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Objective:The authors proposed an intraventricular 'floating' electrode inserted in the third ventricle (V3) adjacent to the ventromedian hypothalamus (VMH) in a freely moving Macaca fascicularis to modulate food intake (FI), body fat (BF), body weight (BW) and body mass index (BMI), as a potential treatment of obesity.Methods:Five adult Macaca fascicularis monkeys were implanted stereotactically in the V3 contiguous to the VMH with one deep brain stimulation (DBS) electrode. The study was divided in two phases: (a) acute 24 h-fasting trials: different electrical stimulation parameters were applied to a fasting primate to determine the best combination in reducing FI; and (b) chronic 8-week stimulation trials: three cycles of intraventricular-VMH DBS lasting 8-10 weeks were performed at 130 Hz, 80 Hz (most effective frequency reducing FI) and 30 Hz, respectively. BMI, BW, BF content, skinfolds and hormones were measured during baseline and at the end of each session of stimulation.Results:Acute 24 h-fasting trials: there was a decrease in FI in all subjects at 80 Hz, (11-19%, mean 15%). Chronic 8-week stimulation trials: a significant decrease in BW and BMI was observed in three out of four monkeys at 80 Hz (mean 8±4.4%). Subcutaneous skinfolds were reduced in all four subjects at 80 Hz and slightly increased at 130 Hz. The sham monkey remained stable. No significant adverse effects were recorded.Conclusion:The stimulation of the VMH region through an intraventricular approach might acutely modulate FI and induce a sustained decrease in BW and fat mass in normal non-human primate. [ABSTRACT FROM AUTHOR]

Introduction: Neurocircuits are involved in the motor, cognitive, and affective dysfunctions of multiple brain disorders. Functional segregation into these domains has been widely defined on a fronto- cortical basis. However, despite considerable interaction, these functional domains remain partitioned to some extent at (sub)thalamic levels (1). To map the functional organization of the the frontal cortex (FC), we employ optimal connectivity profiles from successful deep brain stimulation (DBS) electrodes to the same target, which receives input from the entire FC, in four different disorders. Specifically, we identify cortical projection sites that, on a group level, associate with maximal improvements following subthalamic nucleus (STN) DBS in dystonia (DYT), Parkinson's disease (PD), Tourette syndrome (TS) or obsessive-compulsive disorder (OCD). Patients and Methods: Using Lead-DBS (2), stimulation volumes were estimated for six patient cohorts from six centers, each implanted with DBS to the STN for treatment of either DYT (N = 62), PD (N = 51), TS (N = 14), or OCD (N = 19). Via DBS Network Mapping (3) we derived disease-specific structural connections between cortex and STN from a normative connectome (4) that relate to optimal clinical outcomes. Results: Functional organization in the STN and FC was reflected along a caudo-rostral gradient (Fig. 1). Beneficial DBS networks for DYT predominantly projected to the primary motor cortex, while in PD, electrode connectivity to pre- and supplementary motor areas, in TS to the dorsomedial preFC, and in OCD to ventromedial, dorsal anterior cingulate and dorsolateral preFC emerged. Conclusion: Our findings demonstrate the usefulness of DBS to investigate the organizational gradient of frontal network (dys)function. As such, they bear both interest for cognitive neurosciences as well as clinical-translational value for circuit-guided DBS. References 1. Haynes WIA, Haber SN (2013): The organization of prefrontal-subthalamic inputs in primates provides an anatomical substrate for both functional specificity and integration: Implications for basal ganglia models and deep brain stimulation. J Neurosci 33: 4804–4814. 2. Horn A, Li N, Dembek TA, Kappel A, Boulay C, Ewert S, et al. (2019): Lead-DBS v2: Towards a comprehensive pipeline for deep brain stimulation imaging. Neuroimage 184: 293–316. 3. Horn A, Reich M, Vorwerk J, Li N, Wenzel G, Fang Q, et al. (2017): Connectivity predicts deep brain stimulation outcome in Parkinson disease. Ann Neurol 82: 67–78. 4. Wang F, Dong Z, Tian Q, Liao C, Fan Q, Hoge WS, et al. (2021): In vivo human whole-brain Connectom diffusion MRI dataset at 760 µm isotropic resolution. Sci Data 8: 122. Figure Legend: [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction L’accumulation de preuves avant une prise de décision, et la capacité d’attendre avant d’agir, respectivement nommées « impulsivité décisionnelle » et « impulsivité différée », sont des formes du contrôle du comportement, dysfonctionnel dans le trouble obsessionnel compulsif (TOC). Ce travail a exploré les effets de la stimulation cérébrale profonde (SCP) du noyau sous thalamique (NST) chez ces patients et sur ces deux types d’impulsivité. Matériel et méthodes Douze patients souffrant d’un TOC traités par SCP du NST ont été inclus dans une étude randomisée en double aveugle utilisant un design croisé au cours de laquelle chacun a réalisé une évaluation comportementale en condition de stimulation ON et OFF. Leurs performances ont été comparées à celles d’un groupe de 24 sujets témoins sains appariés (âge, sexe). « L’impulsivité différée » était évaluée par la tâche de « temps de réaction en série à quatre choix », requérant une réponse motrice après avoir détecté un stimulus cible, et « l’impulsivité décisionnelle » via le « test des perles » impliquant une décision après un cumul variable d’informations laissé à l’appréciation du sujet. Résultats La tâche de « temps de réaction en série à quatre choix » a montré que les sujets sains avaient un nombre moindre de réponses prématurées que les patients en condition ON ( p = 0,007), différence non retrouvée en condition OFF ( p = 0,073), suggérant une augmentation de « l’impulsivité différée » en ON. Le test des perles a montré que les patients en condition OFF accumulaient davantage de preuves que les sujets sains avant une prise de décision ( p = 0,021), et que cette différence disparaissait en condition ON ( p = 0,017), témoignant d’une augmentation de « l’impulsivité décisionnelle » en ON. Conclusion L’augmentation retrouvée de ces deux types d’impulsivité pourrait être impliquée dans l’effet thérapeutique de la SCP du NST. [ABSTRACT FROM AUTHOR]

Background: Long term effects of subthalamic nucleus (STN) stimulation on cognition, mood, and behaviour are unknown.Objective: This study evaluated the cognitive, mood, and behavioural effects of bilateral subthalamic nucleus deep brain stimulation (STN DBS) in patients with Parkinson's disease (PD) followed up for three years.Methods: A consecutive series of 77 PD patients was assessed before, one, and three years after surgery. Mean (SD) age at surgery was 55 (8). Seven patients died or were lost for follow up. Neuropsychological assessment included a global cognitive scale, memory, and frontal tests. Depression was evaluated using the Beck depression inventory. Assessment of thought disorders and apathy was based on the unified Parkinson's disease rating scale. Reports of the behavioural changes are mainly based on interviews done by the same neuropsychologist at each follow up.Results: Only two cognitive variables worsened (category fluency, total score of fluency). Age was a predictor of decline in executive functions. Depression improved whereas apathy and thought disorders worsened. Major behavioural changes were two transient aggressive impulsive episodes, one suicide, four suicide attempts, one permanent apathy, one transient severe depression, four psychoses (one permanent), and five hypomania (one permanent).Conclusions: Comparing baseline, one year, and three year postoperative assessments, STN stimulation did not lead to global cognitive deterioration. Apathy scores mildly increased. Depression scores mildly improved. Behavioural changes were comparatively rare and mostly transient. Single case reports show the major synergistic effects of both medication and stimulation on mood and behaviour, illustrating the importance of a correct postoperative management. [ABSTRACT FROM AUTHOR]

In our center, a physiotherapist is present in the operative room to bring relief to the Parkinsonian patient during subthalamic nucleus stimulation surgery under local anesthesia. This study searched to determine the causes of pain and suffering during bilateral electrode implantation and to assess the role of physiotherapy. Ninety-two consecutive patients operated on between 2001 and 2004 were included in this retrospective study. A questionnaire with eight items was developed and mailed to the patients. Seventy-five responses to questionnaires were available. All patients except one experienced physical pain and psychological suffering, alleviated by physiotherapy. These preliminary results need to be confirmed in a prospective randomized study. [ABSTRACT FROM AUTHOR]

Before the introduction of high frequency stimulation of the subthalamic nucleus (STN), many disabled tremor dominant parkinsonian patients underwent lesioning or chronic electrical stimulation of the thalamus. We studied the effects of STN stimulation in patients with previous ventral intermediate nucleus (VIM) surgery whose motor state worsened. Fifteen parkinsonian patients were included in this study: nine with unilateral and two with bilateral VIM stimulation, three with unilateral thalamotomy, and one with both unilateral thalamotomy and contralateral VIM stimulation. The clinical evaluation consisted of a formal motor assessment using the Unified Parkinson's Disease Rating Scale (UPDRS) and neuropsychological tests encompassing a 50 point frontal scale, the Mattis Dementia Rating Scale, and the Beck Depression Inventory. The first surgical procedure was performed a mean (SD) of 8 (5) years after the onset of disease. STN implantation was carried out 10 (4) years later, and duration of follow up after beginning STN stimulation was 24 (20) months. The UPDRS motor score, tremor score, difficulties in performance of activities of daily living, and levodopa equivalent daily dose significantly decreased after STN stimulation. Neither axial symptoms nor neuropsychological status significantly worsened after the implantation of the STN electrodes. The parkinsonian motor state is greatly improved by bilateral STN stimulation even in patients with previous thalamic surgery, and STN stimulation is more effective than VIM stimulation in tremor dominant parkinsonian patients. [ABSTRACT FROM AUTHOR]