Integrative Physiology

Integrative Physiology

• Professor Vaughan G Macefield (School of Medicine, Group Head)
• PhD Candidate
• • Cheree James

Macefield Group;

Keywords: electrophysiology, fMRI, microneurography, single cell recordings.
Collaborators (internal): John Morley (SoM), Antonio Lauto (SBHS), William S Price (SBHS).
Collaborators (external): Luke Henderson (USyd), Ingvars Birznieks (POWMRI).

Research: My work involves inserting microelectrodes into human peripheral nerves, and recording the electrical signals generated by individual nerve fibres (axons), the smallest of which are 1 micron in diameter. This approach is used to study how the brain controls blood pressure and blood flow, and also how the brain uses sensory information in fine control of the hand, for instance. In the last six years I have extended my research into functional magnetic resonance imaging of the human brain to understand the processing of pain and the sites of control of blood pressure for example. We have previously examined physiological models in which the pattern of autonomic activation is known from direct recordings of muscle sympathetic nerve activity (MSNA) and cardiovascular and respiratory parameters. For those experiments we recorded MSNA (i.e. muscle vasoconstrictor activity) and performed fMRI in the same subjects but on different days. In my current work we are recording MSNA concurrently with the brain scanning, to allow us to assess how the pattern of sympathetic nerve activity recorded in the periphery is directly generated within the brain. Each study participant will have a microelectrode inserted percutaneously into a muscle fascicle of the common peroneal nerve at the knee (to record MSNA) and placed in the 3T MRI scanner (at POWMRI) for anatomical and functional MRI. This combination of direct recording of muscle sympathetic nerve activity and fMRI is unique, and has not been attempted anywhere in the world. We have already identified the clusters of cells within the brainstem responsible for the ongoing fluctuations in MSNA, and are now extending this to the whole brain. In addition, we are using this concurrent recording approach to record skin sympathetic nerve activity, to explore emotional processing.

^back to top 

Professor Vaughan Macefield
BsC (Hons), PhD

V Macefield Profile (PDF, 19kb)
V Macefield Short Curriculum Vitae (PDF,17kb)

PhD Candidate

Cheree James

Functional imaging of the brainstem and cortical sites of autonomic control in awake human subjects. Cheree has completed both a Bachelor of Science and a Bachelor of Medical Science (Hons). She is currently completing her PhD at the School of Medicine, University of Western Sydney. Cheree’s research involves utilising different investigative techniques such as microneurography, galvanic vestibular stimulation and functional magnetic resonance imaging (fMRI) to assess cardiovascular function and control in normal and disease states in humans. Her current research involves concurrent sympathetic nerve recording and brain scanning, a world first, to identify brainstem and cortical sites of cardiovascular function in awake human subjects.

^back to top