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BACKGROUND AND OBJECTIVES: The internal capsule is supplied by perforators originating from the internal carotid artery, middle cerebral artery, anterior choroidal artery and anterior cerebral artery. The aim of this study is to examine the vascular anatomy of the internal capsule, along with its related white matter anatomy, in order to prevent potential risks and complications during surgical interventions. METHODS: Twenty injected hemispheres prepared according to the Klingler method were dissected. Dissections were photographed at each stage. The findings obtained from the dissections were illustrated to make them more understandable. Additionally, the origins of the arteries involved in the vascularization of the internal capsule, their distances to bifurcations, and variations in supplying territories have been thoroughly examined. RESULTS: The insular cortex and the branches of the middle cerebral artery on the insula and operculum were observed. Following decortication of the insular cortex, the extreme capsule, claustrum, external capsule, putamen and globus pallidus structures were exposed. The internal capsule is shown together with the lenticulostriate arteries running on the anterior, genu and posterior limbs. Perforators supplying the internal capsule originated from the middle cerebral artery, anterior cerebral artery, internal carotid artery and anterior choroidal artery. The internal capsule's vascular supply varied, with the medial lenticulostriate arteries (MLA) and lateral lenticulostriate arteries (LLA) being the primary arteries. The anterior limb was most often supplied by the MLA, while the LLA and anterior choroidal artery dominated the genu and posterior limb. The recurrent artery of Heubner originated mostly from the A2 segment. The distance from the ICA bifurcation to the origin of the first LLA on M1 is 9.55 ± 2.32 mm, and to the first MLA on A1 is 5.35 ± 1.84 mm. MLA branching from A1 and proximal A2 ranged from 5 to 9, while LLA originating from the MCA ranged from 7 to 12. CONCLUSION: This study provides comprehensive understanding of the arterial supply to the internal capsule by combining white matter dissection. The insights gained from this study can help surgeons plan and execute procedures including oncological, psychosurgical, and vascular more accurately and safely. The illustrations derived from the dissections serve as valuable educational material for young neurosurgeons and other medical professionals.

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Background: Deep brain stimulation (DBS) of the anterior limb of the internal capsule (ALIC) is an emerging treatment for severe, refractory obsessive-compulsive disorder (OCD). The therapeutic effects of DBS are hypothesized to be mediated by direct modulation of a distributed cortico-striato-thalmo-cortical network underlying OCD symptoms. However, the exact underlying mechanism by which DBS exerts its therapeutic effects still remains unclear. Method: In five participants receiving DBS for severe, refractory OCD (3 responders, 2 non-responders), we conducted a DBS On/Off cycling paradigm during the acquisition of functional MRI to determine the network effects of stimulation across a variety of bipolar configurations. We also performed tractography using diffusion-weighted imaging (DWI) to relate the functional impact of DBS to the underlying structural connectivity between active stimulation contacts and functional brain networks. Results: We found that therapeutic DBS had a distributed effect, suppressing BOLD activity within regions such as the orbitofrontal cortex, dorsomedial prefrontal cortex, and subthalamic nuclei compared to non-therapeutic configurations. Many of the regions suppressed by therapeutic DBS were components of the default mode network (DMN). Moreover, the estimated stimulation field from the therapeutic configurations exhibited significant structural connectivity to core nodes of the DMN. Conclusions: Therapeutic DBS for OCD suppresses BOLD activity within a distributed set of regions within the DMN relative to non-therapeutic configurations. We propose that these effects may be mediated by interruption of communication through structural white matter connections surrounding the DBS active contacts.

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Background: Anterior capsulotomy is one of the therapeutic options for refractory obsessive-compulsive disorder (OCD). Safety and efficacy of Gamma Knife Capsulotomy (GKC) have been demonstrated in the past. Objective: To characterize changes induced by GKC using a fixel-based analysis (FBA) and possible predictors of efficacy. Methods: Patients with OCD refractory to other therapies underwent bilateral GKC with 120 Gy as a maximum dose on the anterior limb of the internal capsule (ALIC). The clinical outcome was percent reduction in Yale- Brown Obsessive-Compulsive Scale (Y-BOCS). White Matter changes were analyzed using fixel-based analysis (FBA) for fibre density (FD), fibre-bundle cross-section (FC) and the combination of the two (FDC). Results: Seven patients underwent GKC. Median follow-up was 13 months (range 12-58 months). Mean (±SD) decrease in Y-BOCS score at last follow-up was 61 % ± 35 % with five patients considered as responders. FBA showed a symmetric FD reduction in the ALIC with extension to the anterior fronto-thalamic radiation; a reduction of FC along the superior longitudinal fasciculus (SLF) in both hemispheres with a predominance in the left one. Reductions in FDC were detected predominantly in the right hemisphere, with a similar pattern to FD reductions and associated with a positive correlation (p < 0.05) between Y-BOCS reduction and fibres passing in the ventral part. Conclusions: GKC is safe and efficient in reducing OCD severity in selected patients. Changes induced in white matter by GKC extend over the ALIC. Reduction of fibres passing the ventral part of the right sided ALIC correlates with better results.

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BACKGROUND: The anterior limb of the internal capsule (ALIC) is a white matter structure connecting the prefrontal cortex (PFC) to the brainstem, thalamus, and subthalamic nucleus. It is a target for deep brain stimulation (DBS) for obsessive-compulsive disorder. There is strong interest in improving DBS targeting by using diffusion tractography to reconstruct and target specific ALIC fiber pathways, but this methodology is susceptible to errors and lacks validation. To address these limitations, we developed a novel diffusion tractography pipeline that generates reliable and biologically validated ALIC white matter reconstructions. METHODS: Following algorithm development and refinement, we analyzed 43 control subjects each with 2 sets of 3T MRI data and a subset of 5 controls with 7T data from the Human Connectome Project. We generated 22 segmented ALIC fiber bundles (11 per hemisphere) based on prefrontal PFC regions of interest, and we analyzed the relationships among bundles. RESULTS: We successfully reproduced the topographies established by prior anatomical work using images acquired at both 3T and 7T. Quantitative assessment demonstrated significantly smaller intra-subject variability relative to inter-subject variability for both test and retest groups across all but one PFC region. We examined the overlap between fibers from different PFC regions and a response tract for obsessive-compulsive disorder deep brain stimulation, and we reconstructed the PFC hyperdirect pathway using a modified version of our pipeline. DISCUSSION: Our dMRI algorithm reliably generates biologically validated ALIC white matter reconstructions, allowing for more precise modelling of fibers for neuromodulation therapies.

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OBJECTIVES: Previous studies have shown that microstructural alterations in white matter (WM) could contribute to the symptom manifestation and support the dysconnectivity hypothesis in schizophrenia patients. These alterations were pervasive, non-specific, and reported inconsistently across the literature. This study aimed to specifically investigate the microstructure alterations of the posterior limb of the internal capsule (PLIC) in first-episode, drug-naive schizophrenia patients. Utilizing a multicompartmental biophysical model, we further explored the correlation between these alterations and syndrome scale scores. METHODS: Thirty-two individuals with first-episode, drug-naive schizophrenia (FES) and thirty demographically matched healthy controls were enrolled. High-resolution multi-shell diffusion MRI data were collected, followed by the application of a three-compartment Neurite Orientation Dispersion and Density Imaging (NODDI) model to scrutinize the alterations in white matter microstructure. Changes in sensory and motor fibers within the PLIC were specifically focused on. Additionally, the correlation between these pathological changes and scores on the Positive and Negative Syndrome Scale (PANSS) was investigated. RESULTS: The Neurite density index (NDI) in the left PLIC was significantly lower in FES patients compared to healthy individuals, and positively correlated with PANSS positive syndrome scores (r = 0.0379, p = 0.046). In the sensory component (left superior thalamic radiation within PLIC, STR_P), the NDI was significantly elevated (p < 0.0001). Conversely, the NDI in the motor component (left corticospinal tract within PLIC, CST_P) was reduced (p = 0.007) in FES patients compared to healthy individuals, and strongly correlated with PANSS positive syndrome scores (p < 0.020) and PANSS total scores (p < 0.045). Moreover, the NDI deviation of STR from total PLIC (fSTR_P) and NDI deviation in STR_P and CST_P compared to PLIC region (fPLIC) were significantly higher in FES patients than in healthy controls (p < 0.00001), with an area under the curve (AUC) of fPLIC reaching 0.872. CONCLUSION: The study's findings provided new insights into the discrepancy of white matter microstructure changes associated with the sensory and motor fibers in the PLIC region in FES patients. These results contribute to the growing body of evidence suggesting that WM microstructural alterations play a critical role in schizophrenia pathophysiology.

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The nucleus accumbens (NAc) and the anterior limb of internal capsule (ALIC) are effective targets for treating addiction using deep brain stimulation (DBS). However, there have been no reports on the electrophysiological characteristics of addiction nuclei at the single-cell level in humans. This study aimed to investigate the electrical activity characteristics of neurons in the NAc and ALIC using microelectrode recording (MER) during DBS surgery in patients with addiction, and six patients with addiction were included (five with heroin addiction and one with alcohol addiction). The microelectrode recording trajectories were reconstructed and recording sites at different depths were determined by merging the pre- and post-operative images in the FrameLink system. The results showed that among the 256 neurons, 204 (80 %) were burst neurons. NAc neurons accounted for the majority (57 %), and the mean firing rate (MFR) was the highest (1.94 Hz). ALIC neurons accounted for the least (14 %), and MFR was the lowest (0.44 Hz). MFR increased after entering the NAc and decreased after entering the ALIC. In the patients with addiction treated using DBS, the single-cell level electrophysiological characteristics of the different nuclei were found to be distinct along the surgical trajectory.

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Introduction: Deep cavernomas of eloquent areas, located in the region of the basal nuclei and thalamus, account for 9 to 36% of these encephalic vascular malformations. Internal capsule cavernomas are particularly challenging, as they are surrounded by important projection fibers and their manipulation can lead to permanent deficits. To demonstrate through surgical cases that cavernomas of the internal capsule can be approached by frontal craniotomy, via the superior frontal sulcus, in a curative manner and with low morbidity. Methods: We presented two cases of cavernomas of the internal capsule operated, whose treatment was microsurgical resection via frontal craniotomy and access to the lesion via the superior frontal sulcus, described step-by-step. To elucidate the rationale behind the decision, we used preoperative images with an emphasis on the patients' tractography and the importance of comparing these images with anatomical specimens dissected in the neuroanatomy and microsurgery laboratory. Results: The two cases of internal capsule cavernomas, one in the anterior limb and the other in the posterior limb, were treated surgically via the superior frontal sulcus. Discussion: Both patients showed radiological cure and clinical improvement in the post-operative segment. The patient consented to the procedure and to the publication of his/her image. Treatment of internal capsule cavernomas via the superior frontal sulcus has proven to be a safe and effective option.

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The internal capsule (IC) is a vital brain structure housing descending and ascending fiber tracts, with traditional assumptions about the corticobulbar and corticospinal tracts descending through the genu and anterior third of the posterior limb of internal capsule (PLIC), respectively. However, observations of IC infarctions reveal that symptoms often deviate from the expected fiber pattern, prompting a deeper exploration of these complexities. The posterior limb of the IC receives its blood supply from the lenticulostriate branches of the middle cerebral artery and the anterior choroidal artery (AChA). AChA infarctions present a diverse array of symptoms beyond the classic triad, reflecting the intricate vascular supply and lesion patterns within this region. We present a case of a 74-year-old male farmer with right-hand dominance, who experienced a fall resulting in head and right lower limb injuries. Subsequently, he developed weakness in his left upper and lower limbs, facial deviation, slurred speech, and swelling in the right lower limb. Following these symptoms, his family promptly brought him to the hospital on November 30, 2023. Extensive investigations, including magnetic resonance imaging (MRI), revealed a hyper-acute infarct in the posterior limb of the left IC. The patient was admitted to the intensive care unit (ICU) for three days and later shifted to the neurology ward where medical management was commenced, including physiotherapy protocol that was started on December 2, 2023. Physiotherapy interventions were designed to address the patient's weakness, altered sensation, and diminished reflexes. Therapeutic goals focused on preventing complications, improving posture, enhancing range of motion (ROM), and mitigating breathing difficulties and mobility issues. The physiotherapy aimed to enhance the patient's overall physical and mental well-being, emphasizing independence and improved quality of life. Regular assessments and adjustments to the therapeutic interventions were made based on the patient's progress. This case underscores the importance of tailored physiotherapy interventions in addressing the diverse manifestations of IC infarctions, contributing to a comprehensive understanding of rehabilitation strategies in neurologically compromised individuals.

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BACKGROUND: The prognosis of patients with thalamic hemorrhage is poor, and their long-term neurological impairment is heavy, which seriously affects their work and life.To comparatively analyse the efficacy and prognosis of patients with moderate hemorrhage in the thalamic region who underwent conservative treatment, stereotactic puncture surgery and neuroendoscopic surgery. METHOD: This study retrospectively analyzed hospitalization data from 139 adult patients with moderate-volume cerebral hemorrhage in the thalamo-endocapsular region. They were categorized into a stereotactic group (39cases), a neuroendoscopic group (36cases), and a conventional conservative group (64cases). Logistic regression analysis was used to assess risk factors for severe neurological deficits in patients. Multivariate regression modeling was used to compare the correlation of severe neurological deficits among the three groups of patients. RESULTS: Patients with thalamic moderate-volume cerebral hemorrhage had statistically significantly higher Assessment of Daily Living (ADL) scores in the stereotactic surgery group than in the conservative treatment group and the neuroendoscopic surgery group after 6 months of treatment (p< 0.001).The amount of residual hematoma was significantly lower in the surgery groups than in the conservative treatment group at 3 days, 7 days, and 2 weeks after the onset of the disease (P< 0.001).In multivariate logistic regression analyses, after adjusting for all covariates, the odds ratios for severe neurologic dysfunction in the stereotactic group and the neuroendoscopy group were, respectively, OR: 0.37 (0.12-0.87), P< 0.001 and 0.42 (0.23-1.13), P=0.361). CONCLUSION: In patients with moderate volume cerebral hemorrhage in the thalamus-inner capsule region cerebral hemorrhage, patients treated with stereotactic surgery combined with early hyperbaric oxygen therapy may have better long-term neurological recovery compared with conservative and neuroendoscopic surgical treatments.

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We report a case of isolated left abducens nerve palsy accompanying a right thalamic infarct. The patient, a 43-year-old Malay male with newly diagnosed hypertension, diabetes mellitus, and dyslipidemia, initially reported binocular diplopia on left lateral gaze persisting for five weeks. Subsequently, he experienced acute left-sided body weakness and slurred speech for over one day. Clinical examination revealed restricted left eye lateral gaze (-3) with no relative afferent pupillary defect. Additionally, decreased power (4/5) was noted in the left upper and lower limbs. Brain magnetic resonance imaging (MRI) revealed restricted diffusion in the right thalamus extending to the right posterior internal capsule, left anterior cingulate gyrus, and left caudate nucleus. The patient was initiated on antiplatelet, antihypertensive, and oral hypoglycemic agents, resulting in symptom improvement. This rare neuroophthalmological finding has not been reported previously.

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BACKGROUND: The efficacy of surgical intervention in ameliorating long-term prognosis for moderate volume of cerebral hemorrhage in the thalamus-internal capsule region remains unsubstantiated by clinical investigations. Consequently, the acquisition of credible evidence is imperative to authenticate the effectiveness of these methodologies. METHODS: One hundred and three eligible patients with moderate-volume thalamus-internal capsule region cerebral hemorrhage. Twenty-seven pairs of successful matches after using the 1:1 propensity score matching method, totaling 54 patients, were analyzed. The short- and long-term treatment outcomes of patients in the stereotactic surgery and conservative treatment groups were compared. The prognosis of the 2 groups of patients was analyzed by logistic regression analysis and model comparison. RESULTS: The primary outcome of this study was to assess the assessment of daily living scores after 6 months of treatment. Based on the analysis of this study, the assessment of daily living of the surgical group were significantly higher than those of the conservative treatment group after 6 months of treatment (P < 0.001), and the difference was statistically significant. The amount of residual hematoma was significantly lower in the stereotactic surgery group than in the conservative treatment group at 3 days, 7 days, and 2 weeks after the onset of the disease (P < 0.001), and the complication rate was lower than the conservative treatment group (P < 0.05). Univariate logistic regression showed that the risk of severe neurological dysfunction for patients in the surgery group was (odds ratio -0.27, 95% confidence interval: 0.08-0.86, P < 0.05). In multivariate logistic regression analysis, the odds ratio was 0.29 (95% confidence interval: 0.09-0.96, P < 0.05) after adjusting for all covariates. CONCLUSIONS: For moderate-volume thalamus-internal capsule region cerebral hemorrhage, stereotactic paracentesis has the advantage of a shorter hospital stay and a lower complication rate than conservative treatment. Moreover, it yields superior outcomes in terms of daily living assessment scores after six months of treatment and enhanced neurological recovery.

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Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system, characterized by remyelination failure and axonal dysfunction. Remyelination by oligodendrocytes is critical for improvement of neurological deficits associated with demyelination. Rodent models of demyelination are frequently used to develop and evaluate therapies for MS. However, a suitable mouse model for assessing remyelination-associated recovery of motor functions is currently unavailable. In this review, we describe the development of the mouse model of internal capsule (IC) demyelination by focal injection of lysolecithin into brain and its application in the evaluation of drugs for demyelinating diseases. This mouse model exhibits motor deficits and subsequent functional recovery accompanying IC remyelination. Notably, this model shows enhancement of functional recovery as well as tissue regeneration when treated with clemastine, a drug that promotes remyelination. The IC demyelination mouse model should contribute to the development of novel drugs that promote remyelination and ameliorate neurological deficits in demyelinating diseases.

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A 58-year-old, right-handed man noticed difficulty in typing and speech. On day 3 after onset, the day of admission, he had frontal lobe dysfunction including verbal fluency impairment and impairment of recent memory, although he did not have apraxia or visual agnosia. Moreover, he had difficulty typing in romaji, especially words containing contracted or double consonant sounds, although he was able to do this before onset by visually checking the keyboard. He had mild dysgraphia. MRI showed an infarct in the genu and posterior limb of the left internal capsule. SPECT revealed low-uptake lesions in the left frontal lobe. In the present case, we consider that the subcortical infarction disrupted the network between the thalamus and frontal lobe, resulting in dystypia due to difficulty with recalling romaji spelling.

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BACKGROUND: Deep brain stimulation (DBS) is a promising treatment option for treatment-refractory obsessive-compulsive disorder (OCD). Several stimulation targets have been used, mostly in and around the anterior limb of the internal capsule and ventral striatum. However, the precise target within this region remains a matter of debate. METHODS: Here, we retrospectively studied a multicenter cohort of 82 patients with OCD who underwent DBS of the ventral capsule/ventral striatum and mapped optimal stimulation sites in this region. RESULTS: DBS sweet-spot mapping performed on a discovery set of 58 patients revealed 2 optimal stimulation sites associated with improvements on the Yale-Brown Obsessive Compulsive Scale, one in the anterior limb of the internal capsule that overlapped with a previously identified OCD-DBS response tract and one in the region of the inferior thalamic peduncle and bed nucleus of the stria terminalis. Critically, the nucleus accumbens proper and anterior commissure were associated with beneficial but suboptimal clinical improvements. Moreover, overlap with the resulting sweet- and sour-spots significantly estimated variance in outcomes in an independent cohort of 22 patients from 2 additional DBS centers. Finally, beyond obsessive-compulsive symptoms, stimulation of the anterior site was associated with optimal outcomes for both depression and anxiety, while the posterior site was only associated with improvements in depression. CONCLUSIONS: Our results suggest how to refine targeting of DBS in OCD and may be helpful in guiding DBS programming in existing patients.

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INTRODUCTION: A bilateral anterior capsulotomy effectively treats refractory obsessive-compulsive disorder (OCD). We investigated the geometry of lesions and disruption of white matter pathways within the anterior limb of the internal capsule (ALIC) in patients with different outcomes. METHODS: In this retrospective study, we analyzed data from 18 patients with refractory OCD who underwent capsulotomies. Patients were grouped into "responders" and "nonresponders" based on the percentage of decrease in the Yale-Brown Obsessive-Compulsive Scale (YBOCS) after surgery. We investigated neurobehavioral adverse effects and analyzed the overlap between lesions and the ventromedial prefrontal (vmPFC) and dorsolateral prefrontal (dlPFC) pathways. Probabilistic maps were constructed to investigate the relationship between lesion location and clinical outcomes. RESULTS: Of the 18 patients who underwent capsulotomies, 12 were responders (>35% improvement in YBOCS), and six were nonresponders. The vmPFC pathway was more involved than the dlPFC pathway in responders (p = 0.01), but no significant difference was observed in nonresponders (p = 0.10). The probabilistic voxel-wise efficacy map showed a relationship between ventral voxels within the ALIC with symptom improvement. Weight gains occurred in 11/18 (61%) patients and could be associated with medial voxels within the ALIC. CONCLUSION: The optimal outcome after capsulotomy in refractory OCD is linked to vmPFC disruption in the ALIC. Medial voxels within the ALIC could be associated with weight gains following capsulotomy.

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Echinococcosis is a zoonotic parasitic disease caused by Escherichia larvae. It frequently involves the liver (70%-75%), followed by the lungs (15%-20%), and occasionally the brain, heart, spleen, bone, and other organs. The main pathogenic forms of human echinococcosis currently include cystic echinococcosis (CE) and alveolar echinococcosis (AE). CE is globally distributed, while the distribution of AE is generally restricted to the northern hemisphere. In China, CE accounts for 75% of all echinococcosis cases. With rapid advances in surgical techniques in recent decades, the surgical strategy for CE has changed, especially with the continuous improvement of surgical methods and the expansion of surgical contraindications. To further understand the changes in surgical treatment strategies for hepatic CE, we interpreted and analyzed the existing literature addressing the surgical treatment of hepatic CE both domestically and abroad and briefly summarized them in chronological order. This review aims to provide a deeper understanding of the progress in the surgical treatment of hepatic CE to provide clearer avenues for its clinical diagnosis and treatment.

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Introduction: Around 25% of patients with obsessive-compulsive disorder (OCD) do not respond to medication or psychotherapy, producing significant impairment and treatment challenges. Deep Brain Stimulation (DBS) has been shown in multiple blinded trials to be a safe and durable emerging option for treatment-refractory OCD. Intraoperative device interrogation offers a theoretical anchor for starting outpatient DBS programming; however, no definitive post-operative programming algorithm for psychiatrists exists currently. Case: Here we present a 58-year-old female with childhood-onset, severe, intractable OCD with multiple failed trials of psychotherapy, medication, and electroconvulsive therapy. After interdisciplinary evaluation, she underwent bilateral electrode implantation targeting the anterior limb of the internal capsule, nucleus accumbens (ALIC/NAc). Intraoperative interrogation afforded sparse information about a preferred lead contact or current density target. Subsequent outpatient interrogation consisted of systematic and independent mapping using monopolar cathodic stimulation with constant current. Modulating bipolar and triple monopolar configurations, amplitude, and pulse width all failed to induce observable effects. Given negligible interrogation feedback, we created an electrical field through the ALIC bilaterally, using the three most ventral contacts to create triple monopoles, with a long pulse width and moderate amperage. Conclusion: Three months post-programming, the patient reported significant improvement in OCD symptoms, particularly checking behaviors, with response sustained over the next several months. As with our case, the majority of DBS lead contacts do not induce affective or physiological markers in patients, complicating programming optimization. Here, we discuss an approach to titrating various stimulation parameters and purported mechanisms of physiological markers in DBS for OCD.