Marc Guenot, M.D, Ph.D.
Marc Guenot is Professor of Neurosurgery, ,and Head of the Epilepsy Surgery program in the Dept of Functional & Stereotactic Neurosurgery at the University Hospital of Lyon, France, a position he has held since 2002.
Since the mid 90’s, he could, as an academic neurosurgeon at the Pierre Wertheimer Neurological Hospital of Lyon, develop a scientific, as well as clinical, activity in Epilepsy Surgery.
His scientific researches were devoted to « Electrophysiology applied to Functional Neurosurgery ». His main field of research was dedicated to SEEG and human intracerebral recordings in patients suffering from drug-resistent epilepsies.
Insula, Epilepsy, Pain and Empathy
Pr Marc Guenot, M.D., Ph.D.
Dept of Functional Neurosurgery, University of Lyon, Hospices Civils de Lyon (France)
This presentation intends to tell the story of how our group could, in the past 20 years, contribute to gain a better knowledge of some functional and pathological features of a formerly not well-known brain area : the Human insula.
The insula (« the Island of Reil ») is a phylogenetically ancient structure. The fact that it is made of a deep-seated cortex, which is not visible at the surface of the brain, and that it is covered by a « vascular wall », consisting of the M2 & M3 branches of the middle cerebral artery, does explain that it had been barely investigated in Human untill the 2000’s.
In this context, it appeared logical to our group, which was involved since a long time in chronic pain treatments, as well as in epilepsy surgery, to further investigate the functional role of the Human Insula.
This was mainly done by means of SEEG (which consists in stereotactic implantation of deep electrodes into the brain, in the frame of pre-surgical investigation done for some drug-resistent epilepsy patients), which allowed to obtain long-term recordings, chronic extra-operative stimulations, and evoked potentials, of the insular cortex and adjacent fibers.
The main findings can be summarized as follows :
- Some seizures arising from the insula (and from the insula alone) can be painful.
- Insular cortex stimulation is the only one, in the brain, which can sometimes be painful.
- Evoked potentials resulting from painful peripheral stimulations can be obtained in the insular cortex.
This allows to conclude that the insular cortex (which belongs to the so-called « pain-matrix ») is the primary cortex for nociceptive perception.
Moreover, a supplementary finding is that the insular cortex implicitly (i.e. unconsciously) feels other people’s pain.
In conclusion, the findings which represent our contribution to a better understanding of the functional role of the Human insula are the followings :
- The insular cortex can cause specific partial seizures, which can sometimes generate pain symptoms, and should be taken into account in some cases of epilepsy surgery failures.
- The insular cortex is the primary cortex of pain perception.
- The insula can trigger our empathic reaction to other people’s pain.