Subregion Stimulation Modulates Inhibitory Control.

Patients with Parkinson’s disease (PD) often experience reductions in the proficiency to inhibit actions. The motor symptoms of PD can be effectively treated with deep brain stimulation (DBS) of the subthalamic nucleus (STN), a key structure in the frontal–striatal network that may be directly involved in regulating inhibitory control. However, the precise role of the STN in stopping control is unclear. The STN consists of functional subterritories linked to dissociable cortical networks, although the boundaries of the subregions are still under debate. We investigated whether stimulating the dorsal and ventral subregions of the STN would show dissociable effects on ability to stop. We studied 12 PD patients with STN DBS. Patients with two adjacent contacts positioned within the bounds of the dorsal and ventral STN completed two testing sessions (OFF medication) with low amplitude stimulation (0.4 mA) at either the dorsal or ventral contacts bilaterally, while performing the stop task. Ventral, but not dorsal, DBS improved stopping latencies. Go reactions were similar between dorsal and ventral DBS STN. Stimulation in the ventral, but not dorsal, subregion of the STN improved stopping speed, confirming the involvement of the STN in stopping control and supporting the STN functional subregions.

Interleaved deep brain stimulation for dyskinesia management in Parkinson's disease.

In patients with Parkinson's disease, stimulation above the subthalamic nucleus (STN) may engage the pallidofugal fibers and directly suppress dyskinesia. The objective of this study was to evaluate the effect of interleaving stimulation through a dorsal deep brain stimulation contact above the STN in a cohort of PD patients and to define the volume of tissue activated with antidyskinesia effects. We analyzed the Core Assessment Program for Surgical Interventional Therapies dyskinesia scale, Unified Parkinson's Disease Rating Scale parts III and IV, and other endpoints in 20 patients with interleaving stimulation for management of dyskinesia. Individual models of volume of tissue activated and heat maps were used to identify stimulation sites with antidyskinesia effects. The Core Assessment Program for Surgical Interventional Therapies dyskinesia score in the on medication phase improved 70.9 ± 20.6% from baseline with noninterleaved settings (P < 0.003). With interleaved settings, dyskinesia improved 82.0 ± 27.3% from baseline (P < 0.001) and 61.6 ± 39.3% from the noninterleaved phase (P = 0.006). The heat map showed a concentration of volume of tissue activated dorsally to the STN during the interleaved setting with an antidyskinesia effect. Interleaved deep brain stimulation using the dorsal contacts can directly suppress dyskinesia, probably because of the involvement of the pallidofugal tract, allowing more conservative medication reduction. © 2019 International Parkinson and Movement Disorder Society.

Subthalamic deep brain stimulation aggravates speech problems in Parkinson's disease: Objective and subjective analysis of the influence of stimulation frequency and electrode contact location

BackgroundSpeech disorders, including stuttering and hypophonia, have been reported in patients with Parkinson's disease (PD) after subthalamic deep brain stimulation (STN-DBS). ObjectiveTo evaluate the effect of stimulation frequency or electrode contact location on speech disorders in PD patients with STN-DBS. MethodIn this case-controlled study, we enrolled 50 PD patients with, and 100 PD patients without STN-DBS to compare their vocal intensities, measured by a sound pressure meter, and perceptual speech ratings, obtained from the speech sections of the United Parkinson's Disease Rating Scale (UPDRS) and subjective ratings regarding the impediment of functional communication by stuttering. For patients with STN-DBS, comparisons were made between high-frequency (HFS; 130 Hz), low-frequency (LFS; 80 Hz), and off-stimulation. We also evaluated the effect of electrode contact locations on speech function. ResultsPatients with STN-DBS had decreased vocal intensities and UPDRS scores compared to those without (p < 0.05). Vocal intensity was significantly lower during HFS than during LFS and off-stimulation (both, p < 0.05). Stuttering impeded STN-DBS patients’ communication to greater extent than for those without (p < 0.001). Vocal intensity was lower when active contacts were in the dorsal zone compared to those in the ventral zone (p < 0.05). Only STN-DBS treatment was a predictive factor for low vocal intensity (OR = 9.53, p = 0.04). ConclusionHigh-frequency STN-DBS with dorsal zone contacts can aggravate certain speech problems in PD patients. Therefore, it is important to balance between motor control and speech impairments in these patients.

Chronic Subthalamic Nucleus Stimulation in Parkinson's Disease: Optimal Frequency for Gait Depends on Stimulation Site and Axial Symptoms.

Axial symptoms emerge in a significant proportion of patients with Parkinson's disease (PD) within 5 years of deep brain stimulation (STN-DBS). Lowering the stimulation frequency may reduce these symptoms. The objectives of the current study were to establish the relationship between gait performance and STN-DBS frequency in chronically stimulated patients with PD, and to identify factors underlying variability in this relationship. Twenty-four patients treated chronically with STN-DBS (>4 years) were studied off-medication. The effect of stimulation frequency (40–140 Hz, 20 Hz-steps, constant energy) on gait was assessed in 6 sessions spread over 1 day. Half of the trials/session involved walking through a narrow doorway. The influence of stimulation voltage was investigated separately in 10 patients. Gait was measured using 3D motion capture and axial symptoms severity was assessed clinically. A novel statistical method established the optimal frequency(ies) for each patient by operating on frequency-tuning curves for multiple gait parameters. Narrowly-tuned optimal frequencies (20 Hz bandwidth) were found in 79% of patients. Frequency change produced a larger effect on gait performance than voltage change. Optimal frequency varied between patients (between 60 and 140 Hz). Contact site in the right STN and severity of axial symptoms were independent predictors of optimal frequency (P = 0.009), with lower frequencies associated with more dorsal contacts and worse axial symptoms. We conclude that gait performance is sensitive to small changes in STN-DBS frequency. The optimal frequency varies considerably between patients and is associated with electrode contact site and severity of axial symptoms. Between-subject variability of optimal frequency may stem from variable pathology outside the basal ganglia.

Juvenile Play Behavior in Neonatally Underfed and Sensory Stimulated Wistar Rats

Play development in juvenile rats depends on specific sensory signals integrated at cortical, limbic and brain stem levels to modulate motoric, metabolic, motivational and social responses. Neonatal undernourishment disrupts the morphological and functional organization of the brain for adaptive responses including play performance. These alterations may be restored by preweaning exposure to sensory-enriched environments. This study was designed to determine in four experimental groups, Control (LC), Underfed (LU), Control Ligated/Stimulated (LCS), and Underfed Ligated/Stimulated (LUS), whether changes in juvenile play of neonatally underfed male rats by the nipple-ligated procedure of F0 dams and/or the handling of F1 rats may restore the deficiencies in juvenile play performance. The pinning frequency values in LC, LCS and LUS groups consistently increased until reaching a significant peak between postnatal days (PDs) 25 and 50 and then gradually declining until PD 60, when the play in pairs was significantly higher compared with the play in groups that follows the same sequence but with lower values in the stimulated groups. The results may reflect poor maternal care and lower somatosensory stimulation; and the sensory massage of LU F1 pups compared with the LC, LUS, and LCS rats. Fewer dorsal body contacts occurred in LU and LUS rats when playing in pairs than in groups. Results suggest that although handling has salutary effects on neuronal play structures, the reduced levels of total pinning and dorsal contacts, mainly in the play of rat pairs in LCS vs. LUS groups, were not fully recovered.

On the (Non-)equivalency of monopolar and bipolar settings for deep brain stimulation fMRI studies of Parkinson's disease patients.

The majority of Parkinson's disease patients with deep brain stimulation (DBS) use a monopolar configuration, which presents challenges for EEG and MRI studies. The literature reports algorithms to convert monopolar to bipolar settings. To assess brain responses of Parkinson's disease patients implanted with DBS during fMRI studies using their clinical and presumed equivalent settings using a published conversion recipe. Prospective. Thirteen DBS patients. 1.5T and 3T, fMRI using gradient echo-planar imaging. Patients underwent 30/30sec ON/OFF DBS fMRI scans using monopolar and bipolar settings. To convert to a bipolar setting, the negative contact used for the monopolar configuration remained constant and the adjacent dorsal contact was rendered positive, while increasing the voltage by 30%. fMRI activation/deactivation maps and motor Unified Parkinson's Disease Rating Scale (UPDRS-III) scores were compared for patients in both configurations. T-tests were used to compare UPDRS scores and volumes of tissue activated (VTA) diameters in monopolar and bipolar configurations. The patterns of fMRI activation in the monopolar and bipolar configurations were generally different. The thalamus, pallidum, and visual cortices exhibited higher activation using the patient's clinical settings than the presumed equivalent settings. VTA diameters were lower (7 mm vs. 6.3 mm, P = 0.047) and UPDRS scores were generally higher in the bipolar (33.2 ± 16) than in the monopolar configuration (28.3 ± 17.4), without reaching statistical significance (P > 0.05). Monopolar and bipolar configurations result in different patterns of brain activation while using a previously published monopolar-bipolar conversion algorithm. Clinical benefits may be achieved with varying patterns of brain responses. Blind conversion from one to the other should be avoided for purposes of understanding the mechanisms of DBS. 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.