Safety and Efficacy of Repeat Open-Label AbobotulinumtoxinA Treatment in Pediatric Cerebral Palsy

This was a prospective, repeat-treatment, open-label study (NCT01251380) of abobotulinumtoxinA for the management of lower limb spasticity in children who had completed a double-blind study. Children (2-17 years) received injections into the gastrocnemius-soleus complex, and other distal and proximal muscles as required (maximum total dose per injection cycle: 30 U/kg or 1000U). A total of 216 of the 241 double-blind patients entered the extension study and 207 received ≥1 open label injection into the gastrocnemius-soleus; 17-24% of patients also had injections into the hamstrings. The most frequent adverse events were related to common childhood infections and the most frequent treatment-related adverse event was injection site pain (n = 10). There was no evidence of a cumulative effect on adverse events. Sustained significant clinical improvements in muscle tone (Modified Ashworth Scale), spasticity (Tardieu Scale), overall clinical benefit (Physicians Global Assessment), and goal attainment (Goal Attainment Scale) were also observed across treatment cycles.

Positive autobiographical memory retrieval reduces temporal discounting

People generally prefer rewards sooner rather than later. This phenomenon, temporal discounting, underlies many societal problems, including addiction and obesity. One way to reduce temporal discounting is to imagine positive future experiences. Since there is overlap in the neural circuitry associated with imagining future experiences and remembering past events, here we investigate whether recalling positive memories can also promote more patient choice. We found that participants were more patient after retrieving positive autobiographical memories, but not when they recalled negative memories. Moreover, individuals were more impulsive after imagining novel positive scenes that were not related to their memories, showing that positive imagery alone does not drive this effect. Activity in the striatum and temporo parietal junction during memory retrieval predicted more patient choice, suggesting that to the extent that memory recall is rewarding and involves perspective-taking, it influences decision-making. Furthermore, representational similarity in the ventromedial prefrontal cortex between memory recall and decision phases correlated with the behavioral effect across participants. Thus, we have identified a novel manipulation for reducing temporal discounting-remembering the positive past-and have begun to characterize the psychological and neural mechanisms behind it.

Clinically severe CACNA1A alleles affect synaptic function and neurodegeneration differentially

Dominant mutations in CACNA1A, encoding the α-1A subunit of the neuronal P/Q type voltage-dependent Ca2+ channel, can cause diverse neurological phenotypes. Rare cases of markedly severe early onset developmental delay and congenital ataxia can be due to de novo CACNA1A missense alleles, with variants affecting the S4 transmembrane segments of the channel, some of which are reported to be loss-of-function. Exome sequencing in five individuals with severe early onset ataxia identified one novel variant (p.R1673P), in a girl with global developmental delay and progressive cerebellar atrophy, and a recurrent, de novo p.R1664Q variant, in four individuals with global developmental delay, hypotonia, and ophthalmologic abnormalities. Given the severity of these phenotypes we explored their functional impact in Drosophila. We previously generated null and partial loss-of-function alleles of cac, the homolog of CACNA1A in Drosophila. Here, we created transgenic wild type and mutant genomic rescue constructs with the two noted conserved point mutations. The p.R1673P mutant failed to rescue cac lethality, displayed a gain-of-function phenotype in electroretinograms (ERG) recorded from mutant clones, and evolved a neurodegenerative phenotype in aging flies, based on ERGs and transmission electron microscopy. In contrast, the p.R1664Q variant exhibited loss of function and failed to develop a neurodegenerative phenotype. Hence, the novel R1673P allele produces neurodegenerative phenotypes in flies and human, likely due to a toxic gain of function.

In-depth investigations of adolescents and adults with holoprosencephaly identify unique characteristics

Purpose

With improved medical care, some individuals with holoprosencephaly (HPE) are surviving into adulthood. We investigated the clinical manifestations of adolescents and adults with HPE and explored the underlying molecular causes.

Methods

Participants included 20 subjects 15 years of age and older. Clinical assessments included dysmorphology exams, cognitive testing, swallowing studies, ophthalmic examination, and brain magnetic resonance imaging. Genetic testing included chromosomal microarray, Sanger sequencing for SHH, ZIC2, SIX3, and TGIF, and whole-exome sequencing (WES) of 10 trios.

Results

Semilobar HPE was the most common subtype of HPE, seen in 50% of the participants. Neurodevelopmental disabilities were found to correlate with HPE subtype. Factors associated with long-term survival included HPE subtype not alobar, female gender, and nontypical facial features. Four participants had de novo pathogenic variants in ZIC2. WES analysis of 11 participants did not reveal plausible candidate genes, suggesting complex inheritance in these cases. Indeed, in two probands there was a history of uncontrolled maternal type 1 diabetes.

Conclusion

Individuals with various HPE subtypes can survive into adulthood and the neurodevelopmental outcomes are variable. Based on the facial characteristics and molecular evaluations, we suggest that classic genetic causes of HPE may play a smaller role in this cohort.

Neural response during anticipation of monetary loss is elevated in adult attention deficit hyperactivity disorder

OBJECTIVES

Risky behaviour seriously impacts the life of adult patients with attention deficit hyperactivity disorder (ADHD). Such behaviours have often been attributed to their exaggerated reward seeking, but dysfunctional anticipation of negative outcomes might also play a role.

METHODS

The present study compared adult patients with ADHD (n = 28) with matched healthy controls (n = 28) during anticipation of monetary losses versus gains while undergoing functional magnetic resonance imaging (fMRI) and skin conductance recording.

RESULTS

Skin conductance was higher during anticipation of losses compared to gains in both groups. Affective ratings of predictive cues did not differ between groups. ADHD patients showed increased activity in bilateral amygdalae, left anterior insula (region of interest analysis) and left temporal pole (whole brain analysis) compared to healthy controls during loss versus gain anticipation. In the ADHD group higher insula and temporal pole activations went along with more negative affective ratings.

CONCLUSIONS

Neural correlates of loss anticipation are not blunted but rather increased in ADHD, possibly due to a life history of repeated failures and the respective environmental sanctions. Behavioural adaptations to such losses, however, might differentiate them from controls: future research should study whether negative affect might drive more risk seeking than risk avoidance.

AbobotulinumtoxinA (Dysport®) Improves Function According to Goal Attainment in Children With Dynamic Equinus Due to Cerebral Palsy

This secondary analysis of a large (n = 241), randomized, double-blind study evaluated the efficacy of 2 doses of abobotulinumtoxinA + standard of care (SOC) versus placebo + SOC in enabling children with dynamic equinus due to cerebral palsy to achieve their functional goals using Goal Attainment Scaling. Most parents/caregivers selected goals targeting aspects of gait improvement as most relevant. Mean (95% confidence interval) Goal Attainment Scaling T scores at week 4 were higher for both abobotulinumtoxinA groups versus placebo (treatment difference vs placebo: 10 U/kg/leg: 5.32 [2.31, 8.32], P = .0006, and 15 U/kg/leg 4.65 [1.59, 7.71], P = .0031). Superiority of both abobotulinumtoxinA doses versus placebo was maintained at week 12. Best goal attainment T scores were higher in the abobotulinumtoxinA groups versus placebo for the common goals of improved walking pattern, decreased falling, decreased tripping, and improved endurance. These findings demonstrate that single injections of abobotulinumtoxinA (10 and 15 U/kg/leg) significantly improved the ability of pediatric cerebral palsy patients to achieve their functional goals.

Stress and Decision Making: Effects on Valuation, Learning, and Risk-taking

A wide range of stressful experiences can influence human decision making in complex ways beyond the simple predictions of a fight-or-flight model. Recent advances may provide insight into this complicated interaction, potentially in directions that could result in translational applications. Early research suggests that stress exposure influences basic neural circuits involved in reward processing and learning, while also biasing decisions towards habit and modulating our propensity to engage in risk-taking. That said, a substantial array of theoretical and methodological considerations in research on the topic challenge strong cross study comparisons necessary for the field to move forward. In this review we examine the multifaceted stress construct in the context of human decision making, emphasizing stress' effect on valuation, learning, and risk-taking.

Reward Sensitivity Enhances Ventrolateral Prefrontal Cortex Activation during Free Choice

Expressing one's preference via choice can be rewarding, particularly when decisions are voluntarily made as opposed to being forced. An open question is whether engaging in choices involving rewards recruits distinct neural systems as a function of sensitivity to reward. Reward sensitivity is a trait partly influenced by the mesolimbic dopamine system, which can impact an individual's neural and behavioral response to reward cues. Here, we investigated how reward sensitivity contributes to neural activity associated with free and forced choices. Participants underwent a simple decision-making task, which presented free- or forced-choice trials in the scanner. Each trial presented two cues (i.e., points or information) that led to monetary reward at the end of the task. In free-choice trials, participants were offered the opportunity to choose between different reward cues (e.g., points vs. information), whereas forced-choice trials forced individuals to choose within a given reward cue (e.g., information vs. information, or points vs. points). We found enhanced ventrolateral prefrontal cortex (VLPFC) activation during free choice compared to forced choice in individuals with high reward sensitivity scores. Next, using the VLPFC as a seed, we conducted a PPI analysis to identify brain regions that enhance connectivity with the VLPFC during free choice. Our PPI analyses on free vs. forced choice revealed increased VLPFC connectivity with the posterior cingulate and precentral gyrus in reward sensitive individuals. These findings suggest reward sensitivity may recruit attentional control processes during free choice potentially supporting goal-directed behavior and action selection.

Meta-analysis of psychophysiological interactions: Revisiting cluster-level thresholding and sample sizes

Within the neuroimaging community, coordinate based meta-analyses (CBMAs) are essential for aggregating findings across studies and testing whether those studies report similar anatomical locations. This approach has been predominantly applied to studies that focus on whether activation of a brain region is associated with a given psychological process. In a recent paper, we used CBMA to examine a distinct set of studies-that is, those focusing on whether connectivity between brain regions is modulated by a given psychological process (Smith et al. [2016]: Hum Brain Mapp 37:2904-2917). Specifically, we reviewed 284 studies examining brain connectivity with psychophysiological interactions (PPI). Our meta-analytic results indicated that PPI yields connectivity patterns that are consistent across studies and that can be specific for a given psychological process and seed region. After publication of our findings, we learned that the analysis software we used to conduct our CBMAs (GingerALE v2.3.3) contained an implementation error that led to results that were more liberal than intended. Here, we comment on the impact of this implementation error on the results of our paper, new recommendations for sample sizes in CBMAs, and the importance of communication between software users and developers. We show that our key claims are supported in a reanalysis and that our results are robust to new guidelines on sample sizes. Hum Brain Mapp 38:588-591, 2017. © 2016 Wiley Periodicals, Inc.

Toward a cumulative science of functional integration: A meta-analysis of psychophysiological interactions

Much of the work in cognitive neuroscience is shifting from a focus on single brain regions to a focus on the connectivity between multiple brain regions. These inter-regional connectivity patterns contribute to a wide range of behaviors and are studied with models of functional integration. The rapid expansion of the literature on functional integration offers an opportunity to scrutinize the consistency and specificity of one of the most popular approaches for quantifying connectivity: psychophysiological interaction (PPI) analysis. We performed coordinate-based meta-analyses on 284 PPI studies, which allowed us to test (a) whether those studies consistently converge on similar target regions and (b) whether the identified target regions are specific to the chosen seed region and psychological context. Our analyses revealed two key results. First, we found that different types of PPI studies-e.g., those using seeds such as amygdala and dorsolateral prefrontal cortex (DLPFC) and contexts such as emotion and cognitive control, respectively-each consistently converge on similar target regions, thus supporting the reliability of PPI as a tool for studying functional integration. Second, we also found target regions that were specific to the chosen seed region and psychological context, indicating distinct patterns of brain connectivity. For example, the DLPFC seed reliably contributed to a posterior cingulate cortex target during cognitive control but contributed to an amygdala target in other contexts. Our results point to the robustness of PPI while highlighting common and distinct patterns of functional integration, potentially advancing models of brain connectivity. Hum Brain Mapp 37:2904-2917, 2016. © 2016 Wiley Periodicals, Inc.

Perceived control alters the effect of acute stress on persistence

We often encounter setbacks while pursuing our goals. Success requires that we cope with these negative outcomes and choose to persist in spite of them. For example, learners may be more likely to continue a course after failing an assessment if they control their emotional reactions to the setback and study harder. However, the ability to effectively cope with the negative emotion inherent in such setbacks can be compromised by acute stress present in daily life (e.g., struggles in the household), which can subsequently lead to problems with persisting with a goal. The present study examined whether increasing the perception of control over setbacks (e.g., belief that a setback was caused by a correctable mistake rather than uncontrollable factors) can guard against the influence of a prior acute stressor on reactions to setbacks. Participants underwent a socially evaluated cold water stress or a nonstress control procedure. Afterward, they performed a behavioral task designed to measure persistence through controllable and uncontrollable setbacks. We observed that exposure to an acute stressor led to a detrimental effect on decision making by decreasing persistence behavior. Importantly, we also observed that the perception of control protected against the effect of preexisting stress and helped promote persistence. That is, stress impaired persistence through uncontrollable setbacks, but the impairment was alleviated by presenting setbacks as controllable. The findings demonstrate a potential avenue for improving the maintenance of goals aimed at behavior change, which can be susceptible to effects of stress.

AbobotulinumtoxinA for Equinus Foot Deformity in Cerebral Palsy: A Randomized Controlled Trial

BACKGROUND

Although botulinum toxin is a well-established treatment of focal spasticity in cerebral palsy, most trials have been small, and few have simultaneously assessed measures of muscle tone and clinical benefit.

METHODS

Global, randomized, controlled study to assess the efficacy and safety of abobotulinumtoxinA versus placebo in cerebral palsy children with dynamic equinus foot deformity. Patients were randomized (1:1:1) to abobotulinumtoxinA 10 U/kg/leg, 15 U/kg/leg, or placebo injections into the gastrocnemius-soleus complex (1 or both legs injected). In the primary hierarchical analysis, demonstration of benefit for each dose required superiority to placebo on the primary (change in Modified Ashworth Scale from baseline to week 4) and first key secondary (Physician's Global Assessment at week 4) end points.

RESULTS

Two hundred and forty-one patients were randomized, and 226 completed the study; the intention to treat population included 235 patients (98%). At week 4, Modified Ashworth Scale scores significantly improved with abobotulinumtoxinA; mean (95% confidence interval) treatment differences versus placebo were -0.49 (-0.75 to -0.23; P = .0002) for 15 U/kg/leg and -0.38 (-0.64 to -0.13; P = .003) for 10 U/kg/leg. The Physician's Global Assessment treatment differences versus placebo of 0.77 (0.45 to 1.10) for 15 U/kg/leg and 0.82 (0.50 to 1.14) for 10 U/kg/leg were also significant (both Ps < .0001). The most common treatment-related adverse event was muscular weakness (10 U/Kg/leg = 2; placebo = 1).

CONCLUSIONS

AbobotulinumtoxinA improves muscle tone in children with dynamic equinus resulting in an improved overall clinical impression and is well tolerated.

Using fMRI to study reward processing in humans: past, present, and future

Functional magnetic resonance imaging (fMRI) is a noninvasive tool used to probe cognitive and affective processes. Although fMRI provides indirect measures of neural activity, the advent of fMRI has allowed for1) the corroboration of significant animal findings in the human brain, and2) the expansion of models to include more common human attributes that inform behavior. In this review, we briefly consider the neural basis of the blood oxygenation level dependent signal to set up a discussion of how fMRI studies have applied it in examining cognitive models in humans and the promise of using fMRI to advance such models. Specifically, we illustrate the contribution that fMRI has made to the study of reward processing, focusing on the role of the striatum in encoding reward-related learning signals that drive anticipatory and consummatory behaviors. For instance, we discuss how fMRI can be used to link neural signals (e.g., striatal responses to rewards) to individual differences in behavior and traits. While this functional segregation approach has been constructive to our understanding of reward-related functions, many fMRI studies have also benefitted from a functional integration approach that takes into account how interconnected regions (e.g., corticostriatal circuits) contribute to reward processing. We contend that future work using fMRI will profit from using a multimodal approach, such as combining fMRI with noninvasive brain stimulation tools (e.g., transcranial electrical stimulation), that can identify causal mechanisms underlying reward processing. Consequently, advancements in implementing fMRI will promise new translational opportunities to inform our understanding of psychopathologies.

Electromagnetic interference in intraoperative monitoring of motor evoked potentials and a wireless solution

Intraoperative neurophysiological monitoring (IONM) is utilized to minimize neurological morbidity during spine surgery. Transcranial motor evoked potentials (TcMEPs) are principal IONM signals in which the motor cortex of the subject is stimulated with electrical pulses and the evoked potentials are recorded from the muscles of interest. Currently available monitoring systems require the connection of 40-60 lengthy lead wires to the patient. These wires contribute to a crowded and cluttered surgical environment, and limit the maneuverability of the surgical team. In this work, it was demonstrated that the cumbersome wired system is vulnerable to electromagnetic interference (EMI) produced by operating room (OR) equipment. It was hypothesized that eliminating the lengthy recording wires can remove the EMI induced in the IONM signals. Hence, a wireless system to acquire TcMEPs was developed and validated through bench-top and animal experiments. Side-by-side TcMEPs acquisition from the wired and wireless systems in animal experiments under controlled conditions (absence of EMI from OR equipment) showed comparable magnitudes and waveforms, thus demonstrating the fidelity in the signal acquisition of the wireless solution. The robustness of the wireless system to minimize EMI was compared with a wired-system under identical conditions. Unlike the wired-system, the wireless system was not influenced by the electromagnetic waves from the C-Arm X-ray machine and temperature management system in the OR.

Gambling on visual performance: neural correlates of metacognitive choice between visual lotteries

A lottery is a list of mutually exclusive outcomes together with their associated probabilities of occurrence. Decision making is often modeled as choices between lotteries and-in typical research on decision under risk-the probabilities are given to the subject explicitly in numerical form. In this study, we examined lottery decision task where the probabilities of receiving various rewards are contingent on the subjects' own visual performance in a random-dot-motion (RDM) discrimination task, a metacognitive or second order judgment. While there is a large literature concerning the RDM task and there is also a large literature on decision under risk, little is known about metacognitive decisions when the source of uncertainty is visual. Using fMRI with humans, we found distinct fronto-striatal and fronto-parietal networks representing subjects' estimates of his or her performance, reward value, and the expected value (EV) of the lotteries. The fronto-striatal network includes the dorsomedial prefrontal cortex and the ventral striatum, involved in reward processing and value-based decision-making. The fronto-parietal network includes the intraparietal sulcus and the ventrolateral prefrontal cortex, which was shown to be involved in the accumulation of sensory evidence during visual decision making and in metacognitive judgments on visual performance. These results demonstrate that-while valuation of performance-based lotteries involves a common fronto-striatal valuation network-an additional network unique to the estimation of task-related performance is recruited for the integration of probability and reward information when probability is inferred from visual performance.

The good, the bad and the brain: Neural correlates of appetitive and aversive values underlying decision making

Approaching rewards and avoiding punishments could be considered as core principles governing behavior. Experiments from behavioral economics have shown that choices involving gains and losses follow different policy rules, suggesting that appetitive and aversive processes might rely on different brain systems. Here we contrast this hypothesis with recent neuroscience studies exploring the human brain from brainstem nuclei to cortical areas. Although some circuits show rigid specialization, many others appear to process both appetitive and aversive stimuli, in a flexible manner that depends on a context-wise subjective reference point. Moreover, appetitive and aversive aspects are often integrated into net values that are signaled with enhanced activity in 'positive regions', and suppressed activity in 'negative regions'. This dichotomy might explain why drugs or lesions can produce valence-specific effects, biasing decisions towards approaching a reward or avoiding a punishment.

Functional connectivity with distinct neural networks tracks fluctuations in gain/loss framing susceptibility

Multiple large-scale neural networks orchestrate a wide range of cognitive processes. For example, interoceptive processes related to self-referential thinking have been linked to the default-mode network (DMN); whereas exteroceptive processes related to cognitive control have been linked to the executive-control network (ECN). Although the DMN and ECN have been postulated to exert opposing effects on cognition, it remains unclear how connectivity with these spatially overlapping networks contribute to fluctuations in behavior. While previous work has suggested the medial-prefrontal cortex (MPFC) is involved in behavioral change following feedback, these observations could be linked to interoceptive processes tied to DMN or exteroceptive processes tied to ECN because MPFC is positioned in both networks. To address this problem, we employed independent component analysis combined with dual-regression functional connectivity analysis. Participants made a series of financial decisions framed as monetary gains or losses. In some sessions, participants received feedback from a peer observing their choices; in other sessions, feedback was not provided. Following feedback, framing susceptibility-indexed as the increase in gambling behavior in loss frames compared to gain frames-was heightened in some participants and diminished in others. We examined whether these individual differences were linked to differences in connectivity by contrasting sessions containing feedback against those that did not contain feedback. We found two key results. As framing susceptibility increased, the MPFC increased connectivity with DMN; in contrast, temporal-parietal junction decreased connectivity with the ECN. Our results highlight how functional connectivity patterns with distinct neural networks contribute to idiosyncratic behavioral changes.