Deep Brain Stimulation for Depression

Lateral habenula induces cognitive and affective dysfunctions in mice with neuropathic pain via an indirect pathway to the ventral tegmental area

Neuropathic pain, which has become a major public health concern, is frequently accompanied by the deterioration of affective behavior and cognitive function. However, the brain circuitry underlying these changes is poorly understood. Therefore, we aimed to identify in a mouse model the converging circuit that influences the sensory, affective, and cognitive consequences of neuropathic pain. The lateral habenula (LHb) and ventral tegmental area (VTA) have been confirmed to play critical roles in the regulation of pain, cognition, and depression. Given the essential role of the LHb in depression and cognition, we attempted to clarify how neural circuitry involving the LHb integrates pain-related information. Our data confirmed that the VTA receives projections from the LHb, but our results suggest that inhibition of this direct pathway has no effect on the behavior of mice with chronic neuropathic pain. The rostromedial tegmental nucleus (RMTg), a GABAergic structure believed to underlie the transient inhibition of DAergic neurons in the VTA, received glutamatergic inputs from the LHb and projected strongly to the VTA. Furthermore, our data suggest that a projection from LHb glutamatergic neurons to RMTg GABAergic neurons in the VTA, constituting an indirect LHbGlu → RMTgGABA → VTADA pathway, participates in peripheral nerve injury-induced nociceptive hypersensitivity, depressive-like behavior, and cognitive dysfunction. Ex vivo extracellular recordings of LHb neurons showed that the proportion of burst-firing cells in the LHb was significantly increased in indirect projections rather than in direct projections. This may explain the functional discrepancies between direct and indirect projections of the LHb to the VTA. Collectively, our study identifies a pivotal role of the LHbGlu → RMTgGABA → VTADA pathway in processing pain. This pathway may offer new therapeutic targets to treat neuropathic pain and its associated depressive-like and cognitive impairments.

Pre-operative predictors of response to deep brain stimulation in depression: A systematic review and meta-analysis

Deep Brain Stimulation (DBS) for treatment-resistant depression (TRD) results in about 50 % response and 30 % remission. Response prediction may optimize patient selection, which is currently based on expert opinion. Here, we provide a comprehensive and systematic overview of the available data and explore if expert opinion is supported quantitatively. PubMed, Cochrane, Embase and PsycInfo were searched and studies reporting on DBS for TRD were included if they 1) reported on pre-operative predictors of response or 2) compared responders vs. non-responders. Meta-analysis was performed on outcomes with k ≥ 4 studies reporting data separately for responder/non-responder groups. From 7766 screened references, we included 22 studies on 294 unique patients. Seven studies were included for meta-analysis. No significant responder/non-responder differences were found in meta-analysis, but a trend toward shorter duration of current episode in responders (-0.97 years, p = 0.076, k = 6, n = 105) was found. Neuroimaging studies showed relative hyperactivity of the SCC area in responders (k = 2, n = 41), without volumetric differences (k = 2, n = 85). Multiple other structural, metabolic and (neuro)psychological predictors were found in small samples and have not yet been replicated. We conclude that there is no quantitative support for any of the response predictors based on expert opinion, although depressive chronicity and prior treatment responsiveness may be of interest for future research. For clinical practice, this suggests that patients should not be excluded based on the reviewed characteristics. More than a dozen predictors across structural, metabolic and (neuro)psychological outcomes are presented, awaiting replication and prospective validation in future trials.

The Targets of Deep Brain Stimulation in the Treatment of Treatment-Resistant Depression: A Review

PURPOSE

The purpose of this review is to evaluate the current state and potential future directions of deep brain stimulation (DBS) therapy for treatment-resistant depression (TRD), a condition that significantly impacts patients' quality of life and for which conventional treatments are often ineffective.

METHOD

This review synthesizes evidence from clinical trials and preclinical studies published in five years, identified through PubMed searches using keywords ("Deep Brain Stimulation" OR DBS) AND ("Treatment-Resistant Depression" OR TRD). Included studies encompassed clinical research (randomized/non-randomized trials, cohort studies) and mechanistic preclinical studies, excluding non-English publications and nonhuman experiments. Screening prioritized neuroanatomical targets (e.g., SCG, NAcc) and stimulation parameter optimization data. Examining the therapeutic mechanisms of DBS, the neuroanatomical targets utilized, and the clinical outcomes observed. It also discusses the challenges faced in DBS application and proposes potential technological advancements, such as closed-loop therapy and fiber tracking technology.

FINDING

Preliminary evidence exists regarding the efficacy and safety of DBS in the treatment of TRD in the subcortical cingulate gyrus (SCG), nucleus accumbens (NAcc), ventral capsule/ventral striatum (VC/VS), anterior limb of the internal capsule (ALIC), and so forth. Nevertheless, the optimal stimulation target remains undetermined. The review highlights the complexity of TRD and the need for personalized treatment strategies, noting that genetic, epigenetic, and neurophysiological changes are implicated in DBS's therapeutic effects.

CONCLUSION

In conclusion, while DBS for TRD remains an experimental therapy, it offers a unique and potentially effective treatment option for patients unresponsive to traditional treatments. The review emphasizes the need for further research to refine DBS targets and parameters, improve patient selection, and develop personalized treatment plans to enhance efficacy and safety in TRD management.

Noninvasive Modulation of the Subcallosal Cingulate and Depression With Focused Ultrasonic Waves

BACKGROUND

Severe forms of depression have been linked to excessive subcallosal cingulate cortex (SCC) activity. Stimulation of the SCC with surgically implanted electrodes can alleviate depression, but current noninvasive techniques cannot directly and selectively modulate deep targets. We developed a new noninvasive neuromodulation approach that can deliver low-intensity focused ultrasonic waves to the SCC.

METHODS

Twenty-two individuals with treatment-resistant depression participated in a randomized, double-blind, sham-controlled study. Ultrasonic stimulation was delivered to the bilateral SCC during concurrent functional magnetic resonance imaging to quantify target engagement. Mood state was measured with the Sadness subscale of the Positive and Negative Affect Schedule before and after 40 minutes of real or sham SCC stimulation. Change in depression severity was measured with the 6-item Hamilton Depression Rating Scale at 24 hours and 7 days.

RESULTS

Functional magnetic resonance imaging demonstrated a target-specific decrease in SCC activity during stimulation (p = .028, n = 16). In 7 of 16 participants, SCC neuromodulation was detectable at the individual participant level with a single 10-minute scan (p < .05, small-volume correction). Mood and depression scores improved more with real than with sham stimulation. In the per-protocol sample (n = 19), real stimulation was superior to sham for 6-item Hamilton Depression Rating Scale scores at 24 hours and for Sadness scores (both p < .05, d > 1). Nonsignificant trends were found in the intent-to-treat sample.

CONCLUSIONS

This small pilot study indicates that ultrasonic stimulation modulates SCC activity and can rapidly reduce depressive symptoms. The capability to noninvasively and selectively target deep brain areas creates new possibilities for the future development of circuit-directed therapeutics and for the analysis of deep-brain circuit function in humans.

Effective Stimulation Sites and Networks for Substantia Nigra Pars Reticulata Deep Brain Stimulation for Auditory Verbal Hallucinations in Schizophrenia

Deep brain stimulation (DBS) of the substantia nigra pars reticulata (SNpr) is under investigation for managing auditory-verbal hallucinations (AVH) in treatment-resistant schizophrenia (TR-SZ). We assessed acute AVH suppression during initial SNpr-DBS programming in three TR-SZ patients and mapped associated brain network engagement using normative connectomes. One-month post-implantation, monopolar stimulation at each electrode contact was evaluated for its effect on AVH severity. Volumes of tissue activation (VTA) were integrated with normative structural and functional connectivity data to generate individualized network maps. Among 86 VTAs, stimulation sites associated with greatest AVH relief localized to left anterior-dorsal and right posterior-ventral SNpr. Greater AVH suppression correlated with structural connectivity to sensorimotor cortex, precuneus, angular and supramarginal gyri, and functional connectivity to the mediodorsal thalamus, orbitofrontal cortex, anterior cingulate, and dorsolateral prefrontal cortex. These preliminary results highlight specific SNpr subregions and circuits linked to acute symptom reduction, supporting the potential of network-targeted DBS for TR-SZ.

Investigating low intensity focused ultrasound pulsation in anhedonic depression-A randomized controlled trial

Introduction

Anhedonic depression is a subtype of depression characterized by deficits in reward processing. This subtype of depression is associated with higher suicide risk and longer depressive episodes, underscoring the importance of effective treatments. Anhedonia has also been found to correlate with alterations in activity in several subcortical regions, including the caudate head and nucleus accumbens. Low intensity focused ultrasound pulsation (LIFUP) is an emerging technology that enables non-invasive stimulation of these subcortical regions, which were previously only accessible with surgically-implanted electrodes.

Methods

This double-blinded, sham-controlled study aims to investigate the effects of LIFUP to the left caudate head and right nucleus accumbens in participants with anhedonic depression. Participants in this protocol will undergo three sessions of LIFUP over the span of 5-9 days. To investigate LIFUP-related changes, this 7-week protocol collects continuous digital phenotyping data, an array of self-report measures of depression, anhedonia, and other psychopathology, and magnetic resonance imaging (MRI) before and after the LIFUP intervention. Primary self-report outcome measures include Ecological Momentary Assessment, the Positive Valence Systems Scale, and the Patient Health Questionnaire. Primary imaging measures include magnetic resonance spectroscopy and functional MRI during reward-based tasks and at rest. Digital phenotyping data is collected with an Apple Watch and participants' personal iPhones throughout the study, and includes information about sleep, heart rate, and physical activity.

Discussion

This study is the first to investigate the effects of LIFUP to the caudate head or nucleus accumbens in depressed subjects. Furthermore, the data collected for this protocol covers a wide array of potentially affected modalities. As a result, this protocol will help to elucidate potential impacts of LIFUP in individuals with anhedonic depression.

Lack of neuropsychological effects following short-term subcallosal cingulate gyrus deep brain stimulation in treatment-resistant depression: a randomised crossover study

BACKGROUND

The subcallosal cingulate gyrus (SCG) is integral to cognitive function and mood regulation. Open-label SCG deep brain stimulation (DBS) studies demonstrate improvement or stabilisation of cognitive function in treatment-resistant depression (TRD).

OBJECTIVE

This randomised controlled study aims to evaluate the neuropsychological effects of SCG-DBS.

METHODS

35 participants with TRD received active or sham stimulation over two 3-month periods. A neuropsychological battery was administered to assess processing speed, learning and memory, and cognitive flexibility. Composite measures were derived for each domain after Period I. A mixed model for repeated measures analysis was performed for each test, with further analysis of significant measures to determine sustainability after Period II.

FINDINGS

No significant differences in changes in depression scores were observed between groups. There were no significant deteriorations in cognitive performance following active SCG-DBS. Category Fluency Test performance improved after 3 months of active SCG-DBS (p=0.002); however, this was non-significant after correcting for multiple comparisons and was not observed after Period II (p=0.615).

CONCLUSION AND IMPLICATIONS

While no cognitive deterioration was observed following SCG-DBS, significant improvements in cognitive function were not evident. There may be a transient enhancement in processing speed; however, this effect is not fully understood. Future studies should include larger cohorts and extended stimulation periods to explore the long-term effects of SCG-DBS in TRD and the sustainability of improvements in cognitive domains.

Focused Ultrasound Modulates Dopamine in a Mesolimbic Reward Circuit

Dopamine is a neurotransmitter that plays a significant role in reward and motivation. Dysfunction in the mesolimbic dopamine pathway has been linked to a variety of psychiatric disorders, including addiction. Low-intensity focused ultrasound (LIFU) has demonstrated effects on brain activity, but how LIFU affects dopamine neurotransmission is not known. Here, we applied three different intensities (6.5, 13, and 26 W/cm2 ISPPA) of 2-min LIFU to the prelimbic cortex (PLC) and measured dopamine in the nucleus accumbens (NAc) core using fast-scan cyclic voltammetry. Two minutes of LIFU sonication at 13 W/cm2 to the PLC significantly reduced dopamine release by ~50% for up to 2 h. However, double the intensity (26 W/cm2) resulted in less inhibition (~30%), and half the intensity (6.5 W/cm2) did not result in any inhibition of dopamine. Anatomical controls applying LIFU to the primary somatosensory cortex did not change NAc core dopamine, and applying LIFU to the PLC did not affect dopamine release in the caudate or NAc shell. Histological evaluations showed no evidence of cell damage or death. Modeling temperature rise demonstrates a maximum temperature change of 0.5°C with 13 W/cm2, suggesting that modulation is not due to thermal mechanisms. These studies show that LIFU at a moderate intensity provides a noninvasive, high spatial resolution means to modulate specific mesolimbic circuits that could be used in future studies to target and repair pathways that are dysfunctional in addiction and other psychiatric diseases.

Deep Brain Stimulation in the Bed Nucleus of Stria Terminalis and Medial Forebrain Bundle in Two Patients With Treatment-Resistant Depression and Generalized Anxiety Disorder-A Long-Term Follow-Up

This case report presents positive outcomes from deep brain stimulation (DBS) targeting the bed nucleus of the stria terminalis (BNST) in two patients with treatment-resistant depression and generalized anxiety disorder. DBS effects in the medial forebrain bundle (MFB) area were unclear. Further research into DBS's efficacy when comorbid anxiety is present is required.

Intracranial closed-loop neuromodulation as an intervention for neuropsychiatric disorders: an overview

Recent technological advances in intracranial brain stimulation have enhanced the potential of neuromodulation for addressing neuropsychiatric disorders. We present a review of the methodology and the preliminary outcomes of the pioneering studies exploring intracranial biomarker detection and closed-loop neuromodulation to modulate high-symptom severity states in neuropsychiatric disorders. We searched PubMed, Scopus, Web of Science, Embase, and PsycINFO/PsycNet, followed by the reference and citation lists of retrieved articles. This search strategy yielded a total of 583 articles, of which 5 articles met the inclusion criteria, focusing on depression, obsessive-compulsive disorder, post-traumatic stress disorder, and binge eating disorder. We discuss the methodology of biomarker identification, the biomarkers identified, and the preliminary treatment outcomes for closed-loop neuromodulation. Successful biomarker identification hinges on investigating across various setting. Targeted neuromodulation, either directed at the biomarker or within its associated neural network, offers a promising treatment approach. Future research should seek to understand the mechanisms underlying the effects of neuromodulation as well as the long-term viability of these treatment effects across different neuropsychiatric conditions.

Clinically probable RBD is an early predictor of malignant non-motor Parkinson's disease phenotypes

Non-motor symptoms (NMS) in Parkinson's disease (PD) significantly impact quality of life, especially in later stages. REM sleep behavior disorder (RBD) affects approximately 42% of all PD patients and frequently precedes motor PD symptoms. RBD is linked to increased rates of depression and cognitive decline. This study explores how early RBD can predict the development of NMS profiles in patients, comparing those with and without early RBD. We identified a unique NMS profile associated with early RBD. These patients had a higher rate of cognitive impairment (M2 = 326.84, p < 0.001), apathy (M2 = 332.93, p < 0.001), hallucinations (M2 = 480.05, p < 0.001), depression (M2 = 480.05, p < 0.0001), anxiety (corrected p < 0.01), impulse control disorders (M2 = 77.577, p < 0.001), and autonomic dysfunction (F = 251.8, p < 0001). A survival analysis revealed an association between early RBD and faster progression to cognitive impairment. These NMS profiles may play a critical role in stratifying patients for targeted interventions.

Disturbed hierarchy and mediation in reward-related circuits in depression

BACKGROUNDS/OBJECTIVE

Deep brain stimulation (DBS) has proved the viability of alleviating depression symptoms by stimulating deep reward-related nuclei. This study aims to investigate the abnormal connectivity profiles among superficial, intermediate, and deep brain regions within the reward circuit in major depressive disorder (MDD) and therefore provides references for identifying potential superficial cortical targets for non-invasive neuromodulation.

METHODS

Resting-state functional magnetic resonance imaging data were collected from a cohort of depression patients (N = 52) and demographically matched healthy controls (N = 60). Utilizing existing DBS targets as seeds, we conducted step-wise functional connectivity (sFC) analyses to delineate hierarchical pathways linking to cerebral cortices. Subsequently, the mediation effects of cortical regions on the interaction within reward-related circuits were further explored by constructing mediation models.

RESULTS

In both cohorts, sFC analysis revealed two reward-related pathways from the deepest DBS targets to intermediate regions including the thalamus, insula, and anterior cingulate cortex (ACC), then to the superficial cortical cortex including medial frontal cortex, posterior default mode network (pDMN), and right dorsolateral prefrontal cortex (DLPFC). Patients exhibited reduced sFC in bilateral thalamus and medial frontal cortex in short and long steps respectively compared to healthy controls. We also discovered the disappearance of the mediation effects of superficial cortical regions on the interaction between DBS targets and intermediate regions in reward-related pathways in patients with MDD.

CONCLUSION

Our findings support abnormal hierarchical connectivity and mediation effects in reward-related brain regions at different depth levels in MDD, which might elucidate the underlying pathophysiological mechanisms and inspire novel targets for non-invasive interventions.

Trends in research on novel antidepressant treatments

Mood disorders, such as major depressive disorder and bipolar disorder, are among the most common mental illnesses and a leading cause of disability worldwide. Key symptoms of these conditions include a depressed mood or anhedonia, sleep and psychomotor disturbances, changes in appetite or weight, and fatigue or loss of energy. Prolonged cognitive disturbances further impair the ability to think or concentrate and are often accompanied by persistent feelings of worthlessness or excessive guilt. Collectively, these symptoms underscore depression as a serious, long-term global health issue. In addition, clinical studies indicate a growing number of patients experiencing difficulties in responding to treatment, even in the long term. This phenomenon poses significant challenges for healthcare professionals, families, and patients alike. As a result, there is an urgent need for therapies that are both rapid-acting and safe. This review aims to summarize the prevailing trends in research on novel antidepressants, emphasizing their diversity and multi-directional mechanisms of action. The development of rapid-acting drugs is increasingly focused on achieving high efficacy, particularly for treatment-resistant depression. Such advances offer the potential for rapid therapeutic effects without the prolonged and often tedious administration of older generation antidepressants. Findings from studies using animal models of depression continue to play a crucial role in predicting and designing new therapeutic strategies. These models remain indispensable for understanding the physiological effects of newly developed compounds, thereby guiding the creation of innovative treatments.

Evidence for the contribution of vasopressin V1B receptors in the pathophysiology of depression

Depression is a chronic and recurrent psychiatric condition characterised by depressed mood, loss of interest or pleasure, poor sleep, low appetite, and poor concentration. Research has shown that both heritable and environmental risk factors are involved in the pathogenesis of depression. In addition, several studies have indicated that dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is implicated in the development of depression in adulthood. However, the mechanism underlying the activation of HPA axis-induced depression remains unclear. Arginine vasopressin (AVP), also known as vasopressin (VP), is a hormone synthesised in the hypothalamus that plays important roles in numerous biological functions in mammals, including the regulation of stress and anxiety, and has been implicated in the pathogenesis of many disorders. VP regulates pituitary corticotroph function by binding to the plasma membrane G-protein receptors of the V1B receptor (V1BR), which are coupled to calcium-phospholipid signalling. V1BR, a receptor subtype of VP, plays a pivotal role in HPA axis abnormalities observed in depression. In animals, V1BR antagonists reduce plasma stress hormone levels and have been shown to have antidepressant activity. However, the precise mechanism of V1BR in modulating HPA axis activity remains unclear. We therefore reviewed and integrated the clinical and preclinical literature pertinent to the role of V1BR in depression, while emphasising the effect of V1BR antagonists on attenuating the hyperactivity of the HPA axis. In addition, therapy for depression through the regulation of the HPA axis is briefly discussed. Although effective antidepressants are available, a large proportion of patients do not respond to initial treatment. Therefore, this review describes the exact mechanisms of V1BR in depression and contributes to the development of new therapeutic strategies for this disease.

Neuromodulation as a therapeutic approach for post-traumatic stress disorder: the evidence to date

INTRODUCTION

Post-traumatic stress disorder (PTSD) can have debilitating effects on quality of life, and conventional treatments show mixed results. Neuromodulation is emerging as a promising approach for treating PTSD. This review examines current neuromodulatory treatments for PTSD, and highlights methodologies, clinical outcomes, and gaps in the literature to help guide future research.

AREAS COVERED

A PubMed search identified 252 studies on PTSD and neuromodulation, of which 61 were selected for full review. These included 37 studies on repetitive transcranial magnetic stimulation (rTMS), 10 on transcranial direct current stimulation (tDCS),4 on deep brain stimulation (DBS) and 2 on focused ultrasound (FUS).

EXPERT OPINION

The present review supports the potential of neuromodulation to reduce PTSD symptoms. rTMS and tDCS targeting the dlPFC appear effective through modulating neural circuits involved in fear processing and conditioning, however, literature varies regarding efficacy of stimulation frequencies and hemispheric targets. DBS targeting the amygdala or subcallosal cingulate white matter tracts improves treatment of refractory PTSD with sustained benefits, while FUS may improve symptoms through targeted modulation of brain structures such as the amygdala, though this technique is in the early stages of exploration. Future research should refine established neuromodulatory approaches and address gaps in emerging modalities to enhance treatment efficacy.

Deep Brain Stimulation and Neuropsychiatric Anthropology - The "Prosthetisability" of the Lifeworld

Deep Brain Stimulation (DBS) represents a key area of neuromodulation that has gained wide adoption for the treatment of neurological and experimental testing for psychiatric disorders. It is associated with specific therapeutic effects based on the precision of an evolving mechanistic neuroscientific understanding. At the same time, there are obstacles to achieving symptom relief because of the incompleteness of such an understanding. These obstacles are at least in part based on the complexity of neuropsychiatric disorders and the incompleteness of DBS devices to represent prosthetics that modulate the breadth of pathological processes implicated in these disorders. Neuroprostheses, such as an implanted DBS system, can have vast effects on subjects in addition to the specific neuropsychiatric changes they are intended to produce. These effects largely represent blind spots in the current debate on neuromodulation. Anthropological accounts can illustrate the broad existential dimensions of patients' illness and responses to neural implants. In combination with current neuroscientific understanding, neuropsychiatric anthropology may illuminate the possibilities and limits of neurodevices as technical "world enablers".

Unveiling the Dominant Factors in Subthalamic Stimulation for Improving Depression in Parkinson's Disease

BACKGROUND

Currently, the conclusions of studies on subthalamic nucleus (STN) deep brain stimulation (DBS) for improving Parkinson's disease (PD) with depression are inconsistent, and the reasons for improvement or deterioration remain unclear.

METHODS

The aim was to investigate the prognosis of PD with depression after bilateral STN-DBS and the factors related to the improvement in depression. The local and network effects of DBS on depression in PD (DPD) were further explored based on the volume of tissue activation (VTA). The study analyzed 80 primary PD patients who had undergone bilateral STN-DBS, comprising 47 patients with improved depression and 33 patients without improvement. Two groups of clinical profiles and stimulation parameters were compared, and the network models for improving depression were constructed.

RESULTS

The improvement in depression was closely associated with improvement in anxiety (odd rate [OR] = 1.067, P = 0.006) and the standardized space left y-coordinate (OR = 0.253, P = 0.005). The VTA overlapping with the left motor STN subregion is most significantly associated with improvement in depression (RSpearman = 0.53, P < 0.001; RPearson = 0.43, P < 0.001). The y-coordinates in the improvement group were closer to the optimal stimulation site for improving motor symptoms. Finally, both the structural and functional network models indicate a positive correlation between depression improvement and the connectivity of the sensorimotor cortex.

CONCLUSION

The amelioration of DPD is primarily attributed to the stimulation of bilateral motor STN, particularly on the left. However, this stimulatory effect manifests as an indirect influence.

Defects of parvalbumin-positive interneurons are implicated in psychiatric disorders

Psychiatric disorders are a common cause of severe long-term disability and socioeconomic burden worldwide. Although our understanding of these disorders has advanced substantially over the last few years, little has changed the standards of care for these illnesses. Fast-spiking parvalbumin-positive interneurons (PVIs), a subpopulation of gamma-aminobutyric acid (GABA)ergic interneurons, are widely distributed in the hippocampus and have been reported to play an important role in various mental disorders. However, the mechanisms underlying the regulation of the molecular networks relevant to depression and schizophrenia (SCZ) are unknown. Here, we discuss the functions of PVIs in psychiatric disorders, including depression and SCZ. After reviewing several studies, we concluded that dysfunction in PVIs could cause depression-like behavior, as well as cognitive categories in SCZ, which might be mediated in large part by greater synaptic variability. In summary, this scientific review aims to discuss the current knowledge regarding the function of PVIs in depression and SCZ. Moreover, we highlight the importance of neurogenesis and synaptic plasticity in the pathogenesis of depression and SCZ, which seem to be mediated by PVIs activity. These findings provide a better understanding of the role of PVIs in psychiatric disorders.

Joint Anatomical, Histological, and Imaging Investigation of the Midbrain Target Region for Superolateral Medial Forebrain Bundle Deep Brain Stimulation

INTRODUCTION

Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle (slMFB) is currently being researched in clinical trials and open case series as a therapeutic option for treatment-resistant major depressive disorder and treatment-resistant obsessive-compulsive disorder (TR-OCD). There are numerous publications describing stimulation in such proximity to the ventral tegmental area (VTA) and open questions remain concerning the stimulation target and its functional environment. As of right now, we are not aware of any publications that compare the typical electrode placements with the histologically supported tractographic depiction of the target structure.

METHODS

We used three cadaver midbrain samples with presumed unaltered anatomy. After fixation, staining and slicing, the histological samples were warped to the Montreal Neurological Institute (MNI) big brain environment. Utilizing a tractographic atlas, a qualitative analysis of the typical slMFB stimulation site in the lateral VTA utilizing a subset of clinically implanted DBS electrodes in n = 12 patients, successfully implanted for TR-OCD was performed.

RESULTS

A joint qualitative overlay analysis of predominantly tyrosine hydroxylase stained histology at different resolutions in an anatomical common space was achieved. Localization of the DBS lead bodies was found in the typical positions in front of the red nuclei in the lateral VTA. DBS lead tip region positions explained the oculomotor side effects of stimulation related to paranigral or parabrachial pigmented sub-nuclei of the VTA, respectively. The location of active electrode contacts suggests downstream and antidromic effects on the greater VTA related medial forebrain bundle system.

CONCLUSION

This is the first dedicated joint histopathological overlay analysis of DBS electrodes targeting the slMFB and lateral VTA in a common anatomical space. This analysis might serve to better understand the DBS target region for this procedure.

INTRODUCTION

Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle (slMFB) is currently being researched in clinical trials and open case series as a therapeutic option for treatment-resistant major depressive disorder and treatment-resistant obsessive-compulsive disorder (TR-OCD). There are numerous publications describing stimulation in such proximity to the ventral tegmental area (VTA) and open questions remain concerning the stimulation target and its functional environment. As of right now, we are not aware of any publications that compare the typical electrode placements with the histologically supported tractographic depiction of the target structure.

METHODS

We used three cadaver midbrain samples with presumed unaltered anatomy. After fixation, staining and slicing, the histological samples were warped to the Montreal Neurological Institute (MNI) big brain environment. Utilizing a tractographic atlas, a qualitative analysis of the typical slMFB stimulation site in the lateral VTA utilizing a subset of clinically implanted DBS electrodes in n = 12 patients, successfully implanted for TR-OCD was performed.

RESULTS

A joint qualitative overlay analysis of predominantly tyrosine hydroxylase stained histology at different resolutions in an anatomical common space was achieved. Localization of the DBS lead bodies was found in the typical positions in front of the red nuclei in the lateral VTA. DBS lead tip region positions explained the oculomotor side effects of stimulation related to paranigral or parabrachial pigmented sub-nuclei of the VTA, respectively. The location of active electrode contacts suggests downstream and antidromic effects on the greater VTA related medial forebrain bundle system.

CONCLUSION

This is the first dedicated joint histopathological overlay analysis of DBS electrodes targeting the slMFB and lateral VTA in a common anatomical space. This analysis might serve to better understand the DBS target region for this procedure.

The impact of acupuncture on the brain function of patients with mild to moderate major depressive disorder: a randomized controlled trial protocol

INTRODUCTION

Major depressive disorder (MDD) is a common mental disease that significantly impact the daily lives of those affected. Acupuncture has shown promising therapeutic effects in the treatment of MDD, but its underlying mechanisms remain unclear. This study aims to evaluate the influence of acupuncture on the brain function of patients with MDD and it's therapeutic effects on MDD.

METHODS

This study plans to recruit 112 participants, who will be randomly allocated to either the acupuncture group or the sham acupuncture group in a 1:1 ratio. Both groups will undergo 8 weeks of treatment, consisting of three sessions per week, with each session lasting for 30 min. A follow-up period of 3 months will be conducted after the treatment. Assessments will be conducted at weeks 0, 8, 12, 16, and 20 in this study. The primary outcome measure will be functional near-infrared spectroscopy (fNIRS) brain imaging, while secondary outcome measures will include Beck Depression Inventory II (BDI-II), Self-Rating Anxiety Scale (SAS), 36-Item Short Form Survey Instrument (SF-36), Traditional Chinese Medicine (TCM) syndrome score scale, and symptom elimination rate.

DISCUSSION

While acupuncture has been confirmed to have a certain degree of therapeutic efficacy in the treatment of MDD, research on the mechanisms underlying acupuncture's treatment of MDD remains limited, particularly with regards to its impact on the brain function of individuals with MDD. This study aims to explore both the clinical effectiveness and treatment mechanisms of acupuncture for MDD, with a specific focus on its influence on brain function. This research endeavors to provide new insights into the potential of acupuncture as a therapeutic approach for the treatment of MDD in the future.

TRIAL REGISTRATION

www.chictr.org.cn , ID: ChiCTR2300076292. Registered on 28 September 2023.

What can neuroimaging of neuromodulation reveal about the basis of circuit therapies for psychiatry?

Neuromodulation is increasingly becoming a therapeutic option for treatment resistant psychiatric disorders. These non-invasive and invasive therapies are still being refined but are clinically effective and, in some cases, provide sustained symptom reduction. Neuromodulation relies on changing activity within a specific brain region or circuit, but the precise mechanisms of action of these therapies, is unclear. Here we review work in both humans and animals that has provided insight into how therapies such as deep brain and transcranial magnetic stimulation alter neural activity across the brain. We focus on studies that have combined neuromodulation with neuroimaging such as PET and MRI as these measures provide detailed information about the distributed networks that are modulated and thus insight into both the mechanisms of action of neuromodulation but also potentially the basis of psychiatric disorders. Further we highlight work in nonhuman primates that has revealed how neuromodulation changes neural activity at different scales from single neuron activity to functional connectivity, providing key insight into how neuromodulation influences the brain. Ultimately, these studies highlight the value of combining neuromodulation with neuroimaging to reveal the mechanisms through which these treatments influence the brain, knowledge vital for refining targeted neuromodulation therapies for psychiatric disorders.

The neuroscience of mental illness: Building toward the future

Mental illnesses arise from dysfunction in the brain. Although numerous extraneural factors influence these illnesses, ultimately, it is the science of the brain that will lead to novel therapies. Meanwhile, our understanding of this complex organ is incomplete, leading to the oft-repeated trope that neuroscience has yet to make significant contributions to the care of individuals with mental illnesses. This review seeks to counter this narrative, using specific examples of how neuroscientific advances have contributed to progress in mental health care in the past and how current achievements set the stage for further progress in the future.

Is the Treatment Worse than the Disease?: Key Stakeholders' Views about the Use of Psychiatric Electroceutical Interventions for Treatment-Resistant Depression

Psychiatric electroceutical interventions (PEIs) use electrical or magnetic stimulation to treat psychiatric conditions. For depression therapy, PEIs include both approved treatment modalities, such as electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS), and experimental neurotechnologies, such as deep brain stimulation (DBS) and adaptive brain implants (ABIs). We present results from a survey-based experiment in which members of four relevant stakeholder groups (psychiatrists, patients with depression, caregivers of adults with depression, and the general public) assessed whether treatment with one of four PEIs (ECT, rTMS, DBS, or ABIs) was better or worse than living with treatment-resistant depression (TRD) and then provided a narrative explanation for their assessment. Overall, the prevalence of many narrative themes differed substantially by stakeholder group-with psychiatrists typically offering different reasons for their assessment than non-clinicians-but much less so by PEI modality. A large majority of all participants viewed their assigned PEI as better than living with TRD, with their reasons being a mix of positive views about the treatment and negative views about TRD. The minority of all participants who viewed their assigned PEI as worse than living with TRD tended to express negative affect toward it as well as emphasize its riskiness, negative side effects, and, to a lesser extent, its invasiveness. The richness of these narrative explanations enabled us to put in context and add depth to key patterns seen in recent survey-based research on PEIs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12152-024-09573-2.

Multi-modal MRI for objective diagnosis and outcome prediction in depression

RESEARCH PURPOSE

The low treatment effectiveness in major depressive disorder (MDD) may be caused by the subjectiveness in clinical examination and the lack of quantitative tests. Objective biomarkers derived from magnetic resonance imaging (MRI) may support clinical experts during decision-making. Numerous studies have attempted to identify such MRI-based biomarkers. However, the majority is uni-modal (based on a single MRI modality) and focus on either MDD diagnosis or outcome. Uncertainty remains regarding whether key features or classification models for diagnosis may also be used for outcome prediction. Therefore, we aim to find multi-modal predictors of both, MDD diagnosis and outcome. By addressing these research questions using the same dataset, we eliminate between-study confounding factors. Various structural (T1-weighted, T2-weighted, diffusion tensor imaging (DTI)) and functional (resting-state and task-based functional MRI) scans were acquired from 32 MDD and 31 healthy control (HC) subjects during the first visit at the investigational site (baseline). Depression severity was assessed at baseline and 6 months later. Features were extracted from the baseline MRI images with different modalities. Binary 6-months negative and positive outcome (NO; PO) classes were defined based on relative (to baseline) change in depression severity. Support vector machine models were employed to separate MDD from HC (diagnosis) and NO from PO subjects (outcome). Classification was performed through a uni-modal (features from a single MRI modality) and multi-modal (combination of features from different modalities) approach.

PRINCIPAL RESULTS

Our results show that DTI features yielded the highest uni-modal performance for diagnosis and outcome prediction: mean diffusivity (AUC (area under the curve) = 0.701) and the sum of streamline weights (AUC = 0.860), respectively. Multi-modal ensemble classifiers with T1-weighted, resting-state functional MRI and DTI features improved classification performance for both diagnosis and outcome (AUC = 0.746 and 0.932, respectively). Feature analyses revealed that the most important features were located in frontal, limbic and parietal areas. However, the modality or location of these features was different between diagnostic and prognostic models.

MAJOR CONCLUSIONS

Our findings suggest that combining features from different MRI modalities predict MDD diagnosis and outcome with higher performance. Furthermore, we demonstrated that the most important features for MDD diagnosis were different and located in other brain regions than those for outcome. This longitudinal study contributes to the identification of objective biomarkers of MDD and its outcome. Follow-up studies may further evaluate the generalizability of our models in larger or multi-center cohorts.

Understanding the neurobiology of social behavior through exploring brain-wide dynamics of neural activity

Social behavior is highly complex and adaptable. It can be divided into multiple temporal stages: detection, approach, and consummatory behavior. Each stage can be further divided into several cognitive and behavioral processes, such as perceiving social cues, evaluating the social and non-social contexts, and recognizing the internal/emotional state of others. Recent studies have identified numerous brain-wide circuits implicated in social behavior and suggested the existence of partially overlapping functional brain networks underlying various types of social and non-social behavior. However, understanding the brain-wide dynamics underlying social behavior remains challenging, and several brain-scale dynamics (macro-, meso-, and micro-scale levels) need to be integrated. Here, we suggest leveraging new tools and concepts to explore social brain networks and integrate those different levels. These include studying the expression of immediate-early genes throughout the entire brain to impartially define the structure of the neuronal networks involved in a given social behavior. Then, network dynamics could be investigated using electrode arrays or multi-channel fiber photometry. Finally, tools like high-density silicon probes and miniscopes can probe neural activity in specific areas and across neuronal populations at the single-cell level.

Spiking activities in small neural networks induced by external forcing

Neurons in an excitable mode do not show spiking activity and, therefore, do not contribute to information transfer transmission and its processing. However, some external influences, coupling, or time delay can lead to the appearance of oscillations in individual systems or networks. The main goal of this paper is to uncover the connection parameters and parameters of external influences that lead to the arising of spiking behavior in a small network of locally coupled FitzHugh-Nagumo oscillators. In this study, we analyze the dynamics of a small network in the absence and presence of several types of external influences. First, we consider the impact of periodic-pulse exposure generated as a periodic sequence of Gaussian pulses. Second, we show what behavior can be induced by far less regular pulsed influence (Lévy noise) and its special case called white Gaussian noise. For all types of influences, we have identified the appropriate parameters (local coupling strength, intensity, and frequency) that induce spiking activity in the small network.

Bridging Minds and Machines: The Recent Advances of Brain-Computer Interfaces in Neurological and Neurosurgical Applications

Brain-computer interfaces (BCIs), a remarkable technological advancement in neurology and neurosurgery, mark a significant leap since the inception of electroencephalography in 1924. These interfaces effectively convert central nervous system signals into commands for external devices, offering revolutionary benefits to patients with severe communication and motor impairments due to a myriad of neurological conditions like stroke, spinal cord injuries, and neurodegenerative disorders. BCIs enable these individuals to communicate and interact with their environment, using their brain signals to operate interfaces for communication and environmental control. This technology is especially crucial for those completely locked in, providing a communication lifeline where other methods fall short. The advantages of BCIs are profound, offering autonomy and an improved quality of life for patients with severe disabilities. They allow for direct interaction with various devices and prostheses, bypassing damaged or nonfunctional neural pathways. However, challenges persist, including the complexity of accurately interpreting brain signals, the need for individual calibration, and ensuring reliable, long-term use. Additionally, ethical considerations arise regarding autonomy, consent, and the potential for dependence on technology. Despite these challenges, BCIs represent a transformative development in neurotechnology, promising enhanced patient outcomes and a deeper understanding of brain-machine interfaces.

Target engagement of the subgenual anterior cingulate cortex with transcranial temporal interference stimulation in major depressive disorder: a protocol for a randomized sham-controlled trial

Background

Transcranial temporal interference stimulation (tTIS) is a new, emerging neurostimulation technology that utilizes two or more electric fields at specific frequencies to modulate the oscillations of neurons at a desired spatial location in the brain. The physics of tTIS offers the advantage of modulating deep brain structures in a non-invasive fashion and with minimal stimulation of the overlying cortex outside of a selected target. As such, tTIS can be effectively employed in the context of therapeutics for the psychiatric disease of disrupted brain connectivity, such as major depressive disorder (MDD). The subgenual anterior cingulate cortex (sgACC), a key brain center that regulates human emotions and influences negative emotional states, is a plausible target for tTIS in MDD based on reports of its successful neuromodulation with invasive deep brain stimulation.

Methods

This pilot, single-site, double-blind, randomized, sham-controlled interventional clinical trial will be conducted at St. Michael's Hospital - Unity Health Toronto in Toronto, ON, Canada. The primary objective is to demonstrate target engagement of the sgACC with 130 Hz tTIS using resting-state magnetic resonance imaging (MRI) techniques. The secondary objective is to estimate the therapeutic potential of tTIS for MDD by evaluating the change in clinical characteristics of participants and electrophysiological outcomes and providing feasibility and tolerability estimates for a large-scale efficacy trial. Thirty participants (18-65 years) with unipolar, non-psychotic MDD will be recruited and randomized to receive 10 sessions of 130 Hz tTIS or sham stimulation (n = 15 per arm). The trial includes a pre- vs. post-treatment 3T MRI scan of the brain, clinical evaluation, and electroencephalography (EEG) acquisition at rest and during the auditory mismatch negativity (MMN) paradigm.

Discussion

This study is one of the first-ever clinical trials among patients with psychiatric disorders examining the therapeutic potential of repetitive tTIS and its neurobiological mechanisms. Data obtained from this trial will be used to optimize the tTIS approach and design a large-scale efficacy trial. Research in this area has the potential to provide a novel treatment option for individuals with MDD and circuitry-related disorders and may contribute to the process of obtaining regulatory approval for therapeutic applications of tTIS.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT05295888.

Topographical anatomy of the septum verum and its white matter connections

The human septum verum represents a small but clinically important region of the brain. Based on the results of animal experiments, the stimulation of its medial part was recently proposed with various indications like epilepsy or cognitive impairment after traumatic brain injury. The aim of our study was to present the anatomical relationships of the human septum verum using fiber dissection and histological analysis to support its research and provide essential information for future deep brain stimulation therapies. 16 human cadaveric brains were dissected according to Klingler's method. To validate our macroscopical findings, 12 samples obtained from the dissected brains and 2 additional specimens from unfrozen brains were prepared for histological examinations. We identified the following white matter connections of the septum verum: (1) the precommissural fibers of the fornix; (2) the inferior fascicle of the septum pellucidum; (3) the cingulum; (4) the medial olfactory stria; (5) the ventral amygdalofugal pathway; (6) the stria medullaris of the thalamus and (7) the stria terminalis. Moreover, we could distinguish a less-known fiber bundle connecting the postcommissural column of the fornix to the stria medullaris of the thalamus and the anterior thalamic nuclei. In this study we present valuable anatomical information about this region to promote safe and effective deep brain stimulation therapies in the future.

Safety assessment of brexanolone in the FAERS database: real adverse event analysis and discussion of side effects

BACKGROUND

Postpartum depression (PPD) is linked to hormonal changes. Brexanolone, the first FDA-approved drug for PPD, is a potential treatment. This study analyzes Brexanolone's safety using the FAERS database, highlighting its adverse effects and potential risk factors.

METHODS

We analyzed FAERS data from Q3 2019 to Q3 2023, evaluating adverse reactions to Brexanolone. The analysis includes demographics, reporting regions, reporter identities, and types of adverse reactions.

RESULTS

Most reports are from the United States, with consumers and physicians as primary reporters. Adverse reactions mainly involve severe systemic diseases, administration site reactions, injuries, intoxication, operational complications, and mental disorders. Specific adverse reactions include incorrect drug monitoring, PPD, intrusive thoughts, delayed treatment efficacy, sedation complications, product discontinuation, misuse, infusion site leakage and pain, and medication errors.

CONCLUSION

The study confirms known safety information about Brexanolone and provides comprehensive data for medical practices and public health decisions. However, relying on spontaneous reports may introduce biases and incomplete information. Continued monitoring and reporting of adverse reactions to newer drugs like Brexanolone remain crucial.

A silicon diode-based optoelectronic interface for bidirectional neural modulation

The development of advanced neural modulation techniques is crucial to neuroscience research and neuroengineering applications. Recently, optical-based, nongenetic modulation approaches have been actively investigated to remotely interrogate the nervous system with high precision. Here, we show that a thin-film, silicon (Si)-based diode device is capable to bidirectionally regulate in vitro and in vivo neural activities upon adjusted illumination. When exposed to high-power and short-pulsed light, the Si diode generates photothermal effects, evoking neuron depolarization and enhancing intracellular calcium dynamics. Conversely, low-power and long-pulsed light on the Si diode hyperpolarizes neurons and reduces calcium activities. Furthermore, the Si diode film mounted on the brain of living mice can activate or suppress cortical activities under varied irradiation conditions. The presented material and device strategies reveal an innovated optoelectronic interface for precise neural modulations.

In Search for a Pathogenesis of Major Depression and Suicide-A Joint Investigation of Dopamine and Fiber Tract Anatomy Focusing on the Human Ventral Mesencephalic Tegmentum: Description of a Workflow

Major depressive disorder (MDD) is prevalent with a high subjective and socio-economic burden. Despite the effectiveness of classical treatment methods, 20-30% of patients stay treatment-resistant. Deep Brain Stimulation of the superolateral branch of the medial forebrain bundle is emerging as a clinical treatment. The stimulation region (ventral tegmental area, VTA), supported by experimental data, points to the role of dopaminergic (DA) transmission in disease pathology. This work sets out to develop a workflow that will allow the performance of analyses on midbrain DA-ergic neurons and projections in subjects who have committed suicide. Human midbrains were retrieved during autopsy, formalin-fixed, and scanned in a Bruker MRI scanner (7T). Sections were sliced, stained for tyrosine hydroxylase (TH), digitized, and integrated into the Montreal Neurological Institute (MNI) brain space together with a high-resolution fiber tract atlas. Subnuclei of the VTA region were identified. TH-positive neurons and fibers were semi-quantitatively evaluated. The study established a rigorous protocol allowing for parallel histological assessments and fiber tractographic analysis in a common space. Semi-quantitative readings are feasible and allow the detection of cell loss in VTA subnuclei. This work describes the intricate workflow and first results of an investigation of DA anatomy in VTA subnuclei in a growing naturalistic database.

Impact of pulse exposure on chimera state in ensemble of FitzHugh-Nagumo systems

In this article, we consider the influence of a periodic sequence of Gaussian pulses on a chimera state in a ring of coupled FitzHugh-Nagumo systems. We found that on the way to complete spatial synchronization, one can observe a number of variations of chimera states that are not typical for the parameter range under consideration. For example, the following modes were found: breathing chimera, chimera with intermittency in the incoherent part, traveling chimera with strong intermittency, and others. For comparison, here we also consider the impact of a harmonic influence on the same chimera, and to preserve the generality of the conclusions, we compare the regimes caused by both a purely positive harmonic influence and a positive-negative one.

Presurgical structural imaging and clinical outcome in combined bed nucleus of the stria terminalis-nucleus accumbens deep brain stimulation for treatment-resistant depression

Background

Structural imaging holds great potential for precise targeting and stimulation for deep brain stimulation (DBS). The anatomical information it provides may serve as potential biomarkers for predicting the efficacy of DBS in treatment-resistant depression (TRD).

Aims

The primary aim is to identify preoperative imaging biomarkers that correlate with the efficacy of DBS in patients with TRD.

Methods

Preoperative imaging parameters were estimated and correlated with the 6-month clinical outcome of patients with TRD receiving combined bed nucleus of the stria terminalis (BNST)-nucleus accumbens (NAc) DBS. White matter (WM) properties were extracted and compared between the response/non-response and remission/non-remission groups. Structural connectome was constructed and analysed using graph theory. Distances of the volume of activated tissue (VAT) to the main modulating tracts were also estimated to evaluate the correlations.

Results

Differences in fibre bundle properties of tracts, including superior thalamic radiation and reticulospinal tract, were observed between the remission and non-remission groups. Distance of the centre of the VAT to tracts connecting the ventral tegmental area and the anterior limb of internal capsule on the left side varied between the remission and non-remission groups (p=0.010, t=3.07). The normalised clustering coefficient (γ) and the small-world property (σ) in graph analysis correlated with the symptom improvement after the correction of age.

Conclusions

Presurgical structural alterations in WM tracts connecting the frontal area with subcortical regions, as well as the distance of the VAT to the modulating tracts, may influence the clinical outcome of BNST-NAc DBS. These findings provide potential imaging biomarkers for the DBS treatment for patients with TRD.

Neurobiological basis of stress resilience

A majority of humans faced with severe stress maintain normal physiological and behavioral function, a process referred to as resilience. Such stress resilience has been modeled in laboratory animals and, over the past 15 years, has transformed our understanding of stress responses and how to approach the treatment of human stress disorders such as depression, post-traumatic stress disorder (PTSD), and anxiety disorders. Work in rodents has demonstrated that resilience to chronic stress is an active process that involves much more than simply avoiding the deleterious effects of the stress. Rather, resilience is mediated largely by the induction of adaptations that are associated uniquely with resilience. Such mechanisms of natural resilience in rodents are being characterized at the molecular, cellular, and circuit levels, with an increasing number being validated in human investigations. Such discoveries raise the novel possibility that treatments for human stress disorders, in addition to being geared toward reversing the damaging effects of stress, can also be based on inducing mechanisms of natural resilience in individuals who are inherently more susceptible. This review provides a progress report on this evolving field.

Deep Brain Stimulation of the Medial Forebrain Bundle for Treatment-Resistant Depression: A Systematic Review Focused on the Long-Term Antidepressive Effect

OBJECTIVE

Major depression affects millions of people worldwide and has important social and economic consequences. Since up to 30% of patients do not respond to several lines of antidepressive drugs, deep brain stimulation (DBS) has been evaluated for the management of treatment-resistant depression (TRD). The superolateral branch of the medial forebrain bundle (slMFB) appears as a "hypothesis-driven target" because of its role in the reward-seeking system, which is dysfunctional in depression. Although initial results of slMFB-DBS from open-label studies were promising and characterized by a rapid clinical response, long-term outcomes of neurostimulation for TRD deserve particular attention. Therefore, we performed a systematic review focused on the long-term outcome of slMFB-DBS.

MATERIALS AND METHODS

A literature search using Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was conducted to identify all studies reporting changes in depression scores after one-year follow-up and beyond. Patient, disease, surgical, and outcome data were extracted for statistical analysis. The Montgomery-Åsberg Depression Rating Scale (ΔMADRS) was used as the clinical outcome, defined as percentage reduction from baseline to follow-up evaluation. Responders' and remitters' rates were also calculated.

RESULTS

From 56 studies screened for review, six studies comprising 34 patients met the inclusion criteria and were analyzed. After one year of active stimulation, ΔMADRS was 60.7% ± 4%; responders' and remitters' rates were 83.8% and 61.5%, respectively. At the last follow-up, four to five years after the implantation, ΔMADRS reached 74.7% ± 4.6%. The most common side effects were stimulation related and reversible with parameter adjustments.

CONCLUSIONS

slMFB-DBS appears to have a strong antidepressive effect that increases over the years. Nevertheless, to date, the overall number of patients receiving implantations is limited, and the slMFB-DBS surgical technique seems to have an important impact on the clinical outcome. Further multicentric studies in a larger population are needed to confirm slMFB-DBS clinical outcomes.

Elucidating the influence of familial interactions on geriatric depression: A comprehensive nationwide multi-center investigation leveraging machine learning

OBJECTIVE

A plethora of studies have unequivocally established the profound significance of harmonious familial relationships on the psychological well-being of the elderly. In this study, we elucidate the intergenerational relationships, probing the association between frequent interactions or encounters with their children and the incidence of depression in old age.

METHODOLOGY

We employed a retrospective cross-sectional study design, sourcing our data from the 2018 wave of the China Health and Retirement Longitudinal Study (CHARLS). To identify cases of depression, we utilized the 10-item Center for Epidemiologic Studies Depression Scale (CESD). Employing a five-fold cross-validation methodology, we endeavored to fashion five distinct machine learning models. Subsequently, we crafted learning curves to facilitate the refinement of hyperparameters, assessing model classification performance through metrics such as accuracy and the Area Under the Receiver Operating Characteristic (AUROC) curve. To further elucidate the relationship between variables and geriatric depression, logistic regression was subsequently applied.

RESULTS

Our findings accentuated that sleep patterns emerged as the paramount determinants influencing the onset of depression in the elderly. Relationships with offspring ranked as the second most significant determinant, only surpassed by sleep habits. A negative correlation was observed between sleep patterns (Odds Ratio [OR]: 0.78, 95 % Confidence Interval [CI]: 0.75-0.81, P < 0.01), communication with offspring (OR: 0.86, 95 % CI: 0.82-0.90, P < 0.01), and the prevalence of depressive symptoms. Among the evaluated models, the k-Near Neighbor algorithm demonstrated commendable discriminative power. However, it was the Random Forest algorithm that manifested unparalleled discriminative prowess and precision, establishing itself as the most efficacious classifier.

CONCLUSION

Prolonging the duration of nocturnal sleep, and elevating the frequency of communication with offspring have been identified as measures conducive to mitigating the onset of geriatric depression.

Physiotherapy for patients with depression: Recent research progress

Depression, a common mental illness, seriously affects the health of individuals and has deleterious effects on society. The prevention and treatment of depression has drawn the attention of many researchers and has become an important social issue. The treatment strategies for depression include drugs, psychotherapy, and physiotherapy. Drug therapy is ineffective in some patients and psychotherapy has treatment limitations. As a reliable adjuvant therapy, physiotherapy compensates for the shortcomings of drug and psychotherapy and effectively reduces the disease recurrence rate. Physiotherapy is more scientific and rigorous, its methods are diverse, and to a certain extent, provides more choices for the treatment of depression. Physiotherapy can relieve symptoms in many ways, such as by improving the levels of neurobiochemical molecules, inhibiting the inflammatory response, regulating the neuroendocrine system, and increasing neuroplasticity. Physiotherapy has biological effects similar to those of antidepressants and may produce a superimposed impact when combined with other treatments. This article summarizes the findings on the use of physiotherapy to treat patients with depression over the past five years. It also discusses several methods of physiotherapy for treating depression from the aspects of clinical effect, mechanism of action, and disadvantages, thereby serving as a reference for the in-depth development of physiotherapy research.

No Consistent Antidepressant Effects of Deep Brain Stimulation of the Bed Nucleus of the Stria Terminalis

BACKGROUND

Applying deep brain stimulation (DBS) to several brain regions has been investigated in attempts to treat highly treatment-resistant depression, with variable results. Our initial pilot data suggested that the bed nucleus of the stria terminalis (BNST) could be a promising therapeutic target.

OBJECTIVE

The aim of this study was to gather blinded data exploring the efficacy of applying DBS to the BNST in patients with highly refractory depression.

METHOD

Eight patients with chronic severe treatment-resistant depression underwent DBS to the BNST. A randomised, double-blind crossover study design with fixed stimulation parameters was followed and followed by a period of open-label stimulation.

RESULTS

During the double-blind crossover phase, no consistent antidepressant effects were seen with any of the four stimulation parameters applied, and no patients achieved response or remission criteria during the blinded crossover phase or during a subsequent period of three months of blinded stimulation. Stimulation-related side effects, especially agitation, were reported by a number of patients and were reversible with adjustment of the stimulation parameters.

CONCLUSIONS

The results of this study do not support the application of DBS to the BNST in patients with highly resistant depression or ongoing research utilising stimulation at this brain site. The blocked randomised study design utilising fixed stimulation parameters was poorly tolerated by the participants and does not appear suitable for assessing the efficacy of DBS at this location.

Predicting non-response to ketamine for depression: An exploratory symptom-level analysis of real-world data among military veterans

Ketamine helps some patients with treatment resistant depression (TRD), but reliable methods for predicting which patients will, or will not, respond to treatment are lacking. Herein, we aim to inform prediction models of non-response to ketamine/esketamine in adults with TRD. This is a retrospective analysis of PHQ-9 item response data from 120 patients with TRD who received repeated doses of intravenous racemic ketamine or intranasal eskatamine in a real-world clinic. Regression models were fit to patients' symptom trajectories, showing that all symptoms improved on average, but depressed mood improved relatively faster than low energy. Principal component analysis revealed a first principal component (PC) representing overall treatment response, and a second PC that reflects variance across affective versus somatic symptom subdomains. We then trained logistic regression classifiers to predict overall response (improvement on PC1) better than chance using patients' baseline symptoms alone. Finally, by parametrically adjusting the classifier decision thresholds, we identified optimal models for predicting non-response with a negative predictive value of over 96 %, while retaining a specificity of 22 %. Thus, we could identify 22 % of patients who would not respond based purely on their baseline symptoms. This approach could inform rational treatment recommendations to avoid additional treatment failures.

Novel rapid treatment options for adolescent depression

There is an urgent need for novel fast-acting antidepressants for adolescent treatment-resistant depression and/or suicidal risk, since the selective serotonin reuptake inhibitors that are clinically approved for that age (i.e., fluoxetine or escitalopram) take weeks to work. In this context, one of the main research lines of our group is to characterize at the preclinical level novel approaches for rapid-acting antidepressants for adolescence. The present review summarizes the potential use in adolescence of non-pharmacological options, such as neuromodulators (electroconvulsive therapy and other innovative types of brain stimulation), as well as pharmacological options, including consciousness-altering drugs (mainly ketamine but also classical psychedelics) and cannabinoids (i.e., cannabidiol), with promising fast-acting responses. Following a brief analytical explanation of adolescent depression, we present a general introduction for each therapeutical approach together with the clinical evidence supporting its potential beneficial use in adolescence (mainly extrapolated from prior successful examples for adults), to then report recent and/or ongoing preclinical studies that will aid in improving the inclusion of these therapies in the clinic, by considering potential sex-, age-, and dose-related differences, and/or other factors that might affect efficacy or long-term safety. Finally, we conclude the review by providing future avenues to maximize treatment response, including the need for more clinical studies and the importance of designing and/or testing novel treatment options that are safe and fast-acting for adolescent depression.

Use of Healthcare Claims Data to Generate Real-World Evidence on Patients With Drug-Resistant Epilepsy: Practical Considerations for Research

Objectives: Regulatory bodies, health technology assessment agencies, payers, physicians, and other decision-makers increasingly recognize the importance of real-world evidence (RWE) to provide important and relevant insights on treatment patterns, burden/cost of illness, product safety, and long-term and comparative effectiveness. However, RWE generation requires a careful approach to ensure rigorous analysis and interpretation. There are limited examples of comprehensive methodology for the generation of RWE on patients who have undergone neuromodulation for drug-resistant epilepsy (DRE). This is likely due, at least in part, to the many challenges inherent in using real-world data to define DRE, neuromodulation (including type implanted), and related outcomes of interest. We sought to provide recommendations to enable generation of robust RWE that can increase knowledge of "real-world" patients with DRE and help inform the difficult decisions regarding treatment choices and reimbursement for this particularly vulnerable population. Methods: We drew upon our collective decades of experience in RWE generation and relevant disciplines (epidemiology, health economics, and biostatistics) to describe challenges inherent to this therapeutic area and to provide potential solutions thereto within healthcare claims databases. Several examples were provided from our experiences in DRE to further illustrate our recommendations for generation of robust RWE in this therapeutic area. Results: Our recommendations focus on considerations for the selection of an appropriate data source, development of a study timeline, exposure allotment (specifically, neuromodulation implantation for patients with DRE), and ascertainment of relevant outcomes. Conclusions: The need for RWE to inform healthcare decisions has never been greater and continues to grow in importance to regulators, payers, physicians, and other key stakeholders. However, as real-world data sources used to generate RWE are typically generated for reasons other than research, rigorous methodology is required to minimize bias and fully unlock their value.

Elevating the field for applying neuroimaging to individual patients in psychiatry

Although neuroimaging has been widely applied in psychiatry, much of the exuberance in decades past has been tempered by failed replications and a lack of definitive evidence to support the utility of imaging to inform clinical decisions. There are multiple promising ways forward to demonstrate the relevance of neuroimaging for psychiatry at the individual patient level. Ultra-high field magnetic resonance imaging is developing as a sensitive measure of neurometabolic processes of particular relevance that holds promise as a new way to characterize patient abnormalities as well as variability in response to treatment. Neuroimaging may also be particularly suited to the science of brain stimulation interventions in psychiatry given that imaging can both inform brain targeting as well as measure changes in brain circuit communication as a function of how effectively interventions improve symptoms. We argue that a greater focus on individual patient imaging data will pave the way to stronger relevance to clinical care in psychiatry. We also stress the importance of using imaging in symptom-relevant experimental manipulations and how relevance will be best demonstrated by pairing imaging with differential treatment prediction and outcome measurement. The priorities for using brain imaging to inform psychiatry may be shifting, which compels the field to solidify clinical relevance for individual patients over exploratory associations and biomarkers that ultimately fail to replicate.

Prefrontal network engagement by deep brain stimulation in limbic hubs

Prefrontal circuits in the human brain play an important role in cognitive and affective processing. Neuromodulation therapies delivered to certain key hubs within these circuits are being used with increasing frequency to treat a host of neuropsychiatric disorders. However, the detailed neurophysiological effects of stimulation to these hubs are largely unknown. Here, we performed intracranial recordings across prefrontal networks while delivering electrical stimulation to two well-established white matter hubs involved in cognitive regulation and depression: the subcallosal cingulate (SCC) and ventral capsule/ventral striatum (VC/VS). We demonstrate a shared frontotemporal circuit consisting of the ventromedial prefrontal cortex, amygdala, and lateral orbitofrontal cortex where gamma oscillations are differentially modulated by stimulation target. Additionally, we found participant-specific responses to stimulation in the dorsal anterior cingulate cortex and demonstrate the capacity for further tuning of neural activity using current-steered stimulation. Our findings indicate a potential neurophysiological mechanism for the dissociable therapeutic effects seen across the SCC and VC/VS targets for psychiatric neuromodulation and our results lay the groundwork for personalized, network-guided neurostimulation therapy.

An individualized tractography pipeline for the nucleus basalis of Meynert lateral tract

Background

At the center of the cortical cholinergic network, the nucleus basalis of Meynert (NBM) is crucial for the cognitive domains most vulnerable in Parkinson's disease (PD). Preclinical evidence has demonstrated the positive impact of NBM deep brain stimulation (DBS) on cognition but early human trials have had mixed results. It is possible that DBS of the lateral NBM efferent white matter fiber bundle may be more effective at improving cognitive-motor function. However, precise tractography modelling is required to identify the optimal target for neurosurgical planning. Individualized tractography approaches have been shown to be highly effective for accurately identifying DBS targets but have yet to be developed for the NBM.

Methods

Using structural and diffusion-weighted imaging, we developed a tractography pipeline using manually segmented regions of interest for precise individualized identification of the lateral NBM target tract. Using dice similarity coefficients, the reliability of the tractography outputs was assessed across three cohorts to investigate: 1) whether this manual segmentation pipeline is more reliable than an existing automatic segmentation pipeline currently used in the literature; 2) the inter- and intra-rater reliability of our pipeline in research scans of patients with PD; and 3) the reliability and practicality of this pipeline in clinical scans of DBS patients.

Results

The individualized manual pipeline was found to be significantly more reliable than the existing automated pipeline for both the segmentation of the NBM region itself (p < 0.001) and the reconstruction of the target lateral tract (p = 0.002). There was also no significant difference between the reliability of two different raters in the PD cohort (p = 0.25), which showed high inter- (mean Dice coefficient >0.6) and intra-rater (mean Dice coefficient >0.7) reliability across runs. Finally, the pipeline was shown to be highly reliable within the clinical scans (mean Dice coefficient = 0.77). However, accurate reconstruction was only evident in 7/10 tracts.

Conclusion

We have developed a reliable tractography pipeline for the identification and analysis of the NBM lateral tract in research and clinical-grade imaging of healthy young adult and PD patient scans.

The future of brain circuit-targeted therapeutics

The principle of targeting brain circuits has drawn increasing attention with the growth of brain stimulation treatments such as transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and focused ultrasound (FUS). Each of these techniques can effectively treat different neuropsychiatric disorders, but treating any given disorder depends on choosing the right treatment target. Here, we propose a three-phase framework for identifying and modulating these targets. There are multiple approaches to identifying a target, including correlative neuroimaging, retrospective optimization based on existing stimulation sites, and lesion localization. These techniques can then be optimized using personalized neuroimaging, physiological monitoring, and engagement of a specific brain state using pharmacological or psychological interventions. Finally, a specific stimulation modality or combination of modalities can be chosen after considering the advantages and tradeoffs of each. While there is preliminary literature to support different components of this framework, there are still many unanswered questions. This presents an opportunity for the future growth of research and clinical care in brain circuit therapeutics.

No time to lose: the current state of research in rapid-acting psychotherapeutics

The vast majority of treatments for psychiatric and substance use disorders take weeks to work. Notable exceptions to this rule exist, with some treatments such as intravenous ketamine resolving symptoms in minutes to hours. Current research is focused on identifying novel approaches to rapid-acting psychotherapeutics. Promising results from studies of novel classes of drugs and innovative brain stimulation therapies are currently being studied through both clinical and pre-clinical research, as described here. Research focused on understanding neurobiological mechanisms, effective therapeutic context, and implementation approaches are needed to maximize the potential reach of these therapies.

Deep Brain Stimulation (DBS) in Treatment-Resistant Depression (TRD): Hope and Concern

In this chapter, we explore the historical evolution, current applications, and future directions of Deep Brain Stimulation (DBS) for Treatment-Resistant Depression (TRD). We begin by highlighting the early efforts of neurologists and neurosurgeons who laid the foundations for today's DBS techniques, moving from controversial lobotomies to the precision of stereotactic surgery. We focus on the advent of DBS, emphasizing its emergence as a significant breakthrough for movement disorders and its extension to psychiatric conditions, including TRD. We provide an overview of the neural networks implicated in depression, detailing the rationale for the choice of common DBS targets. We also cover the technical aspects of DBS, from electrode placement to programming and parameter selection. We then critically review the evidence from clinical trials and open-label studies, acknowledging the mixed outcomes and the challenges posed by placebo effects and trial design. Safety and ethical considerations are also discussed. Finally, we explore innovative directions for DBS research, including the potential of closed-loop systems, dual stimulation strategies, and noninvasive alternatives like ultrasound neuromodulation. In the last section, we outline recommendations for future DBS studies, including the use of alternative designs for placebo control, the collection of neural and behavioral recordings, and the application of machine-learning approaches.

Accelerated TMS - moving quickly into the future of depression treatment

Accelerated TMS is an emerging application of Transcranial Magnetic Stimulation (TMS) aimed to reduce treatment length and improve response time. Extant literature generally shows similar efficacy and safety profiles compared to the FDA-cleared protocols for TMS to treat major depressive disorder (MDD), yet accelerated TMS research remains at a very early stage in development. The few applied protocols have not been standardized and vary significantly across a set of core elements. In this review, we consider nine elements that include treatment parameters (i.e., frequency and inter-stimulation interval), cumulative exposure (i.e., number of treatment days, sessions per day, and pulses per session), individualized parameters (i.e., treatment target and dose), and brain state (i.e., context and concurrent treatments). Precisely which of these elements is critical and what parameters are most optimal for the treatment of MDD remains unclear. Other important considerations for accelerated TMS include durability of effect, safety profiles as doses increase over time, the possibility and advantage of individualized functional neuronavigation, use of biological readouts, and accessibility for patients most in need of the treatment. Overall, accelerated TMS appears to hold promise to reduce treatment time and achieve rapid reduction in depressive symptoms, but at this time significant work remains to be done. Rigorous clinical trials combining clinical outcomes and neuroscientific measures such as electroencephalogram, magnetic resonance imaging and e-field modeling are needed to define the future of accelerated TMS for MDD.