Deep brain stimulation between 1947 and 1987: the untold story

Advancements in brain-machine interfaces for application in the metaverse

In recent years, with the shift of focus in metaverse research toward content exchange and social interaction, breaking through the current bottleneck of audio-visual media interaction has become an urgent issue. The use of brain-machine interfaces for sensory simulation is one of the proposed solutions. Currently, brain-machine interfaces have demonstrated irreplaceable potential as physiological signal acquisition tools in various fields within the metaverse. This study explores three application scenarios: generative art in the metaverse, serious gaming for healthcare in metaverse medicine, and brain-machine interface applications for facial expression synthesis in the virtual society of the metaverse. It investigates existing commercial products and patents (such as MindWave Mobile, GVS, and Galea), draws analogies with the development processes of network security and neurosecurity, bioethics and neuroethics, and discusses the challenges and potential issues that may arise when brain-machine interfaces mature and are widely applied. Furthermore, it looks ahead to the diverse possibilities of deep and varied applications of brain-machine interfaces in the metaverse in the future.

Targeting papez circuit for cognitive dysfunction- insights into deep brain stimulation for Alzheimer's disease

Hippocampus is the most widely studied brain area coupled with impairment of memory in a variety of neurological diseases and Alzheimer's disease (AD). The limbic structures within the Papez circuit have been linked to various aspects of cognition. Unfortunately, the brain regions that include this memory circuit are often ignored in terms of understanding cognitive decline in these diseases. To properly comprehend where cognition problems originate, it is crucial to clarify any aberrant contributions from all components of a specific circuit -on both a local and a global level. The pharmacological treatments currently available are not long lasting. Deep Brain Stimulation (DBS) emerged as a new powerful therapeutic approach for alleviation of the cognitive dysfunctions. Metabolic, functional, electrophysiological, and imaging studies helped to find out the crucial nodes that can be accessible for DBS. Targeting these nodes within the memory circuit produced significant improvement in learning and memory by disrupting abnormal circuit activity and restoring the physiological network. Here, we provide an overview of the neuroanatomy of the circuit of Papez along with the mechanisms and various deep brain stimulation targets of the circuit structures which could be significant for improving cognitive dysfunctions in AD.

The history of deep brain stimulation

Deep brain stimulation (DBS) surgery is an established and effective treatment for several movement disorders (tremor, Parkinson's disease, and dystonia), and is under investigation in numerous other neurological and psychiatric disorders. However, the origins and development of this neurofunctional technique are not always well understood and recognized. In this mini-review, we review the history of DBS, highlighting important milestones and the most remarkable protagonists (neurosurgeons, neurologists, and neurophysiologists) who pioneered and fostered this therapy throughout the 20th and early 21st century. Alongside DBS historical markers, we also briefly discuss newer developments in the field, and the future challenges which accompany such progress.

Current perspectives on tractography-guided deep brain stimulation for the treatment of mood disorders

INTRODUCTION

Deep brain stimulation (DBS) is an emerging therapy for mood disorders, particularly treatment-resistant depression (TRD). Different brain areas implicated in depression-related brain networks have been investigated as DBS targets and variable clinical outcomes highlight the importance of target identification. Tractography has provided insight into how DBS modulates disorder-related brain networks and is being increasingly used to guide DBS for psychiatric disorders.

AREAS COVERED

In this perspective, an overview of the current state of DBS for TRD and the principles of tractography is provided. Next, a comprehensive review of DBS targets is presented with a focus on tractography. Finally, the challenges and future directions of tractography-guided DBS are discussed.

EXPERT OPINION

Tractography-guided DBS is a promising tool for improving DBS outcomes for mood disorders. Tractography is particularly useful for targeting patient-specific white matter tracts that are not visible using conventional structural MRI. Developments in tractography methods will help refine DBS targeting for TRD and may facilitate symptom-specific precision neuromodulation. Ultimately, the standardization of tractography methods will be essential to transforming DBS into an established therapy for mood disorders.

Thirty Years of Global Deep Brain Stimulation: "Plus ça change, plus c'est la même chose"?

BACKGROUND

The advent of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease 30 years ago has ushered a global breakthrough of DBS as a universal method for therapy and research in wide areas of neurology and psychiatry. The literature of the last three decades has described numerous concepts and practices of DBS, often branded as novelties or discoveries. However, reading the contemporary publications often elicits a sense of déjà vu in relation to several methods, attributes, and practices of DBS. Here, we review various applications and techniques of the modern-era DBS and compare them with practices of the past.

SUMMARY

Compared with modern literature, publications of the old-era functional stereotactic neurosurgery, including old-era DBS, show that from the very beginning multidisciplinarity and teamwork were often prevalent and insisted upon, ethical concerns were recognized, brain circuitries and rational for brain targets were discussed, surgical indications were similar, closed-loop stimulation was attempted, evaluations of surgical results were debated, and controversies were common. Thus, it appears that virtually everything done today in the field of DBS bears resemblance to old-time practices, or has been done before, albeit with partly other tools and techniques. Movement disorders remain the main indications for modern DBS as was the case for lesional surgery and old-era DBS. The novelties today consist of the STN as the dominant target for DBS, the tremendous advances in computerized brain imaging, the sophistication and versatility of implantable DBS hardware, and the large potential for research.

KEY MESSAGES

Many aspects of contemporary DBS bear strong resemblance to practices of the past. The dominant clinical indications remain movement disorders with virtually the same brain targets as in the past, with one exception: the STN. Other novel brain targets - that are so far subject to DBS trials - are the pedunculopontine nucleus for gait freezing, the anteromedial internal pallidum for Gilles de la Tourette and the fornix for Alzheimer's disease. The major innovations and novelties compared to the past concern mainly the unmatched level of research activity, its high degree of sponsorship, and the outstanding advances in technology that have enabled multimodal brain imaging and the miniaturization, versatility, and sophistication of implantable hardware. The greatest benefit for patients today, compared to the past, is the higher level of precision and safety of DBS, and of all functional stereotactic neurosurgery.

Anthropology of Deep Brain Stimulation; the 30th Anniversary of STN DBS in 2023

Background

The year 2023 marks the 30th anniversary of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease (PD). This procedure prompted a universal interest in DBS for various brain disorders and resulted in a unique expansion of clinical and scientific collaboration between many disciplines, with impact on many aspects of society.

Objective

To study the anthropology of DBS, that is, its ethno-geographic origins, its evolution, its impact on clinicians and scientists, and its influence on society at large.

Material and Methods

The authors scrutinized the geo-ethnic origins of the pioneers of modern DBS, and they evaluated, based on the literature and on a long-term praxis, the development of DBS and its impact on clinicians, on healthcare, and on society.

Results

Scientists and clinicians from various geo-ethnic origins pioneered modern DBS, leading to worldwide spread of this procedure and to the establishment of large multidisciplinary teams in many centers. Neurologists became actively involved in surgery and took on new laborious tasks of programming ever more complicated DBS systems. Publications sky-rocketed and the global spread of DBS impacted positively on several aspects of society, including healthcare, awareness of neurological diseases, interdisciplinary relations, conferences, patient organizations, unemployment, industry, etc.

Conclusions

STN DBS has boosted the field of deep brain electrotherapy for many neurological and psychiatric illnesses, and DBS has generated a global benefit on many aspects of society, well beyond its clinical benefits on symptoms of diseases. With the ever-increasing indications for DBS, more positive global impact is expected.

The Role of Family Members in Psychiatric Deep Brain Stimulation Trials: More Than Psychosocial Support

Family members can provide crucial support to individuals participating in clinical trials. In research on the "newest frontier" of Deep Brain Stimulation (DBS)-the use of DBS for psychiatric conditions-family member support is frequently listed as a criterion for trial enrollment. Despite the significance of family members, qualitative ethics research on DBS for psychiatric conditions has focused almost exclusively on the perspectives and experiences of DBS recipients. This qualitative study is one of the first to include both DBS recipients and their family members as interview participants. Using dyadic thematic analysis-an approach that takes both the individuals and the relationship as units of analyses-this study analyzes the complex ways in which family relationships can affect DBS trial participation, and how DBS trial participation in turn influences family relationships. Based on these findings, we propose ways to improve study designs to better take family relationships into account, and better support family members in taking on the complex, essential roles that they play in DBS trials for psychiatric conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12152-023-09520-7.

Deep brain stimulation for autism spectrum disorder

Deep brain stimulation (DBS) is a medical treatment that aims to obtain therapeutic effects by applying chronic electrical impulses in specific brain structures and neurological circuits. Over the years, DBS has been studied for the treatment of many psychiatric disorders. Scientific research on the use of DBS in people with autism has focused this interest mainly on treatment-resistant obsessive-compulsive disorder, drug-resistant epilepsy, self-injurious behaviors (SIB), and aggressive behaviors toward the self. Autism spectrum disorder (ASD) includes a group of developmental disabilities characterized by patterns of delay and deviance in the development of social, communicative, and cognitive skills and the presence of repetitive and stereotyped behaviors as well as restricted interests. People with autism often have numerous medical and psychiatric comorbidities that worsen the quality of life of patients and their caregivers. Obsessive-compulsive symptoms can be found in up to 81.3% of people with autism. They are often severe, refractory to treatment, and particularly difficult to treat. SIB has a high prevalence in severely retarded individuals and is often associated with autism. Drug treatment of both autism and SIB presents a therapeutic challenge. To describe the current state of the art regarding the efficacy of DBS in people with ASD, a literature search was conducted for relevant studies using the PubMed database. Thirteen studies have been considered in this paper. Up to date, DBS has been used for the stimulation of the nucleus accumbens, globus pallidus internus, anterior limb of the internal capsule, ventral anterior limb of the internal capsule, basolateral amygdala, ventral capsule and ventral striatum, medial forebrain bundle, and posterior hypothalamus. In the total sample of 16 patients, 4 were adolescents, and 12 were adults. All patients had symptoms resistant to multiple drug therapy. Many patients taken into consideration by the studies showed clinical improvements as evidenced by the scores of the psychopathological scales used. In some cases, clinical improvements have varied over time, which may require further investigation. Among the new therapeutic perspectives, DBS could be a valid option. However, further, and more in-depth research is needed in this field.

Pros and Cons of Ablation for Functional Neurosurgery in the Neurostimulation Age

Should one recommend stereotactic ablation for Parkinson disease, tremor, dystonia, and obsessive compulsive disorder, in this era of DBS? The answer depends on several variables such as the symptoms to treat, the patient's preferences and expectations, the surgeons' competence and preference, the availability of financial means (by government health care, by private insurance), the geographical issues, and not least the current and dominating fashion at that particular time. Both ablation and stimulation can be either used alone or even combined (provided expertise in both of them) to treat various symptoms of movement and mind disorders.

Treating Chronic Pain with Deep Brain Stimulation

PURPOSE OF REVIEW

Deep brain stimulation (DBS) for chronic pain has been controversial. Despite the discouraging outcomes from multicenter clinical trial in the twentieth century, there is sustained interest in optimizing its use to improve patient outcomes. Here we provide a concise overview of DBS for chronic pain as a reference for clinicians.

RECENT FINDINGS

Recently published data lends tentative support for DBS as a means of treating chronic pain. Still, high level-of-evidence data remain elusive. There are a handful of ongoing and prospective clinical trials exploring DBS for pain in the context of closed-loop neuromodulation, invasive electroencephalography monitoring, stimulation parameters, and novel intracranial targets. DBS is a potentially viable method of treating chronic pain. Procedure success is dependent on a number of factors including proper patient and intracranial target selection. Outcomes for ongoing and future clinical trials will help clinicians refine DBS use for this clinical indication.

Deep Brain Stimulation of the Interposed Cerebellar Nuclei in a Conditional Genetic Mouse Model with Dystonia

Dystonia is a neurological disease that is currently ranked as the third most common motor disorder. Patients exhibit repetitive and sometimes sustained muscle contractions that cause limb and body twisting and abnormal postures that impair movement. Deep brain stimulation (DBS) of the basal ganglia and thalamus can be used to improve motor function when other treatment options fail. Recently, the cerebellum has garnered interest as a DBS target for treating dystonia and other motor disorders. Here, we describe a procedure for targeting DBS electrodes to the interposed cerebellar nuclei to correct motor dysfunction in a mouse model with dystonia. Targeting cerebellar outflow pathways with neuromodulation opens new possibilities for using the expansive connectivity of the cerebellum to treat motor and non-motor diseases.

Deep brain stimulation for Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative illness with both motor and nonmotor symptoms. Deep brain stimulation (DBS) is an established safe neurosurgical symptomatic therapy for eligible patients with advanced disease in whom medical treatment fails to provide adequate symptom control and good quality of life, or in whom dopaminergic medications induce severe side effects such as dyskinesias. DBS can be tailored to the patient's symptoms and targeted to various nodes along the basal ganglia-thalamus circuitry, which mediates the various symptoms of the illness; DBS in the thalamus is most efficient for tremors, and DBS in the pallidum most efficient for rigidity and dyskinesias, whereas DBS in the subthalamic nucleus (STN) can treat both tremors, akinesia, rigidity and dyskinesias, and allows for decrease in doses of medications even in patients with advanced stages of the disease, which makes it the preferred target for DBS. However, DBS in the STN assumes that the patient is not too old, with no cognitive decline or relevant depression, and does not exhibit severe and medically resistant axial symptoms such as balance and gait disturbances, and falls. Dysarthria is the most common side effect of DBS, regardless of the brain target. DBS has a long-lasting effect on appendicular symptoms, but with progression of disease, nondopaminergic axial features become less responsive to DBS. DBS for PD is highly specialised; to enable adequate selection and follow-up of patients, DBS requires dedicated multidisciplinary teams of movement disorder neurologists, functional neurosurgeons, specialised DBS nurses and neuropsychologists.

Deep brain-machine interfaces: sensing and modulating the human deep brain

Different from conventional brain-machine interfaces that focus more on decoding the cerebral cortex, deep brain-machine interfaces enable interactions between external machines and deep brain structures. They sense and modulate deep brain neural activities, aiming at function restoration, device control and therapeutic improvements. In this article, we provide an overview of multiple deep brain recording and stimulation techniques that can serve as deep brain-machine interfaces. We highlight two widely used interface technologies, namely deep brain stimulation and stereotactic electroencephalography, for technical trends, clinical applications and brain connectivity research. We discuss the potential to develop closed-loop deep brain-machine interfaces and achieve more effective and applicable systems for the treatment of neurological and psychiatric disorders.

Deep brain stimulation and stereotactic-assisted brain graft injection targeting fronto-striatal circuits for Huntington's disease: an update

INTRODUCTION

Huntington's Disease as progressive neurological disorders associated with motor, behavioral, and cognitive impairment poses a therapeutic challenge in case of limited responsiveness to established therapeutics. Pallidal deep brain stimulation and neurorestorative strategies (brain grafts) scoping to modulate fronto-striatal circuits have gained increased recognition for the treatment of refractory Huntington's disease (HD).

AREAS COVERED

A review (2000-2022) was performed in PubMed, Embase, and Cochrane Library covering clinical trials conceptualized to determine the efficacy and safety of invasive, stereotactic-guided deep-brain stimulation and intracranial brain-graft injection targeting the globus pallidus and adjunct structures (striatum).

EXPERT OPINION

Stereotactic brain-grafting strategies were performed in few HD patients with inconsistent findings and mild-to-moderate clinical responsiveness with a recently published large, randomized-controlled trial (NCT00190450) yielding negative results. We identified 19 in-human DBS trials (uncontrolled) targeting the globus pallidus internus/externus along with randomized-controlled trial pending report (NCT02535884). We did not detect any significant changes in the UHDRS total score after restorative injections, while in contrast, the use of deep-brain stimulation resulted in a significant reduction of chorea. GPi-DBS should be considered in cases where selective chorea is present. However, both invasive therapies remain experimental and are not ready for the implementation in clinical use.

Neurostimulation as a Method of Treatment and a Preventive Measure in Canine Drug-Resistant Epilepsy: Current State and Future Prospects

Modulation of neuronal activity for seizure control using various methods of neurostimulation is a rapidly developing field in epileptology, especially in treatment of refractory epilepsy. Promising results in human clinical practice, such as diminished seizure burden, reduced incidence of sudden unexplained death in epilepsy, and improved quality of life has brought neurostimulation into the focus of veterinary medicine as a therapeutic option. This article provides a comprehensive review of available neurostimulation methods for seizure management in drug-resistant epilepsy in canine patients. Recent progress in non-invasive modalities, such as repetitive transcranial magnetic stimulation and transcutaneous vagus nerve stimulation is highlighted. We further discuss potential future advances and their plausible application as means for preventing epileptogenesis in dogs.

Where do we stand now regarding treatment of psychiatric and neurodegenerative disorders? Considerations in using magnetoelectric nanoparticles as an innovative approach

Almost 1000 million people have recently been diagnosed with a mental health or substance disorder (Ritchie & Roser, 2018). Psychiatric disorders, and their treatment, represent a big burden to the society worldwide, causing about 8 million deaths per year (Walker et al., 2015). Daily progress in science enables continuous advances in methods to treat patients; however, the brain remains to be the most unknown and complex organ of the body. There is a growing demand for innovative approaches to treat psychiatric as well as neurodegenerative disorders, disorders with unknown curability, and treatments mostly designed to slow disease progression. Based on that need and the peculiarity of the central nervous system, in the present review, we highlight the handicaps of the existing approaches as well as discuss the potential of the recently introduced magnetoelectric nanoparticles (MENPs) to become a game-changing tool in future applications for the treatment of brain alterations. Unlike other stimulation approaches, MENPs have the potential to enable a wirelessly controlled stimulation at a single-neuron level without requiring genetic modification of the neural tissue and no toxicity has yet been reported. Their potential as a new tool for targeting the brain is discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Neurological Disease.

International Regulatory Standards for the Qualitative Measurement of Deep Brain Stimulation in Clinical Research

Deep brain stimulation (DBS) has progressed to become a promising treatment modality for neurologic and psychiatric disorders like epilepsy and major depressive disorder due to its growing personalization. Despite evidence pointing to the benefits of DBS if tested on these personalized qualitative metrics, rather than randomized-control trial quantitative standards, the evaluation of these novel devices appears to be based on the latter. This study surveyed the presence of this trend in the national regulatory guidelines of the prominent DBS researching countries. It was found that two governing bodies, in the European Union and Australia, acknowledged the option for qualitative measures. These findings support further development of national regulatory guidelines, so the neuroscientific community developing these neurotechnologies can better understand the impact their treatments have on patients.

Past, Present, and Future of Deep Brain Stimulation: Hardware, Software, Imaging, Physiology and Novel Approaches

Deep brain stimulation (DBS) has advanced treatment options for a variety of neurologic and neuropsychiatric conditions. As the technology for DBS continues to progress, treatment efficacy will continue to improve and disease indications will expand. Hardware advances such as longer-lasting batteries will reduce the frequency of battery replacement and segmented leads will facilitate improvements in the effectiveness of stimulation and have the potential to minimize stimulation side effects. Targeting advances such as specialized imaging sequences and “connectomics” will facilitate improved accuracy for lead positioning and trajectory planning. Software advances such as closed-loop stimulation and remote programming will enable DBS to be a more personalized and accessible technology. The future of DBS continues to be promising and holds the potential to further improve quality of life. In this review we will address the past, present and future of DBS.

Where Are We with Deep Brain Stimulation? A Review of Scientific Publications and Ongoing Research

BACKGROUND

Deep brain stimulation (DBS) is a neuromodulatory technique that delivers adjustable electrical stimuli to brain targets to relieve symptoms associated with dysregulated neural circuitry. Over the last several decades, DBS has been applied to a number of conditions, including motor, pain, mood, and cognitive disorders. An assessment of the body of work in this field is warranted to determine where we have been, define the current state of the field, and chart a path toward the future.

OBJECTIVE

The aim of the study was to assess the state of DBS-related research by analyzing the DBS literature as well as active studies sponsored by the National Institutes of Health (NIH) or German Research Foundation (Deutsche Forschungsgemeinschaft [DFG]).

METHODS

Peer-reviewed DBS publications were extracted from PubMed. Active NIH-funded DBS projects were extracted from the RePORT database and active DFG projects from the German Research Foundation database. Records were analyzed using custom-developed algorithms to generate a detailed overview of past and present DBS-related research. Specifically, records were categorized by publication year, journal, language, country of origin, contributing authors, disorder, brain target, study design, and topic. Expected project duration and costs were also provided for active studies.

RESULTS

In total, 8,974 publications, 172 active NIH-funded projects, and 34 active DFG projects were identified. Records spanned 52 different disorders across 31 distinct brain targets and showed a recent shift toward studies examining conditions other than movement disorders. Most published works involved human research (80.6% of published studies), of which 10.2% were identified as clinical trials. Increasingly, studies focused on imaging or electrophysiological changes associated with DBS (69.8% NIH-active and 70.6% DFG-active vs. 25.8% published) or developing new stimulation techniques and adaptive technologies (37.8% NIH-active and 17.6% DFG-active vs. 6.5% published).

CONCLUSIONS

This overview of past and present DBS-related studies provides insight into the status of DBS research and what we can anticipate in the future concerning new indications, improved/novel target selection and stimulation paradigms, closed-loop technology, and a better understanding of the mechanisms of action of DBS.

Neuromodulation Strategies for the Treatment of Depression

For many decades, psychiatric treatment has been primarily guided by two major paradigms of psychopathology: a neurochemical paradigm leading to the development of medications and a psychological paradigm resulting in the development of psychotherapies. A third paradigm positing that psychiatric dysfunction results from abnormal communication within a network of brain regions that regulate mood, thought, and behavior has gained increased attention over the past several years and underlies the development of multiple neuromodulation and neurostimulation therapies. This neural circuit paradigm is not new. In the late 19th and early 20th centuries, it was a common way of understanding psychiatric illness and led to several of our earliest somatic therapies. However, with the rise of effective medications and evidence-based psychotherapies, this paradigm went mostly dormant. Its recent reemergence resulted from a growing recognition that medications and psychotherapy leave many patients inadequately treated, along with technological advances that have revolutionized our ability to understand and modulate the neural circuitry involved in psychiatric disorders. In this overview, the authors review the history and current state of neuromodulation for psychiatric illness and specifically focus on these approaches as a treatment for depression, as this has been the primary indication for these interventions over time.

Neurodegenerative disorders management: state-of-art and prospects of nano-biotechnology

Neurodegenerative disorders (NDs) are highly prevalent among the aging population. It affects primarily the central nervous system (CNS) but the effects are also observed in the peripheral nervous system. Neural degeneration is a progressive loss of structure and function of neurons, which may ultimately involve cell death. Such patients suffer from debilitating memory loss and altered motor coordination which bring up non-affordable and unavoidable socio-economic burdens. Due to the unavailability of specific therapeutics and diagnostics, the necessity to control or manage NDs raised the demand to investigate and develop efficient alternative approaches. Keeping trends and advancements in view, this report describes both state-of-the-art and challenges in nano-biotechnology-based approaches to manage NDs, toward personalized healthcare management. Sincere efforts are being made to customize nano-theragnostics to control: therapeutic cargo packaging, delivery to the brain, nanomedicine of higher efficacy, deep brain stimulation, implanted stimulation, and managing brain cell functioning. These advancements are useful to design future therapy based on the severity of the patient's neurodegenerative disease. However, we observe a lack of knowledge shared among scientists of a variety of expertise to explore this multi-disciplinary research field for NDs management. Consequently, this review will provide a guideline platform that will be useful in developing novel smart nano-therapies by considering the aspects and advantages of nano-biotechnology to manage NDs in a personalized manner. Nano-biotechnology-based approaches have been proposed as effective and affordable alternatives at the clinical level due to recent advancements in nanotechnology-assisted theragnostics, targeted delivery, higher efficacy, and minimal side effects.

Neurorights in History: A Contemporary Review of José M. R. Delgado's "Physical Control of the Mind" (1969) and Elliot S. Valenstein's "Brain Control" (1973)

Scholars from various disciplines discuss the ethical, legal, and social implications of neurotechnology. Some have proposed four concrete “neurorights”. This review presents the research of two pioneers in brain stimulation from the 1950s to 1970s, José M. R. Delgado and Elliot S. Valenstein, who also reflected upon the ethical, legal, and social aspects of their and other scientists’ related research. Delgado even formulated the vision “toward a psychocivilized society” where brain stimulation is used to control, in particular, citizens’ aggressive and violent behavior. Valenstein, by contrast, believed that the brain is not organized in such a way to allow the control or even removal of only negative processes without at the same time diminishing desirable ones. The paper also describes how animal and human experimentation on brain stimulation was carried out in that time period. It concludes with a contemporary perspective on the relevance of neurotechnology for neuroethics, neurolaw, and neurorights, including two recent examples for brain-computer interfaces.

Electrical stimulation in animal models of epilepsy: A review on cellular and electrophysiological aspects

Epilepsy is a debilitating condition, primarily refractory individuals, leading to the search for new efficient therapies. Electrical stimulation is an important method used for years to treat several neurological disorders. Currently, electrical stimulation is used to reduce epileptic crisis in patients and shows promising results. Even though the use of electricity to treat neurological disorders has grown worldwide, there are still many caveats that must be clarified, such as action mechanisms and more efficient stimulation treatment parameters. Thus, this review aimed to explore the comprehension of the main stimulation methods in animal models of epilepsy using rodents to develop new experimental protocols and therapeutic approaches.

Electrical Brain Stimulation for Epilepsy and Emerging Applications

SUMMARY

Electrical brain stimulation is an established therapy for movement disorders, epilepsy, obsessive compulsive disorder, and a potential therapy for many other neurologic and psychiatric disorders. Despite significant progress and FDA approvals, there remain significant clinical gaps that can be addressed with next generation systems. Integrating wearable sensors and implantable brain devices with off-the-body computing resources (smart phones and cloud resources) opens a new vista for dense behavioral and physiological signal tracking coupled with adaptive stimulation therapy that should have applications for a range of brain and mind disorders. Here, we briefly review some history and current electrical brain stimulation applications for epilepsy, deep brain stimulation and responsive neurostimulation, and emerging applications for next generation devices and systems.

Electrical deep neuromodulation in psychiatry

Addressing treatment refractoriness in psychiatric diseases is an essential public health objective. The last two decades have seen an increasing interest for deep brain stimulation (DBS) of several brain targets. In this chapter, we have reviewed the main DBS clinical trials in psychiatric diseases, mainly obsessive compulsive disorders (OCD) and depression, but also emerging research in other psychiatric disorders. While its efficacy and safety are confirmed, DBS is still not considered as standard therapy in psychiatry. However, advances in neuroimaging research combined to behavioral and electrophysiological data uniquely provided by DBS studies improve knowledge on physiopathology in these brain diseases. This will help define the optimal brain targets according to specific phenotype dimensions. Revealing the mechanisms of action and effects of DBS will support that its impact goes beyond a loco-regional brain stimulation and confirms that electrical neuromodulation influences brain networks. Added to the progress in neuromodulation technology, these insights will hopefully facilitate a more widespread application of this promising treatment. Future development of a personalized multimodal assessment of underlying dysfunctional brain networks will open new circuit-specific treatment perspectives that may facilitate better patient outcomes.

Globus Pallidus Internus (GPi) Deep Brain Stimulation for Parkinson's Disease: Expert Review and Commentary

INTRODUCTION

The globus pallidus internus (GPi) region has evolved as a potential target for deep brain stimulation (DBS) in Parkinson's disease (PD). DBS of the GPi (GPi DBS) is an established, safe and effective method for addressing many of the motor symptoms associated with advanced PD. It is important that clinicians fully understand this target when considering GPi DBS for individual patients.

METHODS

The literature on GPi DBS in PD has been comprehensively reviewed, including the anatomy, physiology and potential pitfalls that may be encountered during surgical targeting and post-operative management. Here, we review and address the implications of lead location on GPi DBS outcomes. Additionally, we provide a summary of randomized controlled clinical trials conducted on DBS in PD, together with expert commentary on potential applications of the GPi as target. Finally, we highlight future technologies that will likely impact GPi DBS, including closed-loop adaptive approaches (e.g. sensing-stimulating capabilities), advanced methods for image-based targeting and advances in DBS programming, including directional leads and pulse shaping.

RESULTS

There are important disease characteristics and factors to consider prior to selecting the GPi as the DBS target of PD surgery. Prior to and during implantation of the leads it is critical to consider the neuroanatomy, which can be defined through the combination of image-based targeting and intraoperative microelectrode recording strategies. There is an increasing body of literature on GPi DBS in patients with PD suggesting both short- and long-term benefits. Understanding the GPi target can be useful in choosing between the subthalamic (STN), GPi and ventralis intermedius nucleus as lead locations to address the motor symptoms and complications of PD.

CONCLUSION

GPi DBS can be effectively used in select cases of PD. As the ongoing DBS target debate continues (GPi vs. STN as DBS target), clinicians should keep in mind that GPi DBS has been shown to be an effective treatment strategy for a variety of symptoms, including bradykinesia, rigidity and tremor control. GPi DBS also has an important, direct anti-dyskinetic effect. GPi DBS is easier to program in the outpatient setting and will allow for more flexibility in medication adjustments (e.g. levodopa). Emerging technologies, including GPi closed-loop systems, advanced tractography-based targeting and enhanced programming strategies, will likely be future areas of GPi DBS expansion. We conclude that although the GPi as DBS target may not be appropriate for all PD patients, it has specific clinical advantages.

Advanced Imaging in Psychiatric Neurosurgery: Toward Personalized Treatment

OBJECTIVES

Our aim is to review several recent landmark studies discussing the application of advanced neuroimaging to guide target selection in deep brain stimulation (DBS) for psychiatric disorders.

MATERIALS AND METHODS

We performed a PubMed literature search of articles related to psychiatric neurosurgery, DBS, diffusion tensor imaging, probabilistic tractography, functional magnetic resonance imaging (MRI), and blood oxygen level-dependent activation. Relevant articles were included in the review.

RESULTS

Recent advances in neuroimaging, namely the use of diffusion tensor imaging, probabilistic tractography, functional MRI, and Positron emission tomography have provided higher resolution depictions of structural and functional connectivity between regions of interest. Applying these imaging modalities to DBS has increased understanding of the mechanism of action of DBS from the single structure to network level, allowed for new DBS targets to be discovered, and allowed for individualized DBS targeting for psychiatric indications.

CONCLUSIONS

Advanced neuroimaging techniques may be especially important to guide personalized DBS targeting in psychiatric disorders such as treatment-resistant depression and obsessive-compulsive disorder where symptom profiles and underlying disordered circuitry are more heterogeneous. These articles suggest that advanced imaging can help to further individualize and optimize DBS, a promising next step in improving its efficacy.

Development and Initial Validation of the Chinese Version of the Florida Surgical Questionnaire for Parkinson's Disease

Background

Deep brain stimulation (DBS) for Parkinson's disease (PD) has evolved as a well-established treatment in neurosurgery, and identifying appropriate surgical candidates could contribute to better DBS outcomes. The Florida Surgical Questionnaire for Parkinson Disease (FLASQ-PD) is a reasonable screening tool for assessing DBS candidacy in PD patients; however, a Chinese version of FLASQ-PD is needed for functional neurosurgery units in China. In this study, we translated the FLASQ-PD to Chinese and assessed its reliability and validity for Chinese PD patients.

Methods

The FLASQ-PD was translated before the study formally started. A single-center retrospective analysis of FLASQ-PD was performed at the Ruijin Hospital, affiliated with Shanghai Jiaotong University School of Medicine, between July and December 2019. The Unified Parkinson Disease Rating Scale III (UPDRS-III) was also used to assess PD patients on and off medication. All patients were evaluated for surgical candidacy by specialists.

Results

Overall, 115 PD patients, 25 with parkinsonism and six with multiple system atrophy were consecutively included. Internal consistency of the Chinese FLASQ-PD was roughly adequate (Cronbach's alpha = 0.664). There were significant differences in mean total scores of the Chinese FLASQ-PD between the diagnostic (Kruskal-Wallis H value = 37.450, p ≤ 0.001) and surgery-candidacy groups (H = 48.352, p ≤ 0.001). Drug improvements in UPDRS-III scores were mildly correlated with the Chinese FLASQ-PD scores in the surgery-ready group (Pearson correlation = 0.399, p=0.001).

Conclusions

The Chinese FLASQ-PD, which is a simple and efficient screening tool for clinicians, was developed and initially validated in this retrospective single-center study.

Technology of deep brain stimulation: current status and future directions

Deep brain stimulation (DBS) is a neurosurgical procedure that allows targeted circuit-based neuromodulation. DBS is a standard of care in Parkinson disease, essential tremor and dystonia, and is also under active investigation for other conditions linked to pathological circuitry, including major depressive disorder and Alzheimer disease. Modern DBS systems, borrowed from the cardiac field, consist of an intracranial electrode, an extension wire and a pulse generator, and have evolved slowly over the past two decades. Advances in engineering and imaging along with an improved understanding of brain disorders are poised to reshape how DBS is viewed and delivered to patients. Breakthroughs in electrode and battery designs, stimulation paradigms, closed-loop and on-demand stimulation, and sensing technologies are expected to enhance the efficacy and tolerability of DBS. In this Review, we provide a comprehensive overview of the technical development of DBS, from its origins to its future. Understanding the evolution of DBS technology helps put the currently available systems in perspective and allows us to predict the next major technological advances and hurdles in the field.

Neurons under genetic control: What are the next steps towards the treatment of movement disorders?

Since the implementation of deep-brain stimulation as a therapy for movement disorders, there has been little progress in the clinical application of novel alternative treatments. Movement disorders are a group of neurological conditions, which are characterised with impairment of voluntary movement and share similar anatomical loci across the basal ganglia. The focus of the current review is on Parkinson's disease and Huntington's disease as they are the most investigated hypokinetic and hyperkinetic movement disorders, respectively. The last decade has seen enormous advances in the development of laboratory techniques that control neuronal activity. The two major ways to genetically control the neuronal function are: 1) expression of light-sensitive proteins that allow for the optogenetic control of the neuronal spiking and 2) expression or suppression of genes that control the transcription and translation of proteins. However, the translation of these methodologies from the laboratories into the clinics still faces significant challenges. The article summarizes the latest developments in optogenetics and gene therapy. Here, I compare the physiological mechanisms of established electrical deep brain stimulation to the experimental optogenetical deep brain stimulation. I compare also the advantages of DNA- and RNA-based techniques for gene therapy of familial movement disorders. I highlight the benefits and the major issues of each technique and I discuss the translational potential and clinical feasibility of optogenetic stimulation and gene expression control. The review emphasises recent technical breakthroughs that could initiate a notable leap in the treatment of movement disorders.

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.

On the Right Track to Treat Movement Disorders: Promising Therapeutic Approaches for Parkinson's and Huntington's Disease

Movement disorders are neurological conditions in which patients manifest a diverse range of movement impairments. Distinct structures within the basal ganglia of the brain, an area involved in movement regulation, are differentially affected for every disease. Among the most studied movement disorder conditions are Parkinson’s (PD) and Huntington’s disease (HD), in which the deregulation of the movement circuitry due to the loss of specific neuronal populations in basal ganglia is the underlying cause of motor symptoms. These symptoms are due to the loss principally of dopaminergic neurons of the substantia nigra (SN) par compacta and the GABAergic neurons of the striatum in PD and HD, respectively. Although these diseases were described in the 19th century, no effective treatment can slow down, reverse, or stop disease progression. Available pharmacological therapies have been focused on preventing or alleviating motor symptoms to improve the quality of life of patients, but these drugs are not able to mitigate the progressive neurodegeneration. Currently, considerable therapeutic advances have been achieved seeking a more efficacious and durable therapeutic effect. Here, we will focus on the new advances of several therapeutic approaches for PD and HD, starting with the available pharmacological treatments to alleviate the motor symptoms in both diseases. Then, we describe therapeutic strategies that aim to restore specific neuronal populations or their activity. Among the discussed strategies, the use of Neurotrophic factors (NTFs) and genetic approaches to prevent the neuronal loss in these diseases will be described. We will highlight strategies that have been evaluated in both Parkinson’s and Huntington’s patients, and also the ones with strong preclinical evidence. These current therapeutic techniques represent the most promising tools for the safe treatment of both diseases, specifically those aimed to avoid neuronal loss during disease progression.

Psychosurgery in the History of Stereotactic Functional Neurosurgery

The paper invites to reappraise the role of psychosurgery for and within the development of functional stereotactic neurosurgery. It highlights the significant and long-lived role of stereotactic neurosurgery in the treatment of severe and chronic mental disorders. Stereotactic neurosurgery developed out of psychosurgery. It was leucotomy for psychiatric disorders and chronic pain that paved the way for stereotactic dorsomedial thalamotomy in these indications and subsequently for stereotactic surgery in epilepsy and movement disorders. Through the 1960s stereotactic psychosurgery continued to progress in silence. Due to the increased applications of stereotactic surgery in psychiatric indications, psychosurgery's renaissance was proclaimed in the early 1970s. At the same time, however, a public fearing mind control started to discredit all functional neurosurgery for mental disorders, including stereotactic procedures. In writing its own history, stereotactic neurosurgery's identity as a neuropsychiatric discipline became subsequently increasingly redefined as principally a sort of "surgical neurology," cut off from its psychiatric origin.

The Cerebral Localization of Pain: Anatomical and Functional Considerations for Targeted Electrical Therapies

Millions of people in the United States are affected by chronic pain, and the financial cost of pain treatment is weighing on the healthcare system. In some cases, current pharmacological treatments may do more harm than good, as with the United States opioid crisis. Direct electrical stimulation of the brain is one potential non-pharmacological treatment with a long history of investigation. Yet brain stimulation has been far less successful than peripheral or spinal cord stimulation, perhaps because of our limited understanding of the neural circuits involved in pain perception. In this paper, we review the history of using electrical stimulation of the brain to treat pain, as well as contemporary studies identifying the structures involved in pain networks, such as the thalamus, insula, and anterior cingulate. We propose that the thermal grill illusion, an experimental pain model, can facilitate further investigation of these structures. Pairing this model with intracranial recording will provide insight toward disentangling the neural correlates from the described anatomic areas. Finally, the possibility of altering pain perception with brain stimulation in these regions could be highly informative for the development of novel brain stimulation therapies for chronic pain.

Deep brain stimulation for treatment-resistant depression: a safe and effective option

Introduction: Major depressive disorder (MDD) is the leading cause of years lost to disability worldwide. Pharmacotherapy and psychotherapy are effective treatments in most depressive episodes; but, about 30% of MDD patients remain symptomatic, and relapse is a common event. Recently, deep brain stimulation (DBS) has emerged as a valid therapeutic option in treatment-resistant depression (TRD) patients.Areas covered: In this paper, the authors summarize the findings of studies focused on these pathophysiologic phenomena and specifically on the role of DBS as a therapeutic option in TRD patients. The authors simply reviewed RCTs, open-label studies, neurophysiological mechanisms of DBS in MDD, and the possible role of different targets. Finally, we suggest possible future options.Expert opinion: Depression is a systems-level disorder, involving several brain structures. Neuroimaging studies demonstrate multiple interconnected regions that modulate different neural networks. DBS can modulate different targets, and others are under investigation. Among these subcallosal cingulate gyrus (SCG), ventral capsule and ventral striatum (VC/VS) seems to be the most relevant targets. We believe that, in the next future, DBS for TRD might become a first-line of treatment, especially using directional leads, that may help us to improve therapeutic effects.

Johann Bernhard Aloys von Gudden: The Unrecognized Role of the Psychiatrist and Neuroanatomist in Modern Stereotactic Neurosurgery

Bernhard von Gudden was the founder of the famous school of psychiatry and neuroanatomy in Munich, Germany. Beyond his association with the mysterious death of King Ludwig II of Bavaria, not much is known about Bernhard von Gudden's work in neuroanatomy. He pioneered fiber tract mapping by studying the effects of neurodegeneration following brain lesions. His ideas and work lay the foundation for subsequent fiber tract mapping strategies including the latest method using diffusion tensor magnetic resonance. This paper describes and acknowledges his contribution to the field, now collectively known as connectomics, and describes how it has become an essential tool in modern stereotactic neurosurgery.

Deep brain stimulation in the caudal zona incerta in patients with essential tremor: effects on cognition 1 year after surgery

OBJECTIVE

The ventral intermediate nucleus (VIM) of the thalamus is currently the established target in the use of deep brain stimulation (DBS) to treat essential tremor (ET). In recent years, the caudal zona incerta (cZi), a brain target commonly used during the lesional era, has been revived as the primary target in a number of DBS studies that show evidence of the efficacy of cZi targeting in DBS treatment for controlling the symptoms of ET. The authors sought to obtain comprehensive neuropsychological data and thoroughly investigate the cognitive effects of cZi targeting in patients with ET treated with DBS.

METHODS

Twenty-six consecutive patients with ET who received DBS with cZi as the target at our department from December 2012 to February 2017 were included in this study. All patients were assessed using a comprehensive neuropsychological test battery covering the major cognitive domains both preoperatively and 12 months postoperatively.

RESULTS

The results show no major adverse effects on patient performance on the tests of cognitive function other than a slight decline of semantic verbal fluency.

CONCLUSIONS

This study indicates that the cZi is a safe target from a cognitive perspective in the treatment of ET with DBS.

Role of deep brain stimulation therapy in the magnetic resonance-guided high-frequency focused ultrasound era: current situation and future prospects

Introduction: Deep brain stimulation (DBS) is a well-established treatment of movement disorders; but recently there has been an increasing trend toward the ablative procedure magnetic resonance-guided focused ultrasound (MRgFU). DBS is an efficient neuromodulatory technique but associated with surgical complications. MRIgFUS is an incision-free method that allows thermal lesioning, with fewer surgical complications but irreversible effects.Areas covered: We look at current and prospective aspects of both techniques. In DBS, appropriate patient selection, improvement in surgical expertise, target accuracy (preoperative and intraoperative imaging), neurophysiological recordings, and novel segmented leads need to be considered. However, increased number of older patients with higher comorbidities and risk of DBS complications (mainly intracranial hemorrhage, but also infections, hardware complications) make them not eligible for surgery. With MRgFUS, hemorrhage risks are virtually nonexistent, infection or hardware malfunction are eliminated, while irreversible side effects can appear.Expert commentary: Comparison of the efficacy and risks associated with these techniques, in combination with a growing aged population in developed countries with higher comorbidities and a preference for less invasive treatments, necessitates a review of the indications for movement disorders and the most appropriate treatment modalities.

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.

Electrophysiological and imaging evidence of sustained inhibition in limbic and frontal networks following deep brain stimulation for treatment refractory obsessive compulsive disorder

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder that arises from a complex interaction of environmental and genetic factors. Despite numerous pharmacological and behavioral interventions, approximately 10% of patients remain refractory. High-frequency deep brain stimulation (HF-DBS) has shown promising results for treatment-refractory OCD. We report the follow-up result of up to 6 years of 4 treatment-refractory OCD patients treated by HF-DBS. Targets of stimulation were the anterior limb of the internal capsule (ALIC) in two cases, and the nucleus accumbens (NAc) in the remaining cohort. The clinical profiles were quantified by the Yale-Brown obsessive-compulsive scale (Y-BOCS). Highly significant reductions in Y-BOCS scores were obtained from all patients during the follow-up period. A greater that 90% reduction in Y-BOCS, observed in the most successful case, was achieved with NAc HF-DBS. Y-BOCS scores in the other patients consistently achieved over 50% reductions in OCD symptoms. FDG-PET imaging indicated post-surgical reductions in metabolism, in not only targeted limbic networks, but also other frontal cortical and subcortical regions, suggesting that large-scale network modulation and inhibitions are associated with functional recovery in OCD. This study demonstrates that HF-DBS targeted to the ALIC and NAc is a safe and effective method for ameliorating intractable, treatment-refractory OCD symptoms. The NAc appeared to be the superior target for symptom reduction, and local inhibition of NAc activity and reduced frontal metabolism are key therapeutic indications.

Applying a Sensing-Enabled System for Ensuring Safe Anterior Cingulate Deep Brain Stimulation for Pain

Deep brain stimulation (DBS) of the anterior cingulate cortex (ACC) was offered to chronic pain patients who had exhausted medical and surgical options. However, several patients developed recurrent seizures. This work was conducted to assess the effect of ACC stimulation on the brain activity and to guide safe DBS programming. A sensing-enabled neurostimulator (Activa PC + S) allowing wireless recording through the stimulating electrodes was chronically implanted in three patients. Stimulation patterns with different amplitude levels and variable ramping rates were tested to investigate whether these patterns could provide pain relief without triggering after-discharges (ADs) within local field potentials (LFPs) recorded in the ACC. In the absence of ramping, AD activity was detected following stimulation at amplitude levels below those used in chronic therapy. Adjustment of stimulus cycling patterns, by slowly ramping on/off (8-s ramp duration), was able to prevent ADs at higher amplitude levels while maintaining effective pain relief. The absence of AD activity confirmed from the implant was correlated with the absence of clinical seizures. We propose that AD activity in the ACC could be a biomarker for the likelihood of seizures in these patients, and the application of sensing-enabled techniques has the potential to advance safer brain stimulation therapies, especially in novel targets.

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.

Venous Infarct after Sacrifice of Single Cortical Vein during Deep-Brain Stimulation Surgery

Intracerebral hemorrhage (ICH) is the most feared and dreadful complication related to deep-brain stimulation (DBS). Bleeding may originate from arterial or venous damage. Commonly, hemorrhage is detected by postoperative imaging performed to assess lead positioning in asymptomatic patients. Rarely, hemorrhage leads to stroke, coma, or even death. We present the case of a patient who suffered a severe ICH of venous origins after bilateral DBS. Deep-brain hemorrhages are the most difficult to be predicted and to be prevented because they are caused by small vessels. As superficial hemorrhages are secondary to venous coagulation or sulcal hemorrhage, neurosurgeons must drive all efforts to minimize their occurrence.

Deep Brain Stimulation for Intractable Obsessive-compulsive Disorder: The International and Japanese Situation/Scenario

Deep brain stimulation (DBS) is used to treat symptoms by modulating the cortico-striato-thalamo-cortical (CSTC) loop in the central nervous system (CNS), and attempts to research loop circuit disorders have been globally initiated among the intractable neurological and psychiatric disorders. DBS treatment has been evaluated for all these newly found CNS loop circuit disorders. In 2011, neurosurgical treatments for psychiatric disorders were renamed from “psychosurgery” to “neurosurgery for psychiatric disorders (NPD)” by the World Society for Stereotactic and Functional Neurosurgery (WSSFN). Moreover, in 2014, “Consensus on guidelines for stereotactic neurosurgery for psychiatric disorders” was published by the WSSFN to address the differences in correspondence of stereotactic NPD. Globally, two multicenter prospective randomized control trials regarding DBS of the subcallosal cingulated gyrus and ventral anterior internal capsule/ventral striatum for intractable depression have been terminated after futility analysis. However, DBS for intractable obsessive-compulsive disorder (OCD), unlike for intractable depression, is showing steady development. In Japan, NPDs have not been performed since 1975 following the adoption of “Resolution of total denial for psychosurgery” by the Japanese Society of Psychiatry and Neurology. Nevertheless, a trend to adopt new neuro-modulation techniques for psychiatric disorders, including DBS, are emerging. We have created a clinical research protocol for the use of DBS in intractable OCD, which has been approved by the ethical committee of Hamamatsu University School of Medicine, with the hope of commencing DBS treatment for intractable OCD patients in the near future.

What rodent models of deep brain stimulation can teach us about the neural circuit regulation of prepulse inhibition in neuropsychiatric disorders

Deep brain stimulation (DBS) is routinely used for treatment of movement disorders and it is also under investigation for neuropsychiatric disorders with deficient sensorimotor gating, such as schizophrenia, Tourette's syndrome and obsessive compulsive disorder. Electrical stimulation induces excitation and inhibition both at the stimulation site and at projection sites, thus modulating synchrony and oscillatory behavior of neuronal networks. We first provide background information on DBS in neuropsychiatric disorders accompanied by deficient sensorimotor gating. We then introduce prepulse inhibition (PPI) as a measure for sensorimotor gating in these disorders. Thereafter, we report on the use of DBS in rat models with deficient PPI induced by pharmacologic, genetic and neurodevelopmental manipulation. These models offer the opportunity to define the neuronal circuit regulation that is of relevance to PPI and its deficits in neuropsychiatric disorders with disturbed sensorimotor gating. Finally, we report on the use of the PPI paradigm in human patients operated for DBS on/off stimulation, which may further elucidate the neuronal network involved in regulation of PPI.

Recent advances in deep brain stimulation in psychiatric disorders

Deep brain stimulation (DBS) has been offered to patients suffering of severe and resistant neuropsychiatric disorders like Obsessive Compulsive Disorder (OCD), Gilles de la Tourette Syndrome (TS) and Major Depression (MDD). Modulation of several targets within the cortico-striato-thalamo-cortical circuits can lead to a decrease of symptom severity in those patients. This review focuses on the recent clinical outcomes in DBS in psychiatric disorders. Studies on OCD and TS are now focusing on the long-term effects of DBS, with encouraging results regarding not only the decrease of symptoms, but also quality of life. They also highlighted efficient adjuvant techniques, like cognitive and behavioural therapy and support programs, to enhance an often-partial response to DBS. The application of DBS for MDD is more recent and, despite encouraging initial open-label studies, two large randomised studies have failed to demonstrate an efficacy of DBS in MDD according to evidence-based medicine criteria. Last years, DBS was also tested in other resistant psychiatric disorders, as anorexia nervosa and addiction, with encouraging preliminary results. However, today, no target – whatever the disease – can meet the criteria for clinical efficacy as recently defined by an international committee for neurosurgery for psychiatric disorders. Consequently, DBS in psychiatric disorders still needs to proceed within the frame of clinical trials.