Clinical correlates of frequency analyses of cardiovascular control after spinal cord injury.
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Spinal cord injury (SCI) has profound effects on cardiovascular autonomic function due to injury to descending autonomic pathways, and cardiovascular diseases are the leading causes of morbidity and mortality after SCI. Evaluation of cardiovascular autonomic dysfunction after SCI and appraisal of simple noninvasive autonomic assessments that are clinically meaningful would be useful to SCI clinicians and researchers. We aimed to assess supine and upright cardiovascular autonomic function from frequency analyses of heart rate and blood pressure variability (HRV and BPV) after SCI. We studied 26 subjects with chronic cervical or thoracic SCI and 17 able-bodied controls. We continuously recorded R-R interval (RRI, by ECG) and beat-to-beat blood pressure (by Finometer) in supine and seated positions. Cardiovascular control was assessed from spectral analysis of RRI and blood pressure time series. Cardiac baroreflex control was assessed from cross-spectral analyses of low-frequency spectra. Supine and upright low-frequency HRV and BPV were reduced in cervical SCI subjects, as were total BPV and HRV. Supine high-frequency HRV was reduced in thoracic SCI subjects. Cardiac baroreflex delay was increased in cervical SCI subjects. Supine frequency domain indexes were correlated with sympathetic skin responses, orthostatic cardiovascular responses, and plasma catecholamine levels. SCI results in reduced sympathetic drive to the heart and vasculature and increased baroreflex delay in cervical SCI subjects and reduced cardiac vagal tone in thoracic SCI subjects. Frequency analyses of autonomic function are related to clinical measures of autonomic control after SCI and provide useful noninvasive clinical tools with which to assess autonomic completeness of injury following SCI. (+info)
Increased amygdala activation is related to heart rate during emotion processing in adolescent subjects.
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Emotions have been conceptualized as representations of bodily responses to a stimulus that critically involves the autonomic nervous system (ANS). An association between amygdala activation and ANS activity has been shown in adults. However, to date, no studies have demonstrated this association in adolescents. Examining the interaction between the ANS and amygdala in healthy adolescents may provide information about age-related changes in the association between amygdala activation and ANS measures. Therefore, the aim of this study was to examine the relationship between amygdala activation and heart rate in normal adolescents. Eighteen 12- to 17-year old adolescents participated. Heart rate data was collected during functional magnetic resonance imaging while subjects performed a facial expression matching task that reliably activates the amygdala. Adolescents showed significant amygdala activation for all facial expressions relative to the shape-matching, control task. Moreover, the degree of activation in the right amygdala for Fearful faces was significantly correlated with heart rate (Spearman's rho=0.55, p=0.018, two-tailed). This study shows that amygdala activity is related to heart rate in healthy adolescents. Thus, similar to adults, adolescents show a coupling between processing emotional events and adjusting the ANS accordingly. Furthermore, this study confirms previous adolescent studies showing amygdala activation to Fearful, Angry, and Happy faces. Finally, the results of the present study lay the foundation for future research to investigate whether adolescents with mood or anxiety disorders show an altered coupling between processing emotionally salient events and ANS activity. (+info)
Induction of Fos-immunoreactivity in the rat brain following disinhibition of the dorsomedial hypothalamus.
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Asymmetry in sympathetic and vagal activities during sleep-wake transitions.
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STUDY OBJECTIVES: To explore the role of autonomic nervous system in initiation of sleep-wake transitions. DESIGN: Changes in cardiovascular variability during sleep-wake transitions of adult male Wistar-Kyoto rats on their normal daytime sleep were analyzed. INTERVENTIONS: A 6-h daytime sleep-wakefulness recording session was performed. MEASUREMENTS AND RESULTS: Electroencephalogram and electromyogram (EMG) signals were subjected to continuous power spectral analysis, from which mean power frequency of the electroencephalogram (MPF) and power of the EMG were quantified. Active waking (AW), quiet sleep (QS), and paradoxical sleep (PS) were defined every 8 s according to corresponding MPF and EMG power. Continuous power spectral analysis of R-R intervals was performed to quantify its high-frequency power (HF, 0.6-2.4 Hz), low-frequency power (0.06-0.6 Hz) to HF ratio (LF/HF). MPF exhibited two phases of change during AW-QS and QS-AW transitions: a slowly changing first phase followed by a rapidly changing second phase. HF increased linearly with the decrease of MPF during the first phase of AW-QS transition whereas LF/HF increased linearly with the increase of MPF during the first phase of QS-AW transition. However, the LF/HF was not correlated with the HF. The MPF and HF exhibited only a rapidly changing phase during QS-PS transition. The LF/HF declined transiently during the QS-PS transition, followed by a sustained increase in PS. CONCLUSIONS: The parasympathetic activity before falling asleep and the sympathetic activity before waking up change coincidentally with EEG frequency, and may respectively contain the messages of sleeping and waking drives. (+info)
Laparoscopic pelvic autonomic nerve-preserving surgery for sigmoid colon cancer.
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Responses of caudal vestibular nucleus neurons of conscious cats to rotations in vertical planes, before and after a bilateral vestibular neurectomy.
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Influence of age-related changes in nitric oxide synthase-expressing neurons in the rat supraoptic nucleus on inhibition of salivary secretion.
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Age-related inhibition of salivary secretion has been demonstrated in rats, and the nitric oxide (NO) present in the supraoptic nucleus (SON) and the medial septal area has been reported to play an inhibitory role in the regulation of salivary secretion. In the present study, we investigated the age-related changes occurring in the NO synthase (NOS)-expressing neurons in the SON, which is related to the production of NO, and discussed the interrelation between the age-related changes in the NOS-expressing neurons and the age-related inhibition of salivary secretion. Nissl staining and reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry were performed for young adult and aged rats. Quantitative analysis was also performed using the Nissl-stained and NADPH-d-positive neurons. Although the numbers of the Nissl-stained neurons did not change, significant age-related increases were detected in cell number, cell size and reactive density of the NADPH-d-positive neurons. Therefore, the production of NO in the SON neurons increased with age. We concluded that the age-related increase in the NO in the SON might be a factor that contributes to the age-related inhibition of salivary secretion. (+info)
Carbenoxolone induced depression of rhythmogenesis in the pre-Botzinger Complex.
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