Herma Lina Schaare

Neural Control of Vascular Reactions: Impact of Emotion and Attention

This study investigated the neural regions involved in blood pressure reactions to negative stimuli and their possible modulation by attention. Twenty-four healthy human subjects (11 females; age = 24.75 ± 2.49 years) participated in an affective perceptual load task that manipulated attention to negative/neutral distractor pictures. fMRI data were collected simultaneously with continuous recording of peripheral arterial blood pressure. A parametric modulation analysis examined the impact of attention and emotion on the relation between neural activation and blood pressure reactivity during the task. When attention was available for processing the distractor pictures, negative pictures resulted in behavioral interference, neural activation in brain regions previously related to emotion, a transient decrease of blood pressure, and a positive correlation between blood pressure response and activation in a network including prefrontal and parietal regions, the amygdala, caudate, and mid-brain. These effects were modulated by attention; behavioral and neural responses to highly negative distractor pictures (compared with neutral pictures) were smaller or diminished, as was the negative blood pressure response when the central task involved high perceptual load. Furthermore, comparing high and low load revealed enhanced activation in frontoparietal regions implicated in attention control. Our results fit theories emphasizing the role of attention in the control of behavioral and neural reactions to irrelevant emotional distracting information. Our findings furthermore extend the function of attention to the control of autonomous reactions associated with negative emotions by showing altered blood pressure reactions to emotional stimuli, the latter being of potential clinical relevance.

The age-dependent relationship between resting heart rate variability and functional brain connectivity

&NA; Resting heart rate variability (HRV), an index of parasympathetic cardioregulation and an individual trait marker related to mental and physical health, decreases with age. Previous studies have associated resting HRV with structural and functional properties of the brain – mainly in cortical midline and limbic structures. We hypothesized that aging affects the relationship between resting HRV and brain structure and function. In 388 healthy subjects of three age groups (140 younger: 26.0 ± 4.2 years, 119 middle‐aged: 46.3 ± 6.2 years, 129 older: 66.9 ± 4.7 years), gray matter volume (GMV, voxel‐based morphometry) and resting state functional connectivity (eigenvector centrality mapping and exploratory seed‐based functional connectivity) were related to resting HRV, measured as the root mean square of successive differences (RMSSD). Confirming previous findings, resting HRV decreased with age. For HRV‐related GMV, there were no statistically significant differences between the age groups, nor similarities across all age groups. In whole‐brain functional connectivity analyses, we found an age‐dependent association between resting HRV and eigenvector centrality in the bilateral ventromedial prefrontal cortex (vmPFC), driven by the younger adults. Across all age groups, HRV was positively correlated with network centrality in the bilateral posterior cingulate cortex. Seed‐based functional connectivity analysis using the vmPFC cluster revealed an HRV‐related cortico‐cerebellar network in younger but not in middle‐aged or older adults. Our results indicate that the decrease of HRV with age is accompanied by changes in functional connectivity along the cortical midline. This extends our knowledge of brain‐body interactions and their changes over the lifespan.

Neural dynamics of stress recovery and their relation to hormonal, cardiac, and subjective changes

N = 93 healthy subjects (39 f, 54 m, age = 28 ± 8) completed the Maastricht Vital Exhaustion Questionnaire (Short Form) and reported their physical exercise activities. Multiple linear regression analyses were conducted. The results show a significant influence of physical exercise on vital exhaustion (ˇ = −.300, p < .05). Posthoc analyses show that this association is only evident in female (ˇ = −.368, p < .05), not in male participants (ˇ = .006, p = .966). In the current study the influence of physical exercise on VE in healthy subjects was confirmed only for women. This might be due to the higher range of vital exhaustion scores in women. Further implications of this gender differential effect will be discussed.