Carotid sinus baroafferent signals contribute to cerebral blood flow regulation during acute hypotension in young males: A randomized crossover study.

Cerebral autoregulation is an important factor in prevention of cerebral ischemic events. We tested a traditional but unproven hypothesis that carotid sinus baroafferent signals contribute to dynamic cerebral autoregulation. Middle cerebral artery mean blood velocity (MCA Vmean ) responses to thigh-cuff deflation-induced acute hypotension were compared between conditions using neck suction soon after cuff deflation, without or with a cushion wrapped around the upper neck, in nine healthy males (aged 25 ± 5 years). Neck suction was applied close to the hypotension. The MCA Vmean response was expected to differ between conditions because the cushion was presumed to prevent the carotid sinus distension by neck suction. The cushion hindered bradycardia and depressor responses during sole neck suction. Thigh-cuff deflation decreased mean arterial blood pressure (MAP) and MCA Vmean (Ps < 0.05) with an almost unchanged respiratory rate under both conditions. However, in the neck suction + cushion condition, subsequent MCA Vmean restoration was faster and greater (Ps ≤ 0.0131), despite similar changes in MAP in both conditions. Thus, carotid sinus baroafferent signals would accelerate dynamic cerebral autoregulation during rapid hypotension in healthy young males. Elucidating the mechanism underlying cerebral neural autoregulation could provide a new target for preventing cerebral ischemic events.

Dispersing attentional resources reduces negative emotions.

Research shows that human attentional focus expands under positive emotions and narrows under negative emotions. Moreover, expanding (or contracting) the attentional focus is associated with dispersing (or concentrating) attentional resources. This study investigated whether dispersing or concentrating attentional resources on a target stimulus can change negative emotions to positive ones. We used the flanker task to manipulate the attentional resource allocation range by displaying a peripheral, task-unrelated induction stimulus far from the target stimulus or a central, task-unrelated induction stimulus near the target stimulus. The attentional resources allocated to the target stimulus were measured by recording the P300 component, an event-related potential indicating attention allocation. We also presented negative images before and after the task and used the Self-Assessment Manikin and the Affect Grid to assess the negative emotions induced by the images. The P300 amplitudes for the target stimuli were smaller in the peripheral than in the central condition. Moreover, self-reported negative emotions in the peripheral condition decreased after the task but did not change in the central condition. The dispersion of attentional resources changes negative emotions into a positive orientation.

Differential relationship between decreased muscle oxygenation and blood pressure recovery during supraventricular and ventricular tachycardia.

Vasoconstriction during tachyarrhythmia contributes to maintenance of arterial pressure (AP) by decreasing peripheral blood flow. This cross-sectional observational study aimed to ascertain whether the relationship between peripheral blood flow and AP recovery occurs during both paroxysmal supraventricular (PSVT, n = 19) and ventricular tachycardias (VT, n = 17). Peripheral blood flow was evaluated using forearm tissue oxygen index (TOI), and mean AP (MAP) was measured using a catheter inserted in the brachial or femoral artery during an electrophysiological study. PSVT and VT rapidly decreased MAP with a comparable heart rate (P = 0.194). MAP recovered to the baseline level at 40 s from PSVT onset, but not VT. The forearm TOI decreased during both tachyarrhythmias (P ≤ 0.029). The TOI response was correlated with MAPrecovery (i.e., MAP recovery from the initial rapid decrease) at 20-60 s from PSVT onset (r = -- 0.652 to - 0.814, P ≤ 0.0298); however, this association was not observed during VT. These findings persisted even after excluding patients who had taken vasoactive drugs. Thus, restricting peripheral blood flow was associated with MAP recovery during PSVT, but not VT. This indicates that AP recovery depends on the type of tachyarrhythmia: different cardiac output and/or vasoconstriction ability during tachyarrhythmia.

Avoidant attachment attenuates the need-threat for social exclusion but induces the threat for over-inclusion.

The influence of attachment style-anxious (AX) and avoidant (AV) attachment-on subjective responses to socially excluded experiences termed "Need-Threat" remains inconsistent. Need-Threat is a composite score of four fundamental needs: belonging, self-esteem, control, and meaningful existence. Individuals with high AX tend to spend much effort maintaining strong connections with others, while those with high AV tend to maintain high levels of self-esteem by distancing themselves from others. Therefore, attachment style is most likely to influence the need associated with each style. In addition, since individuals with high AV satisfy their needs by keeping independence from others, they would experience the Need-Threat against excessive inclusion from others. This study aimed to investigate the influence of attachment style on each Need-Threat response to various inclusionary statuses. A total of 133 undergraduate students were equally assigned to low or high groups for each attachment style. Participants played one of the three types of the cyberball task (a ball-tossing game with programmed players): excluded, included, or over-included situation. The high AV group felt fewer threats to self-esteem than the low AV group in the excluded situation (p = 0.02). Furthermore, only in the over-included situation did the high AV group feel more threats to belonging and self-esteem than the low AV group (ps < 0.02). AX did not influence any situation. These findings suggest that individuals with high AV would have a restrictive alleviation effect on adverse subjective responses to socially excluded experiences but demonstrate maladaptive subjective responses to over-included experiences.