Cardiovascular and cortisol reactions to acute psychological stress and cognitive ability in the Dutch Famine Birth Cohort Study

Objective: Recently, in analyses of data from a large community sample, negative cross-sectional and prospective associations between cardiac stress reactivity and obesity were observed. The present study re-examined the association between cardiovascular reactivity and adiposity in the Dutch Famine Birth Cohort, with the additional aim of examining the association between cortisol reactivity and adiposity. Methods: Blood pressure, heart rate, and salivary cortisol were measured at rest and in response to standard laboratory stress tasks in 725 adults. Height, weight, waist and hip circumference, and skin fold thickness were measured. Four to seven years later 460 participants reported current height and weight. Obesity was defined as a BMI > 30kg/m2. Results: Cross-sectional analyses revealed negative associations between all measures of adiposity and heart rate reactivity; those with a greater BMI (ß = -0.39 bpm), waist-hip ratio (ß = -0.15 bpm), and triceps and subscapular skin fold thicknesses (ß = -1.0 bpm and -1.8 bpm), or categorized as obese (-3.9 bpm) displayed smaller cardiac reactions to acute stress (all p <.001). With the exception of waist-hip ratio, the same negative associations emerged for cortisol reactivity (all p ≤ .01). In prospective analyses, low cardiac reactivity was associated with an increased likelihood of becoming or remaining obese in the subsequent 4-7 years (OR 1.03, p = .01). All associations withstood adjustment for a range of possible confounders. Conclusions: The present analyses provide additional support for the hypothesis that it is low not high cardiac and cortisol stress reactivity that is related to adiposity

Increased blood pressure reactions to acute mental stress are associated with 16-year cardiovascular disease mortality

Exaggerated cardiovascular reactions to acute psychological stress may be involved in the aetiology of cardiovascular pathology. The present analysis examined the association between the magnitude of systolic and diastolic blood pressure reactions to stress and cardiovascular disease mortality. Participants were 431 (229 women) from the West of Scotland Twenty-07 Study, aged 63 years at the time of stress testing, where blood pressure was measured during resting baseline and mental arithmetic stress. Participants’ vital status was tracked for the next 16 years, during which time 38 had died of cardiovascular disease. Both systolic and diastolic blood pressure reactions were positively associated with cardiovascular disease mortality. This association could reflect the long term erosive effects of exaggerated reactivity on the vasculature as well as its short term capacity to trigger acute cardiovascular events

Are Large Physiological Reactions to Acute Psychological Stress Always Bad for Health?

How we react physiologically to stress has long been considered to have implications for our health. There is now persuasive evidence that individuals who show large cardiovascular reactions to stress are at increased risk of developing cardiovascular disease, particularly hypertension. By implication, low reactivity is protective or benign. However, there is recent evidence that low reactivity may predict elevated risk for a range of adverse health outcomes, such as depression, obesity, poor self-reported health, and compromised immunity. In addition, low cortisol and cardiovascular reactivity may be a characteristic of individuals with addictions to tobacco and alcohol, as well as those at risk of addiction and those who relapse from abstinence. Our ideas about reactivity may have to be revised in the light of such findings

Social context and sex moderate the association between type D personality and cardiovascular reactivity

peer-reviewedType D personality has been consistently associated with adverse cardiovascular health with atypical cardiovascular reactions to psychological stress one plausible underlying mechanism. However, whether this varies by sex and social context has received little attention. This study examined the interaction between Type D personality, sex and social context on cardiovascular reactivity to acute stress. A sample of 76 healthy undergraduate students (47 female) completed the DS14 Type D measure, before undergoing a traditional cardiovascular reactivity protocol. The social context of the laboratory environment was manipulated to create a social and non-social context using a between-subjects design. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were monitored throughout. No associations were evident for blood pressure. However, a significant personality × sex × social context interaction on HR reactivity was found; here Type D was associated with a higher HR response to the social task amongst males but not females, while Type D females typically exhibited blunted reactions. While these atypical reactions indicate a possible psychophysiological pathway leading to adverse cardiovascular events amongst Type Ds, it appears that Type D males are particularly vulnerable to socially based stressors, exhibiting exaggerated cardiovascular reactions.peer-reviewe

Mis-perception of motion in depth originates from an incomplete transformation of retinal signals

Depth perception requires the use of an internal model of the eye-head geometry to infer distance from binocular retinal images and extraretinal 3D eye-head information, particularly ocular vergence. Similarly for motion in depth perception, gaze angle is required to correctly interpret the spatial direction of motion from retinal images; however, it is unknown whether the brain can make adequate use of extraretinal version and vergence information to correctly transform binocular retinal motion into 3D spatial coordinates. Here, we tested this by asking participants to reconstruct the spatial trajectory of an isolated disparity stimulus moving in depth either peri-foveally or peripherally while participants’ gaze was oriented at different vergence and version angles. We found large systematic errors in the perceived motion trajectory that reflected an intermediate reference frame between a purely retinal interpretation of binocular retinal motion (not accounting for veridical vergence and version) and the spatially correct motion. We quantify these errors with a 3D reference frame model accounting for target, eye and head position upon motion percept encoding. This model could capture the behavior well, revealing that participants tended to underestimate their version by up to 17%, overestimate their vergence by up to 22%, and underestimate the overall change in retinal disparity by up to 64%, and that the use of extraretinal information depended on retinal eccentricity. Since such large perceptual errors are not observed in everyday viewing, we suggest that both monocular retinal cues and binocular extraretinal signals are required for accurate real-world motion in depth perception

Misperception of motion in depth originates from an incomplete transformation of retinal signals.

Depth perception requires the use of an internal model of the eye-head geometry to infer distance from binocular retinal images and extraretinal 3D eye-head information, particularly ocular vergence. Similarly, for motion in depth perception, gaze angle is required to correctly interpret the spatial direction of motion from retinal images; however, it is unknown whether the brain can make adequate use of extraretinal version and vergence information to correctly transform binocular retinal motion into 3D spatial coordinates. Here we tested this hypothesis by asking participants to reconstruct the spatial trajectory of an isolated disparity stimulus moving in depth either peri-foveally or peripherally while participants' gaze was oriented at different vergence and version angles. We found large systematic errors in the perceived motion trajectory that reflected an intermediate reference frame between a purely retinal interpretation of binocular retinal motion (not accounting for veridical vergence and version) and the spatially correct motion. We quantify these errors with a 3D reference frame model accounting for target, eye, and head position upon motion percept encoding. This model could capture the behavior well, revealing that participants tended to underestimate their version by up to 17%, overestimate their vergence by up to 22%, and underestimate the overall change in retinal disparity by up to 64%, and that the use of extraretinal information depended on retinal eccentricity. Since such large perceptual errors are not observed in everyday viewing, we suggest that both monocular retinal cues and binocular extraretinal signals are required for accurate real-world motion in depth perception

Computations underlying the visuomotor transformation for smooth pursuit eye movements

Smooth pursuit eye movements are driven by retinal motion and enable us to view moving targets with high acuity. Complicating the generation of these movements is the fact that different eye and head rotations can produce different retinal stimuli but giving rise to identical smooth pursuit trajectories. However, because our eyes accurately pursue targets regardless of eye and head orientation (Blohm G, Lefèvre P. J Neurophysiol 104: 2103–2115, 2010), the brain must somehow take these signals into account. To learn about the neural mechanisms potentially underlying this visual-to-motor transformation, we trained a physiologically inspired neural network model to combine two-dimensional (2D) retinal motion signals with three-dimensional (3D) eye and head orientation and velocity signals to generate a spatially correct 3D pursuit command. We then simulated conditions of 1) head roll-induced ocular counterroll, 2) oblique gaze-induced retinal rotations, 3) eccentric gazes (invoking the half-angle rule), and 4) optokinetic nystagmus to investigate how units in the intermediate layers of the network accounted for different 3D constraints. Simultaneously, we simulated electrophysiological recordings (visual and motor tunings) and microstimulation experiments to quantify the reference frames of signals at each processing stage. We found a gradual retinal-to-intermediate-to-spatial feedforward transformation through the hidden layers. Our model is the first to describe the general 3D transformation for smooth pursuit mediated by eye- and head-dependent gain modulation. Based on several testable experimental predictions, our model provides a mechanism by which the brain could perform the 3D visuomotor transformation for smooth pursuit