Putative Indices Research Articles

The Stability and Validity of Automated Indices of Vocal Development in Infants With Autistic and Non-Autistic Siblings.

This study evaluates the extent to which automated indices of vocal development are stable and valid for predicting language in infants at increased familial likelihood for autism and/or language impairment and relatively lower likelihood infants. A group of infants with autistic siblings (Sibs-autism; 20 infants) and a comparison group of infants with non-autistic siblings (Sibs-NA; 20 infants) wore Language ENvironment Analysis (LENA) recording devices for 16 hr on 2 days within a 1-week period. Extant software was used to derive several putative indices of vocal development from these recordings. Stability of these variables was examined across and within groups. Expressive and receptive language aggregates were calculated for each participant. Multiple regression analyses were used to (a) evaluate zero-order correlations for variables derived from LENA recordings with concurrent and future language and (b) test whether those associations were moderated by group status. Both stability and validity differed by variable and group status. All variables reached acceptable stability in the Sibs-autism group within two to three observations, whereas stability of most variables was attenuated in the Sibs-NA group. No variables were associated with concurrent language in the theoretically motivated direction across groups, but two variables were strongly associated with concurrent expressive language in only the Sibs-NA group. Additionally, two variables were associated with later expressive language, though these correlations were again stronger in the Sibs-NA versus Sibs-autism group. Although selected automated indices of vocal development were stable in Sibs-autism and/or valid for predicting expressive language within Sibs-NA, no scores showed strong, theoretically motivated associations with language within the Sibs-autism group. Automated indices of vocal development may, thus, have limited validity or clinical utility for predicting language development in infants at elevated familial likelihood for autism. https://doi.org/10.23641/asha.24415735.

Whole plant response of Pongamia pinnata to drought stress tolerance revealed by morpho-physiological, biochemical and transcriptome analysis.

Pongamia is considered an important biofuel species worldwide. Drought stress in the early growth stages of Pongamia influences negatively on the germination and seedling development. Due to lack of cultivar stability under drought stress conditions, establishment of successful plantation in drought hit areas becomes a major problem. To address this issue, drought stress response of four Pongamia genotypes was studied at morphological, physio-chemical and transcriptome levels. Drought stress was levied by limiting water for 15 days on three months old seedlings of four genotypes. A significant effect of water stress was observed on the traits considered. The genotype NRCP25 exhibited superior morpho-physiological, biochemical drought responses. Also, the genotype had higher root length, photosynthetic pigments, higher antioxidant enzymes and solute accumulation compared to other genotypes. In addition, transcript profiling of selected drought responsive candidate genes such as trehalose phosphate synthase 1 (TPS1), abscisic acid responsive elements-binding protein 2 (ABF2-2), heat shock protein 17 (HSP 17kDa), tonoplast intrinsic protein 1(TIP 1-2), zinc finger homeodomain protein 2 (ZFP 2), and xyloglucan endotransglucolase 13 (XET 13) showed only up-regulation in NRCP25. Further, the transcriptome responses are in line with key physio-chemical responses exhibited by NRCP25 for drought tolerance. As of now, there are no systematic studies on Pongamia drought stress tolerance; therefore this study offers a comprehensive understanding of whole plant drought stress responsiveness of Pongamia. Moreover, the results support important putative trait indices with potential candidate genes for drought tolerance improvement of Pongamia.

Putative Quality Indices – Confirmatory Assessment of Commercial Edible Oils

Putative Quality Indices – Confirmatory Assessment of Commercial Edible Oils

Heart rate variability, serum cortisol levels and temperament in a sample of workers exposed to occupational stress: a preliminary report

ABSTRACT Work-related stress is an emerging risk for psychiatric occupational disorders including Adjustment Disorders (AD). The aim of this study was to investigate in workers exposed to occupational stress suffering from AD about putative indices of stress and mental health resilience such as serum cortisol (seC) levels, Heart Rate Variability (HRV) and affective temperaments. We consecutively recruited 15 male and 15 female AD patients between workers evaluated for occupational stress at an Italian Occupational Medicine Unit. SeC levels were measured by specific immunoassay. HRV indices were recorded using Task Force® Monitor system (CNSystems, Graz, Austria). Specific questionnaires were used to measure perceived and occupational stress, psychopathological symptoms and temperament. Women presented higher levels of occupational stress, higher High-Frequency HRV (HF-HRV) and lower Low-Frequency HRV (LF-HRV) than men. SeC levels were positively correlated with LF-HRV values and negatively with HF-HRV values. The LF/HF ratio resulted to be inversely correlated with the score of Harm Avoidance temperament dimension and directly with the score of Reward Dependence temperament dimension. In conclusion, in AD patients exposed to occupational stress high seC levels and reward dependence appear to be associated with a pattern of HRV reflecting less mental health resilience.

Comparing Stop Signal Reaction Times in Alzheimer's and Parkinson's Disease.

To investigate the relative contributions of cerebral cortex and basal ganglia to movement stopping, we tested the optimum combination Stop Signal Reaction Time (ocSSRT) and median visual reaction time (RT) in patients with Alzheimer's disease (AD) and Parkinson's disease (PD) and compared values with data from healthy controls. Thirty-five PD patients, 22 AD patients, and 29 healthy controls were recruited to this study. RT and ocSSRT were measured using a hand-held battery-operated electronic box through a stop signal paradigm. The mean ocSSRT was found to be 309 ms, 368 ms, and 265 ms in AD, PD, and healthy controls, respectively, and significantly prolonged in PD compared to healthy controls (p = 0.001). The ocSSRT but not RT could separate AD from PD patients (p = 0.022). Our data suggest that subcortical networks encompassing dopaminergic pathways in the basal ganglia play a more important role than cortical networks in movement-stopping. Combining ocSSRT with other putative indices or biomarkers of AD (and other dementias) could increase the accuracy of early diagnosis.

Minor Physical Anomalies Among Schizophrenic Patients as a Biomarker of Its Developmental Origin in Northwest Ethiopia.

PurposeAlthough there are highly precise and advanced diagnostic methods, the etiology and pathophysiology of schizophrenia remain poorly understood. There are several theories about schizophrenia origin, among which the neurodevelopmental theory is widely accepted. Our study aimed to assess minor physical anomalies among schizophrenic patients as putative indices of its developmental origin in North West Ethiopia 2018–2019.Patients and MethodsInstitutional-based comparative cross-sectional study design was conducted in Debre Markos comprehensive, specialized hospitals in 190 schizophrenic patients, 190 healthy controls, and 190 1st-degree relatives. Data were collected using standard methods, entered into EpiData version 3.1, and exported to SPSS version 24 for analysis. Descriptive data were analyzed using descriptive statistics, and discriminant function analysis was conducted and a value of 0.03 was taken as the cutoff point for prediction of group status of the study samples.ResultsFive hundred seventy study samples, male 375 (65.8%), and female 195 (34.2%), were included in this study. The discriminate function 1 and 2 revealed a significant association between groups and all predictors, accounting for 83.5% and 16.5% of between-group variability, respectively. However, closer analysis of the structure matrix revealed longitudinally furrowed tongue, ≥Five palate ridges, high steeples palate, transversely and randomly furrowed tongue, protruding supraorbital ridge as significant predictors.ConclusionDepending on predictor variables in this study, minor physical anomalies can serve as a biomarker for early screening of schizophrenic patients and clue for its developmental origin.

Leveling the Field for a Fairer Race between Going and Stopping: Neural Evidence for the Race Model of Motor Inhibition from a New Version of the Stop Signal Task.

The stop signal task (SST) is the gold standard experimental model of inhibitory control. However, neither SST condition-contrast (stop vs. go, successful vs. failed stop) purely operationalizes inhibition. Because stop trials include a second, infrequent signal, the stop versus go contrast confounds inhibition with attentional and stimulus processing demands. While this confound is controlled for in the successful versus failed stop contrast, the go process is systematically faster on failed stop trials, contaminating the contrast with a different noninhibitory confound. Here, we present an SST variant to address both confounds and evaluate putative neural indices of inhibition with these influences removed. In our variant, stop signals occurred on every trial, equating the noninhibitory demands of the stop versus go contrast. To entice participants to respond despite the impending stop signals, responses produced before stop signals were rewarded. This also reversed the go process bias that typically affects the successful versus failed stop contrast. We recorded scalp electroencephalography in this new version of the task (as well as a standard version of the SST with infrequent stop signal) and found that, even under these conditions, the properties of the frontocentral stop signal P3 ERP remained consistent with the race model. Specifically, in both tasks, the amplitude of the P3 was increased on stop versus go trials. Moreover, the onset of this P3 occurred earlier for successful compared with failed stop trials in both tasks, consistent with the proposal of the race model that an earlier start of the inhibition process will increase stopping success. Therefore, the frontocentral stop signal P3 represents a neural process whose properties are in line with the predictions of the race model of motor inhibition, even when the SST's confounds are controlled.

1994. Development of a Meningococcal Serogroup B Serum Bactericidal Assay Using Fetal Bovine Serum

BackgroundThe quadrivalent meningococcal conjugate vaccines do not target serogroup B meningococcus (MenB), an important cause of meningitis and sepsis. MenB vaccines have been recently developed and licensed for infants and young adults. Serum bactericidal activity serves as an immunological index for evaluating the immunogenicity of vaccines. However, there is no standardized serum bactericidal assay (SBA) for MenB owing to difficulty in selecting target strains and complement sources. Using fetal bovine serum, we developed a new SBA by modifying a previous SBA for meningococcal serogroups A, C, W135, and Y and applied it to clinical samples.MethodsAn isolate from an invasive disease and three reference strains were used as the target strains, and the genotypes of the antigens contained in the MenB vaccine (4CMenB) (Bexsero; GlaxoSmithKline) were determined. Non-specific killing was assessed by using baby rabbit serum, fetal bovine serum, and healthy adult serum as complement sources. Serum was obtained from clinical samples of six healthy adults before and 1 month after 4CMenB immunization.ResultsThe isolate and the three reference strains all contained factor H binding protein (fHBP) peptide type 1.1, which was consistent with the fHBP antigens contained in 4CMenB. The bactericidal activity in the serum (complement source) of 30 healthy adults ranged from 53% to 90%. Non-specific killing in baby rabbit serum was greater than 80%. Considering the species specificity of meningococcal fHBP, non-specific killing (82% - 91%) was similar when human factor H was added. Non-specific killing was less than 50% in fetal bovine serum, which was used as the complement source for evaluation of clinical samples. After 4CMenB immunization, the serum bactericidal indices for all the test sera were increased 4 times or more.ConclusionWe identified fetal bovine serum as a potential complement source for the MenB SBA assay. This method should be standardization using reference sera, and the putative protective SBA indices for fetal bovine serum should be determined.Disclosures All authors: No reported disclosures.

Sleep disturbance and kynurenine metabolism in depression

ObjectiveAlthough the interrelationships between sleep disturbance, inflammation, and depression have been found, molecular mechanisms that link these conditions are largely unknown. Kynurenine metabolism is hypothesized to be a key mechanism that links inflammation and depression. Inflammation activates the kynurenine pathway, leading to increases in 3-hydroxykynurenine (3HK) and quinolinic acid (QA), potentially neurotoxic metabolites, and decreases in kynurenic acid (KynA), a potentially neuroprotective compound. This relative neurotoxic shift in the balance of kynurenine metabolites has been associated with depression, but never been examined regarding sleep disturbance. We tested the association between sleep disturbance and this relative neurotoxic shift in 68 currently depressed, 26 previously depressed, and 66 never depressed subjects. MethodsSleep disturbance was assessed using the Pittsburgh Sleep Quality Index. Serum concentrations of kynurenine metabolites were measured using high performance liquid chromatography. Putative neuroprotective indices reflecting the relative activity of neuroprotective and neurotoxic kynurenine metabolites were calculated as KynA/QA and KynA/3HK (primary outcomes). ResultsSleep disturbance was associated with reduced KynA/QA in the currently depressed group only (unadjusted beta −0.43, p<0.001). This association remained significant even after controlling for age, sex, analysis batch, body-mass index, and depressive symptoms in currently depressed subjects (adjusted beta −0.30, p=0.02). There was no significant association between sleep disturbance and KynA/3HK in any of the groups. Sleep disturbance was associated with increased C-reactive protein in currently depressed subjects only (unadjusted beta 0.38, p=0.007; adjusted beta 0.33, p=0.02). ConclusionThese data support the hypothesis that altered kynurenine metabolism may molecularly link sleep disturbance and depression.

Relationship among interthalamic adhesion size, thalamic anatomy and neuropsychological functions in healthy volunteers.

The interthalamic adhesion (ITA) is an understudied neuroanatomical structure that forms a bridge of tissue connecting the thalamus of each hemisphere across the midline whose functional significance remains largely unknown. The likelihood of ITA absence has been reported in some studies to be increased in males, but findings have been inconsistent. We used magnetic resonance imaging to investigate the size and absence of the ITA and their relationship to thalamic volume, putative indices of white matter integrity (fractional anisotropy and mean diffusivity) within the anterior thalamic radiation and neuropsychological functions in 233 (129 M/104 F) healthy volunteers (age range 8-68). To ensure high reliability in this study two operators independently rated the absence of the ITA and measured its size for all individuals. The ITA was absent in 4% of all individuals with no sex differences in its absence. Females had greater ITA size compared to males overall with both groups demonstrating nonlinear age-associated changes across the age range examined. ITA size among females correlated significantly with thalamus volume and lower mean diffusivity in the anterior thalamic radiation. Path modeling indicated that ITA size statistically mediated the relationship between age and attention among females. Our findings provide evidence for sex differences in ITA size across the lifespan, which are associated with the surrounding thalamic anatomy and neuropsychological functions.

Diffusion tensor imaging of Parkinson's disease, multiple system atrophy and progressive supranuclear palsy: a tract-based spatial statistics study.

Although often clinically indistinguishable in the early stages, Parkinson’s disease (PD), Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) have distinct neuropathological changes. The aim of the current study was to identify white matter tract neurodegeneration characteristic of each of the three syndromes. Tract-based spatial statistics (TBSS) was used to perform a whole-brain automated analysis of diffusion tensor imaging (DTI) data to compare differences in fractional anisotropy (FA) and mean diffusivity (MD) between the three clinical groups and healthy control subjects. Further analyses were conducted to assess the relationship between these putative indices of white matter microstructure and clinical measures of disease severity and symptoms. In PSP, relative to controls, changes in DTI indices consistent with white matter tract degeneration were identified in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, anterior thalamic radiation, superior cerebellar peduncle, medial lemniscus, retrolenticular and anterior limb of the internal capsule, cerebral peduncle and external capsule bilaterally, as well as the left posterior limb of the internal capsule and the right posterior thalamic radiation. MSA patients also displayed differences in the body of the corpus callosum corticospinal tract, cerebellar peduncle, medial lemniscus, anterior and superior corona radiata, posterior limb of the internal capsule external capsule and cerebral peduncle bilaterally, as well as the left anterior limb of the internal capsule and the left anterior thalamic radiation. No significant white matter abnormalities were observed in the PD group. Across groups, MD correlated positively with disease severity in all major white matter tracts. These results show widespread changes in white matter tracts in both PSP and MSA patients, even at a mid-point in the disease process, which are not found in patients with PD.

G.P.128: Upper limb muscle MRI fat–water quantification and clinical functional correlation in non-ambulant Duchenne muscular dystrophy

Outcome measures in Duchenne muscular dystrophy (DMD) currently rely on invasive or functional but not very sensitive tests. Muscle MRI could offer a valuable alternative. A reliable evaluation of the upper limb could permit inclusion of non-ambulant DMD individuals not able to perform functional tests such as the 6-min walk test. 16 DMD boys and 10 age gender and age matched controls were included in this on-going study. Fat–water quantification was used to compare fat-infiltration in the forearm muscles of non-ambulant DMD patients and healthy controls. DMD individuals underwent 3T 3-point Dixon imaging of the dominant forearm to measure muscle fat-fraction (f.f.). Ten forearm muscles were segmented and mean f.f. and cross-sectional area recorded. Patients also underwent physiotherapy evaluation: Performance of Upper Limb (PUL) module; wrist extension myometry; and EK2 performance of tasks in daily life interview. Time to loss of ambulation (LOA) was recorded. To date, 8 non-ambulant DMD patients (mean age: 13.6 years; mean duration of non-ambulation 20 months) and 10 volunteers (mean age:14.6 years) have been imaged. Overall mean f.f (±SD) in DMD was significantly higher than healthy controls: (13.4 ± 11% vs 0.8 ± 0.1%, p = 0.002). Total mean area was reduced in DMD (1735 ± 331 mm2) compared to healthy controls (2398 ± 821 mm2, p = 0.04). Overall f.f. correlated with LOA (Spearman r = 0.8, p = 0.02) and wrist extension myometry (r = 0.8, p = 0.004) and less strongly with PUL (r = −0.6, p = 0.09) and with EK2 (r = 0.6, p = 0.09). Final analysis will include longitudinal change at one-year follow up. Initial results support MRI fat quantification as a potential objective biomarker to monitor disease progression in the upper limb in DMD, showing significant correlation between putative MRI pathological indices and clinically meaningful endpoints.

Die zerstreute Erbschaft

Abstract How can narrative come to terms with the past in a world hit by trauma was one of the questions most consistently investigated in the work of Walter Benjamin. Pursuing it in various past and present contexts, he gradually reassessed the marginalized literary tradition of narrative strolling along the scene of the crime, rummaging through and collecting of the putative indices. The chaotic execution site, calling its observers and investigators to responsibility toward its heap of ruins, resists sovereign narrative reconstruction of its emergence. The latter is therefore replaced by various conjectures, repeated preparations and hesitating roundabouts which ultimately turn the plot into a kind of a bewildering rebus, neither a story nor a picture. I read Dubravka Ugrešić’s posttraumatic novel The Museum of Unconditional Surrender (1997) within this tradition of narratives that strategically couple the incompatible registers of discursive and visual presentation, trivial and high literature, the beautiful and the sublime, materiality and immateriality with one another. Its discourse is haunted by a multitude of exiled or absolved voices and gazes who do not permit a homogeneous and transparent story. Ugrešić’s narrator is, like Benjamin’s flaneur, obsessed by their summoning resonance stored in the myriad of dissipated fragments of today’s posttraumatic world.

Interpersonal motor resonance in autism spectrum disorder: evidence against a global “mirror system” deficit

The mirror neuron hypothesis of autism is highly controversial, in part because there are conflicting reports as to whether putative indices of mirror system activity are actually deficient in autism spectrum disorder (ASD). Recent evidence suggests that a typical putative mirror system response may be seen in people with an ASD when there is a degree of social relevance to the visual stimuli used to elicit that response. Individuals with ASD (n = 32) and matched neurotypical controls (n = 32) completed a transcranial magnetic stimulation (TMS) experiment in which the left primary motor cortex (M1) was stimulated during the observation of static hands, individual (i.e., one person) hand actions, and interactive (i.e., two person) hand actions. Motor-evoked potentials (MEP) were recorded from the contralateral first dorsal interosseous, and used to generate an index of interpersonal motor resonance (IMR; a putative measure of mirror system activity) during action observation. There was no difference between ASD and NT groups in the level of IMR during the observation of these actions. These findings provide evidence against a global mirror system deficit in ASD, and this evidence appears to extend beyond stimuli that have social relevance. Attentional and visual processing influences may be important for understanding the apparent role of IMR in the pathophysiology of ASD.

Unravelling the bull fertility proteome

In the last few decades a negative association between the level of milk production and fertility has been observed. Currently, the most utilized method of measuring male fertility employed by the livestock industry is related to the Non-Return Rate (NRR). Through differential proteome analysis, this study evaluated changes in the expression of the protein profile of spermatozoa collected from 16 bulls with different levels of field fertility expressed as an estimated relative conception rate (ERCR). The main aim is to identify putative protein markers to be used as putative indices of fertility. Two dimensional electrophoresis coupled with mass spectrometry analysis was used for protein separation and identification. To improve differential proteome analysis among experimental groups, a part of shotgun MS analysis was also performed. Three protein spots showed a differential expression pattern among all ERCR classes. Alpha enolase was significantly down-regulated in the ERCR- group, while two other proteins, isocitrate dehydrogenase and triosephosphate isomerase, were up-regulated in ERCR- in comparison to ERCR+. Alpha-enolase and isocitrate dehydrogenase subunit alpha (IDH-alpha) have been described in the literature for having a potential role in bull fertility. The possibility of determining protein biomarkers for fertility is more useful and less expensive than ERCR for acquiring rapid estimation of fertility because it does not require the use of field insemination trials. Shotgun MS analysis conducted on the same samples revealed 7 proteins down-regulated in the ERCR- group and 1 protein up-regulated. Among these proteins, calmodulin, ATP synthase mitochondrial subunits alpha and delta, malate dehydrogenase and sperm equatorial segment protein 1 were shown to be linked with sperm fertility.

Anomalies neurologiques et physiques mineures chez des patients présentant un premier épisode psychotique

Over the last several decades, there has been an increasing number of neuroanatomical, neuroimaging, neurophysiological, and neuropsychological studies in search of structural, functional, and cognitive correlates of brain insult(s) that could ultimately lead to unravelling the pathophysiology of schizophrenia. A direct, easily administered, and inexpensive way of investigating brain dysfunction in schizophrenia is the study of neurological soft signs and minor physical anomalies, two putative indices of developmental abnormality. The study of these neurodevelopmental markers in the first-episode psychosis allows the detection of the neurodevelopmental abnormalities at the onset of psychosis. The objectives of our study were to determinate the prevalence, the scores, and the nature of neurological soft signs (NSS) and minor physical anomalies (MPA) in patients with first-episode psychosis and to explore the correlations between these neurodevelopmental markers and the demographic, clinical and therapeutic features. A cross-sectional study was carried-out on 61 patients (mean age: 28.9±9.4years; 86.9% were males), hospitalized for first-episode psychosis (DSM-IV-TR diagnosis of schizophrenia, schizophreniform disorder, brief psychotic disorder, delusional disorder, and psychotic disorder not otherwise specified). The evaluation procedure consisted of a retrospective assessment of the premorbid functioning by the Premorbid Functioning Scale (PAS) and the following clinical scales: Positive and Negative Symptoms Scale (PANSS), Clinical Global Impression (CGI) and Global Assessment of Functioning (GAF), the NSS scale of Krebs et al. (23 items exploring motor coordination, motor integrative function, sensory integration, involuntary movements or posture, quality of lateralization) and the MPA scale of Gourion et al. (41 items, exploring anomalies of face, eyes, ears, mouth, hands and feet). The prevalence of NSS was 83.6% (cut-off point=9.5), with a mean total score of 15.3±6.7. The highest score was for the motor coordination. The prevalence of MPA was 62.7% (cut-off point=5), with a mean total score of 5.8±3.2. The most common MPA were the fine hair (50.8%), adherent earlobes (49.2%) and clinodactyly (31.1%). Correlations were found between the NSS total score and the Poor Premorbid Functioning (r=0.32, P=0.04), the PANSS total score (r=0.36, P=0.005), and the negative (r=0.45, P<0.001) and disorganization sub-scores (r=0.41, P=0.001), the CGI-severity of (r=0.30, P=0.02), the impairment functioning in the GAF (r=-0.26, P=0.04) and with extrapyramidal symptoms (r=0.52, P<0.001). However, no correlation was found between the NSS total scores, age, gender, the PANSS positive sub-score, the daily dosage of antipsychotics, the CGI-improvement score and the MPA total score. There was no correlation between MPA total score and demographic, clinical and therapeutic features of patients. Moreover, there was no correlation between the NSS or MPA scores and the short-term evolution (6months to 1year) towards schizophrenia. These results confirm the data in the literature relating high NSS and MPA scores in patients with a first-episode psychosis. The NSS appear to characterize severe psychotic disorders with more negative and disorganization symptoms and poor social functioning and may be a prognostic indicator.

Prefrontal deviations in function but not volume are putative endophenotypes for schizophrenia

This study sought to systematically investigate whether prefrontal cortex grey matter volume reductions are valid endophenotypes for schizophrenia, specifically investigating their presence in unaffected relatives, heritability, genetic overlap with the disorder itself and finally to contrast their performance on these criteria with putative neuropsychological indices of prefrontal functioning. We used a combined twin and family design and examined four prefrontal cortical regions of interest. Superior and inferior regions were significantly smaller in patients. However, the volumes of these same regions were normal in unaffected relatives and therefore, we could confirm that such deficits were not due to familial effects. Volumes of the prefrontal and orbital cortices were, however, moderately heritable, but neither shared a genetic overlap with schizophrenia. Total prefrontal cortical volume reductions shared a significant unique environmental overlap with the disorder, suggesting that the reductions were not familial. In contrast, prefrontal (executive) functioning deficits were present in the unaffected relatives, were moderately heritable and shared a substantial genetic overlap with liability to schizophrenia. These results suggest that the well recognized prefrontal volume reductions are not related to the same familial influences that increase schizophrenia liability and instead may be attributable to illness related biological changes or indeed confounded by illness trajectory, chronicity, medication or substance abuse, or in fact a combination of some or all of them.

Brain serotonergic and dopaminergic modulators, perceptual responses and endurance exercise performance following caffeine co-ingested with a high fat meal in trained humans

BackgroundThe present study examined putative modulators and indices of brain serotonergic and dopaminergic function, perceptual responses, and endurance exercise performance following caffeine co-ingested with a high fat meal.MethodsTrained humans (n = 10) performed three constant-load cycling tests at 73% of maximal oxygen uptake (VO2max) until exhaustion at 10°C remove space throughout. Prior to the first test, subjects consumed a 90% carbohydrate meal (Control trial) and for the remaining two tests, a 90% fat meal with (FC trial) and without (F trial) caffeine.ResultsTime to exhaustion was not different between the F and FC trials (P > 0.05); [Control trial: 116(88-145) min; F trial: 122(96-144) min; FC trial: 127(107-176) min]. However, leg muscular discomfort during exercise was significantly lower on the FC relative to F trial (P < 0.01). There were no significant differences between F and FC trials in key modulators and indices of brain serotonergic (5-HT) and dopaminergic (DA) function [(i.e. plasma free and total tryptophan (Trp), tyrosine (Tyr), large neutral amino acids (LNAA), Trp:LNAA ratio, free-Trp:Tyr ratio, total Trp:Tyr ratio, and plasma prolactin] (P > 0.05) with the exception of plasma free-Trp:LNAA ratio which was higher at 90 min and at exhaustion during the FC trial (P < 0.05).ConclusionsNeither brain 5-HT nor DA systems would appear to be implicated in the fatigue process when exercise is performed without significant thermoregulatory stress, thus indicating fatigue development during exercise in relatively cold temperatures to occur predominantly due to glycogen depletion.

Effects of multiple study–test repetition on the neural correlates of recognition memory: ERPs dissociate remembering and knowing

Event-related potential (ERP) frontal (300-500 ms) and parietal (500-700 ms) episodic memory (EM) effects are thought to reflect, respectively, familiarity and recollection. However, as most ERP studies use preexperimentally familiar items, an alternative idea is that the frontal EM effect reflects conceptual priming. Repetition of unnameable symbols was used to assess modulations of the putative ERP indices of familiarity and recollection. The same symbols were viewed in each of 4 study/test blocks. Increases in familiarity and conceptual processing of symbols did not modulate the frontal EM effect, suggesting that it reflects neither familiarity nor conceptual priming. The magnitude of the parietal EM effect increased and its onset latency decreased across tests for items given remember (R) but not know (K) judgments. R and K old-new topographies differed. These findings support dual-process proposals that familiarity- and recollection-based processes are distinct.

Delay Aversion in Attention Deficit/Hyperactivity Disorder: An empirical investigation of the broader phenotype

BackgroundDelay-related motivational processes are impaired in children with Attention Deficit/Hyperactivity Disorder (ADHD). Here we explore the impact of ADHD on the performance of three putative indices of Delay Aversion (DAv): (i) the choice for immediate over delayed reward; (ii) slower reaction times following delay; and (iii) increased delay-related frustration—to see whether these tap into a common DAv construct that differentiates ADHD cases from controls and shows evidence of familiality. MethodSeventy seven male and female individuals (age range 6–17) with a research diagnosis combined type ADHD, 65 of their siblings unaffected by ADHD and 50 non-ADHD controls completed three delay tasks. ResultsAs predicted the size of the correlation between tasks was small but a common latent component was apparent. Children with ADHD differed from controls on all tasks (d=.4–.7) and on an overall DAv index (d=.9): The battery as a whole demonstrated moderate sensitivity and specificity. In general, deficits were equally marked in childhood and adolescence and were independent of comorbid ODD. IQ moderated the effect on the MIDA. Scores on the DAv factor co-segregated within ADHD families. DiscussionThere is value in exploring the broader DAv phenotype in ADHD. The results illustrate the power of multivariate approaches to endophenotypes. By highlighting the significant, but limited, role of DAv in ADHD these results are consistent with recent accounts that emphasize neuropsychological heterogeneity.