The study demonstrates that baroreceptor input to cardiac vagal motoneurones involves two pathways and suggests that respiratory modulation of the reflex occurs via summation at the motoneurone membrane.
A study has been made of twenty-three cardiac vagal motoneurones (c.v.m.s) in the nucleus ambiguus of chloralose-anaesthetized cats.2. C.v.m.s were identified as described previously (McAllen gate' early in the pathway but that this phenomenon and the present observations are best explained by summation of influences at the c.v.m. cell membrane.
McAllen et al. (Fri,) studied this question.