PROBING-PAIN

MULTIMODAL FUNCTIONAL NEUROIMAGING TECHNIQUES TO PROBE THE REPRESENTATION OF PAIN IN THE HUMAN BRAIN

Pain may be defined as a primarily aversive perception that is vital for survival, as it incites the individual to respond to stimuli constituting a real or potential menace.

However, pain is also a major healthcare issue, undermining the health and welfare of millions of individuals and imposing a severe financial burden to our societies.

How does the brain process noxious stimuli, and how does this lead to the perception of pain?

In humans, using functional neuroimaging techniques such as electroencephalography (EEG) or functional magnetic resonance imaging (fMRI), a great number of studies have shown that noxious stimuli elicit activity within a widespread network of cortical regions, including the primary and secondary somatosensory cortices, the insula and the anterior cingulate cortex.

However, recent studies have suggested that these responses are largely unspecific for pain and, instead, reflect attentional mechanisms that can be triggered by the occurrence of any salient sensory event, regardless of whether it elicits pain.

Therefore, novel approaches are needed to progress in understanding the neural representation of pain in humans. This constituted the main objective of this project in which we developed a series of approaches to :

1. explore how transient and sustained pain are respectively represented in the human brain,
2. characterize directly the functional connectivity, interdependency and hierarchical organization of the different brain regions involved in the perception of pain and
3. explore the plastic changes in cortical excitability and functional connectivity induced by sustained experimental pain as well as chronic pathological pain.

Several of these approaches are now being validated human biomarkers for analgesic drug development and improved patient stratification.

More