Toro et al. compared cortical thickness in T1-weighted MRI images of adolescent subjects with and without PEMCS 98. Cortical thickness, as measured by volumetric MRI studies, reflects the volume of various cellular components comprising the cortex. In a region-based analysis, the orbito-frontal (OFC), middle frontal and the parahippocampal cortices of the exposed group were found to be thinner compared to the unexposed group, with differences being significant only in females, in whom the thickness of OFC also correlated negatively with self rated assessment of caring. Vertex-based analysis confirmed thinner cortices in exposed group, with maximal thinning at vertices constituting the left lateral OFC in females. The authors hypothesize that thinning of OFC likely reflects nicotine induced dysregulation of the serotonergic and the cholinergic systems with subsequent decrease in activity-triggered neuronal (dendritic) and glial growth, an effect that may persist well beyond the fetal period, modifying the various neural maturational changes during childhood and adolescence192. This regional specificity of the PEMCS effects on the OFC and middle frontal cortex are consistent with the high concentration of nicotinic receptors found in these
