Environment-Related and Body-Related Components of the Minimal Self

Perceptual changes that an agent produces by efferent activity can become part of the agent’s minimal self. Yet, in human agents, efferent activities produce perceptual changes in various sensory modalities and in various temporal and spatial proximities. Some of these changes occur at the “biological” body, and they are to some extent conveyed by “private” sensory signals, whereas other changes occur in the environment of that biological body and are conveyed by “public” sensory signals. We discuss commonalties and differences of these signals for generating selfhood. We argue that despite considerable functional overlap of these sensory signals in generating self-experience, there are reasons to tell them apart in theorizing and empirical research about development of the self.

Transcutaneous auricular vagal nerve stimulation improves functional dyspepsia by enhancing vagal efferent activity

Objectives: This study was designed to investigate whether transcutaneous auricular vagal nerve stimulation (taVNS) would be able to improve major pathophysiologies of functional dyspepsia (FD) in patients with FD. Methods: Acute: Thirty-six FD patients (21F) were studied in two sessions (taVNS and sham-ES). Physiological measurements, including gastric slow waves, gastric accommodation and autonomic functions, were assessed by the electrogastrogram (EGG), a nutrient drink test and the spectral analysis of heart rate variability derived from the electrocardiogram (ECG), respectively. Chronic: Thirty-six FD patients (25F) were randomized to receive 2-week taVNS or sham-ES. The dyspeptic symptom scales, anxiety and depression scores and the same physiological measurements were assessed at the beginning and the end of the 2-week treatment. Results: Acute: In comparison with sham-ES, acute taVNS improved gastric accommodation (p=0.008), increased the percentage of normal gastric slow waves (%NSW, fasting: p=0.010; fed: p=0.007) and vagal activity (fasting: p=0.056; fed: p=0.026). Chronic：In comparison with baseline, 2-week taVNS but not sham-ES reduced symptoms of dyspepsia (p=0.010), decreased the scores of anxiety (p=0.002) and depression (p<0.001), improved gastric accommodation (p<0.001) and the %NSW (fasting: p<0.05; fed: p<0.05) by enhancing vagal efferent activity (fasting: p=0.015; fed: p=0.048). Compared with the HC, the patients showed increased anxiety (p<0.001) and depression (p<0.001), and decreased gastric accommodation (p<0.001) and %NSW (p<0.001) as well as decreased vagal activity (fasting: p=0.047). Conclusions: The noninvasive taVNS has a therapeutic potential for treating non-severe FD by improving gastric accommodation and gastric pace-making activity via enhancing vagal activity.

Sacral nerve stimulation increases gastric accommodation in rats: a spinal afferent and vagal efferent pathway

Impaired gastric accommodation (GA) has been frequently reported in various gastrointestinal diseases. No standard treatment strategy is available for treating impaired GA. We explored the possible effect of sacral nerve stimulation (SNS) on GA and discovered a spinal afferent and vagal efferent mechanism in rats. Sprague-Dawley rats (450–500 g) with a chronically implanted gastric cannula and ECG electrodes were studied in a series of sessions to study: 1) the effects of SNS with different parameters on gastric tone, compliance, and accommodation using a barostat device; two sets of parameters were tested as follows: parameter 1) 5 Hz, 500 µs, 10 s on 90 s off; 90% motor threshold and parameter 2) same as parameter 1 but 25 Hz; 2) the involvement of spinal afferent pathway via detecting c-fos immunoreactive (IR) cells in the nucleus of the solitary tract (NTS) of the brain; 3) the involvement of vagal efferent activity via the spectral analysis of heart rate variability derived from the ECG; and 4) the nitrergic mechanism, Nω-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase (NOS) inhibitor, was given before SNS at 5 Hz. Compared with sham-SNS: 1) SNS at 5 Hz inhibited gastric tone and increased gastric compliance and GA. No difference was noted between the stimulation frequencies of 5 and 25 Hz. 2) SNS increased the expression of c-fos in the NTS. 3) SNS increased cardiac vagal efferent activity and decreased the sympathovagal ratio. 4) l-NAME blocked the relaxation effect of SNS. In conclusion, SNS with certain parameters relaxes gastric fundus and improves gastric accommodation mediated via a spinal afferent and vagal efferent pathway. NEW & NOTEWORTHY Currently, there is no adequate medical therapy for impaired gastric accommodation, since medications that relax the fundus often impair antral peristalsis and thus further delay gastric emptying that is commonly seen in patients with functional dyspepsia or gastroparesis. The advantage of the potential sacral nerve stimulation therapy is that it improves gastric accommodation by enhancing vagal activity, and the enhanced vagal activity would lead to enhanced antral peristalsis rather than inhibiting it.

Influence of nasal CPAP on cardiorespiratory control in healthy neonate

The present study aimed to further unravel the effects of nasal continuous positive airway pressure (nCPAP) on the cardiovascular and respiratory systems in the neonatal period. Six-hour polysomnographic recordings were first performed in seven healthy newborn lambs, aged 2–3 days, without and with nCPAP application at 6 cmH2O (nCPAP-6), in randomized order. The effects of nCPAP-6 on heart rate variability, respiratory rate variability, and cardiorespiratory interrelations were analyzed using a semiautomatic signal processing approach applied to ECG and respiration recordings. Thereafter, a cardiorespiratory mathematical model was adapted to the experimental conditions to gain further physiological interpretation and to simulate higher nCPAP levels (8 and 10 cmH2O). Results from the signal processing approach suggest that nCPAP-6 applied in newborns with healthy lungs: 1) increases heart rate and decreases the time and frequency domain indices of heart rate variability, especially those representing parasympathetic activity, while increasing the complexity of the RR-interval time series; 2) prolongs the respiratory cycle and expiration duration and decreases respiratory rate variability; and 3) slightly impairs cardiorespiratory interrelations. Model-based analysis revealed that nCPAP-6 increases the heart rate and decreases respiratory sinus arrhythmia amplitude, in association with a reduced parasympathetic efferent activity. These results were accentuated when simulating an increased CPAP level. Overall, our results provide a further understanding of the effects of nCPAP in neonates, in the absence of lung disease. NEW & NOTEWORTHY Application of nasal continuous positive airway pressure (CPAP) at 6 cmH2O, a level very frequently used in newborns, alters heart and respiratory rate variability, as well as cardiorespiratory interrelations in a full-term newborn model without lung disease. Moreover, whereas nasal CPAP at 6 cmH2O decreases parasympathetic efferent activity, there is no change in sympathetic efferent activity.