Brainstem neurones and postganglionic sympathetic nerves: Does correlation mean connection?

Abstract

Short-term correlations in activity have been widely used as evidence to connect brainstem units with postganglionic sympathetic nerves. These may be detected by spike-triggered averaging, cross correlation or coherence analysis. The specificity of this type of evidence has been investigated by cross-correlating the activity of identified cutaneous vasoconstrictor postganglionic fibres with that of medullary premotor neurones of like and of unlike functional type, as determined by physiological testing (preoptic warming), in anaesthetised cats. Single medullary premotor neurones of both types were recorded from the subretrofacial nucleus: they were identified by their barosensitivity and, in..