Series step one: unmarried fiber baroreceptor tape
Recordings were obtained from 173 separate single baroreceptor fibres in 26 animals. Initial examination of response curves from these fibres suggested that they could be described using a minimum of four categories. This allowed responses to be grouped by two distinct characteristics (Fig. 2). The second characteristic was the absence or presence of silence (a pressure/pressure range over which a fibre did not fire). Every fibre was placed in a category (types A–D) based on these two response characteristics. For every fibre we quantified five variables. These were the threshold pressure (P th) at which activity began to increase with increasing pressure, and the firing rate at this threshold (F th); the pressure (P maximum) at which activity reached a maximum (F max); and gain (G) as the ratio (F max ? F th)/(P max ? P th). Values of these variables for the four different fibre types were compared using ANOVA followed by Fisher’s LSD.
a,b Classification scheme for single fibre baroreceptor response curves in the left ADN. Continue reading