Neural Correlates of Urinary Retention in Lateral Medullary Infarction / 대한배뇨장애요실금학회지

PURPOSE: The brainstem plays an important role in the control of micturition, and brainstem strokes are known to present with micturition dysfunction. Micturition dysfunction in cases of lateral medullary infarction (LMI) is uncommon, but often manifests as urinary retention. In this study, we investigated the neuro-anatomical correlates of urinary retention in patients with LMI. METHODS: This was a hospital-based retrospective study conducted in the neurology unit of a quaternary-level teaching hospital. Inpatient records from January 2008 to May 2018 were searched using a computerized database. Cases of isolated LMI were identified and those with micturition dysfunction were reviewed. MRI brain images of all patients were viewed, and individual lesions were mapped onto the Montreal Neurological Institute (MNI) space manually using MRIcron. Nonparametric mapping toolbox software was used for voxel-based lesion-symptom analysis. The Liebermeister test was used for statistical analysis, and the resultant statistical map was displayed on the MNI template using MRIcron. RESULTS: During the study period, 31 patients with isolated LMI were identified. Their mean age was 48 years and 28 (90%) were male. Six of these patients (19%) developed micturition dysfunction. All 6 patients had urinary retention and 1 patient each had urge incontinence and overflow incontinence. In patients with LMI, the lateral tegmentum of the medulla showed a significant association with urinary retention. CONCLUSIONS: In patients with isolated LMI, we postulate that disruption of the descending pathway from the pontine micturition centre to the sacral spinal cord at the level of the lateral tegmentum results in urinary retention.

Modulation of cutaneous reflexes in trunk muscles induced by stimulating the cutaneous nerve that innervates the foot during walking and standing in humans / 体力科学

Although the trunk segment shows well-coordinated movements in concert with the arms and legs during bipedal walking, little is understood about the neural mechanisms controlling the trunk muscles in response to sudden tactile sensations in the foot during walking. This study examined the cutaneous reflexes (CR) to shed light on the neural mechanisms underlying the regulation of the trunk muscles during walking and standing. Eleven healthy men participated in the study. Electromyographic (EMG) activities were recorded in the trapezius (TRAP), erector spinae (ES), and rectus abdominis (RA) muscles. To elicit CR, non-noxious electrical stimulation of the sural nerve at the ipsilateral lateral malleolus was applied during treadmill walking and tonic contraction of the test muscles during standing. During walking, cutaneous nerve stimulation in the foot gave rise to facilitatory CR in all the muscles, and the amplitude of the CR was strongly modulated in a phase-dependent manner. The amplitude of the background EMG and the amplitude of the CR showed a highly significant correlation in all the muscle tested during standing. However, this was true only in the ES during walking. In the RA, the inhibitory CR during standing changed to a facilitatory one during walking. In addition, reflex ratios were significantly larger during walking than standing. These findings suggest that common neural mechanisms in limb muscles could function in the TRAP and RA, however, in the ES disparate neural mechanisms play a crucial role in modulating cutaneous reflexes during walking and standing.

Acute application of bilevel positive airway pressure influences the cardiac autonomic nervous system

INTRODUCTION: Noninvasive positive pressure has been used to treat several diseases. However, the physiological response of the cardiac autonomic system during bilevel positive airway pressure (Bilevel) remains unclear. OBJECTIVE: The aim of this study was to evaluate the heart rate variability (HRV) during Bilevel in young healthy subjects. METHODS: Twenty men underwent 10-minute R-R interval recordings during sham ventilation (SV), Bilevel of 8-15 cmH2O and Bilevel of 13-20 cmH2O. The HRV was analyzed by means of the parallel R-R interval (mean R-Ri), the standard deviation of all R-Ri (SDNN), the root mean square of the squares of the differences between successive R-Ri (rMSSD), the number of successive R-Ri pairs that differ by more than 50 milliseconds (NN50), the percentage of successive R-Ri that differ by more than 50 milliseconds (pNN50), the low frequency (LF), the high frequency (HF) and SD1 and SD2. Additionally, physiological variables, including blood pressure, breathing frequency and end tidal CO2, were collected. Repeated-measures ANOVA and Pearson correlation were used to assess the differences between the three studied conditions and the relationships between the delta of Bilevel at 13-20 cmH2O and sham ventilation of the HRV indexes and the physiological variables, respectively. RESULTS: The R-Ri mean, rMSSD, NN50, pNN50 and SD1 were reduced during Bilevel of 13-20 cmH2O as compared to SV. An R-Ri mean reduction was also observed in Bilevel of 13-20 cmH2O compared to 8-15 cmH2O. Both the R-Ri mean and HF were reduced during Bilevel of 8-15 cmH2O as compared to SV, while the LF increased during application of Bilevel of 8-15 cmH2O as compared to SV. The delta (between Bilevel at 13-20 cmH2O and sham ventilation) of ETCO2 correlated positively with LF, HF, the LF/HF ratio, SDNN, rMSSD and SD1. Acute application of Bilevel was able to alter the cardiac autonomic nervous system, resulting in a reduction in parasympathetic...

Moderate-term reproducibility of heart rate variability during rest and light to moderate exercise in children

Previous studies have demonstrated the high reproducibility of heart rate variability (HRV) measures in adults while little information exists concerning HRV reproducibility in children. Subsequently, the aim of the current study was to examine the moderate-term reproducibility of heart rate and frequency domain measures of HRV during rest and light to moderate exercise in children. Ten healthy children (6 males, 4 females) aged between 7 and 12 years of age volunteered for this study with HRV recordings obtained during supine rest and three treadmill walking exercise work rates (¡Ü60 percent maximum heart rate), initially and then 8 weeks later. Differences (P < 0.05) between variables were examined using paired t-tests or Wilcoxon signed rank tests while reliability and reproducibility were examined by intraclass correlation coefficients (ICC), coefficients of variation (CV), and mean bias ratio and ratio limits of agreement (LOA). Heart rate and all measures of HRV at rest and exercise were unchanged after 8 weeks. Significant ICC were documented primarily during rest (0.72-0.85) while weaker relationships (-0.02-0.87) were evident during exercise. A large range of CV was identified during rest (6-33 percent) and exercise (3-128 percent) while the ratio LOA were variable and substantial (1.04-2.73). Despite similar HRV over an 8-week period, variable ICC and sizable CV and ratio LOA indicate moderate to poor reproducibility of HRV in children, particularly during light to moderate exercise. Studies examining HRV in children should include age- or maturation stage-matched control participants to address the age-related change in HRV and inadequate HRV reliability.

Attention and Psychiatric disorders

Attention is a phenomenon hard to define, but can be conceptualized as a mental function ranging from sustaining readiness to perceive stimuli to understanding the nature and value and selecting stimuli that are most relevant to the given situation. Manifestations of attention include vigilance, and focused, directed, selective, divided, and sustained attentions. While basic attentional tone is controlled by the interaction among reticular activating system, thalamus, and prefrontal cortex, direction and selection of attention is controlled by neural circuits of prefrontal, posterior parietal, and limbic cortex. It is expected that understanding of attention and its neural could provide answers to the relationship between pathophysiology and clinical symptoms of some major psychiatric disorders. More effort are required to develop tools to assess more detailed and various aspects of attention in Korea.

ARTERIAL BARORECEPTOR REFLEX IN GROWING RATS / 体力科学

In order to characterize the neural control of the circulation in an organism undergoing a rapid somatic growth, we compared the arterial baroreceptor reflex in two groups of male Wistar rats anesthetized with urethane. The first group consisted of 36 rats of 6-7 weeks old, known to exhibit the greatest rate of increase of the body weight during the life span, whereas the second group consisted of 30 full-grown rats of 20-22 weeks old. When arterial pressure was controlled by phenylephrine or nitroglycerin, the reflex change in renal nerve activity was elicited over the arterial pressure range 15-30 mmHg lower than that of full-grown rats. The difference was attributable partly, but not exclusively, to the lower operating range of arterial baroreceptors in the former groups. Although no difference was observed between the two groups with respect to the reflex fall in arterial pressure in response to graded electrical stimulation of the aortic nerve, the accompanying bradycardia was significantly smaller in 6-7 weeks old rats primarily due to the difference in the vagally mediated component of the reflex response. In conclusion, the arterial baroreceptor reflex of growing rats, as compared to full-grown counterparts, is characterized by deviation of the operating range of arterial baroreceptors as well as the arterial baroreceptor reflex itself to lower arterial pressure range and poor development of the vagally mediated reflex bradycardia.