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Background and Objectives: Paralysis after spinal cord injury involves damage to pathways that connect neurons in the brain to peripheral nerves in the limbs. Re-establishing this communication using neural interfaces has the potential to bridge the gap and restore upper extremity function to people with high tetraplegia. We report a novel approach for restoring upper extremity function using selective peripheral nerve stimulation controlled by intracortical microelectrode recordings from sensorimotor networks, along with restoration of tactile sensation of the hand using intracortical microstimulation., Methods: A 27-year-old right-handed man with AIS-B (motor-complete, sensory-incomplete) C3-C4 tetraplegia was enrolled into the clinical trial. Six 64-channel intracortical microelectrode arrays were implanted into left hemisphere regions involved in upper extremity function, including primary motor and sensory cortices, inferior frontal gyrus, and anterior intraparietal area. Nine 16-channel extraneural peripheral nerve electrodes were implanted to allow targeted stimulation of right median, ulnar (2), radial, axillary, musculocutaneous, suprascapular, lateral pectoral, and long thoracic nerves, to produce selective muscle contractions on demand. Proof-of-concept studies were performed to demonstrate feasibility of using a brain-machine interface to read from and write to the brain for restoring motor and sensory functions of the participant's own arm and hand., Results: Multiunit neural activity that correlated with intended motor action was successfully recorded from intracortical arrays. Microstimulation of electrodes in somatosensory cortex produced repeatable sensory percepts of individual fingers for restoration of touch sensation. Selective electrical activation of peripheral nerves produced antigravity muscle contractions, resulting in functional movements that the participant was able to command under brain control to perform virtual and actual arm and hand movements. The system was well tolerated with no operative complications., Conclusion: The combination of implanted cortical electrodes and nerve cuff electrodes has the potential to create bidirectional restoration of motor and sensory functions of the arm and hand after neurological injury., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background and Objectives: Asleep, image-guided deep brain stimulation (DBS) is a modern alternative to awake, microelectrode recording (MER) guidance. Studies demonstrate comparable efficacy and complications between techniques, although some report lower stimulation thresholds for side effects with image guidance. In addition, few studies directly compare the risk of postoperative transient confusion (pTC) across techniques. The purpose of this study was to compare clinical efficacy, stimulation thresholds for side effects, and rates of pTC with MER-guided DBS vs intraoperative 3D-fluoroscopy (i3D-F) guidance in Parkinson's disease and essential tremor., Methods: Consecutive patients from 2006 to 2021 were identified from the departmental database and grouped as having either MER-guided DBS or i3D-F-guided DBS insertion. Directional leads were used once commercially available. Changes in Unified Parkinson's Disease Rating Scale (UPDRS)-III scores, levodopa equivalent daily dose, Fahn-Tolosa-Marin scores, and stimulation thresholds were assessed, as were rates of complications including pTC., Results: MER guidance was used to implant 487 electrodes (18 globus pallidus interna, GPi; 171 subthalamic nucleus; 76 ventrointermediate thalamus, VIM) in 265 patients. i3D-F guidance was used in 167 electrodes (19 GPi; 25 subthalamic nucleus; 41 VIM) in 85 patients. There were no significant differences in Unified Parkinson's Disease Rating III Scale, levodopa equivalent daily dose, or Fahn-Tolosa-Marin between groups. Stimulation thresholds for side effects were higher with i3D-F guidance in the subthalamic nucleus (MER, 2.80 mA ± 0.98; i3D-F, 3.46 mA ± 0.92; P = .002) and VIM (MER, 2.81 mA ± 1.00; i3D-F, 3.19 mA ± 1.03; P = .0018). Less pTC with i3D-F guidance (MER, 7.5%; i3D-F, 1.2%; P = .034) was also found., Conclusion: Although clinical efficacy between MER-guided and i3D-F-guided DBS was comparable, thresholds for stimulation side effects were higher with i3D-F guidance and the rate of pTC was lower. This suggests that image-guided DBS may affect long-term side effects and pose a decreased risk of pTC., (Copyright © 2024 Written work prepared by employees of the Federal Government as part of their official duties is, under the U.S. Copyright Act, a “work of the United States Government” for which copyright protection under Title 17 of the United States Code is not available. As such, copyright does not extend to the contributions of employees of the Federal Government.)

Background: The Guidelines Task Force conducted a systematic review of the relevant literature on occipital nerve stimulation (ONS) for occipital neuralgia (ON) to update the original 2015 guidelines to ensure timeliness and accuracy for clinical practice., Objective: To conduct a systematic review of the literature and update the evidence-based guidelines on ONS for ON., Methods: The Guidelines Task Force conducted another systematic review of the relevant literature, using the same search terms and strategies used to search PubMed and Embase for relevant literature. The updated search included studies published between 1966 and January 2023. The same inclusion/exclusion criteria as the original guideline were also applied. Abstracts were reviewed, and relevant full text articles were retrieved and graded. Of 307 articles, 18 were retrieved for full-text review and analysis. Recommendations were updated according to new evidence yielded by this update ., Results: Nine studies were included in the original guideline, reporting the use of ONS as an effective treatment option for patients with medically refractory ON. An additional 6 studies were included in this update. All studies in the original guideline and this current update provide Class III evidence., Conclusion: Based on the availability of new literature, the current article is a minor update only that does not result in modification of the prior recommendations: Clinicians may use ONS as a treatment option for patients with medically refractory ON., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Objective: Despite advances in the treatment of psychiatric diseases, currently available therapies do not provide sufficient and durable relief for as many as 30-40% of patients. Neuromodulation, including deep brain stimulation (DBS), has emerged as a potential therapy for persistent disabling disease, however it has not yet gained widespread adoption. In 2016, the American Society for Stereotactic and Functional Neurosurgery (ASSFN) convened a meeting with leaders in the field to discuss a roadmap for the path forward. A follow-up meeting in 2022 aimed to review the current state of the field and to identify critical barriers and milestones for progress., Design: The ASSFN convened a meeting on June 3, 2022 in Atlanta, Georgia and included leaders from the fields of neurology, neurosurgery, and psychiatry along with colleagues from industry, government, ethics, and law. The goal was to review the current state of the field, assess for advances or setbacks in the interim six years, and suggest a future path forward. The participants focused on five areas of interest: interdisciplinary engagement, regulatory pathways and trial design, disease biomarkers, ethics of psychiatric surgery, and resource allocation/prioritization. The proceedings are summarized here., Conclusion: The field of surgical psychiatry has made significant progress since our last expert meeting. Although weakness and threats to the development of novel surgical therapies exist, the identified strengths and opportunities promise to move the field through methodically rigorous and biologically-based approaches. The experts agree that ethics, law, patient engagement, and multidisciplinary teams will be critical to any potential growth in this area., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Sarah Bick receives funding from the Neurosurgery Research and Career Development Program (K12 NS080223) and consulting honoraria from Varian Medical Systems. Rafael Carbunaru owns stock options and is an employee of Boston Scientific, a manufacturer of DBS devices. Jennifer Chandler receives funding from CIHR (Canadian Institutes of Health Research) through the ERANET-Neuron program. Binith Cheeran owns stock options and is an employee of Abbott, a manufacturer of DBS devices. Rachel Davis receives consulting honoraria from Medtronic and speaker fees from Baylor for an OCD conference. Darin Dougherty's research has been funded by the International OCD Foundation, Brain and Behavior Research Foundation, National Institute of Mental Health, Tiny Blue Dot Foundation and Medtronic; he has received honoraria and consultation fees from Medtronic, Sage, and Celanese and has equity in Neurable, Innercosmos, and Intrinsic Powers. Ashley Feinsinger receives funding from the NIH (RF1MH121373 and UH3NS103442), received honoraria for her work on the NIH Neuroethics Workgroup, she is on an advisory board of Vivani Medical Products (Orion Early Feasibility Study), and she is on the data safety monitoring board of R01 MH122431. Kelly Foote reported grants from the National Institutes of Health during the conduct of the study; nonfinancial support from Medtronic (donation of closed-loop DBS devices) outside the submitted work; and grants from Medtronic, Boston Scientific, and Functional Neuromodulation outside the submitted work. Wayne Goodman receives funding from NIH (UH3NS100459), the McNair Foundation, and Biohaven. WG receives royalties from Nview, LLC and OCDscales, LLC as well as consulting honoraria from Biohaven. Aysegul Gunduz receives investigational device donations from Medtronic under the NIH BRAIN Public-Private Partnership agreements, and her research is funded by NIH grants UH3NS095553, R01NS096008, UH3NS119844. Casey Halpern has patents related to sensing and brain stimulation for the treatment of neuropsychiatric disorders, and he works as a consultant for Boston Scientific Neuromodulation and Insightec. Brian Kopell has received consulting honoraria from Abbott and Medtronic. Cynthia Kubu receives grant funding from the NIH (5RO1MH114853, 5RC1NS068086, 3RF1MH123407-01S1) and participates on the data safety monitoring boards for studies investigating the use of DBS for pain (UHS3 BRIAN/UH3 HEAL, 3UH3NS113661). She is the president of the Society for Clinical Neuropsychology. Sarah Lisanby receives funding from the NIMH (1ZIAMH002955) and has a role on the Scientific Advisory Boards of the Aalto University School of Science and the German Center for Brain Stimulation. Cameron McIntyre is a paid consultant for Boston Scientific Neuromodulation, receives royalties from Hologram Consultants, Neuros Medical, Qr8 Health, and is a shareholder in the following companies: Hologram Consultants, Surgical Information Sciences, BrainDynamics, CereGate, Autonomic Technologies, Cardionomic, Enspire DBS. Michael Okun serves as Medical Advisor for the Parkinson's Foundation, and has received research grants from NIH, Parkinson's Foundation, the Michael J. Fox Foundation, the Parkinson Alliance, Smallwood Foundation, the Bachmann-Strauss Foundation, the Tourette Syndrome Association, and the UF Foundation. Michael Okun's research is supported by: NIHR01 NR014852, R01NS096008, UH3NS119844, U01NS119562. Michael Okun is PI of the NIH R25NS108939 Training Grant. Michael Okun has received royalties for publications with Demos, Manson, Amazon, Smashwords, Books4Patients, Perseus, Robert Rose, Oxford and Cambridge (movement disorders books). Nader Pouratian receives research funding from NIH (R24 MH114796, UH3 NS103442, UH3 NS103549, R01 NS097782, UH3 NS113661, R01 GM135420, RF1 MH121373), consulting/presentation honoraria from Abbott, Sensoria Therapeutics, Boston Scientific, and BrainLab. Nader Pouratian is on an advisory board at Abbott Laboratories and has leadership positions in the Congress of Neurological Surgeons and American Society of Stereotactic and Functional Neurosurgery. Robert Raike owns stock options and is an employee of Medtronic, a manufacturer of DBS devices. Patricio Riva-Posse has received honoraria for consulting for Janssen Pharmaceuticals, Abbott Neuromodulation, and LivaNova. Sameer Sheth received funding from the McNair Foundation for this work. SS receives consulting honoraria from Boston Scientific, Neuropace, Zimmer Biomet, and Koh Young. Nora Vanegas-Arroyave receives research funding from NIH and the Michael J. Fox foundation. Alik Widge has received honoraria for consulting for Abbott, he has received device donations from Medtronic, and he has unlicensed patents in the area of deep brain stimulation., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Trigeminal neuralgia (TN) is a syndrome consisting of episodic neuropathic facial pain. Although the precise symptoms vary across individuals, TN is typically described as lancinating electrical shocks triggered by sensory stimuli (light touch, talking, eating, and brushing teeth) that improve with antiepileptic medication (especially carbamazepine), remit spontaneously for weeks to months (pain-free intervals), and do not involve any changes in baseline sensation. The etiology of TN has not been definitively established, but many cases are associated with compression of the trigeminal nerve by a blood vessel at the trigeminal root entry zone adjacent to the brainstem. Patients who do not respond to medical management and who are not candidates for microvascular decompression often benefit from focal therapeutic injury to the trigeminal nerve at some point along its course. Many lesions have been described, including peripheral neurectomies that target distal branches of the trigeminal nerve, rhizotomies of the Gasserian ganglion of the nerve within Meckel's cave, radiosurgery of the trigeminal nerve at its root entry zone, partial sensory rhizotomy at the root entry zone, tractotomy of the spinal nucleus of the trigeminal nerve, and DREZotomy of the trigeminal nucleus caudalis, Though the latter two interventions are seldom done for TN and more commonly performed for trigeminal neuropathic pain. This article reviews the relevant anatomy and lesioning procedures for the treatment of trigeminal neuralgia., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background and Objectives: Brain-computer interfaces (BCIs) are being developed to restore mobility, communication, and functional independence to people with paralysis. Though supported by decades of preclinical data, the safety of chronically implanted microelectrode array BCIs in humans is unknown. We report safety results from the prospective, open-label, nonrandomized BrainGate feasibility study (NCT00912041), the largest and longest-running clinical trial of an implanted BCI., Methods: Adults aged 18-75 years with quadriparesis from spinal cord injury, brainstem stroke, or motor neuron disease were enrolled through 7 clinical sites in the United States. Participants underwent surgical implantation of 1 or 2 microelectrode arrays in the motor cortex of the dominant cerebral hemisphere. The primary safety outcome was device-related serious adverse events (SAEs) requiring device explantation or resulting in death or permanently increased disability during the 1-year postimplant evaluation period. The secondary outcomes included the type and frequency of other adverse events and the feasibility of the BrainGate system for controlling a computer or other assistive technologies., Results: From 2004 to 2021, 14 adults enrolled in the BrainGate trial had devices surgically implanted. The average duration of device implantation was 872 days, yielding 12,203 days of safety experience. There were 68 device-related adverse events, including 6 device-related SAEs. The most common device-related adverse event was skin irritation around the percutaneous pedestal. There were no safety events that required device explantation, no unanticipated adverse device events, no intracranial infections, and no participant deaths or adverse events resulting in permanently increased disability related to the investigational device., Discussion: The BrainGate Neural Interface system has a safety record comparable with other chronically implanted medical devices. Given rapid recent advances in this technology and continued performance gains, these data suggest a favorable risk/benefit ratio in appropriately selected individuals to support ongoing research and development., Trial Registration Information: ClinicalTrials.gov Identifier: NCT00912041., Classification of Evidence: This study provides Class IV evidence that the neurosurgically placed BrainGate Neural Interface system is associated with a low rate of SAEs defined as those requiring device explantation, resulting in death, or resulting in permanently increased disability during the 1-year postimplant period., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Establishment of a diverse neurosurgical workforce includes increasing the recruitment of women in neurosurgery. The impact of pregnancy on the training and career trajectory of female neurosurgeons poses a barrier to recruitment and retention of women in neurosurgery. A recent Women in Neurosurgery survey evaluated female neurosurgeons' perception and experience regarding childbearing of female neurosurgeons and identified several recommendations regarding family leave policies. Additionally, pregnancy may carry higher risk in surgical fields, yet little guidance exists to aid both the pregnant resident and her training program in optimizing the safety of the training environment with specific considerations to risks inherent in neurosurgical training. This review of current literature aims to address best practices that can be adopted by pregnant neurosurgery residents and their training programs to improve the well-being of these residents while considering the impact on their education and the educational environment for their colleagues.

Louisiana estuaries are important habitats in the northern Gulf of Mexico, a region undergoing significant and sustained human- and climate-driven changes. This paper synthesizes data collected over multiple years from four Louisiana estuaries - Breton Sound, Terrebonne Bay, the Atchafalaya River Delta Estuary, and Vermilion Bay - to characterize trends in phytoplankton biomass, community composition, and the environmental factors influencing them. Results highlight similarities in timing and composition of maximum chlorophyll, with salinity variability often explaining biomass trends. Distinct drivers for biomass versus community structure were observed in all four estuarine systems. Systems shared a lack of significant correlation between river discharge and overall phytoplankton biomass, while discharge was important for understanding community composition. Temperature was a significant explanatory variable for both biomass and community composition in only one system. These results provide a regional view of phytoplankton dynamics in Louisiana estuaries critical to understanding and predicting the effects of ongoing change., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: The clinical response of patients with bipolar disorder to medical treatment is variable. A better understanding of the underlying neural circuitry involved in bipolar treatment responsivity subtypes may provide insight into treatment resistance and aid in identifying an effective surgical target for deep brain stimulation (DBS) specific to the disorder. Despite considerable imaging research related to the disease, a paucity of comparative imaging analyses of treatment responsiveness exists. There are also no DBS targets designed expressly for patients with bipolar disorder. Therefore, the authors analyzed cingulum bundle axonal connectivity in relation to cortico-striatal-thalamo-cortical (CSTC) loops implicated in bipolar disorder across subjects who are responsive to treatment (RSP) and those who are refractory to therapy (REF), compared to healthy controls (HCs)., Methods: Twenty-five subjects with bipolar disorder (13 RSP and 12 REF), diagnosed using the Mini International Neuropsychiatric Interview and classified with standardized rating scales, and 14 HCs underwent MRI with diffusion sequences for probabilistic diffusion-weighted tractography analysis. Image processing and tractography were performed using MRTrix. Region of interest (ROI) masks were created manually for 10 anterior cingulum bundle subregions, including surgical targets previously evaluated for the treatment of bipolar disorder (cingulotomy and subgenual cingulate DBS targets). Cortical and subcortical ROIs of brain areas thought to be associated with bipolar disorder and described in animal tract-tracing models were created via FreeSurfer. The number of axonal projections from the cingulum bundle subregion ROIs to cortical/subcortical ROIs for each group was compared., Results: Significant differences were found across groups involving cingulum bundle and CSTC loops. Subjects in the RSP group had increased connections from rostral cingulum bundle to medial orbitofrontal cortex, which is part of the limbic CSTC loop, whereas subjects in the REF group had increased connectivity from rostral cingulum bundle to thalamus. Additionally, compared to HCs, both RSP and REF subjects had decreased cingulum bundle dorsal connectivity (dorsal anterior/posterior cingulate, dorsomedial/lateral frontal cortex) and increased cingulum bundle ventral connectivity (subgenual cingulate, frontal pole, lateral orbitofrontal cortex) involving limbic and associative CSTC loops., Conclusions: Findings demonstrate that bipolar treatment responsivity may be associated with significant differences in cingulum bundle connectivity in relation to CSTC loops, which may help identify a surgical target for bipolar disorder treatment via DBS in the future.

Objective: Stereotactic ablation (cingulotomy) and subcallosal cingulate deep brain stimulation (SCC DBS) of different regions of the cingulum bundle (CB) have been successfully used to treat psychiatric disorders, such as depression and bipolar disorder. They are hypothesized to work by disrupting white matter pathways involved in the clinical manifestation of these disorders. This study aims to compare the connectivity of different CB subregions using tractography to evaluate stereotactic targets for the treatment of mood disorders., Methods: Fourteen healthy volunteers underwent 3T-MR imaging followed by connectivity analysis using probabilistic tractography. Twenty-one anatomic regions of interest were defined for each subject: 10 CB subregions (including the classical cingulotomy and SCC DBS targets) and 11 cortical/subcortical structures implicated in mood disorders. Connectivity results were compared using Friedman and Bonferroni-corrected post-hoc Wilcoxon tests., Results: CB connectivity showed a high degree of regional specificity. Both of the traditional stereotactic targets had widespread connectivity with discrete topology. The cingulotomy target connected primarily to the dorsomedial frontal, dorsal anterior cingulate, and posterior cingulate cortices, whereas the SCC DBS target connected mostly to the subgenual anterior cingulate and medial/central orbitofrontal cortices. However, a region of the rostral dorsal CB, lying between these surgical targets, encompassed statistically equivalent connections to all five cortical regions., Conclusions: The CB is associated with brain structures involved in affective disorders, and the rostral dorsal CB demonstrates connectivity that is comparable to the combined connectivity of cingulotomy and SCC DBS neurosurgical interventions. The rostral dorsal CB represents a surgical target worthy of clinical exploration for mood disorders., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objective: Despite recently heightened advocacy efforts relating to pregnancy and family leave policies in multiple surgical specialties, no studies to date have described female neurosurgeons' experiences with childbearing. The AANS/CNS Section of Women in Neurosurgery created the Women and Pregnancy Task Force to ascertain female neurosurgeons' experiences with and attitudes toward pregnancy and the role of family leave policies., Methods: A voluntary online 28-question survey examined the pregnancy experiences of female neurosurgeons and perceived barriers to childbearing. The survey was developed and electronically distributed to all members of the American Association of Neurological Surgeons and Congress of Neurological Surgeons who self-identified as female in February 2016. Responses from female resident physicians, fellows, and current or retired practicing neurosurgeons were analyzed., Results: A total of 126 women (20.3%) responded to the survey; 57 participants (49%) already had children, and 39 (33%) planned to do so. Participants overwhelmingly had or planned to have children during the early practice and senior residency years. The most frequent obstacles experienced or anticipated included insufficient time to care for newborns (47% of women with children, 92% of women planning to have children), discrimination by coworkers (31% and 77%, respectively), and inadequate time for completion of board requirements (18% and 51%, respectively). There was substantial variability in family leave policies, and a minority of participants (35%) endorsed the presence of any formal policy at their institution. Respondents described myriad unique challenges associated with pregnancy and family leave., Conclusions: Pregnancy and family leave pose significant challenges to the recruitment, retention, and advancement of women in neurosurgery. It is thus imperative to promote clear family leave policies for trainees and practitioners, address discrimination surrounding these topics, and encourage forethought and flexibility to tackle obstacles inherent in pregnancy and the early stages of child rearing.

Background: The cingulum bundle (CB) has long been a target for psychiatric neurosurgical procedures, but with limited understanding of the brain networks being impacted. Recent advances in human tractography could provide a foundation to better understand the effects of neurosurgical interventions on the CB; however, the reliability of tractography remains in question., Objective: To evaluate the ability of different tractography techniques, derived from typical, human diffusion-weighted imaging (DWI) data, to characterize CB connectivity described in animal models. This will help validate the clinical applicability of tractography, and generate insight on current and future neurosurgical targets for psychiatric disorders., Methods: Connectivity of the CB in 15 healthy human subjects was evaluated using DWI-based tractography, and compared to tract-tracing findings from nonhuman primates. Brain regions of interest were defined to coincide with the animal model. Tractography was performed using 3 techniques (FSL probabilistic, Camino probabilistic, and Camino deterministic). Differences in connectivity were assessed, and the CB segment with the greatest connectivity was determined., Results: Each tractography technique successfully reproduced the animal tracing model with a mean accuracy of 72% (68-75%, P < .05). Additionally, one region of the CB, the rostral dorsal segment, had significantly greater connectivity to associated brain structures than all other CB segments (P < .05)., Conclusion: Noninvasive, in vivo human analysis of the CB, using clinically available DWI for tractography, consistently reproduced the results of an animal tract-tracing model. This suggests that tractography of the CB can be used for clinical applications, which may aid in neurosurgical targeting for psychiatric disorders., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Hybrid kinetic and kinematic intracortical brain-computer interfaces (iBCIs) have the potential to restore functional grasping and object interaction capabilities in individuals with tetraplegia. This requires an understanding of how kinetic information is represented in neural activity, and how this representation is affected by non-motor parameters such as volitional state (VoS), namely, whether one observes, imagines, or attempts an action. To this end, this work investigates how motor cortical neural activity changes when three human participants with tetraplegia observe, imagine, and attempt to produce three discrete hand grasping forces with the dominant hand. We show that force representation follows the same VoS-related trends as previously shown for directional arm movements; namely, that attempted force production recruits more neural activity compared to observed or imagined force production. Additionally, VoS-modulated neural activity to a greater extent than grasping force. Neural representation of forces was lower than expected, possibly due to compromised somatosensory pathways in individuals with tetraplegia, which have been shown to influence motor cortical activity. Nevertheless, attempted forces (but not always observed or imagined forces) could be decoded significantly above chance, thereby potentially providing relevant information towards the development of a hybrid kinetic and kinematic iBCI.

Decoders optimized offline to reconstruct intended movements from neural recordings sometimes fail to achieve optimal performance online when they are used in closed-loop as part of an intracortical brain-computer interface (iBCI). This is because typical decoder calibration routines do not model the emergent interactions between the decoder, the user, and the task parameters (e.g. target size). Here, we investigated the feasibility of simulating online performance to better guide decoder parameter selection and design. Three participants in the BrainGate2 pilot clinical trial controlled a computer cursor using a linear velocity decoder under different gain (speed scaling) and temporal smoothing parameters and acquired targets with different radii and distances. We show that a user-specific iBCI feedback control model can predict how performance changes under these different decoder and task parameters in held-out data. We also used the model to optimize a nonlinear speed scaling function for the decoder. When used online with two participants, it increased the dynamic range of decoded speeds and decreased the time taken to acquire targets (compared to an optimized standard decoder). These results suggest that it is feasible to simulate iBCI performance accurately enough to be useful for quantitative decoder optimization and design.

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

Objective: Recent reports indicate that making better assumptions about the user's intended movement can improve the accuracy of decoder calibration for intracortical brain-computer interfaces. Several methods now exist for estimating user intent, including an optimal feedback control model, a piecewise-linear feedback control model, ReFIT, and other heuristics. Which of these methods yields the best decoding performance?, Methods: Using data from the BrainGate2 pilot clinical trial, we measured how a steady-state velocity Kalman filter decoder was affected by the choice of intention estimation method. We examined three separate components of the Kalman filter: dimensionality reduction, temporal smoothing, and output gain (speed scaling)., Results: The decoder's dimensionality reduction properties were largely unaffected by the intention estimation method. Decoded velocity vectors differed by <5% in terms of angular error and speed vs. target distance curves across methods. In contrast, the smoothing and gain properties of the decoder were greatly affected (> 50% difference in average values). Since the optimal gain and smoothing properties are task-specific (e.g. lower gains are better for smaller targets but worse for larger targets), no one method was better for all tasks., Conclusion: Our results show that, when gain and smoothing differences are accounted for, current intention estimation methods yield nearly equivalent decoders and that simple models of user intent, such as a position error vector (target position minus cursor position), perform comparably to more elaborate models. Our results also highlight that simple differences in gain and smoothing properties have a large effect on online performance and can confound decoder comparisons.

Question 1: Is bilateral subthalamic nucleus deep brain stimulation (STN DBS) more, less, or as effective as bilateral globus pallidus internus deep brain stimulation (GPi DBS) in treating motor symptoms of Parkinson's disease, as measured by improvements in Unified Parkinson's Disease Rating Scale, part III (UPDRS-III) scores?, Recommendation: Given that bilateral STN DBS is at least as effective as bilateral GPi DBS in treating motor symptoms of Parkinson's disease (as measured by improvements in UPDRS-III scores), consideration can be given to the selection of either target in patients undergoing surgery to treat motor symptoms. (Level I)., Question 2: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in allowing reduction of dopaminergic medication in Parkinson's disease?, Recommendation: When the main goal of surgery is reduction of dopaminergic medications in a patient with Parkinson's disease, then bilateral STN DBS should be performed instead of GPi DBS. (Level I)., Question 3: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in treating dyskinesias associated with Parkinson's disease?, Recommendation: There is insufficient evidence to make a generalizable recommendation regarding the target selection for reduction of dyskinesias. However, when the reduction of medication is not anticipated and there is a goal to reduce the severity of "on" medication dyskinesias, the GPi should be targeted. (Level I)., Question 4: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in improving quality of life measures in Parkinson's disease?, Recommendation: When considering improvements in quality of life in a patient undergoing DBS for Parkinson's disease, there is no basis to recommend bilateral DBS in 1 target over the other. (Level I)., Question 5: Is bilateral STN DBS associated with greater, lesser, or a similar impact on neurocognitive function than bilateral GPi DBS in Parkinson disease?, Recommendation: If there is significant concern about cognitive decline, particularly in regards to processing speed and working memory in a patient undergoing DBS, then the clinician should consider using GPi DBS rather than STN DBS, while taking into consideration other goals of surgery. (Level I)., Question 6: Is bilateral STN DBS associated with a higher, lower, or similar risk of mood disturbance than GPi DBS in Parkinson's disease?, Recommendation: If there is significant concern about the risk of depression in a patient undergoing DBS, then the clinician should consider using pallidal rather than STN stimulation, while taking into consideration other goals of surgery. (Level I)., Question 7: Is bilateral STN DBS associated with a higher, lower, or similar risk of adverse events compared to GPi DBS in Parkinson's disease?, Recommendation: There is insufficient evidence to recommend bilateral DBS in 1 target over the other in order to minimize the risk of surgical adverse events.  The full guideline can be found at: https://www.cns.org/guidelines/deep-brain-stimulation-parkinsons-disease.

Objective: Brain-computer interfaces (BCIs) can enable individuals with tetraplegia to communicate and control external devices. Though much progress has been made in improving the speed and robustness of neural control provided by intracortical BCIs, little research has been devoted to minimizing the amount of time spent on decoder calibration., Approach: We investigated the amount of time users needed to calibrate decoders and achieve performance saturation using two markedly different decoding algorithms: the steady-state Kalman filter, and a novel technique using Gaussian process regression (GP-DKF)., Main Results: Three people with tetraplegia gained rapid closed-loop neural cursor control and peak, plateaued decoder performance within 3 min of initializing calibration. We also show that a BCI-naïve user (T5) was able to rapidly attain closed-loop neural cursor control with the GP-DKF using self-selected movement imagery on his first-ever day of closed-loop BCI use, acquiring a target 37 s after initiating calibration., Significance: These results demonstrate the potential for an intracortical BCI to be used immediately after deployment by people with paralysis, without the need for user learning or extensive system calibration.

Background: People with chronic tetraplegia, due to high-cervical spinal cord injury, can regain limb movements through coordinated electrical stimulation of peripheral muscles and nerves, known as functional electrical stimulation (FES). Users typically command FES systems through other preserved, but unrelated and limited in number, volitional movements (eg, facial muscle activity, head movements, shoulder shrugs). We report the findings of an individual with traumatic high-cervical spinal cord injury who coordinated reaching and grasping movements using his own paralysed arm and hand, reanimated through implanted FES, and commanded using his own cortical signals through an intracortical brain-computer interface (iBCI)., Methods: We recruited a participant into the BrainGate2 clinical trial, an ongoing study that obtains safety information regarding an intracortical neural interface device, and investigates the feasibility of people with tetraplegia controlling assistive devices using their cortical signals. Surgical procedures were performed at University Hospitals Cleveland Medical Center (Cleveland, OH, USA). Study procedures and data analyses were performed at Case Western Reserve University (Cleveland, OH, USA) and the US Department of Veterans Affairs, Louis Stokes Cleveland Veterans Affairs Medical Center (Cleveland, OH, USA). The study participant was a 53-year-old man with a spinal cord injury (cervical level 4, American Spinal Injury Association Impairment Scale category A). He received two intracortical microelectrode arrays in the hand area of his motor cortex, and 4 months and 9 months later received a total of 36 implanted percutaneous electrodes in his right upper and lower arm to electrically stimulate his hand, elbow, and shoulder muscles. The participant used a motorised mobile arm support for gravitational assistance and to provide humeral abduction and adduction under cortical control. We assessed the participant's ability to cortically command his paralysed arm to perform simple single-joint arm and hand movements and functionally meaningful multi-joint movements. We compared iBCI control of his paralysed arm with that of a virtual three-dimensional arm. This study is registered with ClinicalTrials.gov, number NCT00912041., Findings: The intracortical implant occurred on Dec 1, 2014, and we are continuing to study the participant. The last session included in this report was Nov 7, 2016. The point-to-point target acquisition sessions began on Oct 8, 2015 (311 days after implant). The participant successfully cortically commanded single-joint and coordinated multi-joint arm movements for point-to-point target acquisitions (80-100% accuracy), using first a virtual arm and second his own arm animated by FES. Using his paralysed arm, the participant volitionally performed self-paced reaches to drink a mug of coffee (successfully completing 11 of 12 attempts within a single session 463 days after implant) and feed himself (717 days after implant)., Interpretation: To our knowledge, this is the first report of a combined implanted FES+iBCI neuroprosthesis for restoring both reaching and grasping movements to people with chronic tetraplegia due to spinal cord injury, and represents a major advance, with a clear translational path, for clinically viable neuroprostheses for restoration of reaching and grasping after paralysis., Funding: National Institutes of Health, Department of Veterans Affairs., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objective: Do movements made with an intracortical BCI (iBCI) have the same movement time properties as able-bodied movements? Able-bodied movement times typically obey Fitts' law: [Formula: see text] (where MT is movement time, D is target distance, R is target radius, and [Formula: see text] are parameters). Fitts' law expresses two properties of natural movement that would be ideal for iBCIs to restore: (1) that movement times are insensitive to the absolute scale of the task (since movement time depends only on the ratio [Formula: see text]) and (2) that movements have a large dynamic range of accuracy (since movement time is logarithmically proportional to [Formula: see text])., Approach: Two participants in the BrainGate2 pilot clinical trial made cortically controlled cursor movements with a linear velocity decoder and acquired targets by dwelling on them. We investigated whether the movement times were well described by Fitts' law., Main Results: We found that movement times were better described by the equation [Formula: see text], which captures how movement time increases sharply as the target radius becomes smaller, independently of distance. In contrast to able-bodied movements, the iBCI movements we studied had a low dynamic range of accuracy (absence of logarithmic proportionality) and were sensitive to the absolute scale of the task (small targets had long movement times regardless of the [Formula: see text] ratio). We argue that this relationship emerges due to noise in the decoder output whose magnitude is largely independent of the user's motor command (signal-independent noise). Signal-independent noise creates a baseline level of variability that cannot be decreased by trying to move slowly or hold still, making targets below a certain size very hard to acquire with a standard decoder., Significance: The results give new insight into how iBCI movements currently differ from able-bodied movements and suggest that restoring a Fitts' law-like relationship to iBCI movements may require non-linear decoding strategies.

Lymphangiomatosis is a rare congenital disorder that results in multiorgan system lymphatic invasion. Symptoms due to axial skeletal involvement can range from chronic bone pain to severe deformity resulting in radiculopathy, myelopathy, and even paralysis. The authors present a case of lymphangiomatosis of the clivus, C-1, and C-2, resulting in chronic pain. The patient was successfully treated with percutaneous transoral clivoplasty and vertebroplasty, without disease progression or return of symptoms at 2 years.

Objective: When using an intracortical BCI (iBCI), users modulate their neural population activity to move an effector towards a target, stop accurately, and correct for movement errors. We call the rules that govern this modulation a 'feedback control policy'. A better understanding of these policies may inform the design of higher-performing neural decoders., Approach: We studied how three participants in the BrainGate2 pilot clinical trial used an iBCI to control a cursor in a 2D target acquisition task. Participants used a velocity decoder with exponential smoothing dynamics. Through offline analyses, we characterized the users' feedback control policies by modeling their neural activity as a function of cursor state and target position. We also tested whether users could adapt their policy to different decoder dynamics by varying the gain (speed scaling) and temporal smoothing parameters of the iBCI., Main Results: We demonstrate that control policy assumptions made in previous studies do not fully describe the policies of our participants. To account for these discrepancies, we propose a new model that captures (1) how the user's neural population activity gradually declines as the cursor approaches the target from afar, then decreases more sharply as the cursor comes into contact with the target, (2) how the user makes constant feedback corrections even when the cursor is on top of the target, and (3) how the user actively accounts for the cursor's current velocity to avoid overshooting the target. Further, we show that users can adapt their control policy to decoder dynamics by attenuating neural modulation when the cursor gain is high and by damping the cursor velocity more strongly when the smoothing dynamics are high., Significance: Our control policy model may help to build better decoders, understand how neural activity varies during active iBCI control, and produce better simulations of closed-loop iBCI movements.

Objective: To describe the successful treatment of refractory corneal neuropathic pain with neuromodulation techniques., Design: Single case report., Setting: Academic tertiary care center in the United States of America., Subject and Methods: A 30-year-old woman presented with a 7-year history of refractory bilateral keratoneuralgia following laser-assisted in-situ keratomileusis (LASIK) procedure on both eyes. Having failed all conservative measures, the patient initially underwent trigeminal nerve stimulation and subsequently was implanted with an intrathecal drug delivery system (IDDS) with the catheter placed at the level C1., Results: Following an initial favorable response to the trigeminal nerve stimulator, the pain became refractory to neurostimulation after a few months and the system was explanted. The patient was successfully trialed with an intrathecal catheter placed at the level of C1 delivering a combination of bupivacaine and low dose fentanyl. The patient was then implanted with an IDDS equipped with a patient-activated bolus system. The patient was very satisfied with the treatment and has had greater than 50% pain relief for over a year., Conclusions: Intrathecal delivery of bupivacaine and low dose fentanyl in the upper cervical spine can be effective in controlling refractory eye pain in properly selected patients and treatment centers., (© 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Accurate surgical localization of the varied targets for deep brain stimulation (DBS) is a process undergoing constant evolution, with increasingly sophisticated techniques to allow for highly precise targeting. However, despite the fastidious placement of electrodes into specific structures within the brain, there is increasing evidence to suggest that the clinical effects of DBS are likely due to the activation of widespread neuronal networks directly and indirectly influenced by the stimulation of a given target. Selective activation of these complex and inter-connected pathways may further improve the outcomes of currently treated diseases by targeting specific fiber tracts responsible for a particular symptom in a patient-specific manner. Moreover, the delivery of such focused stimulation may aid in the discovery of new targets for electrical stimulation to treat additional neurological, psychiatric, and even cognitive disorders. As such, advancements in surgical targeting, computational modeling, engineering designs, and neuroimaging techniques play a critical role in this process. This article reviews the progress of these applications, discussing the importance of target localization for DBS, and the role of computational modeling and novel neuroimaging in improving our understanding of the pathophysiology of diseases, and thus paving the way for improved selective target localization using DBS.

Catastrophic epilepsy in infants, often due to extensive cortical dysplasia, has devastating consequences with respect to brain development. Conventional lobar, multilobar, or hemispheric resection in these infants is challenging, carrying an increased operative risk compared with that in older children. Removing a larger tissue volume versus removing or disconnecting the epileptogenic region does not always guarantee better seizure outcome. The authors describe 2 infants with catastrophic epilepsy who benefited from individually tailored disconnections based on a hypothesized epileptogenic zone following intensive presurgical evaluation. Two infants with catastrophic epilepsy and epileptic spasms underwent leukotomies between 3 and 12 months of age. They were followed up postoperatively for 19-36 months. Both patients had 90%-100% seizure reduction and a significantly improved neurodevelopmental outcome without postoperative complication. Cortical malformation was seen in both patients. Modifications of established surgical disconnection techniques, tailored to each patient's specific epileptogenic zone, optimized seizure and neurodevelopmental outcomes while minimizing the risks associated with more extensive resections.

Purpose: This case study reports on 2 novel neuromodulatory approaches in the management of a particularly recalcitrant case of corneal neuropathic pain., Methods: Report of a case, Results: : A 32-year-old woman presented with intractable bilateral dry eye-like symptoms and corneal neuropathic pain after undergoing laser in situ keratomileusis surgery. Extensive ocular and systemic therapies were unsuccessful. Implantation of an electrode for the electrical stimulation of the trigeminal ganglion resulted in complete resolution of symptoms, but pain recurred after lead migration. Implantation of an intrathecal infusion system for fentanyl and bupivacaine delivery at the C1-C2 level resulted in control of her symptoms with excellent pain relief for more than 1 year., Conclusions: Electrical stimulation of the trigeminal ganglion and a high cervical intrathecal pain pump can be used in the management of corneal neuropathic pain unresponsive to ocular and systemic approaches.

Background: Occipital neuralgia (ON) is a disorder characterized by sharp, electrical, paroxysmal pain, originating from the occiput and extending along the posterior scalp, in the distribution of the greater, lesser, and/or third occipital nerve. Occipital nerve stimulation (ONS) constitutes a promising therapy for medically refractory ON because it is reversible with minimal side effects and has shown continued efficacy with long-term follow-up., Objective: To conduct a systematic literature review and provide treatment recommendations for the use of ONS for the treatment of patients with medically refractory ON., Methods: A systematic literature search was conducted using the PubMed database and the Cochrane Library to locate articles published between 1966 and April 2014 using MeSH headings and keywords relevant to ONS as a means to treat ON. A second literature search was conducted using the PubMed database and the Cochrane Library to locate articles published between 1966 and June 2014 using MeSH headings and keywords relevant to interventions that predict response to ONS in ON. The strength of evidence of each article that underwent full text review and the resulting strength of recommendation were graded according to the guidelines development methodology of the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Guidelines Committee., Results: Nine studies met the criteria for inclusion in this guideline. All articles provided Class III Level evidence., Conclusion: Based on the data derived from this systematic literature review, the following Level III recommendation can be made: the use of ONS is a treatment option for patients with medically refractory ON.

Memory loss after brain injury can be a source of considerable morbidity, but there are presently few therapeutic options for restoring memory function. We have previously demonstrated that burst stimulation of the fornix is able to significantly improve memory in a rodent model of traumatic brain injury. The present study is a preliminary investigation with a small group of cases to explore whether theta burst stimulation of the fornix might improve memory in humans. Four individuals undergoing stereo-electroencephalography evaluation for drug-resistant epilepsy were enrolled. All participants were implanted with an electrode into the proximal fornix and dorsal hippocampal commissure on the language dominant (n = 3) or language non-dominant (n = 1) side, and stimulation of this electrode reliably produced a diffuse evoked potential in the head and body of the ipsilateral hippocampus. Each participant underwent testing of verbal memory (Rey Auditory-Verbal Learning Test), visual-spatial memory (Medical College of Georgia Complex Figure Test), and visual confrontational naming (Boston Naming Test Short Form) once per day over at least two consecutive days using novel test forms each day. For 50% of the trials, the fornix electrode was continuously stimulated using a burst pattern (200 Hz in 100 ms trains, five trains per second, 100 µs, 7 mA) and was compared with sham stimulation. Participants and examiners were blinded to whether stimulation was active or not, and the order of stimulation was randomized. The small sample size precluded use of inferential statistics; therefore, data were analysed using descriptive statistics and graphic analysis. Burst stimulation of the fornix was not perceived by any of the participants but was associated with a robust reversible improvement in immediate and delayed performance on the Medical College of Georgia Complex Figure Test. There were no apparent differences on either Rey Auditory-Verbal Learning Test or Boston Naming Test. There was no apparent relationship between performance and side of stimulation (language dominant or non-dominant). There were no complications. Preliminary evidence in this small sample of patients with drug-resistant epilepsy suggests that theta burst stimulation of the fornix may be associated with improvement in visual-spatial memory., (© The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objective: Learning and memory deficits are a source of considerable morbidity after traumatic brain injury (TBI). We investigated the effect of different patterns of hippocampal stimulation via a fornix electrode on cognitively demanding tasks after TBI., Methods: Male Sprague-Dawley rats underwent fluid-percussion injury and were compared with sham-operated rats. Electrodes were implanted into the fornix and hippocampus, and stimulation of the fornix produced robust evoked potentials in the hippocampus. A 60-s delayed non-match-to-sample (DNMS) swim T-maze was serially performed using four stimulation patterns: no stimulation (No Stim), low-frequency stimulation (LFS, 5 Hz), high-frequency stimulation (HFS, 130 Hz), and theta-burst stimulation (TBS, 200 Hz in 50 ms trains, five trains per second; 60 µA biphasic pulses). In a separate cohort of sham and injured animals, Morris water maze (MWM) was performed with or without TBS., Results: In the DNMS swim T-maze, LFS and HFS did not significantly improve performance after TBI. However, there was a significant difference in performance between TBI + No Stim and TBI + TBS groups (P < 0.05) with no significant difference between Sham + No Stim and TBI + TBS. In the MWM, latency in the TBI + TBS group was significantly different from TBI + No Stim starting on day 2 (P < 0.05) and was not different from Sham + No Stim. The TBI + TBS group performed significantly more platform crossings in the probe trial (P < 0.01) and exhibited improved search strategy starting on day 3 (P < 0.05) compared with TBI + No Stim., Conclusions: Deficits in learning and memory after TBI are improved with TBS of the hippocampus. HFS and LFS do not appear to produce as great an effect as TBS., (© 2014 Wiley Periodicals, Inc.)

Objective: mild traumatic brain injury (mTBI) can produce lasting memory deficits even in the absence of cell loss. We investigated changes in hippocampal firing patterns during exploration and during a novel object recognition (NOR) task., Methods: six male Sprague-Dawley rats were subjected to mTBI via fluid percussion injury and were compared with sham-operated rats. Microelectrodes were implanted into CA1 and CA3 and multiple units were recorded from the pyramidal cell layer. Spontaneous "burst" characteristics were analyzed and temporal firing patterns were correlated with object encounters to establish object-specific firing patterns., Results: mTBI was associated with significantly less hippocampal bursting (p<0.05) with a trend toward longer bursts and lower interburst spike frequency. mTBI was also associated with no preference for a novel object at 12h (p<0.05). During the NOR task, a subset of pyramidal cells were identified which consistently demonstrated a transiently increased firing rate upon encounter of a specific object ("object-specific" cell). Across both groups, there was a significant (p<0.05) correlation between preference for object novelty and the difference between the total number of novel object-specific cells and familiar object-specific cells. The proportion of object-specific cells that responded to the unexpected (novel) object compared to those responding to the familiar object was significantly smaller in rats that had been exposed to mTBI (p<0.05)., Conclusion: memory deficits after mTBI are associated with decreased intrinsic burst activity and impaired context-specific firing patterns in the hippocampus during object exploration., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Microelectrode recording helps surgeons accurately localize boundaries of the subthalamic nucleus (STN) and surrounding structures in deep brain stimulation., Objective: To describe a novel adaptation of the Ben gun device to optimize efficient mapping., Methods: Patients who underwent STN deep brain stimulation over a 3-year period were reviewed. For the final year, the Ben gun was rotated 45° and the target was offset 1.4 mm lateral and anterior in the plane orthogonal to the intended trajectory to allow for simultaneous parallel tracks at target, 2.8 mm anterior (localizing the front of STN), and 2.8 mm lateral (identifying the internal capsule). Before this step, the initial pass consisted of 1 to 2 tracks with the frame center targeted to STN. The primary outcome measure was the number of passes required for accurate localization of the nucleus and boundaries., Results: Eighty-three electrodes were implanted in 45 patients (mean age, 62; range, 37-78 years), of which 29 electrodes were placed by the use of the new technique. One electrode (4%) required more than 1 pass using the new technique compared with 36 (67%) using the older technique (P < .01). The distance from original target to final electrode position increased from 0.67 ± 0.13 mm to 1.06 ± 0.15 mm (P < .05) with a greater tendency to move the final electrode position posteriorly. There was no statistically significant difference in benefit from neurostimulation., Conclusion: This technique facilitates reliable localization of the STN with fewer passes, possibly decreasing the risks associated with more passes and longer duration of surgery.

Object: Stimulation of white matter pathways near targeted structures may contribute to therapeutic effects of deep brain stimulation (DBS) for patients with Parkinson disease (PD). Two tracts linking the basal ganglia and cerebellum have been described in primates: the subthalamopontocerebellar tract (SPCT) and the dentatothalamic tract (DTT). The authors used fiber tractography to evaluate white matter tracts that connect the cerebellum to the region of the basal ganglia in patients with PD who were candidates for DBS., Methods: Fourteen patients with advanced PD underwent 3-T MRI, including 30-directional diffusion-weighted imaging sequences. Diffusion tensor tractography was performed using 2 regions of interest: ipsilateral subthalamic and red nuclei, and contralateral cerebellar hemisphere. Nine patients underwent subthalamic DBS, and the course of each tract was observed relative to the location of the most effective stimulation contact and the volume of tissue activated., Results: In all patients 2 distinct tracts were identified that corresponded closely to the described anatomical features of the SPCT and DTT, respectively. The mean overall distance from the active contact to the DTT was 2.18 ± 0.35 mm, and the mean proportional distance relative to the volume of tissue activated was 1.35 ± 0.48. There was a nonsignificant trend toward better postoperative tremor control in patients with electrodes closer to the DTT., Conclusions: The SPCT and the DTT may be related to the expression of symptoms in PD, and this may have implications for DBS targeting. The use of tractography to identify the DTT might assist with DBS targeting in the future.

Patients with intracranial mass lesions are at increased risk of intractable epilepsy even after tumor resection due to the potential epileptogenicity of lesional and perilesional tissue. Risk factors for tumoral epilepsy include tumor location, histology, and extent of tumor resection. In epilepsy that occurs after tumor resection, the epileptogenic zone often does not correspond precisely with the area of abnormality on imaging, and seizures often arise from a relatively restricted area despite widespread changes on imaging. Invasive monitoring via subdural grids and/or depth electrodes can therefore be helpful to delineate areas of eloquence and localize the epileptogenic zone for subsequent resection. Subdural grids offer excellent contiguous coverage of superficial cortex and allow resection using the same craniotomy, facilitating understanding of anatomic relationships. Depth electrodes offer superior coverage of deep structures, are easier to use in cases where a previous craniotomy is present, are not associated with anatomic distortion due to brain shift, and may be associated with a lower complication rate. We review the biology of focal postoperative epilepsy and invasive diagnostic strategies for the surgical evaluation of medically refractory epilepsy in patients who have undergone resection of intracranial mass lesions., (Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.)

Glioblastoma multiforme is a malignant primary brain tumor for which no cure has been developed. However, with aggressive surgical resection, radiation, and the advent of temozolomide, the overall survival of patients with glioblastomas has improved significantly. Despite this multimodal treatment, glioblastoma invariably recurs. Although treatment options for glioblastoma recurrence are limited, one promising therapy is bevacizumab (Avastin). The role of Avastin in the management of recurrent glioblastomas is reviewed., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We present a detailed description of brachial plexus infiltration by acute myelogenous leukemia (AML) in the setting of a remission bone marrow biopsy, without evidence of leukemia by flow cytometric analysis. This case illustrates the possibility of dormant leukemic cells in the peripheral nervous system (PNS) in a patient in apparent clinical remission. In patients with an unexplained brachial plexopathy and a history of AML, leukemic infiltrate of the PNS must be considered., (Copyright © 2011 Wiley Periodicals, Inc.)

Object: Brainstem hemangioblastomas are frequently encountered in patients with von Hippel-Lindau (VHL) disease. These tumors can cause significant morbidity, and their optimal management has not been defined. To better define the outcome and management of these tumors, the authors analyzed the long-term results in patients who underwent resection of brainstem hemangioblastomas., Methods: Consecutive patients with VHL disease who underwent resection of brainstem hemangioblastomas with a follow-up of 12 months or more were included in this study. Serial functional assessments, radiographic examinations, and operative records were analyzed., Results: Forty-four patients (17 male and 27 female) underwent 51 operations for resection of 71 brainstem hemangioblastomas. The most common presenting symptoms were headache, swallowing difficulties, singultus, gait difficulties, and sensory abnormalities. The mean follow-up was 5.9 ± 5.0 years (range 1.0-20.8 years). Immediately after 34 operations (66.7%), the patients remained at their preoperative functional status; they improved after 8 operations (15.7%) and worsened after 9 operations (17.6%) as measured by the McCormick scale. Eight (88.9%) of the 9 patients who were worse immediately after resection returned to their preoperative status within 6 months. Two patients experienced functional decline during long-term follow-up (beginning at 2.5 and 5 years postoperatively) caused by extensive VHL disease-associated CNS disease., Conclusions: Generally, resection of symptomatic brainstem hemangioblastomas is a safe and effective management strategy in patients with VHL disease. Most patients maintain their preoperative functional status, although long-term decline in functional status may occur due to VHL disease-associated progression.

Pleomorphic xanthoastrocytomas are glial-based tumors that arise most frequently in young patients and usually follow a more benign and indolent clinical course than their other glial-based tumor counterparts. These tumors most frequently present with seizures, and only 3 previous case reports exist of hemorrhagic tumor as the clinical presentation. The authors present the first case of life-threatening intracerebral hemorrhage from pleomorphic xanthoastrocytoma in a child.

Retention of the classically conditioned eyeblink response in rats was tested with a conditioned stimulus (CS)-alone extinction test and 2 sessions of reacquisition training. Retention of the eyeblink conditioned response (CR) during both tests was highest 24 hr and 1 month after initial acquisition. Three months after initial acquisition, responding during the CS-alone test was at baseline, but there was significant savings during reacquisition. By 6 months after initial acquisition, the memory for the eyeblink CR was not expressed in either test. The group differences in retention, despite initial acquisition of the eyeblink CR to equal levels, suggest that rat eyeblink conditioning may provide a useful behavioral model for studying the neural processes underlying memory retention and loss.

Divorce, nonmarital childbearing, and cohabitation are reshaping family experience in the United States. Because of these changes, our traditional definitions of families decreasingly capture of the social units of interest. We have noted how a significant proportion of officially defined single-parent families actually are two-parent unmarried families. The present paper expands on this perspective with respect to stepfamilies. We must broaden our definition of stepfamilies to include cohabitations involving a child of only one partner, and must recognize the large role of nonmarital childbearing in the creation of stepfamilies. We find that cohabitation and nonmarital childbearing have been important aspects of stepfamily experience for at least two decades, and that this is increasingly so. To define stepfamilies only in terms of marriage clearly underestimates both the level and the trend in stepfamily experience: when cohabitation is taken into account, about two-fifths of all women and 30% of all children are likely to spend some time in a stepfamily.

Data from the National Survey of Families and Households for 1987-1988 are used to explore methodological and substantive issues concerning marital dissolution in the United States. "The analysis finds that marital disruptions are seriously underreported by males, making the analysis of male marital histories problematic. Also, the potential impact of reconciliations on the estimates of recent marital disruption based on separation is explored; no upward bias is likely to result from the inclusion of separations that may subsequently reconcile. The impact of a wide variety of factors on the risk of marital disruption is examined using proportional hazard techniques. Among them are included parental background factors, respondent's characteristics at the time of marriage, differences in spouses' characteristics, and joint activity statuses of marital partners in the first year of marriage. The risk of marital disruption is highest among women with young age at marriage, low education, a cohabitation history, and those whose spouse has been married previously. Parental family disruption affects marital stability primarily through age at marriage and cohabitation. Religious and educational heterogamy and male unemployment reduce marital stability.", (excerpt)

There was an increase from 62.8 to 79.1 million households in the United States during the 1970s. The number of households increased much more rapidly than the population. This paper decomposes this growth in the number of households into components associated with changing age and martial status composition and changing age by marital status-specific propensities to form households. About one-third of the increase in the number of households was due to increased age by marital status propensity to form households, and two-thirds was due to shifts in the age by marital status distribution and population growth. The increased propensity to form households had its major impact at ages under 35, and primarily among never-married persons. The composition component had its primary impact at ages 25-44 as a result of the baby boom, and also because of the increased fractions never married and separated and divorced.

Data from the 1987-1988 National Survey of Families and Households are used to provide national estimates of cohabitation trends and levels. The rapid increase since around 1970 is documented over both birth cohorts and marriage cohorts. Almost half of the persons in their early 30s and half of the recently married have cohabited. Changes in the proportion ever married are compared with changes in the proportion who have either married or cohabited. Much of the decline in marriage has been offset by increased living together without being married. The stability of unions of various types is compared. Cohabitations end very quickly in either marriage or disruption. About 60 percent of all first cohabitations result in marriage. Cohabiting unions and marriages preceded by cohabitation are much more likely to break up than are unions initiated by marriage. Multivariate analysis reveals higher rates of cohabitation among women, whites, persons who did not complete high school, and those from families who received welfare or who lived in a single-parent family while growing up.

The continuous decline in fertility in the United States since 1957, while affecting all elements of the population, has been most pronounced and most rapid among those groups which previously had the highest fertility - blacks, American Indians and Mexican Americans-all of whom experienced fertility declines more rapid than those experienced by urban whites between 1957-1960 and 1967-1970. Among urban whites, fertility decline has been heavily concentrated among those of low income. The decline was especiallyrapid for third and higher order births, suggesting a heavy concentration of completed fertility at two-child families. The rapid decline, and the narrowing of the traditionalfertility differentials among various subgroups have important implications in the areasof poverty, education, the role of women in society and the dynamics of local area growth.