ID 226 – Inter-individual differences in laser-evoked potentials and operculo-insular morphology

Abstract

Laser-evoked potentials are a useful tool to evaluate the functional state of the spino-thalamic system. While late vertex potentials N2 and P2 are commonly assessed, middle-latency components such as the N1–P1 are under-utilized, due to their smaller amplitude and high inter-individual variability. To optimize their use, we investigate the possible relationship between this variability and anatomo-morphological variations in the operculo-insular region. We recorded laser-evoked potentials using high-density EEG (128 electrodes) in 15 healthy participants. Over the 30 ms following the appearance of the first lateralized N1–P1 scalp topography, the electrodes recording a frontal maximum and a temporo-central minimum were selected. Their positions were put in relation with the orientation of several sulci in the posterior operculo-insular cortex, measured on individual T1-3D MRIs. In all but two participants, a clear lateralized dipolar structure appeared ∼154 ms (±18 ms) after stimulation. There was a significant correlation (r2 = 0.43, p = 0.02, n = 12) between the negative maximum (N1) electrode coordinate in a coronal plane and the orientation of the posterior superior operculo-insular fold (MRI coronal plane). N1–P1 topography is highly related to operculo-insular anatomo-morphology. It remains to be studied whether N1–P1 topography can predict operculo-insular anatomy at the individual level and be used in routine clinical settings.