Effects of graded focal XXXX in rostral areas of the medulla.

@entity308 @entity998 @entity515 @entity1576 @entity616
Unilateral focal cold blocks (20 degrees C) in structures located ventrolaterally in rostral medulla consistently caused apnoea or deep @entity308 of @entity998 . The inhibitory effect could be correlated with the cooling temperature. Apnoeic response occurred either with complete absence of any inspiratory activity or combined with low level tonic inspiratory motor activity ('tonic apnoea'). The appearance of apnoea was @entity515 -independent, whereas the tonic component of the latter increased with increasing levels of PCO2. The results suggest that the structures in the deep, ventro-lateral aspect of rostral medulla, from which apnoea can be induced, correspond partly to the nucleus paragigantocellularis lateralis (nPGL) and the nucleus preolivaris. These structures appear to be relevant for the drive inputs necessary for respiratory rhythmogenesis. Unilateral focal cooling in the rostral medulla, including the 'B  tzinger Complex', caused increments in respiratory rate both in vagotomized and non-vagotomized animals. The increase in respiratory rate in response to cooling in the region of the 'B  tzinger Complex' was combined with either an enhancement or some @entity1576 . This area in the rostral part of the ventral respiratory group (VRG) seems not to be crucial for respiratory rhythmogenesis, but to play a role in determining both the intensity and timing of the respiratory activity. All effects of unilateral @entity616 were bilaterally symmetrical.
