The association between delinquent peer affiliation and disruptive behavior interacts with functional brain correlates of reward sensitivity: a biosocial interaction study in adolescent delinquents.

BACKGROUND: Affiliating with delinquent peers may stimulate the development of antisocial behavior, especially for adolescents who are sensitive to social rewards. The current study examines whether the association between delinquent peer affiliation (DPA) and disruptive behavior interacts with functional brain correlates of reward sensitivity in early onset male adolescents delinquents. METHODS: Childhood arrestees (n = 126, mean age = 17.7 [s.d. 1.6]) completed a DPA questionnaire, and participated in an fMRI study in which reward sensitivity was operationalized through responsiveness of the ventral striatum (VS), amygdala, and medial prefrontal cortex (mPFC) during the monetary incentive delay paradigm (reward anticipation and outcome). Symptoms of disruptive behavior disorders (DBD) were assessed through structured psychiatric interviews (Diagnostic Interview Schedule for Children) with adolescents. RESULTS: DPA had a main effect on DBD symptoms. Adolescents with high VS reward responses showed a stronger significant positive association between DPA and DBD symptoms compared to low VS responders. No evidence for an interaction effect was found for the amygdala and mPFC. Post-hoc analyses revealed the positive association between DPA and DBD was only present in males, with a diminishing effect as age increased. CONCLUSIONS: We found evidence for a biosocial interaction between DPA and reward sensitivity of the VS in relation to DBD symptom severity. This study provides the first evidence of an interaction effect between a brain mechanism and an environmental factor in relation to DBD symptoms, implying that susceptibility to influences of delinquent peers may intertwine with individual biological differences.

Detection and discrimination of electrical stimuli from an upper limb cuff electrode inM. Mulatta.

Objective.Peripheral nerve interfaces seek to restore nervous system function through electrical stimulation of peripheral nerves. In clinical use, these devices should function reliably for years or decades. In this study, we assessed evoked sensations from multi-channel cuff electrode stimulation in macaque monkeys up to 711 d post-implantation.Approach.Three trained macaque monkeys received multi-channel cuff electrode implants at the median or ulnar nerves in the upper arm. Electrical stimuli from the cuff interfaces evoked sensations, which we measured via standard psychophysical tasks. We adjusted pulse amplitude or pulse width for each block with various electrode channel configurations to examine the effects of stimulus parameterization on sensation. We measured detection thresholds and just-noticeable differences (JNDs) at irregular, near-daily intervals for several months using Bayesian inferencing from trial data. We examined data trends using classical models such as Weber's Law and the strength-duration relationship using linear regression.Main results.Detection thresholds were similar between blocks with pulse width modulation and blocks with pulse amplitude modulation when represented as charge per pulse, the product of the amplitude and the pulse width. Conversely, Weber fractions-calculated as the slope of the regression between JND charge values and reference stimulus charge-were significantly different between pulse width and pulse amplitude modulation blocks for the discrimination task.Significance.Weber fractions were lower in blocks with amplitude modulation than in blocks with pulse width modulation, suggesting that pulse amplitude modulation allows finer resolution of sensory encoding above threshold. Consequently, amplitude modulation may enable a greater dynamic range for sensory perception with neuroprosthetic devices.

Neuromodulación del núcleo talámico anterior como opción terapéutica para epilepsia de difícil control / Neuromodulation of the anterior thalamic nucleus as a therapeutic option for difficult-to-control epilepsy

La estimulación cerebral profunda (ECP) consiste en la estimulación eléctrica de las estructuras subcorticales mediante el implante de electrodos conectados a un generador de impulsos. El tálamo, al ser una estructura que posee múltiples conexiones con diversas partes del sistema nervioso central, es un target adecuado para la ECP. El núcleo talámico anterior (NA) sirve como un sitio de relevo importante para el sistema límbico al recibir aferencias desde el hipocampo y los cuerpos mamilares y enviar eferencias hacia el giro del cíngulo, formando así el circuito de Papez. Debido a estas conexiones, el NA constituye una vía idónea para la propagación de la actividad epileptogénica. La ECP-NA tiene excelentes resultados en el control de las crisis parciales complejas. La gran mayoría de pacientes con ECP-NA han demostrado una reducción significativa en la frecuencia de sus crisis de más del 50% (AU)

Deep brain stimulation (DBS) consists of the electrical stimulation of the subcortical structures by implanting electrodes connected to a pulse generator. The thalamus, being a structure that has multiple connections with various parts of the central nervous system, is a suitable target for DBS. The anterior thalamic nucleus (ANT) serves as an important relay site for the limbic system by receiving input from the hippocampus and mammillary bodies, and sending input to the cingulate gyrus; thus forming the Papez circuit. Due to these connections, the ANT constitutes an ideal route for the propagation of epileptogenic activity. ANT-DBS has excellent results in the control of complex partial seizures. The vast majority of patients with ANT-DBS have shown a significant reduction in the frequency of their seizures of more than 50% (AU)

Comparison of technical success and safety of transbronchial versus percutaneous CT-guided fiducial placement for SBRT of lung tumors.

OBJECTIVE: To evaluate the technical success and safety of transbronchial (bronchoscopic) fiducial placement compared to percutaneous CT-guided fiducial placement for stereotactic body radiotherapy (SBRT) of lung tumors. MATERIALS AND METHODS: This IRB-approved, HIPAA-compliant retrospective study was performed at a single tertiary institution. Consecutive patients undergoing lung fiducial placement for purposes of guiding SBRT (CyberKnife®, Accuray, Inc.) between September 2005 to January 2013 were included in the study. Fiducial seeds were placed percutaneously with CT guidance or transbronchially with bronchoscopic guidance. We compared procedure-related complications (pneumothorax, chest tube placement), technical success (defined as implantation enabling adequate treatment planning with CT simulation) and migration rate. The need for repeat procedures and their mode was noted. Statistical analysis was performed using Fisher exact and Chi square probability tests. RESULTS: Two hundred and forty-four patients with lung tumors and 272 fiducial seed placements were included in the study. Two hundred and twenty-one of the 272 (81.2%) fiducial markers were placed percutaneously and 51/272 (18.8%) were placed transbronchially. Pneumothorax was seen in 73/221 (33%) of percutaneously-placed fiducials and in 4/51 (7.8%) of transbronchial placements (p<0.001). No significant difference was seen in the rate of chest tube placement between the two groups: 20/221 (9%) of percutaneously placed fiducials and 2/51 (3.9%) of transbronchially placed fiducials (p=0.39). Fifteen of the 51 (29%) of fiducial placements with transbronchial approach were unsuccessful, as discovered at radiotherapy planning session, and required a repeat procedure. Nine of the 15 (60%) of repeat procedures were performed percutaneously, 5/15 (33%) were placed during repeat bronchoscopy, and 1/15 (7%) was placed at transesophageal endoscopic ultrasound. No repeat fiducial placements were required for patients who had the fiducials placed percutaneously (p<0.001), with a technical success rate of 100%. CONCLUSION: Transbronchial fiducial marker placement has a significantly higher rate of failed seed placements requiring repeat procedures in comparison to percutaneous placement. Complication rate of pneumothorax requiring chest drain placement is similar between the two approaches.

Review: Sustainable livestock systems: anticipating demand-side challenges.

A sustainable livestock economy depends on both production and consumption, inextricably linked in local, national and global markets. At each scale, technical innovation and production practices need to respond to evolving demand for both market and non-market attributes of livestock systems. This review considers recent and evolving demand-side challenges focussing on emerging preferences related to environmental, dietary and health impacts, arising from both production and consumption. It suggests that these attributes need to be integral to any definition of high-producing animal systems. This discussion is mostly framed using neoclassical economic theory, which highlights market failure and the role of negative and positive external effects or social costs. It examines how our understanding of the demand for these attributes is evolving, leading to market segmentation in some cases, and an existential threat to livestock production as consumption decisions change, investors seek to avoid potential liabilities related to greenhouse gas emissions and potentially antimicrobial resistance, and governments intervene to control other undesirable social costs. The discussion distinguishes between market imperatives in high- and lower-income countries, and how income and consumption trajectories may be less deterministic in a more hyperlinked world where product information may accelerate the evolution of preferences towards and away from livestock products. The review acknowledges the limits of a neoclassical approach, drawing attention to more fundamental concepts of biophysical limits to growth and value pluralism, which indicates values (e.g. intrinsic) that lie beyond the neoclassical framing of demand and value.

Synthesis of controlled size starch nanoparticles (SNPs).

Starch nanoparticles (SNPs) are a promising choice for the strategic development of new renewable and biodegradable nanomaterials for novel biomedical and pharmaceutical applications when loaded with antibiotics or with anticancer agents as target drug delivery systems. The final properties of the SNPs are strongly influenced by the synthesis method and conditions being a controlled and monodispersed size crucial for these applications. The aim of this work was to synthesize controlled size SNPs through nanoprecipitation and microemulsion methods by modifying main operating parameters regarding the effect of amylose and amylopectin ratio in maize starches. SNPs were characterized by size and shape. SNPs from 59 to 118 nm were obtained by the nanoprecipitation method, registering the higer values when surfactant was added to the aqueous phase. Microemulsion method led to 35-147 nm sizes observing a higher particle formation capacity. The composition of the maize used influenced the final particle size and shape.

An improved algorithm for solving profit-maximizing cattle diet problems.

Feeding cattle with on-pasture supplementation or feedlot diets can increase animal efficiency and system profitability while minimizing environmental impacts. However, cattle system profit margins are relatively small and nutrient supply accounts for most of the costs. This paper introduces a nonlinear profit-maximizing diet formulation problem for beef cattle based on well-established predictive equations. Nonlinearity in predictive equations for nutrient requirements poses methodological challenges in the application of optimization techniques. In contrast to other widely used diet formulation methods, we develop a mathematical model that guarantees an exact solution for maximum profit diet formulations. Our method can efficiently solve an often-impractical nonlinear problem by solving a finite number of linear problems, that is, linear time complexity is achieved through parametric linear programming. Results show the impacts of choosing different objective functions (minimizing cost, maximizing profit and maximizing profit per daily weight gain) and how this may lead to different optimal solutions. In targeting improved ration formulation on feedlot systems, this paper demonstrates how profitability and nutritional constraints can be met as an important part of a sustainable intensification production strategy.

Robot-assisted abdominal wall excision of a PSMA-detected prostate cancer metastasis.

Recent advances in novel functional imaging techniques such as PSMA PET may now offer the ability to identify small volume metastases which may otherwise go undetected. The treatment of these lesions is controversial, particularly in the oligometastatic state. We report the case of an abdominal wall metastasis detected with PSMA imaging which we treated with surgical excision. This resulted in an undetectable PSA 6 weeks post excision.

Ankylosing Spondylitis Response to TNF Inhibition Is Gender Specific: A 6-Year Cohort Study

Aim Recent studies have suggested gender-specific differences with respect to both baseline disease activity and severity in ankylosing spondylitis (AS). Tumour necrosis factor inhibitors (TNFi) have shown significant benefit in AS but there may be gender-specific differences regarding responses to TNFi therapy. Methods AS patients with active disease despite adequate trials of NSAIDs were commenced on TNFi and followed in a biologic clinic between 2004 and 2011. Response to treatment was measured based on clinical and serological outcomes. Baseline radiographic data were also collected where available. Results 147 AS patients commenced TNFi therapy and were followed in a biologic clinic between 2004 and 2011. One-hundred and six (72%) of the patients were male and 90 (61%) were current or ex-smokers. The specific TNFi prescribed included etanercept (74 patients, 50.3%), adalimumab (51 patients, 34.7%), infliximab (21 patients, 14.2%) and golimumab (1 patient, 0.7%). The median mSASSS score was 11 (interquartile range 5-35). At baseline, the metrology indices (BASMI) were significantly lower in women (2.6 v 4; p=0.01) but all other clinical indices were similar. At 3 months, female patients had significantly worse median disease activity and functional indices (BASDAI: 4 v 2; p<0.01; BASFI: 3 v 2; p=0.03) than male patients. In addition, females had higher median ESR (19 v 6; p<0.01) which correlated with their disease activity indices (r=0.42, p=0.02). Discussion Despite similar disease activity at baseline, post-TNFi therapy women had significantly higher disease activity. Furthermore, ESR levels in women during therapy correlated with their clinical disease activity scores. Further exploration of these gender-specific differences is crucial for a greater understanding of the pathogenesis of AS as well as development of targeted therapies.

Multidimensional family therapy in adolescents with a cannabis use disorder: long-term effects on delinquency in a randomized controlled trial.

BACKGROUND: Substance use and delinquency are considered to be mutual risk factors. Previous studies have shown that multidimensional family therapy (MDFT) is effective in tackling both conditions on the short term. The current study examines the long-term effects of MDFT on criminal offending. METHODS: 109 adolescents with cannabis use disorder and comorbid problem behavior were randomly assigned to either MDFT or cognitive behavioral therapy (CBT). Police arrest data were collected for 6 years: 3 years prior to and 3 years after treatment entry. Using survival analysis and repeated measure General Linear Models (rmGLM), the two treatment groups were compared on number of arrests, type of offence, and severity of offence. Moderator analyses looking at age, disruptive behavior disorders, history of crimes, family functioning, and (severe) cannabis use were conducted (rmGLM). RESULTS: While police arrest rates increased in the 3 years before treatment, the rates decreased substantially after the start of both treatments. No differences were found between the treatment groups with respect to either time to first offence from the start of the treatment or changes in frequency or severity of offending over time. A treatment effect trend favoring MDFT was found for property offending in the subgroup of adolescents with high baseline-severity of cannabis use. CONCLUSIONS: Across a follow-up period of 3 years, MDFT and CBT were similarly effective in reducing delinquency in adolescents with a cannabis use disorder.Trial registration ISRCTN51014277, Registered 17 March 2010-Retrospectively registered, http://www.isrctn.com/ISRCTN51014277.

The value of multimodality imaging in the investigation of a PSA recurrence after radical prostatectomy in the Irish hospital setting.

INTRODUCTION: The diagnostic evaluation of a PSA recurrence after RP in the Irish hospital setting involves multimodality imaging with MRI, CT, and bone scanning, despite the low diagnostic yield from imaging at low PSA levels. We aim to investigate the value of multimodality imaging in PC patients after RP with a PSA recurrence. METHODS: Forty-eight patients with a PSA recurrence after RP who underwent multimodality imaging were evaluated. Demographic data, postoperative PSA levels, and imaging studies performed at those levels were evaluated. RESULTS: Eight (21%) MRIs, 6 (33%) CTs, and 4 (9%) bone scans had PCa-specific findings. Three (12%) patients had a positive MRI with a PSA <1.0 ng/ml, while 5 (56%) were positive at PSA ≥1.1 ng/ml (p = 0.05). Zero patient had a positive CT TAP at a PSA level <1.0 ng/ml, while 5 (56%) were positive at levels ≥1.1 ng/ml (p = 0.03). Zero patient had a positive bone at PSA levels <1.0 ng/ml, while 4 (27%) were positive at levels ≥1.1 ng/ml (p = 0.01). CONCLUSION: The diagnostic yield from multimodality imaging, and isotope bone scanning in particular, in PSA levels <1.0 ng/ml, is low. There is a statistically significant increase in the frequency of positive findings on CT and bone scanning at PSA levels ≥1.1 ng/ml. MRI alone is of investigative value at PSA <1.0 ng/ml. The indication for CT, MRI, or isotope bone scanning should be carefully correlated with the clinical question and how it will affect further management.

Integrating livestock health measures into marginal abatement cost curves.

Improving livestock health offers both private and social benefits. Among the potential social benefits is a reduction in the greenhouse gas (GHG) emissions arising from livestock production. Reductions in emissions intensity (the amount of GHG produced per kilogram of meat, milk or eggs) may occur, as improving health can lead to improvements in the parameters that emissions intensity is sensitive to, such as (for ruminants): maternal fertility and abortion rates, calf and lamb mortality rates and growth rates, milk yields and feed conversion rates. However, improved health is not yet widely recognised as a GHG mitigation measure due, in part, to difficulties in reliably quantifying the financial and GHG effects of disease control options. This paper discusses how the GHG effects of disease control can be quantified and included in a marginal abatement cost curve (MACC). To illustrate some of the challenges, it draws on the experience of including health measures in the most recent (2015) agricultural MACCs in the United Kingdom.

L'amélioration de la santé des animaux d'élevage apporte des bénéfices non seulement aux personnes et entreprises privées mais aussi à la société en général. La réduction des émissions de gaz à effet de serre est l'un des bénéfices potentiels apportés à la société par les élevages. Il est ainsi possible de réduire l'intensité des émissions (c'est-à-dire la quantité de gaz à effet de serre générée par kilogramme de viande, de lait ou d'oeufs), dans la mesure où l'amélioration de la santé animale s'accompagne d'une amélioration des paramètres qui influent sur l'intensité de ces émissions ; par exemple, chez les ruminants, le taux de fécondité, le taux d'avortements, le taux de mortalité néonatale et le taux de croissance chez les ovins et les caprins, la production de lait et le taux de conversion des aliments donnés aux animaux. Or, l'amélioration de la santé n'est pas toujours reconnue comme étant une mesure de réduction des gaz à effet de serre, en raison notamment de la difficulté de quantifier de manière fiable les effets des différentes stratégies zoosanitaires en termes financiers et d'émissions de gaz à effet de serre. Les auteurs proposent une méthode permettant de quantifier les effets des mesures de lutte contre les maladies animales sur les émissions de gaz à effet de serre et de les intégrer dans une courbe de coût marginal d'abattement. Afin d'illustrer certains enjeux en la matière, les auteurs présentent l'expérience conduite récemment (2015) au Royaume-Uni pour intégrer les mesures sanitaires dans les courbes de coût marginal d'abattement du secteur agricole.

El hecho de mejorar el estado de salud del ganado reporta beneficios de índole tanto privada como social. Entre los posibles beneficios sociales figura una reducción de las emisiones de gases de efecto invernadero resultantes de la producción pecuaria. Esas emisiones también pueden ser menos intensas (volumen de gases generados por kilogramo de carne, leche o huevos), pues la intensidad de las emisiones es sensible a una serie de parámetros cuyo valor mejora al hacerlo el estado de salud, tales como (en el caso de los rumiantes): tasas de fertilidad materna y de abortos; tasas de mortalidad y crecimiento en terneros y corderos; y tasas de producción de leche y de conversión alimenticia. Sin embargo, todavía no ha arraigado la idea de que la mejora del estado de salud es una medida de lucha contra los gases de efecto invernadero, debido en parte a las dificultades existentes para cuantificar con fiabilidad los efectos de los métodos de lucha zoosanitaria sobre parámetros económicos o sobre las emisiones. Los autores explican cómo cuantificar los efectos del control de enfermedades sobre los gases de efecto invernadero y a partir de ahí incluirlos en una curva del costo marginal de reducción. Para ilustrar algunos de los problemas que pueden surgir se refieren a la experiencia británica destinada a incluir parámetros que miden el estado de salud en las más recientes (2015) curvas del costo marginal de reducción en el ámbito agropecuario.

Knowledge, attitudes and practices regarding rabies risk in community members and healthcare professionals: Pétionville, Haiti, 2013.

Haiti has the highest human rabies burden in the Western Hemisphere. There is no published literature describing the public's perceptions of rabies in Haiti, information that is critical to developing effective interventions and government policies. We conducted a knowledge, attitudes and practices survey of 550 community members and 116 health professionals in Pétionville, Haiti in 2013 to understand the perception of rabies in these populations. The majority of respondents (85%) knew that dogs were the primary reservoir for rabies, yet only 1% were aware that bats and mongooses could transmit rabies. Animal bites were recognized as a mechanism of rabies transmission by 77% of the population and 76% were aware that the disease could be prevented by vaccination. Of 172 persons reporting a bite, only 37% sought medical treatment. The annual bite incidence rate in respondents was 0·9%. Only 31% of bite victims reported that they started the rabies vaccination series. Only 38% of respondents reported that their dog had been vaccinated against rabies. The majority of medical professionals recognized that dogs were the main reservoir for rabies (98%), but only 28% reported bats and 14% reported mongooses as posing a risk for rabies infection. Bites were reported as a mechanism of rabies transmission by 73% of respondents; exposure to saliva was reported by 20%. Thirty-four percent of medical professionals reported they would wash a bite wound with soap and water and 2·8% specifically mentioned rabies vaccination as a component of post-bite treatment. The majority of healthcare professionals recommended some form of rabies assessment for biting animals; 68·9% recommended a 14-day observation period, 60·4% recommended a veterinary consultation, and 13·2% recommended checking the vaccination status of the animal. Fewer than 15% of healthcare professionals had ever received training on rabies prevention and 77% did not know where to go to procure rabies vaccine for bite victims. Both study populations had a high level of knowledge about the primary reservoir for rabies and the mode of transmission. However, there is a need to improve the level of knowledge regarding the importance of seeking medical care for dog bites and additional training on rabies prevention for healthcare professionals. Distribution channels for rabies vaccines should be evaluated, as the majority of healthcare providers did not know where rabies vaccines could be obtained. Canine rabies vaccination is the primary intervention for rabies control programmes, yet most owned dogs in this population were not vaccinated.

Accuracy of 64-section MDCT in the diagnosis of cruciate ligament tears.

AIM: To evaluate the accuracy of non-arthrographic 64-section multidetector computed tomography (CT) in the assessment of cruciate ligament tears. A secondary goal was to determine its accuracy in the diagnosis of additional soft-tissue injuries around the knee. MATERIALS AND METHODS: Forty consecutive outpatients underwent same-day magnetic resonance imaging (MRI) and 64-slice multidetector CT (MDCT) of the knee in this prospective study. MDCT images were independently evaluated for integrity of the anterior (ACL) and posterior cruciate ligaments (PCL), medial and lateral menisci, and medial and lateral collateral ligaments. Recognised secondary signs of ACL tears were also documented. MRI images were subsequently assessed by two radiologists and a consensus reached. RESULTS: The sensitivity of MDCT for ACL tears was 87.5-100%, with a specificity of 100%. The presence of one or more secondary signs of ACL tears on MDCT had a sensitivity of 50-87.5% with a specificity of 100%. The sensitivity of MDCT for PCL tears was 0-25% with a specificity of 100%. The sensitivity for meniscal tears was 9.1-23.1% with a specificity of 96.3-100%. CONCLUSION: 64-section MDCT has very high sensitivity and specificity for ACL tears and, as on MRI, secondary signs, such as buckling of the PCL, are also useful in their diagnosis. MDCT has a low sensitivity for other soft-tissue injuries at the knee; however, its high specificity indicates that apparent PCL, meniscal, and collateral ligament tears can reliably be treated as true-positive findings.

Representational Uncertainty in the Brain During Threat Conditioning and the Link With Psychopathic Traits.

BACKGROUND: Psychopathy has repeatedly been linked to disturbed associative learning from aversive events (i.e., threat conditioning). Optimal threat conditioning requires the generation of internal representations of stimulus-outcome contingencies and the rate with which these may change. Because mental representations are imperfect, there will always be uncertainty about the accuracy of representations in the brain (i.e., representational uncertainty). However, it remains unclear 1) to what extent threat conditioning is susceptible to different types of uncertainty in representations about contingencies during the acquisition phase and 2) how representational uncertainty relates to psychopathic features. METHODS: A computational model was applied to functional neuroimaging data to estimate uncertainty in representations of contingencies (CoUn) and the rate of change of contingencies (RUn), respectively, from brain activation during the acquisition phase of threat conditioning in 132 adolescents at risk of developing antisocial personality profiles. Next, the associations between these two types of representational uncertainty and psychopathy-related dimensions were examined. RESULTS: The left and right amygdala activations were associated with CoUn, while the bilateral insula and the right amygdala were associated with RUn. Different patterns of relationships were found between psychopathic features and each type of uncertainty. Callous-unemotional traits and impulsive-irresponsible traits uniquely predicted increased CoUn, while only impulsive-irresponsible traits predicted increased RUn. CONCLUSIONS: The findings suggest that 1) the insula and amygdala differ in how these regions are affected by different types of representational uncertainty during threat conditioning and 2) CoUn and RUn have different patterns of relationships with psychopathy-related dimensions.

Spatial co-adaptation of cortical control columns in a micro-ECoG brain-computer interface.

OBJECTIVE: Electrocorticography (ECoG) has been used for a range of applications including electrophysiological mapping, epilepsy monitoring, and more recently as a recording modality for brain-computer interfaces (BCIs). Studies that examine ECoG electrodes designed and implanted chronically solely for BCI applications remain limited. The present study explored how two key factors influence chronic, closed-loop ECoG BCI: (i) the effect of inter-electrode distance on BCI performance and (ii) the differences in neural adaptation and performance when fixed versus adaptive BCI decoding weights are used. APPROACH: The amplitudes of epidural micro-ECoG signals between 75 and 105 Hz with 300 µm diameter electrodes were used for one-dimensional and two-dimensional BCI tasks. The effect of inter-electrode distance on BCI control was tested between 3 and 15 mm. Additionally, the performance and cortical modulation differences between constant, fixed decoding using a small subset of channels versus adaptive decoding weights using the entire array were explored. MAIN RESULTS: Successful BCI control was possible with two electrodes separated by 9 and 15 mm. Performance decreased and the signals became more correlated when the electrodes were only 3 mm apart. BCI performance in a 2D BCI task improved significantly when using adaptive decoding weights (80%-90%) compared to using constant, fixed weights (50%-60%). Additionally, modulation increased for channels previously unavailable for BCI control under the fixed decoding scheme upon switching to the adaptive, all-channel scheme. SIGNIFICANCE: Our results clearly show that neural activity under a BCI recording electrode (which we define as a 'cortical control column') readily adapts to generate an appropriate control signal. These results show that the practical minimal spatial resolution of these control columns with micro-ECoG BCI is likely on the order of 3 mm. Additionally, they show that the combination and interaction between neural adaptation and machine learning are critical to optimizing ECoG BCI performance.

Regional grey matter volume and concentration in at-risk adolescents: Untangling associations with callous-unemotional traits and conduct disorder symptoms.

Structural Magnetic Resonance Imaging studies have reported volume reductions in several brain regions implicated in social cognition and emotion recognition in juvenile antisocial populations. However, it is unclear whether these structural abnormalities are specifically related to antisocial features, or to co-occurring callous-unemotional (CU) traits. The present study employed voxel-based morphometry to assess both grey matter volume (GMV) and grey matter concentration (GMC) in a large representative at-risk sample of adolescents (n=134; mean age 17.7yr), characterized by a broad range of CU trait and conduct disorder (CD) symptom scores. There was a significant interaction between CD symptom and CU trait scores in the prediction of GMV in the anterior insula, with a significant positive association between CU traits and GMV in youth low on CD symptoms only. In addition, we found a significant unique positive association between CD symptoms and GMC in the amygdala, and unique negative associations between CU traits and GMC in the amygdala and insula. These findings are in line with accumulating evidence of distinct associations of CD symptoms and CU traits with amygdala and insula GMC in juvenile antisocial populations.

Fear extinction, persistent disruptive behavior and psychopathic traits: fMRI in late adolescence.

Children diagnosed with a Disruptive Behavior Disorder (DBD, i.e. Oppositional Defiant Disorder or Conduct Disorder), especially those with psychopathic traits, are at risk of developing persistent and severe antisocial behavior. Reduced fear conditioning has been proposed to underlie persistent antisocial development. However, we have recently shown that both DBD persisters and desisters are characterized by increased fear conditioning compared with healthy controls (HCs). In this study, we investigated whether brain function during fear extinction is associated with DBD subgroup-membership and psychopathic traits. Adolescents from a childhood arrestee cohort (mean age 17.6 years, s.d. 1.4) who met criteria for a DBD diagnosis during previous assessments were re-assessed and categorized as persistent DBD (n = 25) or desistent DBD (n = 25). Functional MRI during the extinction phase of a classical fear-conditioning task was used to compare regional brain function between these subgroups and 25 matched controls. Both DBD persisters and desisters showed hyperreactivity during fear extinction, when compared with HCs. Impulsive-irresponsible psychopathic traits were positively associated with responses in the fear neurocircuitry and mediated the association between neural activation and group membership. These results suggest that fear acquisition and fear extinction deficits may provide an endophenotype for an emotionally hyperreactive subtype of antisocial development.