Dissociated motor learning and de-adaptation in patients with functional gait disorders.

Walking onto a stationary platform that had been previously experienced as moving generates a locomotor after-effect-the so-called 'broken escalator' phenomenon. The motor responses that occur during locomotor after-effects have been mapped theoretically using a hierarchal Bayesian model of brain function that takes into account current sensory information that is weighted according to prior contextually-relevant experiences; these in turn inform automatic motor responses. Here, we use the broken escalator phenomenon to explore motor learning in patients with functional gait disorders and probe whether abnormal postural mechanisms override ascending sensory information and conscious intention, leading to maladaptive and disabling gait abnormalities. Fourteen patients with functional gait disorders and 17 healthy control subjects walked onto a stationary sled ('Before' condition, five trials), then onto a moving sled ('Moving' condition, 10 trials) and then again onto the stationary sled ('After' condition, five trials). Subjects were warned of the change in conditions. Kinematic gait measures (trunk displacement, step timing, gait velocity), EMG responses, and subjective measures of state anxiety/instability were recorded per trial. Patients had slower gait velocities in the Before trials (P < 0.05) but were able to increase this to accommodate the moving sled, with similar learning curves to control subjects (P = 0.87). Although trunk and gait velocity locomotor after-effects were present in both groups, there was a persistence of the locomotor after-effect only in patients (P < 0.05). We observed an increase in gait velocity during After trials towards normal values in the patient group. Instability and state anxiety were greater in patients than controls (P < 0.05) only during explicit phases (Before/After) of the task. Mean 'final' gait termination EMG activity (right gastrocnemius) was greater in the patient group than controls. Despite a dysfunctional locomotor system, patients show normal adaptive learning. The process of de-adaptation, however, is prolonged in patients indicating a tendency to perpetuate learned motor programmes. The trend to normalization of gait velocity following a period of implicit motor learning has implications for gait rehabilitation potential in patients with functional gait disorders and related disorders (e.g. fear of falling).

Differing functional mechanisms underlie cognitive control deficits in psychotic spectrum disorders.

Background: Functional underpinnings of cognitive control deficits in unbiased samples (i.e., all comers) of patients with psychotic spectrum disorders (PSD) remain actively debated. While many studies suggest hypofrontality in the lateral prefrontal cortex (PFC) and greater deficits during proactive relative to reactive control, few have examined the full hemodynamic response. Methods: Patients with PSD (n = 154) and healthy controls (n = 65) performed the AX continuous performance task (AX-CPT) during rapid (460 ms) functional neuroimaging and underwent full clinical characterization. Results: Behavioural results indicated generalized cognitive deficits (slower and less accurate) across proactive and reactive control conditions in patients with PSD relative to healthy controls. We observed a delayed/prolonged neural response in the left dorsolateral PFC, the sensorimotor cortex and the superior parietal lobe during proactive control for patients with PSD. These proactive hemodynamic abnormalities were better explained by negative rather than by positive symptoms or by traditional diagnoses according to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision (DSM-IV-TR), with subsequent simulations unequivocally demonstrating how these abnormalities could be erroneously interpreted as hypoactivation. Conversely, true hypoactivity, unassociated with clinical symptoms or DSM-IV-TR diagnoses, was observed within the ventrolateral PFC during reactive control. Limitations: In spite of guidance for AX-CPT use in neuroimaging studies, one-third of patients with PSD could not perform the task above chance and were more clinically impaired. Conclusion: Current findings question the utility of the AX-CPT for neuroimaging-based appraisal of cognitive control across the full spectrum of patients with PSD. Previously reported lateral PFC "hypoactivity" during proactive control may be more indicative of a delayed/prolonged neural response, important for rehabilitative purposes. Negative symptoms may better explain certain behavioural and hemodynamic abnormalities in patients with PSD relative to DSM-IV-TR diagnoses.

Proactive and reactive cognitive control rely on flexible use of the ventrolateral prefrontal cortex.

The role of ventral versus dorsolateral prefrontal regions in instantiating proactive and reactive cognitive control remains actively debated, with few studies parsing cue versus probe-related activity. Rapid sampling (460 ms), long cue-probe delays, and advanced analytic techniques (deconvolution) were therefore used to quantify the magnitude and variability of neural responses during the AX Continuous Performance Test (AX-CPT; N = 46) in humans. Behavioral results indicated slower reaction times during reactive cognitive control (AY trials) in conjunction with decreased accuracy and increased variability for proactive cognitive control (BX trials). The anterior insula/ventrolateral prefrontal cortex (aI/VLPFC) was commonly activated across comparisons of both proactive and reactive cognitive control. In contrast, activity within the dorsomedial and dorsolateral prefrontal cortex was limited to reactive cognitive control. The instantiation of proactive cognitive control during the probe period was also associated with sparse neural activation relative to baseline, potentially as a result of the high degree of neural and behavioral variability observed across individuals. Specifically, the variability of the hemodynamic response function (HRF) within motor circuitry increased after the presentation of B relative to A cues (i.e., late in HRF) and persisted throughout the B probe period. Finally, increased activation of right aI/VLPFC during the cue period was associated with decreased motor circuit activity during BX probes, suggesting a possible role for the aI/VLPFC in proactive suppression of neural responses. Considered collectively, current results highlight the flexible role of the VLPFC in implementing cognitive control during the AX-CPT task but suggest large individual differences in proactive cognitive control strategies.

Mucoepidermoid Carcinoma in the Skull of an Orange-winged Amazon Parrot (Amazona amazonica).

A 33-year-old female intact orange-winged Amazon parrot (Amazona amazonica) presented for a slowly growing mass over the right eye. A computed tomography scan performed with and without intravenous contrast revealed a heterogeneous mixed soft tissue and mineral-dense mass with a small area of non-contrast-enhancing fluid density located between the orbits at the caudal aspect of the nasal passages, with associated lysis of the right caudal nasal passage and the right frontal bone. Following euthanasia, the mass was found to consist of soft tissue between the right eye and nostril over the right frontal bone. Lysis of the underlying bone resulted in a bony defect leading into the infraorbital sinus along the dorsorostral aspect of the right eye. Histopathology revealed an unencapsulated, poorly demarcated, highly cellular neoplasm composed of islands and trabeculae of neoplastic cells embedded in abundant loose fibrovascular stroma which completely obliterated the cortical bone and sinuses of the rostral skull and infiltrated the surrounding muscle and soft tissue. Histologically, the tumor was consistent with a high-grade mucoepidermoid carcinoma, characterized by the presence of epidermoid, intermediate, and mucous-producing cell types. No evidence of metastasis was identified. The tissue of origin was suspected to be salivary or nasal mucous glands, but was difficult to confirm due to distortion of normal tissue architecture as a result of the tumor. Although mucoepidermoid carcinomas are a common salivary gland tumor in human medicine, they are not well recognized in avian species, and no specific case reports exist describing this pathology in an Amazon parrot. Despite the lack of distinct salivary glands in most avian species, mucoepidermoid carcinomas can occur, can cause significant clinical disease, and should be included as a differential diagnosis for avian patients presenting with similar lesions.

Hemodynamic response function abnormalities in schizophrenia during a multisensory detection task.

Functional magnetic resonance imaging (fMRI) of the blood oxygen level dependent (BOLD) response has commonly been used to investigate the neuropathology underlying cognitive and sensory deficits in patients with schizophrenia (SP) by examining the positive phase of the BOLD response, assuming a fixed shape for the hemodynamic response function (HRF). However, the individual phases (positive and post-stimulus undershoot (PSU)) of the HRF may be differentially affected by a variety of underlying pathologies. The current experiment used a multisensory detection task with a rapid event-related fMRI paradigm to investigate both the positive and PSU phases of the HRF in SP and healthy controls (HC). Behavioral results indicated no significant group differences during task performance. Analyses that examined the shape of the HRF indicated two distinct group differences. First, SP exhibited a reduced and/or prolonged PSU following normal task-related positive BOLD activation in secondary auditory and visual sensory areas relative to HC. Second, SP did not show task-induced deactivation in the anterior node of the default-mode network (aDMN) relative to HC. In contrast, when performing traditional analyses that focus on the positive phase, there were no group differences. Interestingly, the magnitude of the PSU in secondary auditory and visual areas was positively associated with the magnitude of task-induced deactivation within the aDMN, suggesting a possible common neural mechanism underlying both of these abnormalities (failure in neural inhibition). Results are consistent with recent views that separate neural processes underlie the two phases of the HRF and that they are differentially affected in SP. Hum Brain Mapp 37:745-755, 2016. © 2015 Wiley Periodicals, Inc.

The inhibin B (InhB) response to the testicular toxicants mono-2-ethylhexyl phthalate (MEHP), 1,3 dinitrobenzene (DNB), or carbendazim (CBZ) following short-term repeat dosing in the male rat.

OBJECTIVE: The objective of this study was to evaluate the utility of plasma Inhibin B (InhB) as a biomarker of testicular injury in adult rats following short-term exposure to the known Sertoli cell toxicants mono-2-ethylhexyl phthalate (MEHP), 1,3 dinitrobenzene (DNB), or carbendazim (CBZ). METHODS: Following oral gavage administration of the compounds for 2 or 7 days, the rats were evaluated for clinical signs, body weight, food consumption, organ weights, plasma hormone levels, and gross and microscopic pathology. RESULTS: MEHP, DNB, and CBZ produced a range of testicular toxicity characterized by minimal exfoliation of germ cells as demonstrated by increased cellular debris in the epididymis (MEHP) to more severe and dose/duration responsive Sertoli cell vacuolation, germ cell degeneration, and multinucleated giant cells of germ cell origin (DNB and CBZ). The slight to moderate Sertoli and germinal cell injuries did not correlate with significant changes in plasma InhB levels following 2- or 7-day exposures. However, more severe injury to germinal epithelium following up to 7 days of exposure, but not after 2 days of exposure, correlated with decreased plasma InhB levels and less consistently with increases in plasma follicle stimulating hormone. CONCLUSION: In conclusion, under the conditions of these studies, changes in InhB were not an effective early onset marker of testicular toxicity or an effective marker for slight to moderate levels of acute injury, and only reflected more severe disruption of spermatogenesis. Changes in plasma InhB and follicle stimulating hormone were poorly correlated except in some instances of moderate to marked testicular toxicity.

The clinical relevance of gray matter atrophy and microstructural brain changes across the psychosis continuum.

Patients with psychotic spectrum disorders (PSD) exhibit similar patterns of atrophy and microstructural changes that may be associated with common symptomatology (e.g., symptom burden and/or cognitive impairment). Gray matter concentration values (proxy for atrophy), fractional anisotropy (FA), mean diffusivity (MD), intracellular neurite density (Vic) and isotropic diffusion volume (Viso) measures were therefore compared in 150 PSD (schizophrenia, schizoaffective disorder, and bipolar disorder Type I) and 63 healthy controls (HC). Additional analyses evaluated whether regions showing atrophy and/or microstructure abnormalities were better explained by DSM diagnoses, symptom burden or cognitive dysfunction. PSD exhibited increased atrophy within bilateral medial temporal lobes and subcortical structures. Gray matter along the left lateral sulcus showed evidence of increased atrophy and MD. Increased MD was also observed in homotopic fronto-temporal regions, suggesting it may serve as a precursor to atrophic changes. Global cognitive dysfunction, rather than DSM diagnoses or psychotic symptom burden, was the best predictor of increased gray matter MD. Regions of decreased FA (i.e., left frontal gray and white matter) and Vic (i.e., frontal and temporal regions and along central sulcus) were also observed for PSD, but were neither spatially concurrent with atrophic regions nor associated with clinical symptoms. Evidence of expanding microstructural spaces in gray matter demonstrated the greatest spatial overlap with current and potentially future regions of atrophy, and was associated with cognitive deficits. These results suggest that this particular structural abnormality could potentially underlie global cognitive impairment that spans traditional diagnostic categories.

In ovo technique for cell injection in the CPM followed by bead implantation in the BA2 of chicken embryos.

The major advantage of chicken embryos model is their accessibility for microsurgical manipulations and the dissection of tissues for ex vivo explant culture. Branchial arches are embryonic structure located next to the top of developing heart. Each arch is made of surface ectoderm, endoderm, myogenic mesoderm cells and cranial neural crest cells. The myogenic mesoderm originates from cranial paraxial mesoderm (CPM), which is transiently migrated to branchial arches (BAs). The first branchial arch (BA1) mesoderm contributes to formation of mastication muscles. The second branchial arch (BA2) mesoderm gives rise to facial expression muscles. This article focuses on cell injection in the CPM and bead implantation (gain of function approaches) in the BA2. In order to follow the migration of mesoderm progenitor cells from CPM to BA2, we injected quail cells in the CPM of stage HH10-11 embryos, followed by implantation of SDF-1 bead at stage HH15-16. Later the attraction of quail cells (CXCR4+) towards the SDF-1 source has been observed, using whole-mount immunostaining of a specific quail antibody (QCPN) at stage HH19-22. •Our method, which involves bead implantation followed by quail cell injection, provides useful tools for tracing migratory mesodermal cells in vivo.•The proposed method does not require any commercial kits and can be used for various developmental process.•It does not employ any complicated methods such as genetically engineered permanent cell labeling, multiplicity of fluorescent markers or clonal analysis.

Exploring the clinical context of adopting an instrumented insole: a qualitative study of clinicians' preferences in England.

OBJECTIVES: This study explores clinicians' views of the clinical uptake of a smart pressure-sensing insole, named Flexifoot, to enhance the care and management of patients with osteoarthritis (OA). Clinicians are key users of wearable technologies, and can provide appropriate feedback for a specific device for successful clinical implementation. DESIGN: Qualitative study with in-depth, semi-structured interviews, analysed using inductive analysis to generate key themes. SETTING: Conducted in a University setting. PARTICIPANTS: 30 clinicians were interviewed (11 physiotherapists, 11 orthopaedic surgeons, 5 general practitioners, 3 podiatrists). RESULTS: All clinicians regarded Flexifoot to be useful for the care and management of patients in adjunction to current methods. Responses revealed four main themes: use, data presentation, barriers to use and future development. Flexifoot data were recognised as capable of enhancing information exchange between clinicians and patients, and also between clinicians themselves. Participants supported the use of feedback for rehabilitation, screening and evaluation of treatment progress/success purposes. Flexifoot use by patients was encouraged as a self-management tool that may motivate them by setting attainment goals. The data interface should be secure, concise and visually appealing. The measured parameters of Flexifoot, its duration of wear and frequency of data output would all depend on the rationale for its use. The clinicians and patients must collaborate to optimise the use of Flexifoot for long-term monitoring of disease for patient care in clinical practice. Many identified potential other uses for Flexifoot. CONCLUSIONS: Clinicians thought that Flexifoot may complement and improve current methods of long-term patient management for OA or other conditions in clinical settings. Flexifoot was recognised to be useful for objective measures and should be tailored carefully for each person and condition to maximise compliance. Adopting the device, and other similar technologies, requires reducing the main barriers to use (time, cost, patient compliance) before its successful implementation.

Proton magnetic resonance spectroscopic imaging of gray and white matter in bipolar-I and schizophrenia.

BACKGROUND: Glutamine plus glutamate (Glx), as well as N-acetylaspartate compounds, (NAAc), a marker of neuronal viability, are quantified with proton magnetic resonance spectroscopy (1H-MRS) and have been reported altered in psychotic disorders. However, few studies have compared these neurometabolites in bipolar disorder and schizophrenia. METHODS: Used 1H-MRS imaging from an axial supraventricular slab of gray matter (GM; medial-frontal and medial-parietal) and white matter (WM; bilateral-frontal and bilateral-parietal) voxels. Bipolar-I with history of psychosis (N = 43), schizophrenia (N = 41) and healthy controls (HC; N = 45) were studied (age range: 17-65). RESULTS: Amongst younger (age ≤40 years-median split) bipolar-I vs HC subjects Glx was increased (p < 0.001), while NAAc was reduced in WM (p < 0.001). In GM, NAAc (p < 0.001) and myo-inositol (p = 0.002) were reduced. Amongst older bipolar-I (vs HC) in WM regions we found reductions in: NAAc (p < 0.001), glycerophospho-choline + phospho-choline (p < 0.001), creatine + phospho-creatine (p < 0.001) and myo-inositol (p < 0.001); in GM only Glx was increased (p < 0.005). Contrasts between bipolar-I and schizophrenia produced fewer results: amongst younger subjects, reduced NAAc (p < 0.001) in WM and lower myo-inositol in GM (p = 0.04) in bipolar-I vs schizophrenia. In the older patients, bipolar-I had lower GM NAAc (p = 0.009) than schizophrenia. LIMITATIONS: First, differential exposure to antipsychotic and mood stabilizing medication across the groups. Second, differences in substance use histories among the groups. Third, neglect of peripheral and ventral cortical and subcortical regions. Finally, limited power to detect bipolar/schizophrenia differences. CONCLUSIONS: Chronically-treated bipolar-I have increased Glx and reduced NAAc, suggestive of neuronal dysfunction. The NAAc reductions are more severe in bipolar-I than in schizophrenia patients.

A symptom-based continuum of psychosis explains cognitive and real-world functional deficits better than traditional diagnoses.

BACKGROUND: Patients with psychotic spectrum disorders share overlapping clinical/biological features, making it often difficult to separate them into a discrete nosology (i.e., Diagnostic and Statistical Manual of Mental Disorders [DSM]). METHODS: The current study investigated whether a continuum classification scheme based on symptom burden would improve conceptualizations for cognitive and real-world dysfunction relative to traditional DSM nosology. Two independent samples (New Mexico [NM] and Bipolar and Schizophrenia Network on Intermediate Phenotypes [B-SNIP]) of patients with schizophrenia (NM: N = 93; B-SNIP: N = 236), bipolar disorder Type I (NM: N = 42; B-SNIP: N = 195) or schizoaffective disorder (NM: N = 15; B-SNIP: N = 148) and matched healthy controls (NM: N = 64; B-SNIP: N = 717) were examined. Linear regressions examined how variance differed as a function of classification scheme (DSM diagnosis, negative and positive symptom burden, or a three-cluster solution based on symptom burden). RESULTS: Symptom-based classification schemes (continuous and clustered) accounted for a significantly larger portion of captured variance of real-world functioning relative to DSM diagnoses across both samples. The symptom-based classification schemes accounted for large percentages of variance for general cognitive ability and cognitive domains in the NM sample. However, in the B-SNIP sample, symptom-based classification schemes accounted for roughly equivalent variance as DSM diagnoses. A potential mediating variable across samples was the strength of the relationship between negative symptoms and impaired cognition. CONCLUSIONS: Current results support suggestions that a continuum perspective of psychopathology may be more powerful for explaining real-world functioning than the DSM diagnostic nosology, whereas results for cognitive dysfunction were sample dependent.

Disconnected and Hyperactive: A Replication of Sensorimotor Cortex Abnormalities in Patients With Schizophrenia During Proactive Response Inhibition.

Inhibitory failure represents a core dysfunction in patients with schizophrenia (SP), which has predominantly been tested in the literature using reactive (ie, altering behavior after a stimulus) rather than proactive (ie, purposefully changing behavior before a stimulus) response inhibition tasks. The current study replicates/extends our previous findings of SP exhibiting sensorimotor cortex (SMC) hyperactivity and connectivity abnormalities in independent samples of patients and controls. Specifically, 49 clinically well-characterized SP and 54 matched healthy controls (HC) performed a proactive response inhibition task while undergoing functional magnetic resonance imaging and resting-state data collection. Results indicated that the majority of SP (84%) and HC (88%) successfully inhibited all overt motor responses following a cue, eliminating behavioral confounds frequently present in this population. Observations of left SMC hyperactivity during proactive response inhibition, reduced cortical connectivity with left SMC, and increased connectivity between left SMC and ventrolateral thalamus were replicated for SP relative to HC in the current study. Similarly, negative symptoms (eg, motor retardation) were again associated with SMC functional and connectivity abnormalities. In contrast, findings of a negative blood oxygenation level-dependent response in the SMC of HC did not replicate. Collectively, current and previous findings suggest that SMC connectivity abnormalities may be more robust relative to evoked hemodynamic signals during proactive response inhibition. In addition, there is strong support that these SMC abnormalities are a key component of SP pathology, along with dysfunction within other sensory cortices, and may be associated with certain clinical deficits such as negative symptoms.

Impaired Midline Theta Power and Connectivity During Proactive Cognitive Control in Schizophrenia.

BACKGROUND: Disrupted proactive cognitive control, a form of early selection and active goal maintenance, is hypothesized to underlie the broad cognitive deficits observed in patients with schizophrenia (SPs). Current research suggests that the disrupted activation within and connectivity between regions of the cognitive control network contribute to disrupted proactive cognitive control; however, no study has examined these mechanisms using an AX Continuous Performance Test task in schizophrenia. METHODS: Twenty-six SPs (17 male subjects; mean age 34.46 ± 8.77 years) and 28 healthy control participants (HCs; 16 male subjects; mean age 31.43 ± 7.23 years) underwent an electroencephalogram while performing the AX Continuous Performance Test. To examine the extent of activation and level of connectivity within the cognitive control network, power, intertrial phase clustering, and intersite phase clustering metrics were calculated and analyzed. RESULTS: SPs exhibited expected general decrements in behavioral performance relative to HCs and a more selective deficit in conditions requiring proactive cognitive control. Additionally, SPs exhibited deficits in midline theta power and connectivity during proactive cognitive control trials. Specifically, HCs exhibited significantly greater theta power for B cues relative to A cues, whereas SPs exhibited no significant differences between A- and B-cue theta power. Additionally, differential theta connectivity patterns were observed in SPs and HCs. Behavioral measures of proactive cognitive control predicted functional outcomes in SPs. CONCLUSIONS: This study suggests that low-frequency midline theta activity is selectively disrupted during proactive cognitive control in SPs. The disrupted midline theta activity may reflect a failure of SPs to proactively recruit cognitive control processes.

Single- and multiple-dose pharmacokinetics of dapoxetine hydrochloride, a novel agent for the treatment of premature ejaculation.

Dapoxetine is a serotonin transporter inhibitor currently in development for the treatment of premature ejaculation. This randomized, 2-sequence, 2-treatment crossover study assessed the single- and multiple-dose pharmacokinetics of dapoxetine following once-daily administration of dapoxetine 30 mg and 60 mg to healthy male volunteers. Dapoxetine was rapidly absorbed following oral administration, with peak plasma concentrations reached approximately 1 hour after dosing; plasma concentrations after single doses of dapoxetine decreased rapidly to approximately 5% of peak concentrations by 24 hours. Elimination was biphasic, with an initial half-life of approximately 1.4 hours and a terminal half-life of approximately 20 hours. Dapoxetine showed time-invariant pharmacokinetics and dose proportionality between doses, and its pharmacokinetics was unaffected by multiple dosing. The pharmacokinetics of dapoxetine metabolites, desmethyldapoxetine and dapoxetine-N-oxide, was similarly unaffected by multiple dosing. There were no serious adverse events; the most commonly reported adverse events were diarrhea, dizziness, and nausea.

Total synthesis of a functional designer eukaryotic chromosome.

Rapid advances in DNA synthesis techniques have made it possible to engineer viruses, biochemical pathways and assemble bacterial genomes. Here, we report the synthesis of a functional 272,871-base pair designer eukaryotic chromosome, synIII, which is based on the 316,617-base pair native Saccharomyces cerevisiae chromosome III. Changes to synIII include TAG/TAA stop-codon replacements, deletion of subtelomeric regions, introns, transfer RNAs, transposons, and silent mating loci as well as insertion of loxPsym sites to enable genome scrambling. SynIII is functional in S. cerevisiae. Scrambling of the chromosome in a heterozygous diploid reveals a large increase in a-mater derivatives resulting from loss of the MATα allele on synIII. The complete design and synthesis of synIII establishes S. cerevisiae as the basis for designer eukaryotic genome biology.