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. Author manuscript; available in PMC: 2010 Aug 31.
Published in final edited form as: Respir Physiol Neurobiol. 2009 Jun 18;168(1-2):19–25. doi: 10.1016/j.resp.2009.06.011

Figure 2. Eupneic pattern of respiratory motor activity in situ.

Figure 2

In control conditions (normocapnia) phrenic (PN) and hypoglossal (HN) have an inspiratory ramp shaped activity envelope whereas abdominal nerve (AbN; lumbar segment 1) exhibits small amplitude post-inspiratory activity. Using 10% carbon dioxide (i.e. 5% above normocapnic conditions), central respiratory drive was raised. This resulted in generation of augmenting expiratory activity in the AbN outflow (Late-E; arrowed) and advanced the onset of pre-inspiratory HN activity relative to PN; the latter indicating reduced airway resistance during both the forced expiration and inspiration. The pattern of PN now showed an abrupt onset in discharge (see Abdala et al. 2009).