Electrical stimulation in anterior limbs of internal capsules in patients with obsessive-compulsive disorder

Application of Deep Brain Stimulation for Treatment-resistant Obsessive Compulsive Disorder: Current Status and Future Perspectives in Japan

As in many Western countries, deep brain stimulation (DBS) is already being used daily in Japan to clinically treat neurological diseases such as Parkinson’s disease, essential tremor, and dystonia. Additionally, in both Europe and the United States, numerous case reports as well as multicenter randomized controlled trials have examined its use for treatment-refractory mental illnesses such as obsessive compulsive disorder (OCD) and major depressive disorder. Based on a number of the reports, the European Union (EU) and the USA Food and Drug Administration (FDA) granted limited approval of DBS for treatment-resistant OCD in 2009. Furthermore, a systematic review and meta-analysis in 2015 showed that DBS therapy for patients with treatment-resistant OCD had efficacy and was safe. Unlike the EU and the USA, DBS is not used to treat OCD or other psychiatric disorders in Japan, even though people with treatment-resistant OCD and their physicians and families urgently need additional treatments. This situation results from the “Resolution of total denial for psychosurgery,” which the Japanese Society of Psychiatry and Neurology adopted in 1975. We believe that the appropriateness of using DBS for treating psychiatric disorders including OCD should be considered after thorough discussion and consideration based on accurate and objective understanding. Currently, the field of psychiatry in Japan seems to lack scientific consideration as well as scientific understanding in this area. Under these circumstances, we hope that this review article will help psychiatrists and other relevant parties in Japan to gain an accurate and scientific understanding of DBS.

Wireless Programmable Recording and Stimulation of Deep Brain Activity in Freely Moving Humans

Uncovering the neural mechanisms underlying human natural ambulatory behavior is a major challenge for neuroscience. Current commercially available implantable devices that allow for recording and stimulation of deep brain activity in humans can provide invaluable intrinsic brain signals but are not inherently designed for research and thus lack flexible control and integration with wearable sensors. We developed a mobile deep brain recording and stimulation (Mo-DBRS) platform that enables wireless and programmable intracranial electroencephalographic recording and electrical stimulation integrated and synchronized with virtual reality/augmented reality (VR/AR) and wearables capable of external measurements (e.g., motion capture, heart rate, skin conductance, respiration, eye tracking, and scalp EEG). When used in freely moving humans with implanted neural devices, this platform is adaptable to ecologically valid environments conducive to elucidating the neural mechanisms underlying naturalistic behaviors and to the development of viable therapies for neurologic and psychiatric disorders.

The Effect of High-Frequency Electrical Stimulation of Bilateral Nucleus Accumbens on the Behavior of Morphine-Induced Conditioned Place Preference Rats at Extinction and Reinstatement Phases

Objective

To explore the optimal time points for deep brain stimulation (DBS) on the treatment of morphine addiction and its possible mechanisms by investigating how high-frequency stimulation (HFS) in bilateral nucleus accumbens (NAc) at different time points influences the addictive behaviors of rats with drug addiction.

Methods

The rats were randomly divided into extinction stimulation group (n = 20) and postextinction stimulation group (n = 20). Ten rats in the extinction stimulation group were treated using 120 Hz HFS during extinction stage while another 10 rats with pseudostimulation were served as control group. The CPP scores were evaluated at the second day after intervention, with total 9 sections accomplished. The CPP scores were evaluated at the second day of the intervention. In the postextinction stimulation group, 120 Hz HFS was intervened during the postextinction stage in 10 experimental rats and pseudostimulation was performed in 10 control rats. Stimulation was performed for 7 days continuously, and a small dose of morphine was administrated to induce relapse after the postextinction period.

Results

During the extinction phase, CPP scores after HFS were significantly higher. During the postextinction phase, relapse CPP scores after HFS were dramatically lower.

Conclusion

HFS of bilateral NAc inhibits the extinction of addictive behavior during the extinction phase, and HFS during the postextinction period suppresses relapse of drug seeking behavior.

Case Report of Dual-Site Neurostimulation and Chronic Recording of Cortico-Striatal Circuitry in a Patient With Treatment Refractory Obsessive Compulsive Disorder

Psychiatric disorders are increasingly understood as dysfunctions of hyper- or hypoconnectivity in distributed brain circuits. A prototypical example is obsessive compulsive disorder (OCD), which has been repeatedly linked to hyper-connectivity of cortico-striatal-thalamo-cortical (CSTC) loops. Deep brain stimulation (DBS) and lesions of CSTC structures have shown promise for treating both OCD and related disorders involving over-expression of automatic/habitual behaviors. Physiologically, we propose that this CSTC hyper-connectivity may be reflected in high synchrony of neural firing between loop structures, which could be measured as coherent oscillations in the local field potential (LFP). Here we report the results from the pilot patient in an Early Feasibility study (https://clinicaltrials.gov/ct2/show/NCT03184454) in which we use the Medtronic Activa PC+ S device to simultaneously record and stimulate in the supplementary motor area (SMA) and ventral capsule/ventral striatum (VC/VS). We hypothesized that frequency-mismatched stimulation should disrupt coherence and reduce compulsive symptoms. The patient reported subjective improvement in OCD symptoms and showed evidence of improved cognitive control with the addition of cortical stimulation, but these changes were not reflected in primary rating scales specific to OCD and depression, or during blinded cortical stimulation. This subjective improvement was correlated with increased SMA and VC/VS coherence in the alpha, beta, and gamma bands, signals which persisted after correcting for stimulation artifacts. We discuss the implications of this research, and propose future directions for research in network modulation in OCD and more broadly across psychiatric disorders.

Appraising the effectiveness of electrical and magnetic brain stimulation techniques in acute major depressive episodes: an umbrella review of meta-analyses of randomized controlled trials

Electrical and magnetic brain stimulation techniques present distinct mechanisms and efficacy in the acute treatment of depression. This was an umbrella review of meta-analyses of randomized controlled trials of brain stimulation techniques for managing acute major depressive episodes. A systematic review was performed in the PubMed/MEDLINE databases from inception until March 2020. We included the English language meta-analysis with the most randomized controlled trials on the effects of any brain stimulation technique vs. control in adults with an acute depressive episode. Continuous and dichotomous outcomes were assessed. A Measurement Tool to Assess Systematic Reviews-2 was applied and the credibility of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation framework. Seven meta-analyses were included (5,615 patients), providing evidence for different modalities of brain stimulation techniques. Three meta-analyses were evaluated as having high methodological quality, three as moderate, and one as low. The highest quality of evidence was found for high frequency-repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation, and bilateral rTMS. There is strong clinical research evidence to guide future clinical use of some techniques. Our results confirm the heterogeneity of the effects across these techniques, indicating that different mechanisms of action lead to different efficacy profiles.

Endovascular deep brain stimulation: Investigating the relationship between vascular structures and deep brain stimulation targets

BACKGROUND

Endovascular delivery of current using 'stentrodes' - electrode bearing stents - constitutes a potential alternative to conventional deep brain stimulation (DBS). The precise neuroanatomical relationships between DBS targets and the vascular system, however, are poorly characterized to date.

OBJECTIVE

To establish the relationships between cerebrovascular system and DBS targets and investigate the feasibility of endovascular stimulation as an alternative to DBS.

METHODS

Neuroanatomical targets as employed during deep brain stimulation (anterior limb of the internal capsule, dentatorubrothalamic tract, fornix, globus pallidus pars interna, medial forebrain bundle, nucleus accumbens, pedunculopontine nucleus, subcallosal cingulate cortex, subthalamic nucleus, and ventral intermediate nucleus) were superimposed onto probabilistic vascular atlases obtained from 42 healthy individuals. Euclidian distances between targets and associated vessels were measured. To determine the electrical currents necessary to encapsulate the predefined neurosurgical targets and identify potentially side-effect inducing substrates, a preliminary volume of tissue activated (VTA) analysis was performed.

RESULTS

Six out of ten DBS targets were deemed suitable for endovascular stimulation: medial forebrain bundle (vascular site: P1 segment of posterior cerebral artery), nucleus accumbens (vascular site: A1 segment of anterior cerebral artery), dentatorubrothalamic tract (vascular site: s2 segment of superior cerebellar artery), fornix (vascular site: internal cerebral vein), pedunculopontine nucleus (vascular site: lateral mesencephalic vein), and subcallosal cingulate cortex (vascular site: A2 segment of anterior cerebral artery). While VTAs effectively encapsulated mfb and NA at current thresholds of 3.5 V and 4.5 V respectively, incremental amplitude increases were required to effectively cover fornix, PPN and SCC target (mean voltage: 8.2 ± 4.8 V, range: 3.0-17.0 V). The side-effect profile associated with endovascular stimulation seems to be comparable to conventional lead implantation. Tailoring of targets towards vascular sites, however, may allow to reduce adverse effects, while maintaining the efficacy of neural entrainment within the target tissue.

CONCLUSIONS

While several challenges remain at present, endovascular stimulation of select DBS targets seems feasible offering novel and exciting opportunities in the neuromodulation armamentarium.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

Neuromodulation in Psychiatric disorders: Experimental and Clinical evidence for reward and motivation network Deep Brain Stimulation: Focus on the medial forebrain bundle

Deep brain stimulation (DBS) in psychiatric illnesses has been clinically tested over the past 20 years. The clinical application of DBS to the superolateral branch of the medial forebrain bundle in treatment-resistant depressed patients-one of several targets under investigation-has shown to be promising in a number of uncontrolled open label trials. However, there are remain numerous questions that need to be investigated to understand and optimize the clinical use of DBS in depression, including, for example, the relationship between the symptoms, the biological substrates/projections and the stimulation itself. In the context of precision and customized medicine, the current paper focuses on clinical and experimental research of medial forebrain bundle DBS in depression or in animal models of depression, demonstrating how clinical and scientific progress can work in tandem to test the therapeutic value and investigate the mechanisms of this experimental treatment. As one of the hypotheses is that depression engenders changes in the reward and motivational networks, the review looks at how stimulation of the medial forebrain bundle impacts the dopaminergic system.

Functional Magnetic Resonance Imaging Correlates of Ventral Striatal Deep Brain Stimulation for Poststroke Pain

OBJECTIVE

Deep brain stimulation (DBS) for pain has largely been implemented in an uncontrolled manner to target the somatosensory component of pain, with research leading to mixed results. We have previously shown that patients with poststroke pain syndrome who were treated with DBS targeting the ventral striatum/anterior limb of the internal capsule (VS/ALIC) demonstrated a significant improvement in measures related to the affective sphere of pain. In this study, we sought to determine how DBS targeting the VS/ALIC modifies brain activation in response to pain.

MATERIALS AND METHODS

Five patients with poststroke pain syndrome who were blinded to DBS status (ON/OFF) and six age- and sex-matched healthy controls underwent functional magnetic resonance imaging (fMRI) measuring blood oxygen level-dependent activation in a block design. In this design, each participant received heat stimuli to the affected or unaffected wrist area. Statistical comparisons were performed using fMRI z-maps.

RESULTS

In response to pain, patients in the DBS OFF state showed significant activation (p < 0.001) in the same regions as healthy controls (thalamus, insula, and operculum) and in additional regions (orbitofrontal and superior convexity cortical areas). DBS significantly reduced activation of these additional regions and introduced foci of significant inhibitory activation (p < 0.001) in the hippocampi when painful stimulation was applied to the affected side.

CONCLUSIONS

These findings suggest that DBS of the VS/ALIC modulates affective neural networks.

Neural correlates of improvements in personality and behavior following a neurological event

Research on changes in personality and behavior following brain damage has focused largely on negative outcomes, such as increased irritability, moodiness, and social inappropriateness. However, clinical observations suggest that some patients may actually show positive personality and behavioral changes following a neurological event. In the current work, we investigated neuroanatomical correlates of positive personality and behavioral changes following a discrete neurological event (e.g., stroke, benign tumor resection). Patients (N = 97) were rated by a well-known family member or friend on five domains of personality and behavior: social behavior, irascibility, hypo-emotionality, distress, and executive functioning. Ratings were acquired during the chronic epoch of recovery, when psychological status was stabilized. We identified patients who showed positive changes in personality and behavior in one or more domains of functioning. Lesion analyses indicated that positive changes in personality and behavior were most consistently related to damage to the bilateral frontal polar regions and the right anterior dorsolateral prefrontal region. These findings support the conclusion that improvements in personality and behavior can occur after a neurological event, and that such changes have systematic neuroanatomical correlates. Patients who showed positive changes in personality and behavior following a neurological event were rated as having more disturbed functioning prior to the event. Our study may be taken as preliminary evidence that improvements in personality and behavior following a neurological event may involve dampening of (premorbidly) more extreme expressions of emotion.

Long-Term Deep Brain Stimulation in Treatment-Resistant Obsessive-Compulsive Disorder: Outcome and Quality of Life at Four to Eight Years Follow-Up

BACKGROUND

Obsessive compulsive disorder (OCD) is a severe disabling disease, and around 10% of patients are considered to be treatment-resistant (tr) in spite of guideline-based therapy. Deep brain stimulation (DBS) has been proposed as a promising treatment for patients with trOCD. However, the optimal site for stimulation is still a matter of debate, and clinical long-term follow-up observations including data on quality of life are sparse. We here present six trOCD patients who underwent DBS with electrodes placed in the bed nucleus of the stria terminalis/anterior limb of the internal capsule (BNST/ALIC), followed for four to eight years after lead implantation.

MATERIALS AND METHODS

In this prospective observational study, six patients (four men, two women) aged 32-51 years and suffering from severe to extreme trOCD underwent DBS of the BNST/ALIC. Symptom severity was assessed using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), and quality of life using the World Health Organization Quality of Life assessment scale (WHO-QoL BREF). Follow-up was obtained at least for four years in all patients.

RESULTS

With chronic DBS for four to eight years, four of the six patients had sustained improvement. Two patients remitted and two patients responded (defined as >35% symptom reduction), while the other two patients were considered nonresponders on long-term. Quality of life markedly improved in remitters and responders. We did not observe peri-interventional side effects or adverse effects of chronic stimulation.

CONCLUSIONS

Chronic DBS of ALIC provides long-term benefit up to four to eight years in trOCD, although not all patients take profit. Targeting the BNST was not particularly relevant since no patient appeared to benefit from direct stimulation of the BNST. Quality of life improved in DBS responders, documented by improved QoL scores and, even more important, by regaining of autonomy and improving psychosocial functioning.

A Systematic Review of Deep Brain Stimulation Targets for Obsessive Compulsive Disorder

BACKGROUND

Obsessive compulsive disorder (OCD) is a complex neuropsychiatric disease characterized by obsessions and compulsions. Deep brain stimulation (DBS) has demonstrated efficacy in improving symptoms in medically refractory patients. Multiple targets have been investigated.

OBJECTIVE

To systematically review the current level and quality of evidence supporting OCD-DBS by target region with the goal of establishing a common nomenclature.

METHODS

A systematic literature review was performed using the PubMed database and a patient/problem, intervention, comparison, outcome search with the terms "DBS" and "OCD." Of 86 eligible articles that underwent full-text review, 28 were included for review. Articles were excluded if the target was not specified, the focus on nonclinical outcomes, the follow-up period shorter than 3 mo, or the sample size smaller than 3 subjects. Level of evidence was assigned according to the American Association of Neurological Surgeons/Congress of Neurological Surgeons joint guideline committee recommendations. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Selected publications included 9 randomized controlled trials, 1 cohort study, 1 case-control study, 1 cross-sectional study, and 16 case series. Striatal region targets such as the anterior limb of the internal capsule, ventral capsule/ventral striatum, and nucleus accumbens were identified, but stereotactic coordinates were similar despite differing structural names. Only 15 of 28 articles included coordinates.

CONCLUSION

The striatal area is the most commonly targeted region for OCD-DBS. We recommend a common nomenclature based on this review. To move the field forward to individualized therapy, active contact location relative to stereotactic coordinates and patient specific anatomical and clinical variances need to be reported.

The Bed Nucleus of the Stria Terminalis: Translational Deep Brain Stimulation to Reduce Anxiety

Recent clinical evidence has put forward a new region of interest for the treatment of psychiatric disorders. Deep brain stimulation in the bed nucleus of the stria terminalis (BST) significantly attenuates symptoms in patients suffering from severe, treatment-resistant obsessive-compulsive disorder (OCD). The BST is not typically implicated in OCD neuropsychopathology but is certainly not an unknown in the field of emotional learning and memory. Substantial evidence supports its involvement in anxiety responses, particularly to ambiguous threats. This seems consistent with the intolerance of uncertainty and tendency to overestimate danger, which fuel obsessions and compulsions in many patients with OCD. Translational research in rodents can help to obtain a deeper understanding of the effects of high-frequency electrical stimulation in the BST on anxiety, which may be valuable to improve treatment for psychiatric patients.

Deep brain stimulation: current challenges and future directions

The clinical use of deep brain stimulation (DBS) is among the most important advances in the clinical neurosciences in the past two decades. As a surgical tool, DBS can directly measure pathological brain activity and can deliver adjustable stimulation for therapeutic effect in neurological and psychiatric disorders correlated with dysfunctional circuitry. The development of DBS has opened new opportunities to access and interrogate malfunctioning brain circuits and to test the therapeutic potential of regulating the output of these circuits in a broad range of disorders. Despite the success and rapid adoption of DBS, crucial questions remain, including which brain areas should be targeted and in which patients. This Review considers how DBS has facilitated advances in our understanding of how circuit malfunction can lead to brain disorders and outlines the key unmet challenges and future directions in the DBS field. Determining the next steps in DBS science will help to define the future role of this technology in the development of novel therapeutics for the most challenging disorders affecting the human brain.

Brain Stimulation in Obsessive-Compulsive Disorder (OCD): A Systematic Review

Background

Obsessive-compulsive disorder (OCD) is a highly prevalent, severe, and chronic disease. There is a need for alternative strategies for treatment-resistant OCD.

Objective

This review aims to assess the effect of brain stimulation techniques in OCD.

Method

We included papers published in peer-reviewed journals dealing with brain stimulation techniques in OCD. We conducted treatment-specific searches for OCD (Technique AND ((randomized OR randomised) AND control* AND trial) AND (magnetic AND stimulation OR (rTMS OR dTMS)) AND (obsess* OR compuls* OR OCD)) on six databases, i.e., PubMed, Cochrane, Scopus, CINAHL, PsycINFO, and Web of Science to identify randomised controlled trials and ClinicalTrials.gov for possible additional results.

Results

Different add-on stimulation techniques could be effective for severely ill OCD patients unresponsive to drugs and/or behavioural therapy. Most evidence regarded deep brain stimulation (DBS) and transcranial magnetic stimulation (TMS), while there is less evidence regarding transcranial direct current stimulation (tDCS), electroconvulsive therapy, and vagus nerve stimulation (for these last two there are no sham-controlled studies). Low-frequency TMS may be more effective over the supplementary motor area or the orbitofrontal cortex. DBS showed best results when targeting the crossroad between the nucleus accumbens and the ventral capsule or the subthalamic nucleus. Cathodal tDCS may be better than anodal in treating OCD. Limitations. We had to include methodologically inconsistent underpowered studies.

Conclusion

Different brain stimulation techniques are promising as an add-on treatment of refractory OCD, although studies frequently reported inconsistent results. TMS, DBS, and tDCS could possibly find some use with adequate testing, but their standard methodology still needs to be established.

Deep brain stimulation for obsessive-compulsive disorder: A systematic review of randomised controlled trials

Deep brain stimulation (DBS) is considered a promising intervention for treatment-resistant obsessive-compulsive disorder (trOCD). We conducted a systematic search to investigate the efficacy and safety of DBS for OCD. Primary outcomes included the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), adverse events (AE), and quality of life. We assessed affective state, global functioning, cognition, and tolerability as secondary outcomes. Eight studies comprising 80 patients with trOCD were analysed both individually and collectively. We found a pooled mean reduction in Y-BOCS of 38.68 %, indicating DBS could be considered an effective therapy for trOCD. Most AE were mild and transient, however there were five severe surgery-related AE: intracerebral haemorrhage in three patients and infection in two. Mood-related serious AE were one completed suicide, three suicide attempts in two patients, and suicidal thoughts and depression in four. Despite this, affective state improved following stimulation. Despite being limited by significant heterogeneity across studies, our review has shown DBS to be an effective treatment in otherwise trOCD. There is a need to standardise study methodology in future research.

Cognitive Task Performance During Titration Predicts Deep Brain Stimulation Treatment Efficacy: Evidence From a Case Study

Device titration is a major challenge when using deep brain stimulation (DBS) to treat behavioral disorders. Unlike in movement disorders, there is no reliable real-time clinical feedback for changes in complex behaviors resulting from DBS. Here, a female patient receiving DBS of the nucleus accumbens for the treatment of morbid obesity underwent cognitive testing via the flanker task alongside traditional methods of device titration. One set of stimulation parameters administered during titration resulted in acute cognitive improvement (p = 0.033) and increased frontal engagement as measured by electroencephalography (left anterior: p = 0.007, right anterior: p = 0.005) relative to DBS-OFF. The same parameters resulted in the most weight-loss during long-term continuous stimulation (47.8 lbs lost in 129 days) compared to the results of other stimulation settings. Diffusion tensor imaging analyses showed increased connectivity to dorsal attention networks and decreased connectivity to the default mode network for optimal parameters (p < 0.01). Our results provide evidence that targeted cognitive testing is a potentially useful tool for capturing acute effects of DBS stimulation during titration and predicting long-term treatment outcomes.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov, identifier: NCT01512134.

Resting-state functional connectivity modulates the BOLD activation induced by nucleus accumbens stimulation in the swine brain

INTRODUCTION

While the clinical efficacy of deep brain stimulation (DBS) the treatment of motor-related symptoms is well established, the mechanism of action of the resulting cognitive and behavioral effects has been elusive.

METHODS

By combining functional magnetic resonance imaging (fMRI) and DBS, we investigated the pattern of blood-oxygenation-level-dependent (BOLD) signal changes induced by stimulating the nucleus accumbens in a large animal model.

RESULTS

We found that diffused BOLD activation across multiple functional networks, including the prefrontal, limbic, and thalamic regions during the stimulation, resulted in a significant change in inter-regional functional connectivity. More importantly, the magnitude of the modulation was closely related to the strength of the inter-regional resting-state functional connectivity.

CONCLUSIONS

Nucleus accumbens stimulation affects the functional activity in networks that underlie cognition and behavior. Our study provides an insight into the nature of the functional connectivity, which mediates activation effect via brain networks.

Improving long term patient outcomes from deep brain stimulation for treatment-refractory obsessive-compulsive disorder

Introduction: Deep brain stimulation (DBS) has emerged as an effective treatment for patients with severe treatment-refractory obsessive-compulsive disorder (OCD). Over the past two decades, several clinical trials with multiple years of follow-up have shown that DBS offers long-term symptom relief for individuals with severe OCD, though a portion of patients do not achieve an adequate response.Areas covered: This review sought to summarize the literature on the efficacy and long-term effectiveness of DBS for OCD, and to identify strategies that have the potential to improve treatment outcomes.Expert opinion: Although this literature is just emerging, a small number of DBS enhancement strategies have shown promising initial results. More posterior targets along the striatal axis and at the bed nucleus of the stria terminalis appear to offer greater symptom relief than more anterior targets. Research is also beginning to demonstrate the feasibility of maximizing treatment outcomes with target selection based on neural activation patterns during symptom provocation and clinical presentation. Finally, integrating DBS with post-surgery exposure and response prevention therapy appears to be another promising approach. Definitive conclusions about these strategies are limited by a low number of studies with small sample sizes that will require multi-site replication.

Conflicts of interest and industry professional relationships in psychiatric neurosurgery: a comparative literature review

OBJECTIVE The research required to establish that psychiatric treatments are effective often depends on collaboration between academic clinical researchers and industry. Some of the goals of clinical practice and those of commercial developers of psychiatric therapies overlap, such as developing safe and effective treatments. However, there might also be incompatible goals; physicians aim to provide the best care they can to their patients, whereas the medical industry ultimately aims to develop therapies that are commercially successful. In some cases, however, clinical research may be aiming both at improved patient care and commercial success. It is in these cases that a conflict of interest (COI) arises. The goal of this study was to identify differences and commonalities regarding COIs between 2 kinds of somatic psychiatric interventions: pharmacological and neurosurgical. METHODS The authors conducted a study focused on professional concerns regarding pharmacological and neurosurgical psychiatric interventions. They used medical and bioethics journal articles as an indicator of professionals' concerns and carried out a thematic content analysis of peer-reviewed articles published between 1960 and 2015, using PubMed and Google Scholar. RESULTS One hundred thirty-seven relevant articles were identified, of which 86 papers focused primarily on psychopharmacology and 51 on neurosurgery. The intervention most discussed in the psychiatric neurosurgery data set was deep brain stimulation (n = 42). While there were no significant differences at the level of categories, pharmacological and neurosurgical interventions differ in the underlying themes discussed. Two issues widely discussed in the articles on pharmaceutical interventions, but largely neglected in the neurosurgery articles, were medical professional issues and industry involvement. CONCLUSIONS COIs are a neglected issue in the discussion of ethics concerns regarding medical devices in psychiatry. Yet as these interventions become more common, it is important to address them in part through learning from the discussion regarding COIs in the pharmaceutical industry and by developing approaches to address those aspects of COIs that are unique to the medical device industry.

Anterior capsulotomy for obsessive-compulsive disorder: a review of old and new literature

Over the last two decades, deep brain stimulation (DBS) has gained popularity as a treatment of severe and medically refractory obsessive-compulsive disorder (OCD), often using brain targets informed by historical lesional neurosurgical procedures. Paradoxically, the use of DBS in OCD has led some multidisciplinary teams to revisit the use of lesional procedures, especially anterior capsulotomy (AC), although significant aversion still exists toward the use of lesional neurosurgery for psychiatric disorders. This paper aims to review all literature on the use of AC for OCD to examine its effectiveness and safety profile.All publications on AC for OCD were searched. In total 512 patients were identified in 25 publications spanning 1961-2018. In papers where a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score was available, 73% of patients had a clinical response (i.e., > 35% improvement in Y-BOCS score) and 24% patients went into remission (Y-BOCS score < 8). In the older publications, published when the Y-BOCS was not yet available, 90% of patients were deemed to have had a significant clinical response and 39% of patients were considered symptom free. The rate of serious complications was low.In summary, AC is a safe, well-tolerated, and efficacious therapy. Its underuse is likely a result of historical prejudice rather than lack of clinical effectiveness.

New Directions in the Use of Brain Stimulation Interventions in Patients with Obsessive-Compulsive Disorder

Obsessive-Compulsive Disorder (OCD) is a highly disabling condition with early onset and chronic course in most of the affected patients. In addition, OCD may show high comorbidity and suicide attempt rates, which worsen the overall burden of the disease for patients and their caregivers. First-line treatments for OCD consist of pro-serotonergic compounds and cognitive-behavioral therapy. Nonetheless, many patients show only limited benefit from such interventions and require additional "next-step" interventions, including augmentative antipsychotics and glutamate-modulating agents. Based on the knowledge about altered neurocircuitry in OCD, brain stimulation techniques, including transcranial magnetic and electrical stimulations (TMS and tDCS) and deep brain stimulation (DBS), have been increasingly investigated over the last decade, revealing positive results for otherwise intractable and treatment-refractory patients. Available evidence in the field is in continuous evolution and professionals actively involved in the management of OCD patients, psychiatrists in particular, need to be updated about latest developments. Through the analysis of controlled studies, meta-analyses, and International treatment guidelines, the present article is aimed at providing the state of the art on the use of brain stimulation techniques for the treatment of OCD.

Transcending the brain: is there a cost to hacking the nervous system?

Great advancements have recently been made to understand the brain and the potential that we can extract out of it. Much of this has been centred on modifying electrical activity of the nervous system for improved physical and cognitive performance in those with clinical impairment. However, there is a risk of going beyond purely physiological performance improvements and striving for human enhancement beyond traditional human limits. Simple ethical guidelines and legal doctrine must be examined to keep ahead of technological advancement in light of the impending mergence between biology and machine. By understanding the role of modern ethics, this review aims to appreciate the fine boundary between what is considered ethically justified for current neurotechnology.

Deep brain stimulation of ventral internal capsule for refractory obsessive-compulsive disorder

The main objective of this study is to assess the effectiveness of deep brain stimulation (DBS) of the ventral striatum (VS) of the anterior limb of internal capsule for patients suffering from refractory obsessive-compulsive disorder (OCD) and to compare its result with traditional anterior capsulotomy. The present study consisted of two patients subjected to stimulation of ventral capsule (VC)/VS region of internal capsule for refractory OCD. Leads were implanted on both sides stereotactically using fused images of magnetic resonance imaging and computed tomography scan brain and connected to pulse generator (Medtronic). Outcome of both the patients was measured by Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Beck Depression Inventory (BDI), and Mini-Mental Status Examination. The first case was followed for 4 years and 6 months, while the second case was followed for 2 years and 6 months. Both the patients responded very well to stimulation with reduction of Y-BOCS from 38 to 12 (68.42% improvement) in the first patient and 38 to 10 (78.68% improvement) in the second patient after 1 year. BDI also improved in both the patients with no significant change in mental state. No adverse effect was seen in any of the patient. The beneficial effect of DBS persisted in both the patients till follow-up and was much superior to the beneficial effect of anterior capsulotomy. We conclude that DBS of VC/VS complex is very safe and effective in refractory OCD and shows considerable promise for the future. The result of two treated patients was much better as compared to lesioning (anterior capsulotomy) and the beneficial effect persisted for long time.

The effects of deep-brain non-stimulation in severe obsessive-compulsive disorder: an individual patient data meta-analysis

Non-intervention-related effects have long been recognized in an array of medical interventions, to which surgical procedures like deep-brain stimulation are no exception. While the existence of placebo and micro-lesion effects has been convincingly demonstrated in DBS for major depression and Parkinson's disease, systematic investigations for obsessive-compulsive disorder (OCD) are currently lacking. We therefore undertook an individual patient data meta-analysis with the aim of quantifying the effect of DBS for severe, treatment-resistant OCD that is not due to the electrical stimulation of brain tissue. The MEDLINE/PubMed database was searched for double-blind, sham-controlled randomized clinical trials published in English between 1998 and 2018. Individual patient data was obtained from the original authors and combined in a meta-analysis. We assessed differences from baseline in obsessive-compulsive symptoms following sham treatment, as measured by the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Four studies met the inclusion criteria, randomizing 49 patients to two periods of active or sham stimulation. To preclude confounding by period effects, our estimate was based only on data from those patients who underwent sham stimulation first (n = 24). We found that sham stimulation induced a significant change in the Y-BOCS score (t = -3.15, P < 0.005), lowering it by 4.9 ± 1.6 points [95% CI = (-8.0, -1.8)]. We conclude that non-stimulation-related effects of DBS exist also in OCD. The identification of the factors determining the magnitude and occurrence of these effects will help to design strategies that will ultimately lead to a betterment of future randomized clinical trials.

Results of Gamma Knife anterior capsulotomy for refractory obsessive-compulsive disorder: results in a series of 10 consecutive patients

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a severe psychiatric condition. The authors present their experience with Gamma Knife radiosurgery (GKRS) in the treatment of patients with OCD resistant to any medical therapy.

METHODS

Patients with severe OCD resistant to all pharmacological and psychiatric treatments who were treated with anterior GKRS capsulotomy were retrospectively reviewed. These patients were submitted to a physical, neurological, and neuropsychological examination together with structural and functional MRI before and after GKRS treatment. Strict study inclusion criteria were applied. Radiosurgical capsulotomy was performed using two 4-mm isocenters targeted at the midputaminal point of the anterior limb of the capsule. A maximal dose of 120 Gy was prescribed for each side. Clinical global changes were assessed using the Clinical Global Impression (CGI) scale, Global Assessment of Functioning (GAF) scale, EQ-5D, Beck Depression Inventory (BDI), and State-Trait Anxiety Inventory (STAI). OCD symptoms were determined by the Yale–Brown Obsessive Compulsive Scale (Y-BOCS).

RESULTS

Ten patients with medically refractory OCD (5 women and 5 men) treated between 2006 and 2015 were included in this study. Median age at diagnosis was 22 years, median duration of illness at the time of radiosurgery was 14.5 years, and median age at treatment was 38.8 years. Before GKRS, the median Y-BOCS score was 34.5 with a median obsession score of 18 and compulsion score of 17. Seven (70%) of 10 patients achieved a full response at their last follow-up, 2 patients were nonresponders, and 1 patient was a partial responder. Evaluation of the Y-BOCS, BDI, STAI-Trait, STAI-State, GAF, and EQ-5D showed statistically significant improvement at the last follow-up after GKRS. Neurological examinations were normal in all patients at each visit. At last follow-up, none of the patients had experienced any significant adverse neuropsychological effects or personality changes.

CONCLUSIONS

GKRS anterior capsulotomy is effective and well tolerated with a maximal dose of 120 Gy. It reduces both obsessions and compulsions, improves quality of life, and diminishes depression and anxiety.

The Bed Nucleus of the Stria Terminalis, Homeostatic Satiety, and Compulsions: What Can We Learn From Polydipsia?

A compulsive phenotype characterizes several neuropsychiatric illnesses - including but not limited to - schizophrenia and obsessive compulsive disorder. Because of its perceived etiological heterogeneity, it is challenging to disentangle the specific neurophysiology that precipitates compulsive behaving. Using polydipsia (or non-regulatory water drinking), we describe candidate neural substrates of compulsivity. We further postulate that aberrant neuroplasticity within cortically projecting structures [i.e., the bed nucleus of the stria terminalis (BNST)] and circuits that encode homeostatic emotions (thirst, hunger, satiety, etc.) underlie compulsive drinking. By transducing an inaccurate signal that fails to represent true homeostatic state, cortical structures cannot select appropriate and adaptive actions. Additionally, augmented dopamine (DA) reactivity in striatal projections to and from the frontal cortex contribute to aberrant homeostatic signal propagation that ultimately biases cortex-dependent behavioral selection. Responding becomes rigid and corresponds with both erroneous, inflexible encoding in both bottom-up structures and in top-down pathways. How aberrant neuroplasticity in circuits that encode homeostatic emotion result in the genesis and maintenance of compulsive behaviors needs further investigation.

Deep brain stimulation for obsessive-compulsive disorder

Neurosurgical interventions have been used for decades to treat severe, refractory obsessive-compulsive disorder (OCD). Deep brain stimulation (DBS) is a neurosurgical procedure that is used routinely to treat movement disorders such as Parkinson's disease and essential tremor. Over the past two decades, DBS has been applied to OCD, building on earlier experience with lesional procedures. Promising results led to Humanitarian Device Exemption (HDE) approval of the therapy from the United States Food and Drug Administration in 2009. In this review, the authors describe the development of DBS for OCD, the most recent outcome data, and areas for future research.

Preventing morphine reinforcement with high-frequency deep brain stimulation of the lateral hypothalamic area

Deep brain stimulation (DBS) has been proposed as a promising intervention for patients with treatment-refractory substance use disorder. Here, we investigated if high-frequency DBS in the lateral hypothalamic area (LHA) could affect drug-induced reinforcement. Rats were bilaterally implanted with bipolar stimulation electrodes in the LHA and trained to the morphine conditioned place preference. DBS (monophasic square pulses, 130 Hz, 100-microsecond pulse duration and 150 μA) was applied during the morphine-pairing trials (30 minutes daily for 4 days) or drug-free postconditioning test (15 minutes) to determine its effect on the acquisition or expression of morphine reward, respectively. LHA DBS during morphine-conditioning trials blocked subsequent preference for the drug-associated context. In contrast, DBS in the postconditioning phase failed to inhibit expression of morphine-induced conditioned place preference. These results were further controlled by ruling out significant changes by DBS in physical performance and anxiety-like behavior as measured by an open field test and by precluding anhedonia-like behavior as measured by sucrose consumption test. Our results suggest that LHA DBS can prevent development of morphine reward without diminishing the motivation for naturally rewarding stimuli. Therefore, the LHA could be a potential target for research in the field of DBS-based treatment of intractable substance use disorder. Further studies will be necessary to assess the translatability of these findings to the clinic.

Role of basal ganglia neurocircuitry in the pathology of psychiatric disorders

Over the last few decades, advances in human and animal-based techniques have greatly enhanced our understanding of the neural mechanisms underlying psychiatric disorders. Many of these studies have indicated connectivity between and alterations within basal ganglia structures to be particularly pertinent to the development of symptoms associated with several of these disorders. Here we summarize the connectivity, molecular composition, and function of sites within basal ganglia neurocircuits. Then we review the current literature from both human and animal studies concerning altered basal ganglia function in five common psychiatric disorders: obsessive-compulsive disorder, substance-related and addiction disorders, major depressive disorder, generalized anxiety disorder, and schizophrenia. Finally, we present a model based upon the findings of these studies that highlights the striatum as a particularly attractive target for restoring normal function to basal ganglia neurocircuits altered within psychiatric disorder patients.

Animal Models and Animal Experimentation in the Development of Deep Brain Stimulation: From a Specific Controversy to a Multidimensional Debate

In this article, we explore a specific controversy about animal experimentation and animal models in the recent history of deep brain stimulation (DBS), and we question its ramifications. DBS development intertwines clinical practice with fundamental research and stands at the crossroads of multiple legacies. We take up the various issues and controversies embedded in this rarely addressed dispute, from a standpoint that combines socio-anthropological and legal aspects. Our starting point is a debate on the role of animal experimentation in the development of DBS between Jarrod Bailey, a researcher promoting the abolition of animal experimentation, and Alim Louis Benabid, Marwan Hariz, and Mahlon DeLong, three key figures in the area of DBS and neuroscience. By clarifying the positions of the different protagonists and retracing the issues raised in these discussions, our objective is to show how this specific debate has extended from its initial space and how it provides an object of study with heuristic scope. We first present this partially polemic discussion about the history of DBS, and its link with a more general debate on the validity and use of animal models and the need for animal experiments. Then, we raise the issue of the relations and interactions between experiments on animals and on humans in the logics of biomedical innovation. The third step is to situate the discussion within the wider framework of opposition towards animal experimentation and the promotion of animal' rights. Finally, combining these interweaved issues, possible implications emerge regarding the future of DBS. We show that behind these several controversies lie the question of translational research and the model of medicine upheld by DBS. We describe how the technology contributes to blurring the lines between research (fundamental, preclinical and clinical research) and care, as well as between humans and animals as substrates and objects of knowledge. The dynamics of DBS future development might then become a point of convergence for neuroscientists and animal rights defenders' interests.

A Randomized Trial Directly Comparing Ventral Capsule and Anteromedial Subthalamic Nucleus Stimulation in Obsessive-Compulsive Disorder: Clinical and Imaging Evidence for Dissociable Effects

BACKGROUND

Deep brain stimulation (DBS) is an emerging treatment for severe obsessive-compulsive disorder (OCD). We compared the efficacy of ventral capsule/ventral striatal (VC/VS) and anteromedial subthalamic nucleus (amSTN) DBS in the same patients and tested for mechanistic differences on mood and cognitive flexibility and associated neural circuitry. The possible synergistic benefit of DBS at both sites and cognitive behavioral therapy was explored.

METHODS

Six patients with treatment-refractory OCD (5 men; Yale-Brown Obsessive Compulsive Scale score >32) entered double-blind counterbalanced phases of 12-week amSTN or VC/VS DBS, followed by 12-week open phases when amSTN and VC/VS were stimulated together, in which optimal stimulation parameters were achieved and adjunctive inpatient cognitive behavioral therapy was delivered. OCD and mood were assessed with standardized scales and cognitive flexibility with the Cambridge Neuropsychological Test Automated Battery Intra-Extra Dimensional Set-Shift task. Diffusion-weighted and intraoperative magnetic resonance imaging scans were performed for tractography from optimally activated electrode contacts.

RESULTS

DBS at each site significantly and equivalently reduced OCD symptoms with little additional gain following combined stimulation. amSTN but not VC/VS DBS significantly improved cognitive flexibility, whereas VC/VS DBS had a greater effect on mood. The VC/VS effective site was within the VC. VC DBS connected primarily to the medial orbitofrontal cortex, and amSTN DBS to the lateral orbitofrontal cortex, dorsal anterior cingulate cortex, and dorsolateral prefrontal cortex. No further improvement followed cognitive behavioral therapy, reflecting a floor effect of DBS on OCD.

CONCLUSIONS

Both the VC/VS and amSTN are effective targets for severe treatment-refractory OCD. Differential improvements in mood and cognitive flexibility and their associated connectivity suggest that DBS at these sites modulates distinct brain networks.

Nucleus Accumbens Deep Brain Stimulation for Obsessive-Compulsive Disorder and Aggression in an Autistic Patient: A Case Report and Hypothesis of the Role of Nucleus Accumbens in Autism and Comorbid Symptoms

BACKGROUND

Autism spectrum disorder represents a set of developmental disorders characterized by lack of social interaction and verbal and nonverbal communication in the first 3 years of life. It is also associated with several comorbidities, including epilepsy, aggression, self-mutilating behavior, and obsessive-compulsive behavior. In some cases, obsessive-compulsive disorder (OCD) develops. The nucleus accumbens (NAc) plays a key role in reward circuitry and is involved in the control of OCD and aggression.

CASE DESCRIPTION

A 42-year-old woman with autism was offered NAc deep brain stimulation for her comorbidities of OCD and aggression. The NAc was targeted using standard stereotactic methods, and postoperative scans confirmed the position of the active electrode to be within the NAc. The patient experienced significant symptom relief. At 1-year follow-up, the Yale-Brown Obsessive Compulsive Scale score for OCD, excluding items 1-5 of the scale, improved from 19 to 5. Hamilton Depression Scale and Hamilton Anxiety Scale scores similarly improved from 20 to 15 and from 30 to 18, respectively. Social Communication Questionnaire Current version for autism score improved from 26 to 16. Subscores for reciprocal social interactionimproved from 13 to 8; for communication improved from 5 to 4; and for restricted, repetitive, and stereotyped patterns of behavior improved from 6 to 3.

CONCLUSIONS

This case report illustrated the role of the NAc in OCD and aggression in an autistic patient. We discussed the role of the NAc as a target to explain the outcome of this case.

Anatomic Review of the Ventral Capsule/Ventral Striatum and the Nucleus Accumbens to Guide Target Selection for Deep Brain Stimulation for Obsessive-Compulsive Disorder

BACKGROUND

Disturbances in the reward network of the brain underlie addiction, depression, and obsessive-compulsive disorder. The ventral capsule/ventral striatum and nucleus accumbens (NAc) region is a clinically approved target for deep brain stimulation for obsessive-compulsive disorder.

METHODS

We performed a comprehensive literature review to define clinically relevant anatomy and connectivity of the ventral capsule/ventral striatum and NAc region to guide target selection for deep brain stimulation.

RESULTS

Architecturally and functionally, the NAc is divided into the core and the shell, with each area having different connections. The shell primarily receives limbic information, and the core typically receives information from the motor system. In general, afferents from the prefrontal cortex, hippocampus, and amygdala are excitatory. The dopaminergic projections to the NAc from the ventral tegmental area modulate the balance of these excitatory inputs. Several important inputs to the NAc converge at the junction of the internal capsule (IC) and the anterior commissure (AC): the ventral amygdalofugal pathways that run parallel to and underneath the AC, the precommissural fornical fibers that run anterior to the AC, axons from the ventral prefrontal cortex and medial orbitofrontal cortex that occupy the most ventral part of the IC and embedding within the NAc and AC, and the superolateral branch of the medial forebrain bundle located parallel to the anterior thalamic radiation in the IC.

CONCLUSIONS

The caudal part of the NAc passing through the IC-AC junction may be an effective target for deep brain stimulation to improve behavioral symptoms associated with obsessive-compulsive disorder.

Evolution in the Treatment of Psychiatric Disorders: From Psychosurgery to Psychopharmacology to Neuromodulation

The treatment of psychiatric patients presents significant challenges to the clinical community, and a multidisciplinary approach to diagnosis and management is essential to facilitate optimal care. In particular, the neurosurgical treatment of psychiatric disorders, or “psychosurgery,” has held fascination throughout human history as a potential method of influencing behavior and consciousness. Early evidence of such procedures can be traced to prehistory, and interest flourished in the nineteenth and early twentieth century with greater insight into cerebral functional and anatomic localization. However, any discussion of psychosurgery invariably invokes controversy, as the widespread and indiscriminate use of the transorbital lobotomy in the mid-twentieth century resulted in profound ethical ramifications that persist to this day. The concurrent development of effective psychopharmacological treatments virtually eliminated the need and desire for psychosurgical procedures, and accordingly the research and practice of psychosurgery was dormant, but not forgotten. There has been a recent resurgence of interest for non-ablative therapies, due in part to modern advances in functional and structural neuroimaging and neuromodulation technology. In particular, deep brain stimulation is a promising treatment paradigm with the potential to modulate abnormal pathways and networks implicated in psychiatric disease states. Although there is enthusiasm regarding these recent advancements, it is important to reflect on the scientific, social, and ethical considerations of this controversial field.

Evolution of gamma knife capsulotomy for intractable obsessive-compulsive disorder

For more than half a century, stereotactic neurosurgical procedures have been available to treat patients with severe, debilitating symptoms of obsessive-compulsive disorder (OCD) that have proven refractory to extensive, appropriate pharmacological, and psychological treatment. Although reliable predictors of outcome remain elusive, the establishment of narrower selection criteria for neurosurgical candidacy, together with a better understanding of the functional neuroanatomy implicated in OCD, has resulted in improved clinical efficacy for an array of ablative and non-ablative intervention techniques targeting the cingulum, internal capsule, and other limbic regions. It was against this backdrop that gamma knife capsulotomy (GKC) for OCD was developed. In this paper, we review the history of this stereotactic radiosurgical procedure, from its inception to recent advances. We perform a systematic review of the existing literature and also provide a narrative account of the evolution of the procedure, detailing how the procedure has changed over time, and has been shaped by forces of evidence and innovation. As the procedure has evolved and adverse events have decreased considerably, favorable response rates have remained attainable for approximately one-half to two-thirds of individuals treated at experienced centers. A reduction in obsessive-compulsive symptom severity may result not only from direct modulation of OCD neural pathways but also from enhanced efficacy of pharmacological and psychological therapies working in a synergistic fashion with GKC. Possible complications include frontal lobe edema and even the rare formation of delayed radionecrotic cysts. These adverse events have become much less common with new radiation dose and targeting strategies. Detailed neuropsychological assessments from recent studies suggest that cognitive function is not impaired, and in some domains may even improve following treatment. We conclude this review with discussions covering topics essential for further progress of this therapy, including suggestions for future trial design given the unique features of GKC therapy, considerations for optimizing stereotactic targeting and dose planning using biophysical models, and the use of advanced imaging techniques to understand circuitry and predict response. GKC, and in particular its modern variant, gamma ventral capsulotomy, continues to be a reliable treatment option for selected cases of otherwise highly refractory OCD.

Deep Brain Stimulation for Obsessive Compulsive Disorder: Evolution of Surgical Stimulation Target Parallels Changing Model of Dysfunctional Brain Circuits

Obsessive compulsive disorder (OCD) is a common, disabling psychiatric disease characterized by persistent, intrusive thoughts and ritualistic, repetitive behaviors. Deep brain stimulation (DBS) is thought to alleviate OCD symptoms by modulating underlying disturbances in normal cortico-striato-thalamo-cortical (CSTC) circuitry. Stimulation of the ventral portion of the anterior limb of the internal capsule (ALIC) and underlying ventral striatum (“ventral capsule/ventral striatum” or “VC/VS” target) received U.S. FDA approval in 2009 for patients with severe, treatment-refractory OCD. Over the decades, DBS surgical outcome studies have led to an evolution in the electrical stimulation target. In parallel, advancements in neuroimaging techniques have allowed investigators to better visualize and define CSTC circuits underlying the pathophysiology of OCD. A critical analysis of these new data suggests that the therapeutic mechanism of DBS for OCD likely involves neuromodulation of a widespread cortical/subcortical network, accessible by targeting fiber bundles in the ventral ALIC that connect broad network regions. Future studies will include advances in structural and functional imaging, analysis of physiological recordings, and utilization of next-generation DBS devices. These tools will enable patient-specific optimization of DBS therapy, which will hopefully further improve outcomes.

Deep Brain Stimulation for Refractory Obsessive-Compulsive Disorder: Towards an Individualized Approach

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder featuring repetitive intrusive thoughts and behaviors associated with a significant handicap. Of patients, 20% are refractory to medication and cognitive behavioral therapy. Refractory OCD is associated with suicidal behavior and significant degradation of social and professional functioning, with high health costs. Deep brain stimulation (DBS) has been proposed as a reversible and controllable method to treat refractory patients, with meta-analyses showing 60% response rate following DBS, whatever the target: anterior limb of the internal capsule (ALIC), ventral capsule/ventral striatum (VC/VS), nucleus accumbens (NAcc), anteromedial subthalamic nucleus (amSTN), or inferior thalamic peduncle (ITP). But how do we choose the "best" target? Functional neuroimaging studies have shown that ALIC-DBS requires the modulation of the fiber tract within the ventral ALIC via the ventral striatum, bordering the bed nucleus of the stria terminalis and connecting the medial prefrontal cortex with the thalamus to be successful. VC/VS effective sites of stimulation were found within the VC and primarily connected to the medial orbitofrontal cortex (OFC) dorsomedial thalamus, amygdala, and the habenula. NAcc-DBS has been found to reduce OCD symptoms by decreasing excessive fronto-striatal connectivity between NAcc and the lateral and medial prefrontal cortex. The amSTN effective stimulation sites are located at the inferior medial border of the STN, primarily connected to lateral OFC, dorsal anterior cingulate, and dorsolateral prefrontal cortex. Finally, ITP-DBS recruits a bidirectional fiber pathway between the OFC and the thalamus. Thus, these functional connectivity studies show that the various DBS targets lie within the same diseased neural network. They share similar efficacy profiles on OCD symptoms as estimated on the Y-BOCS, the amSTN being the target supported by the strongest evidence in the literature. VC/VS-DBS, amSTN-DBS, and ALIC-DBS were also found to improve mood, behavioral adaptability and potentially both, respectively. Because OCD is such a heterogeneous disease with many different symptom dimensions, the ultimate aim should be to find the most appropriate DBS target for a given refractory patient. This quest will benefit from further investigation and understanding of the individual functional connectivity of OCD patients.

Indian guidelines on neurosurgical interventions in psychiatric disorders

Neurosurgery for psychiatric disorders (NPD) has been practiced for >80 years. However, the interests have waxed and waned, from 1000s of surgeries in 1940-1950s to handful of surgery in 60-80s. This changed with the application of deep brain stimulation surgery, a surgery, considered to be "reversible" there has been a resurgence in interest. The Indian society for stereotactic and functional neurosurgery (ISSFN) and the world society for stereotactic and functional neurosurgery took the note of the past experiences and decided to form the guidelines for NPD. In 2011, an international task force was formed to develop the guidelines, which got published in 2013. In 2018, eminent psychiatrists from India, functional neurosurgeon representing The Neuromodulation Society and ISSFN came-together to deliberate on the current status, need, and legal aspects of NPD. In May 2018, Mental Health Act also came in to force in India, which had laid down the requirements to be fulfilled for NPD. In light of this after taking inputs from all stakeholders and review of the literature, the group has proposed the guidelines for NPD that can help to steer these surgery and its progress in India.

Deep brain stimulation in the treatment of obsessive-compulsive disorder: current perspectives

Deep brain stimulation (DBS) is a neuro-psychosurgical technique widely accepted in movement disorders, such as Parkinson's disease. Since 1999, DBS has been explored for severe, chronic and treatment-refractory psychiatric diseases. Our review focuses on DBS in obsessive-compulsive disorder (OCD), considered as a last treatment resort by most of learned societies in psychiatry. Two main stimulation areas have been studied: the striatal region and the subthalamic nucleus. But, most of the trials are open-labeled, and the rare controlled ones have failed to highlight the most efficient target. The recent perspectives are otherwise encouraging. Indeed, clinicians are currently considering other promising targets. A case series of 2 patients reported a decrease in OCD symptoms after DBS in the medial forebrain bundle and an open-label study is exploring bilateral habenula stimulation. New response criteria are also investigating such as quality of life, or subjective and lived-experience. Moreover, first papers about cost-effectiveness which is an important criterion in decision making, have been published. The effectiveness of tractography-assisted DBS or micro-assisted DBS is studying with the aim to improve targeting precision. In addition, a trial involving rechargeable pacemakers is undergoing because this mechanism could be efficient and have a positive impact on cost-effectiveness. A recent trial has discussed the possibility of using combined cognitive behavioral therapy (CBT) and DBS as an augmentation strategy. Finally, based on RDoc Research, the latest hypotheses about the understanding of cortico-striato-thalamo-cortical circuits could offer new directions including clinical predictors and biomarkers to perform adaptive closed-loop systems in the next future.

Personalized striatal targets for deep brain stimulation in obsessive-compulsive disorder

BACKGROUND

Psychiatric conditions currently treated with deep brain stimulation (DBS), such as obsessive-compulsive disorder (OCD), are heterogeneous diseases with different symptomatic dimensions, indicating that fixed neuroanatomical DBS targets for all OCD cases may not be efficacious.

OBJECTIVE/HYPOTHESIS

We tested whether the optimal DBS target for OCD is fixed for all patients or whether it is individualized and related to each patient's symptomatic content. Further, we explored if the optimal target can be predicted by combining functional neuroimaging and structural connectivity.

METHODS

In a prospective, randomized, double-blinded study in 7 OCD patients, symptomatic content was characterized pre-operatively by clinical interview and OCD symptom-provocation during functional MRI. DBS electrode implantation followed a trajectory placing 4 contacts along a striatal axis (nucleus accumbens to caudate). Patients underwent three-month stimulation periods for each contact (and sham), followed by clinical evaluation. Probabilistic tractography, applied to diffusion-weighted images acquired pre-operatively, was used to study the overlap between projections from the prefrontal areas activated during symptom provocation and the volume of activated tissue of each electrode contact.

RESULTS

Six patients were classified responders, with median symptomatic reduction of 50% achieved from each patient's best contact. This was located at the caudate in 4 cases and at the accumbens in 2. Critically, the anatomical locus of the best contact (accumbens or caudate) was related to an index derived by combining functional MRI responses to prevailing symptom provocation and prefronto-cortico-striatal projections defined by probabilistic tractography.

CONCLUSION

Our results therefore represent a step towards personalized, content-specific DBS targets for OCD.

Differential Effects of Deep Brain Stimulation of the Internal Capsule and the Striatum on Excessive Grooming in Sapap3 Mutant Mice

BACKGROUND

Deep brain stimulation (DBS) is an effective treatment for patients with obsessive-compulsive disorder (OCD) that do not respond to conventional therapies. Although the precise mechanism of action of DBS remains unknown, modulation of activity in corticofugal fibers originating in the prefrontal cortex is thought to underlie its beneficial effects in OCD.

METHODS

To gain more mechanistic insight into DBS in OCD, we used Sapap3 mutant mice. These mice display excessive self-grooming and increased anxiety, both of which are responsive to therapeutic drugs used in OCD patients. We selected two clinically relevant DBS targets through which activity in prefronto-corticofugal fibers may be modulated: the internal capsule (IC) and the dorsal part of the ventral striatum (dVS).

RESULTS

IC-DBS robustly decreased excessive grooming, whereas dVS-DBS was on average less effective. Grooming was reduced rapidly after IC-DBS onset and reinstated upon DBS offset. Only IC-DBS was associated with increased locomotion. DBS in both targets induced c-Fos expression around the electrode tip and in different regions of the prefrontal cortex. This prefronto-cortical activation was more extensive after IC-DBS, but not associated with behavioral effects. Furthermore, we found that the decline in grooming cannot be attributed to altered locomotor activity and that anxiety, measured on the elevated plus maze, was not affected by DBS.

CONCLUSIONS

DBS in both the IC and dVS reduces compulsive grooming in Sapap3 mutant mice. However, IC stimulation was more effective, but also produced motor activation, even though both DBS targets modulated activity in a similar set of prefrontal cortical fibers.

Reporting Guidelines and Issues to Consider for Using Intracranial Brain Stimulation in Studies of Human Declarative Memory

Participants with stimulating and recording electrodes implanted within the brain for clinical evaluation and treatment provide a rare opportunity to unravel the neuronal correlates of human memory, as well as offer potential for modulation of behavior. Recent intracranial stimulation studies of memory have been inconsistent in methodologies employed and reported conclusions, which renders generalizations and construction of a framework impossible. In an effort to unify future study efforts and enable larger meta-analyses we propose in this mini-review a set of guidelines to consider when pursuing intracranial stimulation studies of human declarative memory and summarize details reported by previous relevant studies. We present technical and safety issues to consider when undertaking such studies and a checklist for researchers and clinicians to use for guidance when reporting results, including targeting, placement, and localization of electrodes, behavioral task design, stimulation and electrophysiological recording methods, details of participants, and statistical analyses. We hope that, as research in invasive stimulation of human declarative memory further progresses, these reporting guidelines will aid in setting standards for multicenter studies, in comparison of findings across studies, and in study replications.