How ‘love’ and ‘hate’ differ from ‘sleep’: Using combined electro/magnetoencephalographic data to reveal the sources of early cortical responses to emotional words

Emotional words—as symbols for biologically relevant concepts—are preferentially processed in brain regions including the visual cortex, frontal and parietal regions, and a corticolimbic circuit including the amygdala. Some of the brain structures found in functional magnetic resonance imaging are not readily apparent in electro‐ and magnetoencephalographic (EEG; MEG) measures. By means of a combined EEG/MEG source localization procedure to fully exploit the available information, we sought to reduce these discrepancies and gain a better understanding of spatiotemporal brain dynamics underlying emotional‐word processing. Eighteen participants read high‐arousing positive and negative, and low‐arousing neutral nouns, while EEG and MEG were recorded simultaneously. Combined current‐density reconstructions (L2‐minimum norm least squares) for two early emotion‐sensitive time intervals, the P1 (80–120 ms) and the early posterior negativity (EPN, 200–300 ms), were computed using realistic individual head models with a cortical constraint. The P1 time window uncovered an emotion effect peaking in the left middle temporal gyrus. In the EPN time window, processing of emotional words was associated with enhanced activity encompassing parietal and occipital areas, and posterior limbic structures. We suggest that lexical access, being underway within 100 ms, is speeded and/or favored for emotional words, possibly on the basis of an “emotional tagging” of the word form during acquisition. This gives rise to their differential processing in the EPN time window. The EPN, as an index of natural selective attention, appears to reflect an elaborate interplay of distributed structures, related to cognitive functions, such as memory, attention, and evaluation of emotional stimuli. Hum Brain Mapp 35:875–888, 2014. © 2012 Wiley Periodicals, Inc.     

Rapid brain responses to affective pictures indicate dimensions of trauma-related psychopathology in adolescents

A variety of mental disorders are related to deviant brain activity, but these neural alterations do not validate psychiatric diagnostic categories. High symptom overlap and variable symptom patterns encourage a dimensional approach. Following the logic of the Research Domain Criteria (RDoC), we investigated trauma survivors for symptom clusters that might be associated with characteristics of ERPs, in particular with the early posterior negativity (EPN) elicited during affective picture processing. In rapid serial visual presentation, 90 adolescents (40 male/50 female, age M = 15.0 ± 2.5 years) who had been exposed to varying amounts of traumatic stress passively viewed a stream of high-arousing positive and low-arousing neutral pictures taken from the International Affective Picture System (IAPS). Using standardized interviews, symptoms of trauma-related mental disorders were assessed (including those for PTSD, depression, borderline personality disorder, and behavioral problems). A principal component analysis was performed to derive potential dimensions of psychopathology. Multiple regression analysis confirmed a factor comprising problems concentrating, sleeping difficulties, and mistrust as a predictor of a larger EPN difference between high-arousing positive and low-arousing neutral IAPS pictures (β = 0.19, p < 0.05). Sex predicted the magnitude of the EPN (β = 0.45, p < 0.001). Male adolescents displayed a stronger EPN suppression than female adolescents. The result suggests that problems concentrating, sleeping difficulties, and mistrust seem to be trans-diagnostic elements related to diminished early emotional discrimination represented by the EPN. Furthermore, our findings indicate that the EPN in response to emotional processing is modulated by sex.     

Following the time course of face gender and expression processing: A task-dependent ERP study

The effects of task demands and the interaction between gender and expression in face perception were studied using event-related potentials (ERPs). Participants performed three different tasks with male and female faces that were emotionally inexpressive or that showed happy or angry expressions. In two of the tasks (gender and expression categorization) facial properties were task-relevant while in a third task (symbol discrimination) facial information was irrelevant. Effects of expression were observed on the visual P100 component under all task conditions, suggesting the operation of an automatic process that is not influenced by task demands. The earliest interaction between expression and gender was observed later in the face-sensitive N170 component. This component showed differential modulations by specific combinations of gender and expression (e.g., angry male vs. angry female faces). Main effects of expression and task were observed in a later occipito-temporal component peaking around 230 ms post-stimulus onset (EPN or early posterior negativity). Less positive amplitudes in the presence of angry faces and during performance of the gender and expression tasks were observed. Finally, task demands also modulated a positive component peaking around 400 ms (LPC, or late positive complex) that showed enhanced amplitude for the gender task. The pattern of results obtained here adds new evidence about the sequence of operations involved in face processing and the interaction of facial properties (gender and expression) in response to different task demands.     

Enhancement of activity of the primary visual cortex during processing of emotional stimuli as measured with event-related functional near-infrared spectroscopy and event-related potentials

In this study we investigated whether event-related near-infrared spectroscopy (NIRS) is suitable to measure changes in brain activation of the occipital cortex modulated by the emotional content of the visual stimuli. As we found in a previous pilot study that only positive but not negative stimuli differ from neutral stimuli (with respect to oxygenated haemoglobin), we now measured the event-related EEG potentials and NIRS simultaneously during the same session. Thereby, we could evaluate whether the subjects (n = 16) processed the positive as well as the negative emotional stimuli in a similar way. During the task, the subjects passively viewed positive, negative, and neutral emotional pictures (40 presentations were shown in each category, and pictures were taken from the International Affective Picture System, IAPS). The stimuli were presented for 3 s in a randomized order (with a mean of 3 s interstimulus interval). During the task, we measured the event-related EEG potentials over the electrode positions O1, Oz, O2, and Pz and the changes of oxygenated and deoxygenated haemoglobin by multichannel NIRS over the occipital cortex. The EEG results clearly show an increased early posterior negativity over the occipital cortex for both positive as well as negative stimuli compared to neutral. The results for the NIRS measurement were less clear. Although positive as well as negative stimuli lead to significantly higher decrease in deoxygenated haemoglobin than neutral stimuli, this was not found for the oxygenated haemoglobin.     

Mediterranean diet habits in older individuals: Associations with cognitive functioning and brain volumes

To examine the association between dietary habits, cognitive functioning and brain volumes in older individuals, data from 194 cognitively healthy individuals who participated in the Prospective Investigation of the Vasculature in Uppsala Seniors cohort were used. At age 70, participants kept diaries of their food intake for 1 week. These records were used to calculate a Mediterranean diet (MeDi) score (comprising dietary habits traditionally found in Mediterranean countries, e.g. high intake of fruits and low intake of meat), with higher scores indicating more pronounced MeDi-like dietary habits. Five years later, participants' cognitive capabilities were examined by the seven minute screening (7MS) (a cognitive test battery used by clinicians to screen for dementia), and their brain volumes were measured by volumetric magnetic resonance imaging. Multivariate linear regression analyses were constructed to examine the association between the total MeDi score and cognitive functioning and brain volumes. In addition, possible associations between MeDi's eight dietary features and cognitive functioning and brain volumes were investigated. From the eight dietary features included in the MeDi score, pertaining to a low consumption of meat and meat products was linked to a better performance on the 7MS test (P = 0.001) and greater total brain volume (i.e. the sum of white and gray matter, P = 0.03) when controlling for potential confounders (e.g. BMI) in the analysis. Integrating all dietary features into the total MeDi score explained less variance in cognitive functioning and brain volumes than its single dietary component meat intake. These observational findings suggest that keeping to a low meat intake could prove to be an impact-driven public health policy to support healthy cognitive aging, when confirmed by longitudinal studies. Further, they suggest that the MeDi score is a construct that may mask possible associations of single MeDi features with brain health domains in elderly populations.     

Is delayed neurotoxicity a property of all organophosphorus compounds? A study with a model compound: Parathion

A recently reported hypothesis of other investigators that the induction of delayed neurotoxicity is a property of all organophosphorus compounds including parathion was evaluated in light of the inability of parathion to induce in our laboratory any clinical, histological, or biochemical signs of delayed neurotoxicity in hens following a very sensitive dosing regimen. Parathion was administered orally or applied dermally as 1 mg/kg/day for 1 week and then the dose was increased by 1 mg/kg/day at weekly intervals up to 6 mg/kg/day which was given thereafter until a total of 90 doses. Results indicate that parathion either orally or dermally did not produce delayed neurotoxicity in hens comparable to that induced by tri-ortho-cresyl phosphate (TOCP) in this experiment. This finding is supported by clinical, histological, and biochemical evidences. No clinical signs or histopathological changes in spinal cords and sciatic nerves of the type associated with delayed neurotoxicity were observed in any of the surviving parathion- treated hens. Moreover, this existence treatment with parathion resulted in no significant in vivo effect on neurotoxic esterase, an esterase believed to be the initial target in the genesis of delayed neurotoxicity. These results agree with the general hypothesis that delayed neurotoxicity is a special toxic effect of some but not all of the organophosphorus esters.     

Stereospecific hydrolysis of a phosphoramidate as a model to understand the role of biotransformation in the neurotoxicity of chiral organophosphorus compounds

Calcium-dependent and EDTA-resistant hydrolyses of R and S isomers of O-hexyl O-2,5-dicholorophenyl phosphoramidate (HDCP) were observed in serum and subcellular fractions of liver, kidney and brain from hen, rat and rabbit. In serum, the Ca(2+)-dependent hydrolysis was much higher in rabbit than in other species. Liver showed a higher activity than kidney and brain. The S-HDCP isomer was hydrolysed to a higher extent than the other isomer. The fact that this stereospecificity favours the S-isomer is more clearly observed in rabbit serum, and in rat and rabbit liver particulate fractions. In such tissues and species, the EDTA-resistant hydrolysis was not stereospecific. Soluble fractions of rat brain and of hen liver, kidney and brain, showed a lower total activity but with a higher proportion of EDTA-resistant activity and a higher hydrolysis of the R-HDCP isomer. The Ca(2+)-dependent stereoselective biodegradation of S-HDCP is dominant in the most active tissues in rabbit and rat. It can therefore be concluded that S-HDCP would be biodegraded faster than R-HDCP. Furthermore, R-HDCP is the isomer that will remain at a higher proportion to be available for interaction with the target of neurotoxicity.     

Could platelet to leucocytic count ratio (PLR) predict sepsis and clinical outcomes in patients with emphysematous pyelonephritis?

ObjectivesTo study risk factors for sepsis and mortality evaluating the role of platelet to leucocytic count ratio (PLR) as a marker for urosepsis and clinical outcomes in cases of emphysematous pyelonephritis (EPN).MaterialsPatients with EPN were retrospectively reviewed. Patients' age, sex, diabetes mellitus (DM), Body Mass Index (BMI), hydronephrosis, types of EPN, air locules volume, serum creatinine, leucocytic count, and platelet count, PLR, albumin, INR and the line of treatment were analyzed as risk factors of sepsis. Correlation between PLR and other variables was done using Pearson correlation coefficient. Univariate and multivariate analyses for sepsis and mortality were performed.ResultsOf fifty four patients, 38 patients had SIRS ≥2 criteria on admission. Twenty patients developed sepsis requiring ICU admission. In univariate analysis, male gender, lower BMI, higher INR, higher WBCs count and lower PLR were associated with sepsis (P = 0.0001, 0.009, 0.04, 0.003 and 0.001, respectively). In multivariate analysis, PLR ≤18.4, male sex and BMI ≤24.2 were independent risk factors. Lower PLR directly correlated with serum albumin (P = 0.01) and inversely correlated with serum creatinine and random blood glucose level and Klebsiella infection (P = 0.001, 0.007 and 0.005, respectively). Also, it was correlated with a higher total score of qSOFA and SOFA (P = 0.02 and 0.04). Lower PLR was independent risk factors for death in EPN patients with (P = 0.003).ConclusionEPN is associated with sepsis development. Lower PLR is an independent simple predictor for sepsis and mortality in patients with EPN.     

Distribution and metabolism of O-Ethyl O-4-nitrophenyl phenylphosphonothioate after a single oral dose in one-week old chicks

The toxicokinetics and metabolism of a single 1 mg (2.7 Ci/kg) oral dose of uniformly phenyl-labeled [¹⁴C]EPN (O-ethyl O-4-nitrophenyl [¹⁴C]phenylphosphonothioate) have been studied in 1-week old chicks. One control and three treated chicks were killed at each of the following time intervals: 0.5, 2, 4, 8, and 12 days. Radioactivity was rapidly absorbed from the gastrointestinal tract and distributed in all tissues. ¹⁴C in tissues reached a peak of 16.9% of the dose after 0.5 day and decreased to 0.6% at 4 days. The tissues of the gastrointestinal tract had the highest concentration of radioactivity, followed by bile and liver. Among nervous tissues, concentration of ¹⁴C was highest in the peripheral nerves. The spinal cord had the next highest concentration, while the brain had the least. After 4 days 91.3% of the ¹⁴C had been eliminated in the combined urinary-fecal excreta. By the end of the 12-day experiment this percentage reached 93.1%. No ¹⁴C was detected in the expired CO₂. Following the oral administration of [14C]EPN, a monophasic body level curve was observed. The half-life for the elimination of ¹⁴C from chick body was 16 h, corresponding to a rate constant of 0.04 h^–1. Most of the excreted ¹⁴C materials were identified as O-ethyl phenylphosphonic acid, phenylphosphonic acid, and O-ethyl phenylphosphonothioic acid.     

Using ERPs to investigate valence processing in the affect misattribution procedure

The construct validity of the affect misattribution procedure (AMP) has been challenged by theories proposing that the task does not actually measure affect misattribution. The current study tested the validity of the AMP as a measure of affect misattribution by examining three components of the ERP known to be associated with the allocation of motivated attention. Results revealed that ERP amplitudes varied in response to affectively ambiguous targets as a function of the valence of preceding primes. Furthermore, differences in ERP responses to the targets were largely similar to differences in ERPs elicited by the primes. The existence of valence differentiation in both the prime‐locked and the target‐locked ERPs, along with the similarity in this differentiation, provides evidence that the affective content of the primes is psychologically registered, and that this content influences the processing of the subsequent, evaluatively ambiguous targets, both of which are required if the priming effects found in the AMP are the result of affect misattribution. However, the behavioral priming effect was uncorrelated with ERP amplitudes, leaving some question as to the locus of this effect in the information‐processing system. Findings are discussed in light of the strengths and weaknesses of using ERPs to understand the priming effects in the AMP.