Functional magnetic resonance imaging (fMRI) is particularly suited to investigating the effects of pharmacological agents on pain processing within the human central nervous system.
The measures are based on the haemodynamic resonse to a neuronal event and constitute indirect measures of excitatory and inhibitory neuronal activity. The neuronal activation is associated with an increase of the oxygen extraction fraction from the capillaries and with an increase in regional cerebral blood flow. The measure which derived from blood oxygenation is called the BOLD effect.
Read more: http://www.clinicaltrials.gov/ct2/show/NCT01226615?cond=%22Arthritis%22&lup_s=07/28/2011&lup_d=30
