Selective processing of food words during insulin-induced hypoglycemia in healthy humans

Rationale: Hypoglycemia leads to undernutrition of the brain. Favoring selective processing of food stimuli would be an adaptive cognitive strategy. However, hypoglycemia is known to impair several aspects of cognitive function, and it is unknown whether selective cognitive processing of food stimuli occurs during insulin-induced hypoglycemia. Methods: In a single-blind repeated measures design, healthy young adults (n=12, six female, mean age 28 years; mean body mass index 22.5kg/m2) performed a standard Stroop word-color test, as well as a variant with food words designed to detect selective processing of food cues. Two sessions were scheduled with a 4-week interval. In each session, a hyperinsulinemic clamp method produced a normoglycemic (plasma glucose: 4.7mmol/l) period, followed on 1 day by a hypoglycemic (2.7mmol/l) testing period, and on the other day a second normoglycemic testing period (counterbalanced order). Results: Color naming verbal reaction time (RT) increased during hypoglycemia (P<0.0001). The extent of the Stroop cognitive interference was independent of plasma glucose level. The key finding is that RT for food words increased more than for non-food control words (P<0.004), and this effect was not predicted by hunger ratings. Conclusions: Our data provide new evidence that during hypoglycemia, attention is directed selectively to food-relevant stimuli. The results are discussed in terms of adaptatio

SensorMapRT – a System for Real-Time Acquisition, Visualization and Analysis of Mobile Sensor Data in an Urban Context

The use of wearables in citizens’ daily life will increase significantly in the coming years. By analyzing these sensor data, it is possible to detect the emotional well-being in urban areas, which is highly relevant for urban planning purposes. Through the combination of several physiological and other sensor data such as GPS, "stress spots" in the urban environment can be recognized and located. A major objective of this project is therefore, to combine and evaluate various research approaches in the field of human as sensorswith wearables. This is the reason why the project group will be an interdisciplinary cooperation between spatial planning, psychophysiology and computer technology.Together with the project partner cities of Neustadt an der Weinstraße and Pirmasens in the German Federal State Rhineland-Palatine, the project group aims to show exemplary the influence of potential stressing factors in the urban area such as traffic and noise and creates scientifically-robust models of stress detection in urban areas. Besides this, a visualization for planning purposes with the tool GeoVisualizer as well as an evaluation of the resilience of such informtion and their potential use for urban planning is aim of the project

Reduced vagal activity in salt-sensitive subjects during mental challenge

Background: Salt-sensitive normotensive men exhibit an enhanced pressor and heart rate (HR) response to mental stress. Stress-induced HR acceleration may result from sympathetic activation or vagal withdrawal. We studied the importance of vagal withdrawal for the increased stress responsiveness of salt-sensitive subjects. Methods: We studied cardiovascular reactivity to mental challenge in 17 salt-sensitive healthy white male students and 56 salt-resistant control subjects who were comparable with respect to age, body mass index, and physical fitness. Salt sensitivity was determined by a 2-week dietary protocol (20 mmol v 240 mmol sodium/day). Mental stress was induced by a computerized information-processing task (manometer test). Electrocardiogram and finger blood pressure (BP; Finapres, Ohmeda, Louisville, CO) were registered continuously to determine HR and interbeat-interval length. Time and frequency domain (spectral power) based measures of respiratory-related heart rate variability (HRV) were calculated to estimate vagal cardiac control; diastolic BP reactivity was assessed to estimate peripheral sympathetic effects. Results: Stress-induced increase in HR was higher in salt-sensitive than in salt-resistant subjects. Salt-sensitive subjects, in comparison to salt-resistant subjects, showed significantly reduced respiratory-related HRV during baseline and mental stress conditions (P < .01). The increase in diastolic BP during mental challenge was significantly greater in salt-sensitive subjects (P < .05). Conclusions: Our findings suggest reduced vagal and increased sympathetic tone during mental challenge in salt-sensitive subjects. Altered autonomic nervous system function may contribute to later development of hypertension in salt-sensitive individuals. Am J Hypertens 2003; 16:531-536 @ 2003 American Journal of Hypertension, Lt

Cortisol rapidly increases baroreflex sensitivity of heart rate control, but does not affect cardiac modulation of startle

Cortisol, the final product of human HPA axis activation, rapidly modulates the cortical processing of afferent signals originating from the cardiovascular system. While peripheral effects have been excluded, it remains unclear whether this effect is mediated by cortical or subcortical (e.g. brainstem) CNS mechanisms. Cardiac modulation of startle (CMS) has been proposed as a method to reflect cardio-afferent signals at subcortical (potentially brainstem-) level. Using a single blind, randomized controlled design, the cortisol group (n = 16 volunteers) received 1 mg cortisol intravenously, while the control group (n = 16) received a placebo substance. The CMS procedure involved the assessment of eye blink responses to acoustic startle stimuli elicited at six different latencies to ECG-recorded R-waves (R + 0, 100, 200, 300, 400 and 500 ms). CMS was assessed at four measurement points: baseline, -16 min, +0 min, and +16 min relative to substance application. Baroreflex sensitivity (BRS) of heart rate (HR) control was measured non-invasively based on spontaneous beat-to-beat HR and systolic blood pressure changes. In the cortisol group, salivary cortisol concentration increased after IV cortisol administration, indicating effective distribution of the substance throughout the body. Furthermore, BRS increased in the cortisol group after cortisol infusion. There was no effect of cortisol on the CMS effect, however. These results suggest that low doses of cortisol do not affect baro-afferent signals, but central or efferent components of the arterial baroreflex circuit presumably via rapid, non-genomic mechanisms

Rising Sound Intensity: An Intrinsic Warning Cue Activating the Amygdala

Human subjects overestimate the change of rising intensity sounds compared with falling intensity sounds. Rising sound intensity has therefore been proposed to be an intrinsic warning cue. In order to test this hypothesis, we presented rising, falling, and constant intensity sounds to healthy humans and gathered psychophysiological and behavioral responses. Brain activity was measured using event-related functional magnetic resonance imaging. We found that rising compared with falling sound intensity facilitates autonomic orienting reflex and phasic alertness to auditory targets. Rising intensity sounds produced neural activity in the amygdala, which was accompanied by activity in intraparietal sulcus, superior temporal sulcus, and temporal plane. Our results indicate that rising sound intensity is an elementary warning cue eliciting adaptive responses by recruiting attentional and physiological resources. Regions involved in cross-modal integration were activated by rising sound intensity, while the right-hemisphere phasic alertness network could not be supported by this stud

T cell immunosenescence after early life adversity: association with cytomegalovirus infection.

Early life adversity (ELA) increases the risk for multiple age-related diseases, such as diabetes type 2 and cardiovascular disease. As prevalence is high, ELA poses a major and global public health problem. Immunosenescence, or aging of the immune system, has been proposed to underlie the association between ELA and long-term health consequences. However, it is unclear what drives ELA-associated immunosenescence and which cells are primarily affected. We investigated different biomarkers of immunosenescence in a healthy subset of the EpiPath cohort. Participants were either parent-reared (Ctrl, n = 59) or had experienced separation from their parents in early childhood and were subsequently adopted (ELA, n = 18). No difference was observed in telomere length or in methylation levels of age-related CpGs in whole blood, containing a heterogeneous mixture of immune cells. However, when specifically investigating T cells, we found a higher expression of senescence markers (CD57) in ELA. In addition, senescent T cells (CD57+) in ELA had an increased cytolytic potential compared to senescent cells in controls. With a mediation analysis we demonstrated that cytomegalovirus (CMV) infection, which is an important driving force of immunosenescence, largely accounted for elevated CD57 expression observed in ELA. Leukocyte telomere length may obscure cell-specific immunosenescence; here, we demonstrated that the use of cell surface markers of senescence can be more informative. Our data suggest that ELA may increase the risk of CMV infection in early childhood, thereby mediating the effect of ELA on T cell-specific immunosenescence. Thus, future studies should include CMV as a confounder or selectively investigate CMV seronegative cohorts

The Eletrophysiology of Prepulse Inhibition

The acoustic startle response is decreased by a prepulse occurring 30-500 ms earlier. This prepulse inhibition (PPI) is interpreted in terms of the Interruption and Protection hypotheses, in which startle responding interrupts prepulse processing, and PPI indicates the degree to which prepulse processing is protected from that interruption. We evaluated this hypotheses by measuring startle responding and evoked potentials (N1, P2) to both prepulse and startle stimuli under different attentional conditions (Attend Startle, Attend Prepulse, Ignore Both). 192 trials were presented in randomized order: Startle Alone (105dB noise), Prepulse Alone (70dB noise), and prepulse+startle stimuli with a stimulus onset asynchrony (SOA) of 120 (PPI120) or 500 ms (PPI500). 36 participants, randomly assigned to the three attention conditions, pressed a key to the startle or to the pre-pulse or did not respond. A 32-channel EEG and eyeblink EMG were measured. Independent of the attentional conditions, the EMG startle response was decreased by a pre-pulse at both SOAs, illustrating PPI. Prepulse N1/P2 amplitude was identical for the Prepulse Alone, PPI120, and PPI500 stimuli independent of the attentional conditions, demonstrating protection of primary sensory prepulse processing. N1/P2 potentials to the startle stimulus were affected by the SOAs and the attentional conditions, suggesting a change in startle processing by both variables. The results suggest a complete protection of prepulse processing. The reduced N1/P2 amplitudes to the startle stimulus at both SOAs suggest that the eliciting properties of the startle stimulus are decreased by the prepulse

Parental divorce is associated with an increased risk to develop mental disorders in women

Background: Parental divorce has been associated with reduced well-being in young adults. It is, however, unclear whether this finding is clinically relevant as studies using structural clinical interviews are missing. This study, therefore, investigated if young adults with divorced parents are at risk to develop mental disorders. Furthermore, differences in parental care, social connectedness, chronic stress and traumatic experiences between children of divorced and non-divorced parents were investigated. Methods: 121 women (mean age: 23 years) were interviewed using the Structured Clinical Interview for DSMIV Axis I (i.e., major mental disorders) and II (i.e., personality disorders) Disorders and asked to complete questionnaires assessing parental care, social connectedness (loneliness, attachment anxiety and avoidance), chronic stress, childhood trauma and depression. Results: Young adults of divorced parents had a higher risk for Axis I but not Axis II disorders as compared to young adults of non-divorced parents. Participants from divorced families as compared to non-divorced families reported more depression, loneliness, childhood trauma, attachment avoidance, attachment anxiety, chronic stress and less parental care. Limitations: Due to the cross-sectional design of this study, conclusions about causality remain speculative. Conclusion: The increased vulnerability of children of divorced parents to develop mental disorders, and to experience more chronic stress, loneliness, attachment avoidance, attachment anxiety, and traumatic experiences during childhood is alarming and highlights the importance of prevention programs and psycho-education during the process of parental divorce. Parental support with regard to adequate caregiving is needed to help parents to better support their children during and after their divorce

Visceral-afferent signals from the cardiovascular system, but not urinary urge, affect startle eye blink

The aim of the current study was to investigate if startle methodology is suitable to reflect urinary urgency. Eighteen healthy men were tested on two separate days, each including an ingestion of fluid until 80% of the subjective urge to micturate was reached. EMG responses to acoustic startle stimuli were assessed before and after micturition, as well as in the early and late cardiac cycle phases (230 vs. 530 ms after a cardiac R-wave). Sonographic assessment confirmed bladder-filling status. Emotional arousal, stress, urge and unpleasantness ratings, as well as mean blood pressure were higher before than after micturition. Startle eye blink responses were lower during the early than during the late cardiac cycle phase, but were not affected by bladder filling status. We conclude that startle methodology is suitable for the investigation of afferent signals from the cardiovascular system, but not to reflect urinary urgency. This result may be due to different neurophysiological mechanisms underlying afferent signals from the bladder compared to other visceral organs or interference with affective states or sympathetic activation associated with bladder filling. Notwithstanding, the present research protocol of fluid intake, sonographic assessment of the bladder, and subjective reports, can be applied to examine visceral-afferent signals from the bladder