Human cerebral activity with increasing inspiratory force: a study using positron emission tomography.. Fink, Gereon R., Douglas R. Corfield, Kevin Murphy, Ichiro Kobayashi, Christian Dettmers, Lewis Adams, Richard S. J. Frackowiak, Abraham Guz. Wellcome Department of Cognitive Neurology, Institute of Neurology, London WC1N 3BG and MRC Cyclotron Unit, Hammersmith Hospital, London W12 OHS, UK; Department of Medicine, Charing Cross & Westminster Medical School, London W6 8RF, UK; Max-Planck Institute for Neurological Research, Cologne, FRG; Neurologische Universit[umlaut]atsklinik and Poliklinik, Bonn, FRG
APStracts 3:0238A, 1996.
The major aim of this study was to use positron emission tomography (PET) to assess dose-dependent effects of inspiratory loads upon relative regional cerebral blood flow as an indication of neuronal activation and recruitment. Six normal males underwent H215O PET scanning during unloaded breathing and with external inspiratory loads (generating mouth pressures of -5, -10 and -15 cm H2O); positive pressure ventilation against relaxed respiratory muscles acted as control. During unloaded breathing, the supplementary motor area was significantly activated. With the addition of the smallest load, activations also occured in the right premotor area and bilaterally in the superolateral motor cortex (MI) in areas previously shown to be activated with deeper breathing. There was little further change in these areas with greater loads. Additional force-related activations occurred in the inferolateral sensorimotor cortex, parietal cortex and midbrain/hypothalamus. The results suggest that volitionally-induced increases in inspiratory muscle force are achieved via a complex integration of neuronal activations in cortical and subcortical regions associated with motor control. 

Received 25 January 1996; accepted in final form 26 April 1996.
APS Manuscript Number A79-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 May 96