Reafference and the origin of the self in early nervous system evolution

Discussions of the function of early nervous systems usually focus on a causal flow from sensors to effectors, by which an animal coordinates its actions with exogenous changes in its environment. We propose, instead, that much early sensing was reafferent ; it was responsive to the consequences of the animal's own actions. We distinguish two general categories of reafference—translocational and deformational—and use these to survey the distribution of several often-neglected forms of sensing, including gravity sensing, flow sensing and proprioception. We discuss sensing of these kinds in sponges, ctenophores, placozoans, cnidarians and bilaterians. Reafference is ubiquitous, as ongoing action, especially whole-body motility, will almost inevitably influence the senses. Corollary discharge—a pathway or circuit by which an animal tracks its own actions and their reafferent consequences—is not a necessary feature of reafferent sensing but a later-evolving mechanism. We also argue for the importance of reafferent sensing to the evolution of the body-self , a form of organization that enables an animal to sense and act as a single unit. This article is part of the theme issue ‘Basal cognition: multicellularity, neurons and the cognitive lens’.

Reafference and the origin of the self in early nervous system evolution

Discussions of the function of early nervous systems usually focus on a causal flow from sensors to effectors, by which an animal coordinates its actions with exogenous changes in its environment. We propose, instead, that much early sensing was reafferent; it was responsive to the consequences of the animal's own actions. We distinguish two general categories of reafference – translocational and deformational – and use these to survey the distribution of several often-neglected forms of sensing, including gravity sensing, flow sensing, and proprioception. We discuss sensing of these kinds in sponges, ctenophores, placozoans, cnidarians and bilaterians. Reafference is ubiquitous, as ongoing action, especially whole-body motility, will almost inevitably influence the senses. Corollary discharge – a pathway or circuit by which an animal tracks its own actions and their reafferent consequences – is not a necessary feature of reafferent sensing but a later- evolving mechanism. We also argue for the importance of reafferent sensing to the evolution of the body-self, a form of organization that enables an animal to sense and act as a single unit.

O15 ESOPHAGEAL MOTILITY OF LUNG TRANSPLANT RECIPIENTS DIAGNOSED WITH SYSTEMIC CONNECTIVE TISSUE DISORDER: A SINGLE-CENTER EXPERIENCE

Aim To examine the esophageal motility of lung transplant recipients diagnosed with systemic connective tissue disorder, and to evaluate the changes Backgrounds The decision to offer lung transplantation to patients diagnosed with a systemic connective tissue disorder (CTD) is frequently complicated by associated esophageal dysmotility. Absent or ineffective esophageal motility and associated gastroesophageal reflux disease are serious risk factors of posttransplant bronchiolitis obliterans syndrome and subsequent allograft dysfunction. The aim of our study was to evaluate esophageal motility of lung transplant recipients with systemic CTDs, focusing on 1-year survival. Methods After IRB approval of this retrospective cohort study, we reviewed patients who underwent lung transplant at our institution between January 2012 and December 2017. Patients with systemic CTDs such as scleroderma, rheumatoid arthritis, systemic lupus erythematosus, polymyositis, dermatomyositis, mixed connective tissue disorder, and Sjögren syndrome were included. Endoscopy studies, high-resolution manometry (HRM), and ambulatory pH studies were re-evaluated. Results A total of 545 patients underwent lung transplant during study period; of these, 34 met study criteria. Detailed demographic characteristics of the study cohort are shown in Table 1. The overall 1-year survival was 85.3%. Of the 34 patients diagnosed with a systemic CTD (mean age: 59.24 ± 10.44 years; 24/34 women [70.6%]), 27 had both pre- and posttransplant esophageal function testing data available. 7 patients were diagnosed with complete aperistalsis, 5 patients had ineffective esophageal motility, and the remaining 15 patients had normal or hypercontractile esophageal motility (Figure 1). Pathologic distal acid exposure in each of these groups was 57.1%, 40.0%, and 26.7%, respectively. Seven patients with aperistalsis (5 with scleroderma, 1 with polymyositis, and 1 with dermatomyositis) showed no improvement in esophageal body motility, regardless of underlying CTD. 1-year survival in these patients was 55.5%. Five patients with ineffective esophageal motility (3 with rheumatoid arthritis, 1 with scleroderma, 1 with mixed connective tissue disorder) showed significant peristaltic improvement (mean positive change in distal contractile integral: 1288 ± 391.3 mmHg*cm*s and in the number of normal swallows 6.4 ± 1.4 out of 10). All 5 patients with ineffective esophageal motility were alive 1 year posttransplant. Conclusion In our experience, preexisting absent esophageal body motility (i.e., peristalsis) is unlikely to improve after transplantation in patients with systemic CTDs. This cohort of patients appeared to have a significantly decreased 1-year survival. In contrast, ineffective esophageal body motility improved significantly after transplant and was associated with excellent 1-year survival. Detailed esophageal evaluation is necessary in patients with a systemic connective tissue disorder to minimize the risk of future allograft injury.

Study on Effects of Electrical Stimulation on Rabbit Esophageal Body Motility In Vivo

Electric stimulation (ES) could induce contraction of intestinal smooth muscle. The aim of this study was to analyze the effects of ES on esophageal motility and the underlying mechanism in vivo. Twenty-eight rabbits were equipped with a pair of subserosa electrodes (connected to an electrical stimulator) in the lower segment of the esophagus. The ES signal consisted of bipolar rectangular pulse trains, lasting for 3 s, with different amplitudes (1 mA, 3 mA, 5 mA and 10 mA), and frequencies (10 Hz, 20 Hz and 50 Hz). The amplitude of the contraction was recognized by high-resolution manometry. The effect of ES was tested under anesthesia and following administration of atropine, phentolamine or L-NAME. ES induced esophageal contraction at the stimulated site. A statistically significant increase in esophageal pressure was observed when the stimulation amplitude was above 3 mA. The increase in esophageal pressure was associated with the amplitude of stimulus as well as the frequency. During stimulation, atropine, phentolamine and L-NAME had no effect on the increase of esophageal pressure induced by ES. These findings implied that ES induced esophageal contraction were not mediated via the NANC, adrenergic or cholinergic pathway. The amplitude of esophageal contraction was current and frequency dependent.