Interoception Laboratory

Laboratory Head

Dr Michael Farrell BAppSc(Phty) MSc PhD

Contact Details

Email:

michael.farrell@florey.edu.au

Phone:

+61 (0)3 8344 1941

Fax:

+61 (0)3 9347 0446

Number of

Staff:        1

Students:  4

Research Interests

The Interoception Laboratory investigates the neural representation of sensations that are generated by afferent signals from within the body. Interoceptive sensations such as thirst, hunger and pain motivate behaviours that contribute to the maintenance of homeostasis. Ageing and co-morbidity can adversely affect processes involved in interoception, placing people at risk of additional disease and suffering. Studies undertaken by the group aim to identify the processes in the human brain that contribute to interoception under physiological conditions, and to establish how these processes are modified by factors known to change the experience of interoception.

Current Projects

The Laboratory has a wide range of projects. The investigation of thirst is a major focus, with studies examining age-related changes in thirst activations, BOLD imaging of the effects of hydration status on cortical responses to thirst cues, and arterial spin labelling measures of brain activity following dehydration subsequent to exercise and fluid deprivation. The study of age-related change in thirst builds on a long standing collaboration with the Research Imaging Center (RIC) in San Antonio, Texas. PET imaging studies undertaken at the RIC have been instrumental in the group’s successful brain mapping of thirst, air hunger, thermal sensations and more recently, the interaction of thirst and pain.

The capacity of the Laboratory to image brain processes involved in interoception has been recently enhanced with the introduction of the arterial spin labelling (ASL) technique. ASL is a measure of brain perfusion that is free of the low frequency noise that complicates BOLD imaging of slowly evolving states. Members of the group worked in collaboration with scientists from the Center for Functional and Molecular Imaging (Georgetown University Medical Center, Washington, DC) and the University Of Pennsylvania to validate the imaging sequence, which is now operating on the 3 Telsa magnet at the Murdoch Children’s Research Institute. A major study of hunger involving lean subjects, obese subjects and laproscopic adjustable gastic band patients is currently underway using the ASL imaging sequence. The ASL technique is also being employed to investigate the neural correlates of sexual arousal in men in a collaborative study with the University of Groningen in the Netherlands.

The impact of disease on interocpetion is currently being investigated in two studies of pain. In the first of these studies, recent results from an investigation of pain processing in Alzheimer’s disease will be extended to explore the interaction between cognitive impairment and attention to noxious stimuli. The second study is assessing pain sensitivity in patients with Parkinson’s disease during ‘off’ and ‘on’ states after abstinence and subsequent compliance with levadopa medication.

The group have recently contributed to the imaging of brain responses during the inhalation of capsaicin. The perceptible urge that may or may not culminate in a cough can be a distressing symptom of acute or chronic airways disease. Despite its prevalence, virtually nothing is known about the cortical representation of the urge to, and suppression of cough. In collaboration with Dr Stuart Mazzone of the Systems Neurobiology Group, BOLD imaging was used to implicate brain regions activated by the inhalation of capsaicin at tailored doses compatible with the suppression of coughing. The results of the experiment will provide important new insights into the neural correlates of the urge to cough.

Laboratory Techniques

Funding

Additional Information

Please see PubMed.

Research