The role of vagal afferent information during inspiration in determining phrenic motoneurone output

1980 ◽  
Vol 39 (2) ◽  
pp. 149-167 ◽  
Author(s):  
Brenda A. Cross ◽  
P.W. Jones ◽  
A. Guz
2021 ◽  
Vol 118 (30) ◽  
pp. e2104137118
Author(s):  
Vandana Sampathkumar ◽  
Andrew Miller-Hansen ◽  
S. Murray Sherman ◽  
Narayanan Kasthuri

Higher order thalamic neurons receive driving inputs from cortical layer 5 and project back to the cortex, reflecting a transthalamic route for corticocortical communication. To determine whether or not individual neurons integrate signals from different cortical populations, we combined electron microscopy “connectomics” in mice with genetic labeling to disambiguate layer 5 synapses from somatosensory and motor cortices to the higher order thalamic posterior medial nucleus. A significant convergence of these inputs was found on 19 of 33 reconstructed thalamic cells, and as a population, the layer 5 synapses were larger and located more proximally on dendrites than were unlabeled synapses. Thus, many or most of these thalamic neurons do not simply relay afferent information but instead integrate signals as disparate in this case as those emanating from sensory and motor cortices. These findings add further depth and complexity to the role of the higher order thalamus in overall cortical functioning.


Author(s):  
Marian Kollarik ◽  
Fei Ru ◽  
Nikoleta Pavelkova ◽  
John Mulcahy ◽  
John Hunter ◽  
...  

1991 ◽  
Vol 161 (1) ◽  
pp. 347-365 ◽  
Author(s):  
DAVID J. McKENZIE ◽  
MARK L. BURLESON ◽  
DAVID J. RANDALL

Present address and address for reprint requests: Istituto di Scienze Farmacologiche, via Balzaretti 9, Università di Milano, Milano 20133, Italy. The role of sensory afferent information from the gills of Amia calva in cardiovascular and ventilatory control was investigated by bilateral branchial denervation and pseudobranch ablation. Aquatic hypoxia or 1 mg of sodium cyanide (NaCN) in the water flowing over the gills stimulated bradycardia, and gill and air ventilation in sham-operated fish. Sodium cyanide, noradrenaline (NA) and adrenaline (A) infusion into the dorsal aorta increased gill ventilation, and NA and A infusion also stimulated tachycardia and an increase in blood pressure. Following denervation and pseudobranch ablation, O2 consumption (V·OO2), airbreathing frequency (fAB) and arterial O2 tension (PaOO2) declined, and circulating NA levels increased, as compared with sham-operated fish. Cardiovascular and air-breathing responses to hypoxia were abolished and gill ventilatory responses attenuated. All ventilatory and cardiovascular responses to NaCN were abolished and gill ventilatory responses to NA and A were attenuated in animals following denervation and pseudobranch ablation. These results demonstrate that O2-sensitive chemoreceptors in the gills and pseudobranch control reflex bradycardia and air-breathing responses in Amia, but that gill ventilatory responses to hypoxia, NA and A are partially mediated by extrabranchial mechanisms. Plasma NA levels increased during hypoxia in shamoperated and denervated animals, indicating that circulating NA may have mediated gill ventilatory responses in denervated animals.


2007 ◽  
Vol 293 (2) ◽  
pp. R635-R641 ◽  
Author(s):  
Maria A. Zafra ◽  
Filomena Molina ◽  
Amadeo Puerto

Learned flavor preferences can be established after intragastric nutrient administration by two different behavioral procedures, concurrent and sequential. In a concurrent procedure, two flavored stimuli are offered separately but at the same time on a daily basis: one stimulus is paired with the simultaneous intragastric administration of partially digested food and the other with physiological saline. In sequential learning, the two stimuli are presented during alternate sessions. Neural mechanisms underlying these learning modalities have yet to be fully elucidated. The aim of this study was to examine the role of vagal afferent fibers in the visceral processing of rewarding nutrients during concurrent ( experiment 1) and sequential ( experiment 2) flavor preference learning in Wistar rats. For this purpose, capsaicin, a neurotoxin that destroys slightly myelinated or unmyelinated sensory axons, was applied to the subdiaphragmatic region of the esophagus to selectively damage most of the vagal afferent pathways that originate in the gastrointestinal system. Results showed that capsaicin [1 mg of capsaicin dissolved in 1 ml of vehicle (10% Tween 80 in oil)] blocked acquisition of concurrent but not sequential flavor preference learning. These results are interpreted in terms of a dual neurobiological system involved in processing the rewarding effects of intragastrically administered nutrients. The vagus nerve, specifically capsaicin-sensitive vagal afferent fibers, would only be essential in concurrent flavor preference learning, which requires rapid processing of visceral information.


1972 ◽  
Vol 42 (3) ◽  
pp. 251-263 ◽  
Author(s):  
Diana Trenchard ◽  
D. Gardner ◽  
A. Guz

1. The administration of the polysaccharide carageenin through a catheter into the lungs of cats and rabbits has produced an inflammatory lesion confined to one lobe of a lung. The lesion consisted of an alveolar and interstitial infiltration with polymorphonuclear leucocytes and, subsequently, macrophages. There was no apparent damage to alveolar walls and no pleurisy. The rest of the lung remained normal. 2. In both conscious cats and anaesthetized rabbits there was an increased frequency of breathing dependent on an intact vagus nerve on the same side as the lesion. It was independent of changes in body temperature and was not due to hypoxaemia. 3. By using a direct current to the right cervical vagus nerve in the rabbits (with the left vagus nerve sectioned), it has been possible to block conduction in myelinated fibres; the non-myelinated fibres conduct normally. Studies with this differentially blocked nerve have shown that the increased frequency of breathing is dependent on activity in the non-myelinated vagal afferent fibres.


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