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Transcranial magnetic stimulation (TMS) is increasingly used as a noninvasive technique for neuromodulation in research and clinical applications, yet its mechanisms are not well understood. Here, we present the neurophysiological effects of TMS using intracranial electrocorticography (iEEG) in neurosurgical patients. We first evaluated safety in a gel-based phantom. We then performed TMS-iEEG in 22 neurosurgical participants with no adverse events. We next evaluated intracranial responses to single pulses of TMS to the dorsolateral prefrontal cortex (dlPFC) (N = 10, 1414 electrodes). We demonstrate that TMS is capable of inducing evoked potentials both locally within the dlPFC and in downstream regions functionally connected to the dlPFC, including the anterior cingulate and insular cortex. These downstream effects were not observed when stimulating other distant brain regions. Intracranial dlPFC electrical stimulation had similar timing and downstream effects as TMS. These findings support the safety and promise of TMS-iEEG in humans to examine local and network-level effects of TMS with higher spatiotemporal resolution than currently available methods., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Delivering ethical care in global plastic surgery is challenging due to the unique complexities of resource-limited settings. Additionally, the rise of medical tourism has highlighted the importance of informed consent and awareness of the potential risks that are associated with seeking medical care in foreign countries. This article aims to consider core medical ethics principles and apply them in the context of delivering global plastic surgery., Methods: This article examines the application of the four core medical ethics principles in a framework set forth by Beauchamp and Childress, namely autonomy, beneficence, nonmaleficence, and justice, in the context of delivering plastic surgery in international settings. A literature review was performed, where all potential global plastic surgery articles were reviewed to better understand the application of the four core medical ethics framework in this context., Results: Increased communication between visiting surgeons and local healthcare providers; heightened education of surgeons traveling to low-to-middle-income countries regarding local medical practices, resource availability, and cultural norms before providing surgical education; and a greater emphasis on collecting and publishing data analyzing short- and long-term outcomes in low-to-middle-income countries are all likely to improve the success of international medical missions, ensuring that all patients receive medical treatment in a manner that upholds Beauchamp and Childress' four core medical ethics principles., Conclusion: Providing plastic and reconstructive surgery abroad can be done ethically if the four main principles of medical ethics (respect for autonomy, beneficence, nonmaleficence, and justice) are used., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Direct electrical stimulation has been used for decades as a gold standard clinical tool to map cognitive function in neurosurgery patients 1-8 . However, the molecular impact of electrical stimulation in the human brain is unknown. Here, using state-of-the-art transcriptomic and epigenomic sequencing techniques, we define the molecular changes in bulk tissue and at the single-cell level in the human cerebral cortex following direct electrical stimulation of the anterior temporal lobe in patients undergoing neurosurgery. Direct electrical stimulation surprisingly had a robust and consistent impact on the expression of genes related to microglia-specific cytokine activity, an effect that was replicated in mice. Using a newly developed deep learning computational tool, we further demonstrate cell type-specific molecular activation, which underscores the effects of electrical stimulation on gene expression in microglia. Taken together, this work challenges the notion that the immediate impact of electrical stimulation commonly used in the clinic has a primary effect on neuronal gene expression and reveals that microglia robustly respond to electrical stimulation, thus enabling these non-neuronal cells to sculpt and shape the activity of neuronal circuits in the human brain.

Temporal lobe (TL) epilepsy surgery is an effective treatment option for patients with drug-resistant epilepsy. However, neurosurgery poses a risk for cognitive deficits - up to one third of patients have a decline in naming ability following TL surgery. In this study, we aimed to better understand the neural correlates associated with reduced naming performance after TL surgery, with the goal of informing surgical planning strategies to mitigate the risk of dysnomia. We retrospectively identified 85 patients who underwent temporal lobe (TL) resective surgery (49 left TL, 36 right TL) for whom naming ability was assessed before and >3 months post-surgery using the Boston Naming Test (BNT). We used multivariate lesion-symptom mapping to identify resection sites associated with naming decline, and we used lesion-network mapping to evaluate the broader functional and structural connectivity profiles of resection sites associated with naming decline. We validated our findings in an independent cohort of 59 individuals with left temporal lobectomy, along with repeating all analyses after combining the cohorts. Lesion laterality and location were important predictors of post-surgical naming performance. Naming performance significantly improved after right temporal lobectomy (P = 0.015) while a decrement in performance was observed following left temporal lobectomy (P = 0.002). Declines in naming performance were associated with surgical resection of the left anterior middle temporal gyrus (Brodmann area 21, r =0.41, P = <.001), along with a previously implicated basal temporal language area. Resection sites linked to naming decline showed a functional connectivity profile featuring a left-lateralized network closely resembling the extended semantic \ default mode network, and a structural connectivity profile featuring major temporo-frontal association white matter tracts coursing through the temporal stem. This extends prior work by implicating the left anterior middle temporal gyrus in naming decline and provides additional support for the role of the previously identified basal temporal language area in naming decline. Importantly, the structural and functional connectivity profiles of these regions suggest they are key nodes of a broader extended semantic network. Together these regional and network findings may help in surgical planning and discussions of prognosis., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Background: Postoperative delirium may be mediated by perioperative systemic- and neuro-inflammation. By inhibiting the pro-inflammatory actions of plasmin, tranexamic acid (TXA) may decrease postoperative delirium. To explore this hypothesis, we modified an ongoing randomised trial of TXA, adding measures of postoperative delirium, cognitive function, systemic cytokines, and astrocyte activation., Methods: Adults undergoing elective posterior lumbar fusion randomly received intraoperative intravenous TXA (n=43: 10 mg kg -1 loading dose, 2 mg kg -1 h -1 infusion) or Placebo (n=40). Blood was collected pre- and at 24 h post-operatively (n=32) for biomarkers of systemic inflammation (cytokines) and astrocyte activation (S100B). Participants had twice daily delirium assessments using the 3-minute diagnostic interview for Confusion Assessment Method (n=65). Participants underwent 4 measures of cognitive function preoperatively and during post-discharge follow-up., Results: Delirium incidence in the TXA group (7/32=22%) was not significantly less than in the Placebo group (11/33=33%); P =0.408, absolute difference=11%, relative difference=33%, effect size = -0.258 (95% CI -0.744 to 0.229). In the Placebo group (n=16), delirium severity was associated with the number of instrumented vertebral levels ( P =0.001) and with postoperative interleukin -8 and -10 concentrations ( P =0.00008 and P =0.005, respectively) and these associations were not significantly modified by TXA. In the Placebo group, delirium severity was associated with S100B concentration ( P =0.0009) and the strength of the association was decreased by TXA ( P =0.002)., Conclusions: A potential 33% relative decrease in postoperative delirium incidence justifies an adequately powered clinical trial to determine if intraoperative TXA decreases delirium in adults undergoing lumbar fusion.

Laser thermal ablation has become a prominent neurosurgical treatment approach, but in epilepsy patients it cannot currently be safely implemented with intracranial recording electrodes that are used to study interictal or epileptiform activity. There is a pressing need for computational models of laser interstitial thermal therapy (LITT) with and without intracranial electrodes to enhance the efficacy and safety of optical neurotherapies. In this paper, we aimed to build a biophysical bioheat and ray optics model to study the effects of laser heating in the brain, with and without intracranial electrodes in the vicinity of the ablation zone during the LITT procedure. COMSOL Multiphysics finite element method (FEM) solver software was used to create a bioheat thermal model of brain tissue, with and without blood flow incorporation via Penne's model, to model neural tissue response to laser heating. We report that the close placement of intracranial electrodes can increase the maximum temperature of the brain tissue volume as well as impact the necrosis region volume if the electrodes are placed too closely to the laser coupled diffuse fiber tip. The model shows that an electrode displacement of 4 mm could be considered a safe distance of intracranial electrode placement away from the LITT probe treatment area. This work, for the first time, models the impact of intracranially implanted recording electrodes during LITT, which could improve the understanding of the LITT treatment procedure on the brain's neural networks a sufficient safe distance to the implanted intracranial recording electrodes. We recommend modeling safe distances for placing the electrodes with respect to the infrared laser coupled diffuse fiber tip., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Fatima Toor reports was provided by The University of Iowa. Editor-in-Chief Dr. Chris Petkov is a co-author of this manuscript and should be recused from serving as an editor for this manuscript. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Background: Mind-body treatments can improve coping mechanisms to deal with pain, improve the quality of life of patients with fibromyalgia syndrome (FMS), and reduce perceived pain in some cases. However, responses to these treatments are highly variable, the mechanisms underpinning them remain unclear, and reliable predictors of treatment response are lacking. We employed resting-state blood oxygen level-dependent (rsBOLD) functional magnetic resonance imaging (fMRI) to examine changes in brain functional connectivity (FC) following mind-body treatment that may relate to and predict pain relief., Methods: We recruited patients with FMS who underwent either mindfulness-based stress reduction (MBSR; n  = 18) or a psychoeducational program (FibroQoL; n  = 22) and a treatment-as-usual FMS group (TAU; n  = 18). We collected rsBOLD data, alongside subjective pain, anxiety, depression, and catastrophizing measures prior to and following treatments. We examined behavioral changes and FC changes in the salience network (SN) and sensorimotor network (SMN) and performed regression analyses to identify predictors for treatment response., Results: The MBSR and FibroQoL groups experienced significant reductions in pain catastrophizing. After treatment, the FC of the sensorimotor cortex with the rest of the SMN became significantly reduced in the MBSR group compared to the TAU group. The FC between the SN and the SMN at baseline was negatively correlated with pain reductions following MBSR but positively correlated with pain reductions in the FibroQoL group. These results yielded large to very large effect sizes. Following MBSR, only for those patients with lower baseline SMN-SN FC, minutes of mindfulness practice were positively associated with clinical improvement (small to medium effect size)., Conclusions: Different mind-body treatments are underpinned by discrete brain networks. Measures of the functional interplay between SN and SMN have the potential as predictors of mind-body treatment response in patients with FMS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Medina, O’Daly, Howard, Feliu-Soler and Luciano.)

Abstract: The high frequency stimulation (HFS) model can be used alongside quantitative sensory testing (QST) to assess the sensitisation of central nociceptive pathways. However, the validity and between-session reliability of using QST z -score profiles to measure changes in mechanical and thermal afferent pathways in the HFS model are poorly understood. In this study, 32 healthy participants underwent QST before and after HFS (5× 100 Hz trains; 10× electrical detection threshold) in the same heterotopic skin area across 2 repeated sessions. The only mechanical QST z -score profiles that demonstrated a consistent gain of function across repeated test sessions were mechanical pain threshold (MPT) and mechanical pain sensitivity (MPS), which were associated with moderate and good reliability, respectively. There was no relationship between HFS intensity and MPT and MPS z -score profiles. There was no change in low intensity, but a consistent facilitation of high-intensity pin prick stimuli in the mechanical stimulus response function across repeated test sessions. There was no change in cold pain threshold (CPT) and heat pain threshold (HPT) z -score profiles across session 1 and 2, which were associated with moderate and good reliability, respectively. There were inconsistent changes in the sensitivity to innocuous thermal QST parameters, with cool detection threshold (CDT), warm detection threshold (WDT), and thermal sensory limen (TSL) all producing poor reliability. These data suggest that HFS-induced changes in MPS z -score profiles is a reliable way to assess experimentally induced central sensitisation and associated secondary mechanical hyperalgesia in healthy participants., (Copyright © 2023 International Association for the Study of Pain.)

Purpose: Resistance exercise can attenuate muscular impairments associated with multiple sclerosis (MS), and blood flow restriction (BFR) may provide a viable alternative to prescribing heavy training loads. The purpose of this investigation was to examine the progression of upper and lower body low-load (30% of one-repetition maximum [1RM]) resistance training (RT) with BFR applied intermittently during the exercise intervals (RT + BFR) versus volume-matched heavy-load (65% of 1RM) RT., Methods: Men and women with MS (n = 16) were randomly assigned to low-load RT + BFR (applied intermittently) or heavy-load RT and completed 12 weeks (2 × /week) of RT that consisted of bilateral chest press, seated row, shoulder press, leg press, leg extension, and leg curl exercises. Exercise load, tonnage, and rating of perceived exertion were assessed at baseline and every 6 weeks., Results: Training load increased to a greater extent and sometimes earlier for RT + BFR (57.7-106.3%) than heavy-load RT (42.3-54.3%) during chest press, seated row, and leg curl exercises, while there were similar increases (63.5-101.1%) for shoulder press, leg extension, and leg press exercises. Exercise tonnage was greater across all exercises for RT + BFR than heavy-load RT, although tonnage only increased during the chest press (70.7-80.0%) and leg extension (89.1%) exercises. Perceptions of exertion (4.8-7.2 au) and compliance (97.9-99.0%) were similar for both interventions., Conclusion: The training-induced increases in load, high compliance, and moderate levels of exertion suggested that RT + BFR and heavy-load RT are viable interventions among people with MS. RT + BFR may be a preferred modality if heavy loads are not well tolerated and/or to promote early-phase training responses., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Delirium is risky and indicates poor outcomes for patients. Therefore, it is crucial to create an effective delirium detection method. However, the epigenetic pathophysiology of delirium remains largely unknown. We aimed to discover reliable and replicable epigenetic (DNA methylation: DNAm) markers that are associated with delirium including post-operative delirium (POD) in blood obtained from patients among four independent cohorts. Blood DNA from four independent cohorts (two inpatient cohorts and two surgery cohorts; 16 to 88 patients each) were analyzed using the Illumina EPIC array platform for genome-wide DNAm analysis. We examined DNAm differences in blood between patients with and without delirium including POD. When we compared top CpG sites previously identified from the initial inpatient cohort with three additional cohorts (one inpatient and two surgery cohorts), 11 of the top 13 CpG sites showed statistically significant differences in DNAm values between the delirium group and non-delirium group in the same directions as found in the initial cohort. This study demonstrated the potential value of epigenetic biomarkers as future diagnostic tools. Furthermore, our findings provide additional evidence of the potential role of epigenetics in the pathophysiology of delirium including POD., (© 2024. The Author(s).)

Low-intensity Transcranial Ultrasound Stimulation (TUS) is a promising non-invasive technique for deep-brain stimulation and focal neuromodulation. Research with animal models and computational modelling has raised the possibility that TUS can be biased towards enhancing or suppressing neural function. Here, we first conduct a systematic review of human TUS studies for perturbing neural function and alleviating brain disorders. We then collate a set of hypotheses on the directionality of TUS effects and conduct an initial meta-analysis on the human TUS study reported outcomes to date ( n = 32 studies, 37 experiments). We find that parameters such as the duty cycle show some predictability regarding whether the targeted area's function is likely to be enhanced or suppressed. Given that human TUS sample sizes are exponentially increasing, we recognize that results can stabilize or change as further studies are reported. Therefore, we conclude by establishing an Iowa-Newcastle (inTUS) resource for the systematic reporting of TUS parameters and outcomes to support further hypothesis testing for greater precision in brain stimulation and neuromodulation with TUS.

Background: Transcranial magnetic stimulation (TMS) is believed to alter ongoing neural activity and cause circuit-level changes in brain function. While the electrophysiological effects of TMS have been extensively studied with scalp electroencephalography (EEG), this approach generally evaluates low-frequency neural activity at the cortical surface. However, TMS can be safely used in patients with intracranial electrodes (iEEG), allowing for direct assessment of deeper and more localized oscillatory responses across the frequency spectrum., Objective/hypothesis: Our study used iEEG to understand the effects of TMS on human neural activity in the spectral domain. We asked (1) which brain regions respond to cortically-targeted TMS, and in what frequency bands, (2) whether deeper brain structures exhibit oscillatory responses, and (3) whether the neural responses to TMS reflect evoked versus induced oscillations., Methods: We recruited 17 neurosurgical patients with indwelling electrodes and recorded neural activity while patients underwent repeated trials of single-pulse TMS at either the dorsolateral prefrontal cortex (DLPFC) or parietal cortex. iEEG signals were analyzed using spectral methods to understand the oscillatory responses to TMS., Results: Stimulation to DLPFC drove widespread low-frequency increases (3-8 Hz) in frontolimbic cortices and high-frequency decreases (30-110 Hz) in frontotemporal areas, including the hippocampus. Stimulation to parietal cortex specifically provoked low-frequency responses in the medial temporal lobe. While most low-frequency activity was consistent with phase-locked evoked responses, anterior frontal regions exhibited induced theta oscillations following DLPFC stimulation., Conclusions: By combining TMS with intracranial EEG recordings, our results suggest that TMS is an effective means to perturb oscillatory neural activity in brain-wide networks, including deeper structures not directly accessed by stimulation itself., Competing Interests: Declaration of competing interest CJK holds equity in Alto Neuroscience, Inc. and is a consultant for Flow Neuroscience. EAS has previously received compensation for ad-hoc technical consulting for Nia Therapeutics, a company intended to develop and commercialize brain stimulation therapies. No other conflicts of interest, financial or otherwise, are declared by the authors., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Auditory semantic novelty - a new meaningful sound in the context of a predictable acoustical environment - can probe neural circuits involved in language processing. Aberrant novelty detection is a feature of many neuropsychiatric disorders. This large-scale human intracranial electrophysiology study examined the spatial distribution of gamma and alpha power and auditory evoked potentials (AEP) associated with responses to unexpected words during performance of semantic categorization tasks. Participants were neurosurgical patients undergoing monitoring for medically intractable epilepsy. Each task included repeatedly presented monosyllabic words from different talkers ("common") and ten words presented only once ("novel"). Targets were words belonging to a specific semantic category. Novelty effects were defined as differences between neural responses to novel and common words. Novelty increased task difficulty and was associated with augmented gamma, suppressed alpha power, and AEP differences broadly distributed across the cortex. Gamma novelty effect had the highest prevalence in planum temporale, posterior superior temporal gyrus (STG) and pars triangularis of the inferior frontal gyrus; alpha in anterolateral Heschl's gyrus (HG), anterior STG and middle anterior cingulate cortex; AEP in posteromedial HG, lower bank of the superior temporal sulcus, and planum polare. Gamma novelty effect had a higher prevalence in dorsal than ventral auditory-related areas. Novelty effects were more pronounced in the left hemisphere. Better novel target detection was associated with reduced gamma novelty effect within auditory cortex and enhanced gamma effect within prefrontal and sensorimotor cortex. Alpha and AEP novelty effects were generally more prevalent in better performing participants. Multiple areas, including auditory cortex on the superior temporal plane, featured AEP novelty effect within the time frame of P3a and N400 scalp-recorded novelty-related potentials. This work provides a detailed account of auditory novelty in a paradigm that directly examined brain regions associated with semantic processing. Future studies may aid in the development of objective measures to assess the integrity of semantic novelty processing in clinical populations., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Telomeres are important to chromosomal stability, and changes in their length correlate with disease, potentially relevant to brain disorders. Assessing telomere length in human brain is invasive, but whether peripheral tissue telomere length correlates with that in brain is not known. Saliva, buccal, blood, and brain samples were collected at time points before, during, and after subjects undergoing neurosurgery ( n = 35) for intractable epilepsy. DNA was isolated from samples and average telomere length assessed by qPCR. Correlations of telomere length between tissue samples were calculated across subjects. When data were stratified by sex, saliva telomere length correlated with brain telomere length in males only. Buccal telomere length correlated with brain telomere length when males and females were combined. These findings indicate that in living subjects, telomere length in peripheral tissues variably correlates with that in brain and may be dependent on sex. Peripheral tissue telomere length may provide insight into brain telomere length, relevant to assessment of brain disorder pathophysiology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Carver, Hing, Elser, Lussier, Yamanashi, Howard, Kawasaki, Shinozaki and Stevens.)

Resting functional magnetic resonance imaging (fMRI) studies have identified intrinsic spinal cord activity, which forms organised motor (ventral) and sensory (dorsal) resting-state networks. However, to facilitate the use of spinal fMRI in, for example, clinical studies, it is crucial to first assess the reliability of the method, particularly given the unique anatomical, physiological, and methodological challenges associated with acquiring the data. Here, we characterise functional connectivity relationships in the cervical cord and assess their between-session test-retest reliability in 23 young healthy volunteers. Resting-state networks were estimated in two ways (1) by estimating seed-to-voxel connectivity maps and (2) by calculating seed-to-seed correlations. Seed regions corresponded to the four grey matter horns (ventral/dorsal and left/right) of C5-C8 segmental levels. Test-retest reliability was assessed using the intraclass correlation coefficient. Spatial overlap of clusters derived from seed-to-voxel analysis between sessions was examined using Dice coefficients. Following seed-to-voxel analysis, we observed distinct unilateral dorsal and ventral organisation of cervical spinal resting-state networks that was largely confined in the rostro-caudal extent to each spinal segmental level, with more sparse connections observed between segments. Additionally, strongest correlations were observed between within-segment ipsilateral dorsal-ventral connections, followed by within-segment dorso-dorsal and ventro-ventral connections. Test-retest reliability of these networks was mixed. Reliability was poor when assessed on a voxelwise level, with more promising indications of reliability when examining the average signal within clusters. Reliability of correlation strength between seeds was highly variable, with the highest reliability achieved in ipsilateral dorsal-ventral and dorso-dorsal/ventro-ventral connectivity. However, the spatial overlap of networks between sessions was excellent. We demonstrate that while test-retest reliability of cervical spinal resting-state networks is mixed, their spatial extent is similar across sessions, suggesting that these networks are characterised by a consistent spatial representation over time., (© 2024 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

Purpose: Pharmacologic ascorbate (P-AscH-) is hypothesized to be an iron (Fe)-dependent tumor-specific adjuvant to chemoradiation in treating glioblastoma (GBM). This study determined the efficacy of combining P-AscH- with radiation and temozolomide in a phase II clinical trial while simultaneously investigating a mechanism-based, noninvasive biomarker in T2* mapping to predict GBM response to P-AscH- in humans., Patients and Methods: The single-arm phase II clinical trial (NCT02344355) enrolled 55 subjects, with analysis performed 12 months following the completion of treatment. Overall survival (OS) and progression-free survival (PFS) were estimated with the Kaplan-Meier method and compared across patient subgroups with log-rank tests. Forty-nine of 55 subjects were evaluated using T2*-based MRI to assess its utility as an Fe-dependent biomarker., Results: Median OS was estimated to be 19.6 months [90% confidence interval (CI), 15.7-26.5 months], a statistically significant increase compared with historic control patients (14.6 months). Subjects with initial T2* relaxation < 50 ms were associated with a significant increase in PFS compared with T2*-high subjects (11.2 months vs. 5.7 months, P < 0.05) and a trend toward increased OS (26.5 months vs. 17.5 months). These results were validated in preclinical in vitro and in vivo model systems., Conclusions: P-AscH- combined with temozolomide and radiotherapy has the potential to significantly enhance GBM survival. T2*-based MRI assessment of tumor iron content is a prognostic biomarker for GBM clinical outcomes. See related commentary by Nabavizadeh and Bagley, p. 255., (©2023 American Association for Cancer Research.)

Pathogenic variants in SCN1B have been linked to severe developmental epileptic encephalopathies including Dravet syndrome. Scn1b knock-out (KO) mice model SCN1B loss-of-function (LOF) disorders, demonstrating seizures, developmental delays, and early death. SCN1B encodes the protein β1, an ion channel auxiliary subunit that also has roles in cell adhesion, neurite outgrowth, and gene expression. The goal of this project is to better understand of how loss of Scn1b alters information processing in the brain, resulting in seizures and associated cognitive dysfunction. Using slice electrophysiology in the CA1 region of the hippocampus from male and female Scn1b KO mice and wild-type (WT) littermates, we found that processing of physiologically relevant patterned Schaffer collateral (SC) stimulation produces larger, prolonged depolarizations and increased spiking in KO neurons compared with WTs. KO neurons exhibit enhanced intrinsic excitability, firing more action potentials with current injection. Interestingly, SC stimulation produces smaller, more facilitating excitatory and IPSCs in KO pyramidal neurons, but larger postsynaptic potentials (PSPs) with the same stimulation. We also found reduced intrinsic firing of parvalbumin (PV)-expressing interneurons and disrupted recruitment of both parvalbumin-expressing and somatostatin (SST)-expressing interneurons in response to patterned synaptic stimulation. Neuronal information processing relies on the interplay between synaptic properties, intrinsic properties that amplify or suppress incoming synaptic signals, and firing properties that produce cellular output. We found changes at each of these levels in Scn1b KO pyramidal neurons, resulting in fundamentally altered cellular information processing in the hippocampus that likely contributes to the complex phenotypes of SCN1B -linked epileptic encephalopathies. SIGNIFICANCE STATEMENT Genetic developmental epileptic encephalopathies have limited treatment options, in part because of our lack of understanding of how genetic changes result in dysfunction at the cellular and circuit levels. SCN1B is a gene linked to Dravet syndrome and other developmental epileptic encephalopathies, and Scn1b knock-out (KO) mice phenocopy the human disease, allowing us to study underlying neurophysiological changes. Here, we found changes at all levels of neuronal information processing in brains lacking Scn1b , including intrinsic excitability, synaptic properties, and synaptic integration, resulting in greatly enhanced input/output functions of the hippocampus. Our study shows that loss of Scn1b results in a complex array of cellular and network changes that fundamentally alters information processing in the hippocampus., (Copyright © 2023 the authors.)

AbstractPurpose: to characterize ethics course content, structure, resources, pedagogic methods, and opinions among academic administrators and course directors at U.S. medical schools., Method: An online questionnaire addressed to academic deans and ethics course directors identified by medical school websites was emailed to 157 Association of American Medical Colleges member medical schools in two successive waves in early 2022. Descriptive statistics were utilized to summarize responses., Results: Representatives from 61 (39%) schools responded. Thirty-two (52%) respondents were course directors; 26 (43%) were deans of academic affairs, medical education, or curriculum; and 3 with other roles also completed the survey (5%). All 61 schools reported some form of formal ethics education during the first year of medical school, with most ( n = 54, 89%) reporting a formal mandatory introductory course during preclinical education. Schools primarily utilized lecture and small-group teaching methods. Knowledge-based examinations, attendance, and participation were most commonly used for assessment. A large majority regarded ethics as equally or more important than other foundational courses, but fewer ( n = 37, 60%) provided faculty training for teaching ethics., Conclusions: Despite a response rate of 39 percent, the authors conclude that medical schools include ethics in their curricula in small-group and lecture formats with heterogeneity regarding content taught. Preclinical curricular redesigns must innovate and implement best practices for ensuring sound delivery of ethics content in future curricula. Additional large-scale research is necessary to determine said best practices.

Young men (ages 15–24) may benefit from community-based connections to care since many have sexual and reproductive health (SRH) needs and low care use. This study describes nonclinical community-based youth-serving professionals’ (YSPs) SRH knowledge, confidence, past behaviors, and future intentions to talk with young men about SRH and refer them to care, and examines factors associated with care referral intentions. YSPs ( n = 158) from 22 settings in one mid-Atlantic city answered questions about the study’s goal, their demographics and work environment from August 2014 to December 2015. Poisson regression assessed factors associated with YSPs’ care referral intentions. On average, YSPs answered 58% of knowledge questions correctly, knew 5 of 8 SRH care dimensions of where to refer young men, and perceived being somewhat/very confident talking with young men about SRH (63%) and referring them to care (77%). During the past month, the majority (63%) talked with young men about SRH but only one-third made care referrals; the majority (66%) were somewhat/very likely to refer them to care in the next 3 months. Adjusted models indicated YSPs were more likely to refer young men if they had a very supportive work environment to talk about SRH (adjusted RR = 1.51, 95% CI [1.15, 1.98]), greater confidence in SRH care referral (1.28 [1.00, 1.62]), and greater SRH care referrals in the past month (1.16 [1.02, 1.33]). Nonclinical community-based YSPs have poor-to-moderate knowledge about young men’s SRH care, and less than one-third reported referrals in the past month. Findings have implications for educating YSPs about young men’s SRH care.

Postictal apnea is thought to be a major cause of sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying postictal apnea are unknown. To understand causes of postictal apnea, we used a multimodal approach to study brain mechanisms of breathing control in 20 patients (ranging from pediatric to adult) undergoing intracranial electroencephalography for intractable epilepsy. Our results indicate that amygdala seizures can cause postictal apnea. Moreover, we identified a distinct region within the amygdala where electrical stimulation was sufficient to reproduce prolonged breathing loss persisting well beyond the end of stimulation. The persistent apnea was resistant to rising CO2 levels, and air hunger failed to occur, suggesting impaired CO2 chemosensitivity. Using es-fMRI, a potentially novel approach combining electrical stimulation with functional MRI, we found that amygdala stimulation altered blood oxygen level-dependent (BOLD) activity in the pons/medulla and ventral insula. Together, these findings suggest that seizure activity in a focal subregion of the amygdala is sufficient to suppress breathing and air hunger for prolonged periods of time in the postictal period, likely via brainstem and insula sites involved in chemosensation and interoception. They further provide insights into SUDEP, may help identify those at greatest risk, and may lead to treatments to prevent SUDEP.

This article covers the epidemiology of delirium and the overlapping condition of altered mental status and encephalopathy that is relevant to those who practice in the emergency department., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The human brain extracts meaning using an extensive neural system for semantic knowledge. Whether broadly distributed systems depend on or can compensate after losing a highly interconnected hub is controversial. We report intracranial recordings from two patients during a speech prediction task, obtained minutes before and after neurosurgical treatment requiring disconnection of the left anterior temporal lobe (ATL), a candidate semantic knowledge hub. Informed by modern diaschisis and predictive coding frameworks, we tested hypotheses ranging from solely neural network disruption to complete compensation by the indirectly affected language-related and speech-processing sites. Immediately after ATL disconnection, we observed neurophysiological alterations in the recorded frontal and auditory sites, providing direct evidence for the importance of the ATL as a semantic hub. We also obtained evidence for rapid, albeit incomplete, attempts at neural network compensation, with neural impact largely in the forms stipulated by the predictive coding framework, in specificity, and the modern diaschisis framework, more generally. The overall results validate these frameworks and reveal an immediate impact and capability of the human brain to adjust after losing a brain hub., (© 2023. Springer Nature Limited.)

Purpose: To develop a second-order and slice-specific linear shimming technique and investigate its efficiency in the mitigation of signal loss and distortions, and the increase of temporal signal-to-noise ratio (tSNR) within the spinal cord during functional Magnetic Resonance Imaging (fMRI) of the human cervical spinal cord., Methods: All scans were performed on a General Electric Discovery MR750 3 T scanner, using a head, neck and spine coil and a neurovascular array. To improve B 0 homogeneity, a field map was acquired, and second-order shims (SOS) were optimized over manually defined regions of interest (ROIs). Signal loss from dephasing by susceptibility-induced gradients was reduced by optimizing slice-specific x-, y- and z-shims to maximize signal within the spinal cord. Spectral-spatial excitation pulses were used in both the slice-specific linear shimming calibration scan and fMRI acquisitions. The shimming technique's efficiency was initially tested on eight healthy volunteers by comparing tSNR between images acquired with the manufacturer's standard linear shimming and with our SOS and xyz-shimming technique. Subsequently, using an increased spatial resolution as needed for fMRI of the spinal cord, tSNR measurements were performed on resting-state fMRI images from 14 healthy participants., Results: Spinal fMRI images acquired with only the standard linear shimming suffered from severe signal loss below the C5 vertebral level. The developed shimming technique compensated for this loss especially at levels C6 and C7, while tSNR was significantly higher at all vertebral levels with SOS and xyz-shimming than without it., Conclusion: A comprehensive shimming approach which includes the use of spectral-spatial excitation pulses along with both second-order and slice-specific linear shim optimization reduces regional signal loss and increases tSNR along the c-spine (C3-C7), improving the ability to record functional signals from the human spinal cord., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose of Review: This review explores the potential of using novel imaging approaches to deepen our understanding of descending modulatory mechanisms in pain, focussing on functional magnetic resonance imaging (fMRI) of the spinal cord and novel approaches to combining molecular and fMRI data. This review sheds light on the neural processes involved in pain modulation, paving the way for the development of targeted treatments., Recent Findings: The reviewed literature demonstrates significant advancements in pain research. Recent studies show the potential of using fMRI to investigate the spinal cord's role in pain modulation. Furthermore, novel analytical approaches integrating molecular and fMRI data show promise in elucidating the complex neurobiological processes underlying pain regulation. The main themes explored here include the identification of neurochemical markers associated with pain modulation and the characterisation of neural circuits involved in descending pain control., Summary: A comprehensive understanding of descending modulatory mechanisms in pain can inform the development of novel treatments, targeting dysfunction of these key pathways. By leveraging spinal fMRI and integrating molecular data into brain fMRI, researchers can identify potential therapeutic targets throughout the neuraxis. These advances may contribute to the development of personalised medicine approaches, allowing for tailored interventions based on individual pain profiles., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Altered mental status (including delirium) is a common presentations among older adults to the emergency department (ED). We aimed to report the association between altered mental status in older ED patients and acute abnormal findings on head computed tomogram (CT)., Methods: A systematic review was conducted using Ovid Medline, Embase, Clinicaltrials.gov, Web of Science, and Cochrane Central from conception to April 8th, 2021. We included citations if they described patients aged 65 years or older who received head imaging at the time of ED assessment, and reported whether patients had delirium, confusion, or altered mental status. Screening, data extraction, and bias assessment were performed in duplicate. We estimated the odds ratios (OR) for abnormal neuroimaging in patients with altered mental status., Results: The search strategy identified 3031 unique citations, of which two studies reporting on 909 patients with delirium, confusion or altered mental status were included. No identified study formally assessed for delirium. The OR for abnormal head CT findings in patients with delirium, confusion or altered mental status was 0.35 (95% CI 0.031 to 3.97) compared to patients without delirium, confusion or altered mental status., Conclusion: We did not find a statistically significant association between delirium, confusion or altered mental status and abnormal head CT findings in older ED patients., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to evaluate monetary trends in Medicare reimbursement rates for 30 abdominal wall reconstruction surgical procedures over a 20-year period (2000 to 2020)., Methods: The Physician Fee Schedule Look-Up Tool from the Centers for Medicare and Medicaid Services was used for each of the 30 included current CPT codes, and reimbursement data were extracted. Monetary data were adjusted for inflation to 2020 U.S. dollars using changes to the United States consumer price index. The R 2 values for the average annual percentage change and the average total percentage change in reimbursement were calculated based on these adjusted trends for all included procedures., Results: After adjusting for inflation, the average reimbursement for all procedures decreased by 17.1% from 2000 to 2020. The greatest mean decrease was observed for CPT code 49568 (the implantation of mesh or other prosthesis for open incisional or ventral hernia repair or mesh for closure of débridement for necrotizing soft-tissue infection, -34.4%). The only procedure with an increased adjusted reimbursement rate throughout the study period was CPT code 20680 (+3.9%). From 2000 to 2020, the adjusted reimbursement rate for all included procedures decreased by an average of 0.85% each year, with an average R 2 value of 0.78, indicating a stable decline throughout the study period., Conclusions: Reimbursement rates are declining when adjusted for inflation. Increased awareness of these trends is helpful to maintain access to optimal abdominal reconstruction care in the United States., (Copyright © 2023 by the American Society of Plastic Surgeons.)

We report a case of a woman who experienced unexplained recurrent rashes of varying severity after multiple exposures to anesthesia, and then 2 successful surgeries under general anesthesia with no resultant rashes after removing propofol from her anesthetic plans. We infer her previous postanesthetic rashes were likely associated with drug-induced subacute cutaneous lupus erythematosus (DI-SCLE) triggered by propofol., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the International Anesthesia Research Society.)

The perception of pitch is a fundamental percept, which is mediated by the auditory system, requiring the abstraction of stimulus properties related to the spectro-temporal structure of sound. Despite its importance, there is still debate as to the precise areas responsible for its encoding, which may be due to species differences or differences in the recording measures and choices of stimuli used in previous studies. Moreover, it was unknown whether the human brain contains pitch neurons and how distributed such neurons might be. Here, we present the first study to measure multiunit neural activity in response to pitch stimuli in the auditory cortex of intracranially implanted humans. The stimulus sets were regular-interval noise with a pitch strength that is related to the temporal regularity and a pitch value determined by the repetition rate and harmonic complexes. Specifically, we demonstrate reliable responses to these different pitch-inducing paradigms that are distributed throughout Heschl's gyrus, rather than being localized to a particular region, and this finding was evident regardless of the stimulus presented. These data provide a bridge across animal and human studies and aid our understanding of the processing of a critical percept associated with acoustic stimuli., (© The Author(s) 2023. Published by Oxford University Press.)

The human brain exhibits complex interactions across micro, meso-, and macro-scale organisational principles. Recent synergistic multi-modal approaches have begun to link micro-scale information to systems level dynamics, transcending organisational hierarchies and offering novel perspectives into the brain's function and dysfunction. Specifically, the distribution of micro-scale properties (such as receptor density or gene expression) can be mapped onto macro-scale measures from functional MRI to provide novel neurobiological insights. Methodological approaches to enrich functional imaging analyses with molecular information are rapidly evolving, with several streams of research having developed relatively independently, each offering unique potential to explore the trans-hierarchical functioning of the brain. Here, we address the three principal streams of research - spatial correlation, molecular-enriched network, and in-silico whole brain modelling analyses - to provide a critical overview of the different sources of molecular information, how this information can be utilised within analyses of fMRI data, the merits and pitfalls of each methodology, and, through the use of key examples, highlight their promise to shed new light on key domains of neuroscientific inquiry., Competing Interests: Conflicts of interest disclosure All authors have no formal conflicts of interest to declare., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Enhanced recovery after surgery protocols have become increasingly adopted for autologous breast reconstruction, demonstrating improved quality of care and reduced hospital stays. Despite this, average length of stay remains over 3 days. We have found, in appropriately selected patients, hospital length of stay can be safely reduced to less than 48 hours., Methods: Retrospective review was performed of patients who underwent microsurgical breast reconstruction by the senior author (M.H.) from April 2019 to December 2021. Demographics, operative details, length of stay, and postoperative complications are reported to assess for safety of discharge within 48 hours, with the primary outcome measure being flap loss., Results: In total, 188 flaps were performed on 107 patients. Average age was 51.4 years (SD 10.1 years) with average BMI 26.6 kg/m 2 (SD 4.8 kg/m 2 ). Average length of stay was 1.97 days (SD 0.61 days), and 96 patients (89.7%) were discharged within 48 hours. Six flaps (3.2%) required operative takebacks. Five of the six (83.3%) takebacks occurred on postoperative days zero or one, and all five of these flaps were salvaged. There were four breast hematomas (2.1%), four breast seromas (2.1%), eight breast infections (4.3%), 13 breasts (6.9%) with wound dehiscence, four flaps (2.1%) with partial flap loss, and 24 breasts (12.8%) with mastectomy flap necrosis. One hundred fifty flaps (79.8%) had no complications. Overall success rate of flap reconstruction was 99.5%., Conclusion: Hospital discharge in 24-48 hours is safe in appropriately selected patients undergoing autologous tissue breast reconstruction., Competing Interests: The authors have no financial interest to declare in relation to the content of this article. Disclosure statements are at the end of this article, following the correspondence information., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Background: Decompressive hemicraniectomy (DHC) is performed to relieve life-threatening intracranial pressure elevations. After swelling abates, a cranioplasty is performed for mechanical integrity and cosmesis. Cranioplasty is costly with high complication rates. Prior attempts to obviate second-stage cranioplasty have been unsuccessful. The Adjustable Cranial Plate (ACP) is designed for implantation during DHC to afford maximal volumetric expansion with later repositioning without requiring a second major operation., Methods: The ACP has a mobile section held by a tripod fixation mechanism. Centrally located gears adjust the implant between the up and down positions. Cadaveric ACP implantation was performed. Virtual DHC and ACP placement were done using imaging data from 94 patients who had previously undergone DHC to corroborate our cadaveric results. Imaging analysis methods were used to calculate volumes of cranial expansion., Results: The ACP implantation and adjustment procedures are feasible in cadaveric testing without wound closure difficulties. Results of the cadaveric study showed total volumetric expansion achieved was 222 cm 3 . Results of the virtual DHC procedure showed the volume of cranial expansion achieved by removing a standardized bone flap was 132 cm 3 (range, 89-171 cm 3 ). Applied to virtual craniectomy patients, the total volume of expansion achieved with the ACP implantation operation was 222 cm 3 (range, 181-263 cm 3 )., Conclusions: ACP implantation during DHC is technically feasible. It achieves a volume of cranial expansion that will accommodate that observed following survivable hemicraniectomy operations. Moving the implant from the up to the down position can easily be performed as a simple outpatient or inpatient bedside procedure, thus potentially eliminating second-stage cranioplasty procedures., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: It is essential that treatment effects reported from retrospective observational studies are as reliable as possible. In a retrospective analysis of spine surgery patients, we obtained a spurious result: tranexamic acid (TXA) had no effect on intraoperative blood loss. This statistical tutorial explains how this result occurred and why statistical analyses of observational studies must consider the effects of individual surgeons., Methods: We used an observational database of 580 elective adult spine surgery patients, supplemented with a review of perioperative medication records. We tested whether common statistical methods (multivariable regression or propensity score-based methods) could adjust for surgeons' selection bias in TXA administration., Results: Because TXA administration (frequency, timing, and dose) and surgeon were linked (collinear), estimating and testing the independent effect of TXA on outcome using multivariable regression without including surgeon as a variable would provide biased (spurious) results. Likewise, because of surgeon/TXA linkage, assumptions of propensity score-based analysis were violated, statistical methods to improve comparability between groups failed, and spurious blood loss results were worsened. Others numerous differences among surgeons existed in intraoperative and postoperative practices and outcomes., Conclusions: In observational studies in which individual surgeons determine whether their patients receive the treatment of interest, consideration must be given to inclusion of surgeon as an independent variable in all analyses. Failure to include the surgeon in an analysis of observational data carries a substantial risk of obtaining spurious results, either creating a spurious treatment effect or failing to detect a true treatment effect., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Neuroimaging studies in healthy and clinical populations strongly associate the amygdala with emotion, especially negative emotions. The consequences of surgical resection of the amygdala on mood are not well characterized. We tested the hypothesis that amygdala resection would result in mood improvement. In this study, we evaluated a cohort of 52 individuals with medial temporal lobectomy for intractable epilepsy who had resections variably involving the amygdala. All individuals achieved good post-surgical seizure control and had pre- and post-surgery mood assessment with the Beck Depression Inventory (BDI) ratings. We manually segmented the surgical resection cavities and performed multivariate lesion-symptom mapping of change in BDI. Our results showed a significant improvement in average mood ratings from pre- to post-surgery across all patients. In partial support of our hypothesis, resection of the right amygdala was significantly associated with mood improvement (r = 0.5, p = 0.008). The lesion-symptom map also showed that resection of the right hippocampus and para-hippocampal gyrus was associated with worsened post-surgical mood. Future studies could evaluate this finding prospectively in larger samples while including other neuropsychological outcome measures., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Over the past 10 years, smartphones have become ubiquitous, and mobile apps serve a seemingly endless number of functions in our everyday lives. These functions have entered the realm of plastic surgery, impacting patient care, education, and delivery of services. This article reviews the current uses of plastic surgery mobile apps, app awareness within the plastic surgery community, and the ethical issues surrounding their use in patient care., Methods: A scoping review of electronically available literature within PubMed, Embase, and Scopus databases was conducted in two waves in November and May 2022. Publications discussing mobile application use in plastic surgery were screened for inclusion., Results: Of the 80 nonduplicate publications retrieved, 20 satisfied the inclusion criteria. Articles acquired from the references of these publications were reviewed and summarized when relevant. The average American Society of Plastic Surgeons evidence rating of the publications was 4.2. Applications could be categorized broadly into three categories: patient care and surgical applications, professional development and education, and marketing and practice development., Conclusions: Mobile apps related to plastic surgery have become an abundant resource for patients, attending surgeons, and trainees. Many help bridge gaps in patient care and surgeon-patient communication, and facilitate marketing and practice development. Others make educational content more accessible to trainees and performance assessment more efficient and equitable. The extent of their impact on patient decision-making and expectations has not been completely elucidated., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Background: In response to the opioid epidemic, the United States declared a public health emergency in 2017. We evaluated pain medication prescribing practices among plastic and reconstructive surgeons, assessing pain medication prescription rates and opioid-related mortality both nationally and regionally within the United States., Methods: A retrospective analysis of Medicare Part D prescriber data among plastic surgeons from 2013 through 2017 was conducted. Pain medications were categorized as opioid and nonopioid medications. Trends in surgeon prescribing habits were evaluated using the Cochrane-Armitage trend test., Results: A total of 708,817 pain medication claims were identified: 612,123 claims (86%) were for opioid pain medications and 96,694 claims (14%) were for nonopioid pain medications. Total pain medication claims decreased from 44% of all medications in 2013 to 37% in 2017 (P < 0.001). Opioid medications decreased from 37% of total medication claims to 32% (P < 0.001). The overall opioid prescription rate fell from 1.53 claims per beneficiary in 2013 to 1.32 in 2017 (P < 0.001). Nonopioid pain medications decreased from 7% in 2013 to 6% in 2017 (P < 0.001); nonsteroidal anti-inflammatory drug claims increased by 44%. The prescription rate of nonopioid medications decreased from 2.40 claims per beneficiary in 2013 to 2.32 in 2017 (P < 0.001). An overall increase in opioid-related mortality was observed. Trends in pain medication prescriptions varied significantly among US regions and divisions., Conclusions: Plastic surgeons are prescribing less opioids and relying more on nonopioid pain medications. Increased adoption of multimodal pain treatment approaches among surgeons is a likely explanation for this trend in face of the current opioid crisis., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: We are developing a novel intradural spinal cord stimulator for treatment of neuropathic pain and spasticity. A key feature is the means by which it seals the dura mater to prevent leakage of cerebrospinal fluid (CSF). We have built and employed a test rig that enables evaluation of candidate seal materials., Methods: To guide the design of the test rig, we reviewed the literature on neurosurgical durotomies. The test rig has a mock durotomy slot with a dural substitute serving as the surrogate dura mater and water as the CSF. The primary experimental goal was to evaluate the effectiveness of candidate gasket materials as seals against CSF leakage in an implanted prototype device, at both normal and super-physiologic pressures. A secondary goal was to measure the transmembrane flows in a representative dural substitute material, to establish its baseline aqueous transport properties., Results: The seals prevented leakage of water at the implantation site over periods of ≈ ten days, long enough for the scar tissue to form in the clinical situation. The seals also held at water pressure transients approaching 250 mm Hg. The residual volumetric flux of water through the dura substitute membrane (Durepair®) was δV T /A ≈ 0.24 mm 3 /min/cm 2 , consistent with expectations for transport through the porous membrane prior to closure and equalization of internal/external pressures., Conclusions: We have demonstrated the workability of obtaining robust seal against leakage at the implantation site of a novel intradural stimulator using a custom-designed test rig. Extension of the method to in vivo testing in a large animal model will be the next step., (© 2019 International Neuromodulation Society.)

Voice and face processing occur through convergent neural systems that facilitate speaker recognition. Neuroimaging studies suggest that familiar voice processing engages early visual cortex, including the bilateral fusiform gyrus (FG) on the basal temporal lobe. However, what role the FG plays in voice processing and whether it is driven by bottom-up or top-down mechanisms is unresolved. In this study we directly examined neural responses to famous voices and faces in human FG with direct cortical surface recordings (electrocorticography) in epilepsy surgery patients. We tested the hypothesis that neural populations in human FG respond to famous voices and investigated the temporal properties of voice responses in FG. Recordings were acquired from five adult participants during a person identification task using visual and auditory stimuli from famous speakers (U.S. Presidents Barack Obama, George W. Bush, and Bill Clinton). Patients were presented with images of presidents or clips of their voices and asked to identify the portrait/speaker. Our results demonstrate that a subset of face-responsive sites in and near FG also exhibit voice responses that are both lower in magnitude and delayed (300-600 ms) compared with visual responses. The dynamics of voice processing revealed by direct cortical recordings suggests a top-down feedback-mediated response to famous voices in FG that may facilitate speaker identification. NEW & NOTEWORTHY Interactions between auditory and visual cortices play an important role in person identification, but the dynamics of these interactions remain poorly understood. We performed direct brain recordings of fusiform face cortex in human epilepsy patients performing a famous voice naming task, revealing the dynamics of famous voice processing in human fusiform face cortex. The findings support a model of top-down interactions from auditory to visual cortex to facilitate famous voice recognition.