The Effect of Yawning on Cerebrospinal Fluid and Blood Flow through the Neck
Introduction
Research into yawning has received little attention, despite being a widespread behaviour amongst most mammals, amphibians, and reptiles [1]. Yet, beyond simple characterisation, investigation into the mechanism of yawning is limited [2]. The purpose of this study is to investigate the effect of respiration on the flow of neurofluids (cerebrospinal fluid (CSF) and blood) during yawning. By observing neurofluid movement through the C3 vertebra, using sagittal real time and phase contrast scans, we expect that the flow will be driven by differences between spinal and cranial pressures and not only a cranial fluid volume balance as commonly thought [3].
Materials and Methods
MRI data was collected using a 3T Philips IngeniaTX. During the scans, subjects were shown video clips of people and/or animals yawning to induce contagious yawns. The scans collected included anatomical scans of the head-neck region, and real time phase contrast MRI scans to measure blood and CSF flow during yawning and quiet breathing using real-timePC-MRI protocols. Respiratory motion was also recorded concurrently with the MRI scans using a respiratory monitoring band, placed on the sternum, measuring thorax displacement.
Results
Typical data obtained from the MRI scans and respiration band in a representative subject during periods of normal breathing and yawning. We collected data on CSF and blood flow (carotid and vertebral arteries and the internal jugular vein (IJV)). The most pronounced changes in neurofluid flow were noticed during the sharp inspiration, “gaping”, and sharp exhalation. IJV and CSF flow were found to move caudally during inspiration and rostrally during expiration.
Discussion and Conclusions
Our findings are in line with recent investigations into a holistic view of cranial and spinal respiratory CSF flow [4], where cervical CSF flow directions during respiratory manoeuvres (coughs and sniffs) depend on the difference between spinal and cranial pressures.
Research funding source: The authors would like to thank the NHMRC for providing financial support for this project (NHMRC Investigator Grant #APP1172988 (RG183247)), and the Australian Government for providing an RTP Scholarship to AM.
References
1. Baenninger, R. Psychon Bull Rev 4, 198–207 (1997).
2. Guggisberg, A. G., Mathis, J., Schnider, A., & Hess, C. W. (2010). Neuroscience and Biobehavioral Reviews, 34, 1267-1276.
3. Dreha-Kulaczewski S, Konopka M, Joseph AA, et al. Respiration and the watershed of spinal CSF flow in humans. Sci Rep. 2018;8(1):5594.
4. Lloyd RA, Butler JE, Gandevia SC, et al. J Physiol. 2020;598(24):5789-5805.
Research into yawning has received little attention, despite being a widespread behaviour amongst most mammals, amphibians, and reptiles [1]. Yet, beyond simple characterisation, investigation into the mechanism of yawning is limited [2]. The purpose of this study is to investigate the effect of respiration on the flow of neurofluids (cerebrospinal fluid (CSF) and blood) during yawning. By observing neurofluid movement through the C3 vertebra, using sagittal real time and phase contrast scans, we expect that the flow will be driven by differences between spinal and cranial pressures and not only a cranial fluid volume balance as commonly thought [3].
Materials and Methods
MRI data was collected using a 3T Philips IngeniaTX. During the scans, subjects were shown video clips of people and/or animals yawning to induce contagious yawns. The scans collected included anatomical scans of the head-neck region, and real time phase contrast MRI scans to measure blood and CSF flow during yawning and quiet breathing using real-timePC-MRI protocols. Respiratory motion was also recorded concurrently with the MRI scans using a respiratory monitoring band, placed on the sternum, measuring thorax displacement.
Results
Typical data obtained from the MRI scans and respiration band in a representative subject during periods of normal breathing and yawning. We collected data on CSF and blood flow (carotid and vertebral arteries and the internal jugular vein (IJV)). The most pronounced changes in neurofluid flow were noticed during the sharp inspiration, “gaping”, and sharp exhalation. IJV and CSF flow were found to move caudally during inspiration and rostrally during expiration.
Discussion and Conclusions
Our findings are in line with recent investigations into a holistic view of cranial and spinal respiratory CSF flow [4], where cervical CSF flow directions during respiratory manoeuvres (coughs and sniffs) depend on the difference between spinal and cranial pressures.
Research funding source: The authors would like to thank the NHMRC for providing financial support for this project (NHMRC Investigator Grant #APP1172988 (RG183247)), and the Australian Government for providing an RTP Scholarship to AM.
References
1. Baenninger, R. Psychon Bull Rev 4, 198–207 (1997).
2. Guggisberg, A. G., Mathis, J., Schnider, A., & Hess, C. W. (2010). Neuroscience and Biobehavioral Reviews, 34, 1267-1276.
3. Dreha-Kulaczewski S, Konopka M, Joseph AA, et al. Respiration and the watershed of spinal CSF flow in humans. Sci Rep. 2018;8(1):5594.
4. Lloyd RA, Butler JE, Gandevia SC, et al. J Physiol. 2020;598(24):5789-5805.
