Resting Baseline Period Research Articles

Type D personality and cardiovascular reactivity to acute psychological stress: A systematic review and meta-analysis.

Type D personality has been associated with adverse cardiovascular health, with atypical cardiovascular reactions to psychological stress considered a possible mechanism of effect. However, studies examining Type D personality and cardiovascular reactions to acute stress have yielded mixed findings. Here, we conducted a systematic review and meta-analyses to examine if, and under what conditions, Type D personality is associated with cardiovascular reactivity to stress; a particular focus was placed on sex and the social salience of the stressor as potential moderators of effects. Electronic databases (Medline, PsycArticles, PsycInfo, CINAHL, PubMed, Web of Science) were searched for relevant publications. A total of 401 articles were retrieved and screened for eligibility. Inclusion criteria included studies with nonclinical samples employing a resting baseline period followed by a psychological stress task period and measurement of cardiovascular reactivity. Following screening and removal of irrelevant articles, 17 peer-reviewed studies were included in the review. Type D personality was associated with lower blood pressure reactivity to acute psychological stress. Subgroup analyses revealed an association between Type D personality and lower cardiovascular reactivity among females, but not males. Additionally, Type D personality was primarily associated with lower cardiovascular reactivity in response to nonsocial stressors. Type D personality is associated with lower blood pressure reactivity to acute psychological stress, particularly among females and in response to nonsocial stressors. This lower response may be indicative of blunted cardiovascular reactivity and therefore signals an increased risk of adverse health outcomes. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Creative Minds at Rest: Creative Individuals are More Associative and Engaged with Their Idle Thoughts

ABSTRACT Despite an established body of research characterizing how creative individuals explore their external world, relatively little is known about how such individuals navigate their inner mental life, especially in unstructured contexts such as periods of awake rest. Across two studies, the present manuscript tested the hypothesis that creative individuals are more engaged with their idle thoughts and more associative in the dynamic transitions between them. Study 1 captured the real-time conscious experiences of 81 adults as they voiced aloud the content of their mind moment-by-moment across a 10-minute unconstrained baseline period. Higher originality scores on a divergent thinking task were associated with less perceived boredom, more words spoken overall, more freely moving thoughts, and more loosely-associative (as opposed to sharp) transitions during the baseline rest period. In Study 2, across 2,612 participants, those who reported higher self-rated creativity also reported less perceived boredom during the COVID-19 pandemic, a time during which many people experienced unusually extended periods of unstructured free time. Overall, these results suggest a tendency for creative individuals to be more engaged and explorative with their thoughts when task demands are relaxed, raising implications for resting state functional MRI and societal trends to devalue idle time.

Institutional status and identity dimensions to cardiovascular stress responses

AbstractThis study aimed to examine the effect of shared social identity (i.e., whether the source of information about a stressor comes from an ingroup vs. outgroup member) and message content (i.e., whether people were informed that the task is stressful vs. challenging) on cardiovascular reactivity to stress (CVR) across two higher education institutions differing in status (University vs. Institute of Technology [IoT]). The study employed a quasi‐experimental 2 × 2 × 2 design. 80 healthy undergraduate students (38 female, 47.5%) were recruited from two institutions—a University (n = 40) and an IoT (n = 40). All students underwent a standardised cardiovascular stress testing protocol (i.e., baseline rest period, manipulation, stress task). Blood pressure and heart rate were continuously monitored throughout. Results indicated that IoT students who were informed that the task would be stressful by an outgroup member (a University student) displayed relatively higher SBP reactivity (M = 17.53, SD = 4.72). Interestingly, those from the University who were informed that the task would be stressful by an ingroup member (also a University student) similarly displayed high level of reactivity (M = 19.45, SD = 4.33). It appears that being told the task is stressful had different effects depending on what institution the person was in, and who provided the information. These findings provide preliminary evidence to suggest that cardiovascular responses to stress may not simply be impacted by the source or content, but also the status or social position of the informants group.

Effects of Low-Intensity Aerobic Exercise on Neurophysiological and Behavioral Correlates of Cognitive Function.

Acute aerobic exercise exerts a small beneficial effect on cognition. Previous research primarily examines cognitive changes following a bout of exercise, while little is currently known about changes in cognitive performance during exercise. The primary purpose of this study was to examine the effects of low-intensity cycling on cognitive function indexed by behavioral (response accuracy; reaction time) and neurocognitive (P3 mean amplitude; P3 centroid latency) responses. Twenty-seven (Mage = 22.9 ± 3.0 years old) individuals were counterbalanced into low-intensity exercise (EX) and seated control (SC) conditions spread across two testing sessions. During each condition, participants completed a 10 min resting baseline period, 20 min of either sustained cycling or seated rest, and a 20 min recovery period. Primary outcomes were assessed at 10 min intervals (five blocks total) throughout each condition via a modified visual oddball task while electroencephalography (EEG) responses were measured. Across time blocks, both conditions exhibited faster reaction times on frequent trials but reduced accuracy to rare trials, suggesting a speed-accuracy tradeoff. There were no differences between conditions in P3 centroid latency, whereas a significant reduction in P3 amplitude was observed during the 20 min exercise period compared to the control condition. Taken together, results suggest that exercise at lower doses may have minimal influence on behavioral outcomes of cognitive performance but may impact more basic measures of brain function. Information gathered from this study may aid in the development of appropriate exercise prescriptions for populations looking to specifically target cognitive function deficits.

Beat-to-beat resting blood pressure variability in patients with type 2 diabetes: effect of statin therapy

Type 2 diabetes (T2D) is a major health concern affecting more than 30 million people in the United States alone. Approximately two-thirds of patients with T2D develop hypertension, a major risk factor for cardiovascular disease. In addition to higher resting absolute blood pressure (BP), increased variability in BP has also been related to greater cardiovascular disease risk. However, whether patients with T2D display greater beat-to-beat BP variability remains unknown. Herein, we hypothesized that patients with T2D would exhibit greater beat-to-beat BP variability than age and body-weight-matched control subjects. In addition, since previous literature has shown that statins lower cardiovascular disease risk through favorable pleiotropic mechanisms, we further hypothesized that patients with T2D taking statins (T2D+statin) would have a lower beat-to-beat BP variability compared to patients with T2D not taking statins (T2D-statin). Beat-to-beat BP (finger photoplethysmography) and heart rate (ECG) were continuously measured, and absolute BP (automated sphygmomanometer) was measured periodically in patients with T2D (N=23; T2D+statin: N=10, T2D-statin: N=13) and age and body weight-matched control subjects (N=17). Measurements were made over the course of a quiet resting baseline period (9.5±1.3 minutes) with subjects in a supine position. Beat-to-beat BP variability was quantified as standard deviation (SD), range, and average real variability (average change in BP from one heartbeat to the next). Data are presented as mean ± standard deviation. Resting absolute systolic BP, diastolic BP, and mean arterial pressure (MAP) were not different between control subjects and T2D patients (P>0.05 for all). There was also no difference in beat-to-beat systolic BP, diastolic BP, or MAP variability between the groups (e.g., MAP SD: control: 4.5±1.3 mmHg, T2D: 4.7±1.1 mmHg, P=0.763). When comparing T2D patients taking statins and those not taking statins, no difference was observed in absolute resting BP (P>0.05). Likewise, systolic BP variability was not different between groups (SD: T2D-statin: 7.0±2.2 mmHg, T2D+statin: 6.3±1.4 mmHg, P=0.369). However, diastolic BP variability was significantly higher in T2D-statin patients (SD: T2D-statin: 4.1±1.1 mmHg, T2D+statin: 3.1±0.6 mmHg, P=0.013) and MAP variability tended to be higher (SD: T2D-statin: 5.2±1.4 mmHg, T2D+statin: 4.3±0.7 mmHg, P=0.061). Similar results were found for BP range and average real variability. These preliminary findings suggest that statin therapy may have a beneficial effect in lowering BP variability in patients with T2D. Supported by American Heart Association (AHA) - Institutional Award for Undergraduate Student Training - #915555. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Diminished baseline autonomic outflow in semantic dementia relates to left-lateralized insula atrophy

In semantic dementia (SD), asymmetric degeneration of the anterior temporal lobes is associated with loss of semantic knowledge and alterations in socioemotional behavior. There are two clinical variants of SD: semantic variant primary progressive aphasia (svPPA), which is characterized by predominant atrophy in the anterior temporal lobe and insula in the left hemisphere, and semantic behavioral variant frontotemporal dementia (sbvFTD), which is characterized by predominant atrophy in those structures in the right hemisphere. Previous studies of behavioral variant frontotemporal dementia, an associated clinical syndrome that targets the frontal lobes and anterior insula, have found impairments in baseline autonomic nervous system activity that correlate with left-lateralized frontotemporal atrophy patterns and disruptions in socioemotional functioning. Here, we evaluated whether there are similar impairments in resting autonomic nervous system activity in SD that also reflect left-lateralized atrophy and relate to diminished affiliative behavior. A total of 82 participants including 33 people with SD (20 svPPA and 13 sbvFTD) and 49 healthy older controls completed a laboratory-based assessment of respiratory sinus arrhythmia (RSA; a parasympathetic measure) and skin conductance level (SCL; a sympathetic measure) during a two-minute resting baseline period. Participants also underwent structural magnetic resonance imaging, and informants rated their current affiliative behavior on the Interpersonal Adjective Scale. Results indicated that baseline RSA and SCL were lower in SD than in healthy controls, with significant impairments present in both svPPA and sbvFTD. Voxel-based morphometry analyses revealed left-greater-than-right atrophy related to diminished parasympathetic and sympathetic outflow in SD. While left-lateralized atrophy in the mid-to-posterior insula correlated with lower RSA, left-lateralized atrophy in the ventral anterior insula correlated with lower SCL. In SD, lower baseline RSA, but not lower SCL, was associated with lower gregariousness/extraversion. Neither autonomic measure related to warmth/agreeableness, however. Through the assessment of baseline autonomic nervous system physiology, the present study contributes to expanding conceptualizations of the biological basis of socioemotional alterations in svPPA and sbvFTD.

0185 N2 Sleep Spindle Activity is Associated with Better Next-Day Emotion Regulation in Healthy Children

Abstract Introduction Children's day-to-day mental health is dependent on adequate quantity and quality of sleep, but far less is known about the microstructural sleep features that support emotional functioning in children. NREM sleep spindles (rhythmic EEG oscillations between 10 and 15 Hz) are closely linked with intellectual abilities and cognitive processing, and have also been shown to relate to children’s emotional behavior, both concurrently and longitudinally. For example, socially-anxious youth showed reduction in sleep spindle activity compared to healthy controls, which correlated negatively with subjective reports of arousal in response to negative images (Wilhelm et al., 2017). In younger children, greater NREM 2 spindle density was associated with greater prosocial behavior concurrently and fewer behavioral and social problems one year later (Mikoteit et al., 2012; 2013). However, studies in pediatric samples are limited overall and haven’t examined spindles in relation to objective measures of emotion regulation. Methods We examined relationships between spindle activity during NREM stage 2 (N2) and next-day subjective and objective emotional responses among N=26 healthy children, 7-11 years old. Children completed a full-night of at-home PSG monitoring (10hr sleep opportunity) followed by two in-lab tasks. In task 1, children rated arousal/reactivity in response to negative images from the International Affective Pictures System (IAPS). In task 2, respiratory sinus arrhythmia (RSA) was measured while children were directed to suppress all facial expressions of emotion (i.e., regulate emotional responses to negative content) while watching negatively-valenced movie clips. All analyses controlled for total sleep time on PSG night and RSA analyses controlled for a resting baseline period. Results Greater C3 spindle count (r = .51, p < .05) and density (r = .53, p < .05) were significantly associated with less child-reported arousal towards negative images. Greater F3 peak spindle frequency was positively associated with higher RSA during negative movies (r = .54, p < .05), suggesting better regulatory control of emotional responses to correspond with greater spindle peak frequency. Conclusion Together with previous data, our findings suggest that sleep spindle activity may partially reflect children’s capacity to regulate emotional responses in relation to stressful situations, thereby potentially reducing risk of mental health problems. Support (If Any)

Redundancy in the International Anorectal Physiology Working Group Manometry Protocol: A Diagnostic Accuracy Study in Fecal Incontinence.

Anorectal manometry (ARM) is essential for identifying sphincteric dysfunction. The International Anorectal Physiology Working Group (IAPWG) protocol and London Classification provide a standardized format for performing and interpreting ARM. However, there is scant evidence to support timing and number of constituent maneuvers. To assess the impact of protocol modification on diagnostic accuracy in patients with fecal incontinence. Retrospective analysis of high-resolution ARM recordings from consecutive patients based on the current IAPWG protocol and modifications thereof: (1) baseline rest period (60 vs. 30 vs. 10s); (2) number of abnormal short squeezes (SS) out of 3 (SS1/SS2/SS3) based on maximal incremental squeeze pressures over 5s; (3) resting anal pressures (reflecting recovery) at 25-30 versus 15-20s after SS1. One hundred patients (86 F, median age 55 [IQR: 39-65]; median St. Mark's incontinence score 14 [10-17]) were studied. 26% and 8% had anal hypotonia and hypertonia, respectively. Compared with 60-s resting pressure, measurements had perfect correlation (κ = 1.0) over 30s, and substantial correlation (κ = 0.85) over 10s. After SS1, SS2, and SS3, 43%, 49%, and 46% had anal hypocontractility, respectively. Correlation was substantial between SS1 and SS2 (κ = 0.799) and almost perfect between SS2 and SS3 (κ = 0.9). Compared to resting pressure of 5s before SS1, pressure recordings at 25-30 and 15-20s after SS1 were significantly correlated. A 30-s resting anal pressure, analysis of 2 short-squeezes with a 20-s between-maneuver recovery optimizes study duration without compromising diagnostic accuracy. These findings indicate the IAPWG protocol has redundancy.

Resting state heart rate variability and false memories

Recent studies have shown higher resting-state vagally-mediated heart rate variability (vmHRV) to be related to greater memory retrieval. Research has not yet linked resting vmHRV with memory encoding and retrieval, as both are thought to play an important role in correctly distinguishing between true and false memories. The current study investigated this possible link in n = 71 undergraduate students. VmHRV was assessed during a 5-minute resting baseline period. Participants then completed the Deese-Roediger-McDermott (DRM) task, where they first viewed 6 word lists (12 words per list), and were later asked to identify previously shown words (true memories) and reject non-presented words. Results showed that participants with lower resting vmHRV were less able to discriminate true from false items. These data extend previous work on resting vmHRV and memory suggesting that resting vmHRV represents a psychophysiological pathway involved in both the proper encoding and retrieval of memories.

Linking Parental Monitoring and Psychological Control with Internalizing Symptoms in Early Adolescence: The Moderating Role of Vagal Tone

The present study investigated baseline respiratory sinus arrhythmia (RSA) as moderator of the prospective association between parenting (i.e., monitoring knowledge, psychological control) and internalizing symptoms among typically developing adolescents across the transition to middle school. Gender differences in the aforementioned association were tested as an exploratory aim. At Time 1 (5th grade), participants included 100 young adolescents (53% boys; 57% European American; Mage = 11.05years, SD = 0.33) and their mothers (Mage = 41.25years, SD = 6.22; 96.0% biological). At Time 2 (6th grade), 89 adolescents and their mothers returned. To address study aims, a multi-informant, multi-method, longitudinal design was used. At Time 1, mothers reported on monitoring knowledge and psychological control, and adolescents' baseline RSA was measured during a resting baseline period. At Times 1 and 2, adolescents reported on three indices of internalizing symptoms (depressive symptoms, social anxiety, loneliness and social dissatisfaction). Results from multiple regression analyses revealed that higher levels of psychological control predicted higher levels of depressive symptoms and loneliness over time. Further, among boys, lower baseline RSA exacerbated the link between maternal psychological control and higher levels of depressive symptoms and loneliness, whereas higher baseline RSA attenuated the effect. Overall, our findings for boys were consistent with prior evidence of lower baseline RSA as a risk factor and higher baseline RSA as a protective factor against psychopathology. Findings contribute to the growing literature on biopsychosocial interactions and youth mental health.

Establishing the validity of a novel passive stress task.

Laboratory tasks used to elicit a cardiovascular stress response in the laboratory can involve either active or passive coping. However, in previous work, passive stress tasks often incorporate a distinct physical stress element, such as the handgrip or cold pressor task, meaning observed changes in cardiovascular parameters may be the result of the physical element of the stressor rather than truly reflecting psychological stress. The present study aimed to establish the validity of a psychological passive stressor; one more analogous to active tasks than those previously employed in laboratory studies. Twenty-six young, healthy adults completed a speech task in the laboratory following a resting baseline period. Twelve months later, they were invited back to the laboratory and watched the video recording of their speech. Analyses confirmed that while both tasks elicited significant SBP and DBP change (all ps<.001), only the active task was associated with HR and CO reactivity (both ps<.001), while only the passive task was associated with TPR reactivity (p=.028). Furthermore, the passive stressor was associated with a mixed hemodynamic profile, whereas the active stressor was associated with a clear myocardial profile. This study confirms that watching a video recording of oneself complete a speech task is associated with a more vascular response profile, a response associated with passive coping contexts.

Effect of nutritive and non-nutritive sweeteners on hemodynamic responses to acute stress: a randomized crossover trial in healthy women

BackgroundThe mechanisms by which chronic stress increases the risk of non-communicable diseases remain poorly understood. On one hand, chronic stress may increase systemic vascular resistance (SVR) and blood pressure, which may lead to blood vessels injury and altered myocardial perfusion. On the other hand, chronic stress may promote the overconsumption of sugar-containing foods and favor obesity. There is indeed evidence that sweet foods are preferentially consumed to alleviate stress responses. The effects of nutritive and non-nutritive sweeteners (NNS) on hemodynamic stress responses remain however largely unknown.Objective/designThis study aimed at comparing the effects of sucrose-containing and NNS-containing drinks, as compared to unsweetened water, on hemodynamic responses to acute stress in twelve healthy female subjects. Acute stress responses were elicited by a 30-min mental stress (5-min Stroop’s test alternated with 5-min mental arithmetic) and a 3-min cold pressure test (CPT), each preceded by a resting baseline period. Hemodynamic stress responses were investigated by the repeated measurement of mean arterial pressure and the continuous monitoring of cardiac output by thoracic electrical bioimpedance measurement. SVR was selected as a primary outcome because it is a sensitive measure of hemodynamic responses to acute stress procedures.ResultsWith all three drinks, SVR were not changed with mental stress (P = 0.437), but were increased with CPT (P = 0.045). Both mental stress and CPT increased mean arterial pressure and heart rate (all P < 0.001). Cardiac output increased with mental stress (P < 0.001) and remained unchanged with CPT (P = 0.252). No significant differences in hemodynamic responses were observed between water, sucrose and NNS (stress × condition, all P > 0.05).ConclusionsThese results demonstrate that sucrose and NNS do not alter hemodynamic responses to two different standardized acute stress protocols.

The Restorative Health Benefits of a Tactical Urban Intervention: An Urban Waterfront Study

Increasing access to urban waterfronts hold much promise for promoting healthy behaviors. While many US cities are revitalising their waterfronts, the health and well-being benefits associated with these urban design initiatives are largely unknown. Tactical urban interventions (such as parklets and pop-ups) are short-term projects that experiment with and gather input on potential urban design changes. To date, the effect of these projects on individual health outcomes has not been measured. This study reports a pilot quasi-experimental study which compares real-time exposure to an urban waterfront that was manipulated to provide a control versus an intervention ‘treatment’ condition that increased levels of comfort and fascination in the setting. Our study utilized a repeated-measures crossover randomized design and captured measures of stress and well-being whilst participants walked in each condition (n=23). First, real-time stress was captured using a smart watch to capture heart rate variability (HRV) during the walk, including for a resting baseline period of measurement pre-walk. Second, subjective mood (i.e. stress, arousal and hedonic tone) was assessed pre and post walk using the UWIST MACL Mood Scale (Matthews et al., 1990). Third, two measures of perceived restorativeness (i.e. fascination and being away) were captured pre and post walk using the PRS Scale (Hartig et al., 1997), together with two indicators of social well-being (i.e. place belonging and social trust). Results showed a statistically significant reduction in perceived stress from walking in the intervention, as compared to the control condition (p<0.05). This was matched by positive and statistically significant change on our measures of perceived restoration and social well-being from walking in the intervention. R¬esults showed an increase in parasympathetic response (as measured by HRV) from exposure to the intervention, indicating lower stress, and the opposite pattern whilst walking in the control condition (i.e. increased stress), albeit only significant at the 0.055 level. We discuss future directions for this type of experimental study design and how findings on short-term tactical urban designs could be usefully applied to direct longer-term urban design changes for public health gains.

Cardiorespiratory and Cerebrovascular Responses to Leg Cycling Exercise during Muscle Metaboreflex Activation with Blood Flow Restriction in Moderate Normobaric Hypoxia

Skeletal muscle blood flow restriction and normobaric hypoxia are strategies adopted during exercise training because the associated reductions in local or systemic oxygenation may enhance athletic performance. Both manoeuvres evoke cardiorespiratory and cerebrovascular responses but have not been studied in combination. Blood flow restriction during exercise activates metabolically sensitive group III and IV skeletal muscle afferents (i.e., muscle metaboreflex activation), while systemic hypoxia activates the peripheral chemoreflex. We sought to determine whether the cardiorespiratory and cerebrovascular response to muscle metaboreflex activation with blood flow restriction during leg cycling exercise is augmented in moderate normobaric hypoxia.Nine healthy men (age 23±2 years; mean±SE) participated in two experimental trials performed under normoxic (fraction of inspired O2 [FiO2] = 21 %) and hypoxic (FiO2 = 13.5 %; equivalent of altitude of 3500 m) conditions whilst seated in a semi‐recumbent position in an environmental chamber. Trials consisted of a resting baseline period (3 min), followed by low intensity leg cycling exercise (64±7 Watts) under free‐flow conditions (~3½ min), and then bilateral thigh cuff inflation to 100 mmHg to induce blood flow restriction and muscle metaboreflex activation (~3 ½ min). Peripheral capillary oxygen saturation (SpO2; finger pulse oximetry), mean arterial pressure (MAP; Finometer and SunTech), heart rate (HR; electrocardiogram), the partial pressure of end‐tidal carbon dioxide (PETCO2; capnography), minute ventilation (VE; pneumotachometer) and middle cerebral artery mean blood flow velocity (MCAV; transcranial Doppler) were recorded.At baseline, SpO2 was lower during hypoxia (87±1 %) than normoxia (97±1 %; P&lt;0.05), but MAP, HR, PETCO2, VE and MCAv were not different between trials (P&gt;0.05). Leg cycling under free‐flow conditions significantly increased MAP, HR, PETCO2, VE and MCAv (P&lt;0.05 vs. baseline), with no differences observed between hypoxic and normoxic trials (P&gt;0.05). MAP (Δ14±2 vs. Δ16±2 mmHg; P=0.215), HR (Δ10±2 vs. Δ8±3 b·min−1; P=0.251), PETCO2 (Δ−1.1±0.3 vs. Δ−3.4±1.8 mmHg; P=0.596), VE (Δ4±1 vs. Δ4±1 L·min−1; P=0.446) and MCAv (Δ4±2 vs. Δ4±1 cm·s−1; P=0.408) responses to blood flow restriction during leg cycling (i.e., muscle metaboreflex activation) were not different in the hypoxic and normoxic trials.These preliminary findings suggest that moderate normobaric hypoxia (FiO2 = 13.5 %) does not augment the cardiorespiratory and cerebrovascular responses to muscle metaboreflex activation with blood flow restriction during low intensity leg cycling.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Altered EEG alpha and theta oscillations characterize apathy in Parkinson's disease during incentivized movement.

Apathy is a common non-motor symptom of Parkinson's disease (PD) that is difficult to quantify and poorly understood. Some studies have used incentivized motor tasks to assess apathy, as the condition is often associated with a reduction in motivated behavior. Normally event-related desynchronization, a reduction of power in specific frequency bands, is observed in the motor cortex during the peri-movement period. Also, alpha (8–12 Hz) and theta (4–7 Hz) oscillations are sensitive to rewards that are closely related to motivational states however these oscillations have not been widely investigated in relation to apathy in PD. Using EEG recordings, we investigated the neural oscillatory characteristics of apathy in PD during an incentivized motor task with interleaved rest periods. Apathetic and non-apathetic PD subjects on dopaminergic medication and healthy control subjects were instructed to squeeze a hand grip device for a monetary reward proportional to the subject's grip force and the monetary value attributed to that trial. Apathetic PD subjects exhibited higher alpha and theta powers in the pre-trial baseline rest period compared to non-apathetic PD subjects and healthy subjects. Further, we found that both resting power and relative power in alpha and theta bands during incentivized movement predicted PD subjects' apathy scores. Our results suggest that apathetic PD patients may need to overcome greater baseline alpha and theta oscillatory activity in order to facilitate incentivized movement. Clinically, resting alpha and theta power as well as alpha and theta event-related desynchronization during movement may serve as potential neural markers for apathy severity in PD.

Poincaré plot indices as measures of sympathetic cardiac regulation: Responses to psychological stress and associations with pre-ejection period

The Poincaré plot is a visual representation of the R-R time series within a Cartesian plane constructed by plotting each R-R interval as a function of the previous one. The plot can be characterized by parameters that quantify the standard deviation (SD) of short- and long-term R-R interval variability (SD1 and SD2, respectively). Claims regarding the use of Poincaré plot analysis as an alternative to conventional time-domain and spectral analytic measures of parasympathetic contributions to heart rate variability (HRV) have been evaluated somewhat extensively. However, its proposed utility for characterizing sympathetic influences on HRV during periods of acute mental stress, using SD2 and the SD1/SD2 ratio, has received minimal attention. In the present study, the electrocardiogram was used to record R-R interval variability in healthy participants during a resting baseline period, while they performed a challenging reaction time task, and then during a recovery period. Simultaneously, the thoracic impedance cardiogram was used to derive the pre-ejection period (PEP), which reflects sympathetic cardiac control. HRV was quantified using time-domain, spectral analytic, and Poincaré plot indices. Task performance elicited significant reductions in HRV and PEP parameters, indicating withdrawal of parasympathetic tone with concomitant sympathetic activation. Following cessation of task performance, all HRV and impedance measures returned to baseline levels, signaling resumption of parasympathetic dominance. Bivariate associations linking SD2 and the SD1/SD2 ratio to PEP were observed; however, these were not large in magnitude, were exceeded in size by associations between the Poincaré metrics and conventional HRV markers of parasympathetic cardiac influences, and were eliminated when the latter were controlled statistically. These observations challenge the proposal that the Poincaré SD2 and SD1/SD2 metrics are suitable markers of sympathetic cardiac regulation in research concerned with mental and physical health.

T50. Freezing of gait does not modulate neural oscillations in motor cortices

Introduction Walking abilities are severely affected in patients with freezing of gait (FOG), a common phenomenon in advanced stages of Parkinson’s disease (PD). Despite the high occurrence of FOG, little is known about the underlying mechanisms. Interestingly, it was reported that patients with FOG are still able to ride a bike (Snijders AH et al., Bicycling breaks the ice for freezers of gait, Mov Disord 2011). While similar brain networks are involved in walking and bicycling (Fukuyama H et al., Brain functional activity during gait in normal subjects: A SPECT study, Neurosci Lett 1997; Christensen LOD et al., Cerebral activation during bicycle movements in man, Exp Brain Res 2000), it is not completely understood why both types of movement are differently affected in PD patients with FOG. A recent study from our group demonstrated that the oscillatory activity within the subthalamic nucleus (STN) differs between patients with and without FOG (Storzer L et al., Bicycling suppresses abnormal beta synchrony in the Parkinsonian basal ganglia, Ann Neurol 2017). In particular, it was shown that patients with FOG present a characteristic increase of oscillatory activity at ∼18 Hz. The aim of the study was to examine movement-associated cortical oscillatory activity in PD patients with and without FOG. Methods We analyzed EEG data of 19 PD patients with FOG (65.5 ± 7.2 years), 13 PD patients without FOG (61.6 ± 8.1 years), and 16 healthy controls (63.3 ± 7.3 years). Patients were recorded OFF dopaminergic medication using a portable EEG system (Porti, TMSi, Enschede, The Netherlands). Data were recorded during unconstrained walking and bicycling on a stationary bicycle. Measurements consisted of a baseline rest period, continuous movement, and an alternating sequence of rest and movement, i.e. bicycling or walking, for 10 s each. Furthermore, measurements included 180° turns around the body axis during walking condition. Turns were rated for the occurrence of FOG episodes by two different raters. Analyses were focused on oscillatory activity in the beta band and the Cz electrode overlying the leg area of both motor cortices. Statistical testing was performed by fitting linear mixed models using package lme 1.1–13 for R. Results Bicycling and walking were associated with beta power suppression (13–35 Hz). This suppression was stronger for bicycling than for walking ( β = −0.37, p β = −0.11, p = 0.72). Furthermore, within the group of Freezers we did not find cortical differences between turns with FOG and turns without FOG either( β = 0.66, p = 0.4). Conclusion We did not observe cortical beta power changes specifically related to freezing. This finding does not support the notion that the primary motor cortex is crucially involved in generating freezing.

Disrupted physiological reactivity among children with a history of suicidal ideation: Moderation by parental expressed emotion-criticism

ObjectiveThe goal of this study was to examine physiological reactivity during parent-child interactions in children with and without a history of suicidal ideation (SI), a group known to be at increased risk for suicidal thoughts and behaviors in the future. We also examined the potential moderating role of parental expressed emotion-criticism (EE-Crit) to determine whether the presence of parental criticism may help to identify a subgroup of children with a history of SI most at risk for physiological dysregulation. MethodParticipants were 396 children (age 7–11; 54% male, 71.7% Caucasian) and their biological parent. Children’s levels of high frequency heart rate variability (HF-HRV) were assessed during a resting baseline period followed by a positive and negative discussion with their parent. Additionally, parents completed the Five-Minute Speech Sample to determine levels of EE-Crit toward their child, and children completed an interview assessing their history of SI. ResultsConsistent with our hypothesis, we found that exposure to parental criticism moderated the relation between a child’s history of SI and their HF-HRV reactivity to the discussions. Specifically, while most children exhibited the typical pattern of HF-HRV suppression from baseline to both interactions, the highest risk children (i.e., children with a history of SI who also had highly critical parents) did not display any change in HF-HRV across the tasks, suggesting a failure to engage a typical psychophysiological response during emotional contexts. ConclusionsThese results suggest a specific physiological mechanism that may place these children at risk for suicidal thoughts and behaviors in the future.

Preliminary evidence of attenuated blood pressure reactivity to acute stress in adults following a recent marital separation

Objective: This study explores cardiovascular reactivity during an acute-stress task in a sample of recently separated adults.Design: In a cross-sectional design, we examined the association between adults’ subjective separation-related distress and changes in heart rate and blood pressure across the acute-stress laboratory paradigm in a sample of 133 (n = 49 men) recently separated adults.Main outcome measures: Heart rate (HR) and Blood pressure (BP) were recorded across a resting baseline period, a math stressor task, and a recovery period.Results: Multilevel analyses revealed that adults who reported greater separation-related distress exhibited higher initial BP and a slower linear increase in BP across the study period. In addition, adults reporting greater separation-related distress evidenced significantly slower declines in diastolic blood pressure (DBP) following the acute-stress task. HR reactivity was not moderated by separation-related distress.Conclusions: In recently separated adults, preliminary evidence suggests that the context of the stressors may reveal differential patterns of problematic reactivity (exaggerated or blunted responding). Greater emotional intrusion and hyperactivity symptoms may index increased risk for blunted cardiovascular reactivity to general stressors. This pattern of reactivity is consistent with models of allostatic load that emphasise the deleterious effect of hyporesponsivity to environmental demands.

EP 60. Bicycling suppresses beta power more strongly than walking in the subthalamic nucleus of Parkinsonian patients

Introduction Walking abilities are severely affected in patients suffering from Freezing of Gait (FOG), a common phenomenon in advanced Parkinson’s disease (PD). Despite the high occurrence of the symptom in the progression of the disease, little is known about the underlying mechanisms. Remarkably, it was recently reported that patients with FOG are still able to ride a bike ( [Snijders et al., 2011] , [Snijders et al., 2012] ). While similar brain networks are involved in walking and bicycling ( [Fukuyama et al., 1997] , [Christensen et al., 2002] ), it is not understood why both types of movement are differently affected in patients with FOG. Therefore, this study aimed to investigate neural oscillations underlying bicycling and walking in PD patients. Patients and methods Seven PD patients (mean age 55.4±6.3 y) clinically selected for bilateral deep brain stimulation (DBS) therapy were included in the study. Using a portable EEG system (Porti, TMSi, Enschede, The Netherlands), local field potentials from the subthalamic nucleus (STN) were recorded using externalised leads the day after implantation of DBS electrodes. Patients were recorded while OFF any dopaminergic medication during unconstrained bicycling and walking on a stationary bicycle. The paradigm consisted of a baseline rest period, continuous movement, and an alternating sequence of rest and movement, i.e. bicycling or walking, in order to study both movement initiation and movement termination. For each STN the bipolar channel with the highest baseline beta peak power was selected for further analyses. Three of 14 STNs had to be excluded because of movement artefact contamination and a broken externalised lead in one patient. Differences were determined using cluster-based permutation tests as implemented in the FieldTrip analysis toolbox ( Oostenveld et al., 2011 ). Results Movement initiation was accompanied by power decreases in the alpha–beta range (8–35 Hz) in bicycling and walking. Contrasting both conditions revealed a stronger beta power decrease in bicycling (p 0.05). Conclusions Our finding that bicycling leads to a stronger power decrease in the beta band than walking is particularly interesting as Parkinson’s disease is generally associated with abnormally increased beta band activity in the corticobasal ganglia loop ( Oswal et al., 2013 ). The difference between oscillatory activity underlying bicycling and walking was specific to beta power suppression during movement, whereas beta rebound after movement termination was equally strong. In this sense, bicycling seems to promote the suppression of pathological oscillations in the basal ganglia, as opposed to walking. This may be due to the more continuous movement in bicycling with both legs being pushed forward permanently. In walking, stance and swing phases alternate. Therefore, one may speculate that bicycling may be less hampered in FOG because the more continuous nature of this movement promotes beta suppression and thus, facilitates movement.