Abstract
The periaqueductal grey (PAG) is a nucleus within the midbrain, and evidence from animal models has identified its role in many homeostatic systems including respiration. Animal models have also demonstrated a columnar structure that subdivides the PAG into four columns on each side, and these subdivisions have different functions with regard to respiration. In this study we used ultra-high field functional MRI (7T) to image the brainstem and superior cortical areas at high resolution (1mm3voxels), aiming to identify activation within the columns of the PAG associated with respiratory control. Our results showed deactivation in the lateral and dorsomedial columns of the PAG corresponding with short (~10s) breath holds, along with cortical activations consistent with previous respiratory imaging studies. These results demonstrate the involvement of the lateral and dorsomedial PAG in the network of conscious respiratory control for the first time in humans. This study also reveals the opportunities of 7T functional MRI for non-invasively investigating human brainstem nuclei at high-resolutions.
Highlights
The study of respiratory control is largely focused on the nuclei of the respiratory rhythm generators in the medulla, whilst suprapontine control of respiration is less well understood
One of these deactivation clusters followed the lateral column on the right side of the periaqueductal grey (PAG) (12 voxels), and the second was located in the right caudal dorsolateral PAG (8 voxels)
The deactivation seen within the lPAG, in particular, follows a columnar structure that is consistent with previous work from animal models
Summary
The study of respiratory control is largely focused on the nuclei of the respiratory rhythm generators in the medulla, whilst suprapontine control of respiration is less well understood. The PAG has been proposed to be subdivided into four columns on each side; ventrolateral (vlPAG), lateral (lPAG), dorsolateral (dlPAG) and dorsomedial (dmPAG) (Bandler and Shipley, 1994; Dampney et al, 2013; Subramanian, 2012; Subramanian et al, 2008) Direct excitation of these columns in animals has revealed distinct respiratory functions, such as irregular breathing with the vlPAG, prolonged inspirations, expirations and vocalisations from the lPAG, active breathing and tachypnea from the dlPAG, and slow, deep breathing from the dmPAG (Subramanian, 2012; Subramanian et al, 2008).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
