Functional connectivity between brain stem midline neurons with respiratory-modulated firing rates

• DOI: 10.1152/jn.1992.67.4.890
• Publication Date: 2017-12-24T16:00:53Z
• Authors: B. G. Lindsey; Y. M. Hernandez; K. F. Morris; R. Shannon
• Keywords: Raphe; Raphe nuclei; Decerebrate State; Tonic (physiology)

1. Recent evidence supports the idea that neurons distributed along midline of brain stem contribute to regulation breathing. This study sought for functional connections between with respiratory-modulated firing rates. 2. Experiments were conducted on 38 anesthetized, paralyzed, bilaterally vagotomized, artificially ventilated cats. Planar arrays tungsten microelectrodes used monitor spike trains two or more simultaneously in regions n. raphe obscurus, pallidus, and magnus. Efferent phrenic nerve activity was recorded. Data analyzed auto- cross-correlograms cycle-triggered histograms. Spike also tested respiratory modulation by an analysis variance use a subjects-by-treatments experimental design. 3. Of 584 studied, 99.1% tonic, i.e., they had probabilities greater than zero all phases cycle. Fifty-three percent rates; 223 cells active during expiratory (E) interval; 88 inspiratory (I)-related. The remaining classified as having no respiratory-related rate (NRR). 4. 210 1,078 pairs (19.5%) exhibited short-time scale correlations indicative paucisynaptic interactions. Primary cross-correlogram features included 129 central peaks, 45 offset troughs, 57 troughs. Twenty-two neuronal both peaks Correlograms from additional 35 multiple troughs without significant primary feature. 5. frequency neuron composed rates follows: E-E, 40/185 (22%); E-I, 23/111 (21%); E-NRR, 45/297 (15%); I-I, 11/25 (44%); I-NRR, 13/104 (13%). NRR (79/357) correlations. 6. Thirty cell antidromically identified axonal projection extending at least third cervical segment. mean estimated conduction velocity based single-site stimulation method 26.5 +/- 9.9 (SD) m/s. 7. results provide inhibitory excitatory neurons. support hypothesis discharge patterns are, part, consequence synaptic actions other cells.(ABSTRACT TRUNCATED AT 400 WORDS)