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Functional subdivision of the human periaqueductal grey in respiratory control using 7 tesla fMRI.

Faull OK, Jenkinson M, Clare S, Pattinson KT - Neuroimage (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK. Electronic address: olivia.faull@ndcn.ox.ac.uk.

No MeSH data available.


a) Schematic diagram of the venturi mask used in the breathing system. A: Loose plastic venturi mask B: Venturi entrainment device (1:1). b) A section of a respiratory trace from one subject demonstrating the tidal CO2 trace (top) and the tidal volume trace from the bellows (bottom). The end-tidal CO2 (PETCO2) trace was formed by interpolating between the end expiration peaks (dotted line, top trace). The breath hold duration was calculated from the time between the end of expiration CO2 trace and the beginning of the subsequent expiration trace, to minimise inclusion of head movement. The vocalisation duration was calculated from the duration between the beginning and end of a vocalisation expiration trace.
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f0005: a) Schematic diagram of the venturi mask used in the breathing system. A: Loose plastic venturi mask B: Venturi entrainment device (1:1). b) A section of a respiratory trace from one subject demonstrating the tidal CO2 trace (top) and the tidal volume trace from the bellows (bottom). The end-tidal CO2 (PETCO2) trace was formed by interpolating between the end expiration peaks (dotted line, top trace). The breath hold duration was calculated from the time between the end of expiration CO2 trace and the beginning of the subsequent expiration trace, to minimise inclusion of head movement. The vocalisation duration was calculated from the duration between the beginning and end of a vocalisation expiration trace.

Mentions: A breathing system was used to allow the administration of small CO2 challenges mixed with room air, via a venturi entrainment system (Fig. 1a). The CO2 challenges were administered to dissociate the changes in global BOLD signal due to changes in arterial PCO2 from local BOLD signal changes correlating to activity associated with breath holds and vocalisations (Pattinson et al., 2009a). During scanning, medical air was administered through a loose fitting venturi mask (Ventimask, Intersurgical Ltd, Berkshire, UK) with a 1:1 entrainment ratio of compressed gas:room air. Gas was delivered to the mask at a rate of 20 L/min, and the mask was designed to entrain an equivalent amount of room air. The resulting high gas flow rate delivered by this system (40 L/min) minimises rebreathing of expired gases. The ventimask is loose fitting and therefore considerably more comfortable than a tight fitting mask, but its gas delivery characteristics allows control of end-tidal gases in the volunteer. For the CO2 challenges during the functional scan, the medical air was substituted for a CO2 mixture (10% CO2, 21% O2, balance nitrogen) at 20 L/min for periods of 10 s, the entrainment system meant that approximately 5% CO2 was delivered to the face mask. The CO2 challenges aimed to elevate end-tidal partial pressure of CO2 (PETCO2) by approximately 0.8%, to match elevations caused by breath holds and vocalisations.


Functional subdivision of the human periaqueductal grey in respiratory control using 7 tesla fMRI.

Faull OK, Jenkinson M, Clare S, Pattinson KT - Neuroimage (2015)

a) Schematic diagram of the venturi mask used in the breathing system. A: Loose plastic venturi mask B: Venturi entrainment device (1:1). b) A section of a respiratory trace from one subject demonstrating the tidal CO2 trace (top) and the tidal volume trace from the bellows (bottom). The end-tidal CO2 (PETCO2) trace was formed by interpolating between the end expiration peaks (dotted line, top trace). The breath hold duration was calculated from the time between the end of expiration CO2 trace and the beginning of the subsequent expiration trace, to minimise inclusion of head movement. The vocalisation duration was calculated from the duration between the beginning and end of a vocalisation expiration trace.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4441042&req=5

f0005: a) Schematic diagram of the venturi mask used in the breathing system. A: Loose plastic venturi mask B: Venturi entrainment device (1:1). b) A section of a respiratory trace from one subject demonstrating the tidal CO2 trace (top) and the tidal volume trace from the bellows (bottom). The end-tidal CO2 (PETCO2) trace was formed by interpolating between the end expiration peaks (dotted line, top trace). The breath hold duration was calculated from the time between the end of expiration CO2 trace and the beginning of the subsequent expiration trace, to minimise inclusion of head movement. The vocalisation duration was calculated from the duration between the beginning and end of a vocalisation expiration trace.
Mentions: A breathing system was used to allow the administration of small CO2 challenges mixed with room air, via a venturi entrainment system (Fig. 1a). The CO2 challenges were administered to dissociate the changes in global BOLD signal due to changes in arterial PCO2 from local BOLD signal changes correlating to activity associated with breath holds and vocalisations (Pattinson et al., 2009a). During scanning, medical air was administered through a loose fitting venturi mask (Ventimask, Intersurgical Ltd, Berkshire, UK) with a 1:1 entrainment ratio of compressed gas:room air. Gas was delivered to the mask at a rate of 20 L/min, and the mask was designed to entrain an equivalent amount of room air. The resulting high gas flow rate delivered by this system (40 L/min) minimises rebreathing of expired gases. The ventimask is loose fitting and therefore considerably more comfortable than a tight fitting mask, but its gas delivery characteristics allows control of end-tidal gases in the volunteer. For the CO2 challenges during the functional scan, the medical air was substituted for a CO2 mixture (10% CO2, 21% O2, balance nitrogen) at 20 L/min for periods of 10 s, the entrainment system meant that approximately 5% CO2 was delivered to the face mask. The CO2 challenges aimed to elevate end-tidal partial pressure of CO2 (PETCO2) by approximately 0.8%, to match elevations caused by breath holds and vocalisations.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK. Electronic address: olivia.faull@ndcn.ox.ac.uk.

No MeSH data available.