[N200: an electrophysiological signal associated with inhibitory control, as an endophenotype candidate in attention...

N200 (N2) is an electrophysiological component related with the analysis of perceptual disruptions and with the recognition of a stop signal (inhibitory control); neuroanatomically, it has been associated with right-hand orbitofrontal structures. Its modulation has been studied with go/no go-type tasks and the Stop Signal Task (SST).

While the SST is being carried out in subjects with attention deficit hyperactivity disorder (ADHD), differences in the amplitude of the N2 have been observed in comparison to control subjects. Moreover, a number of studies have reported that ADHD has a high degree of inheritability, with linkages to several susceptibility loci. From all this, it is acknowledged that inhibitory control, and more particularly N2 modulation, is a quantitative trait that may be expressed in different ways in the members of families with and without ADHD, as well as in unaffected subjects from the general population, while also being a candidate as an endophenotype of the disorder. This hypothesis has been confirmed in 141 families with the genetic isolate of Antioquia, in which differences have been identified in this electrical signal on comparing the members of affected and unaffected families and these two groups with unaffected members of the general population.

These findings suggest that N2 is an electrophysiological signal that is modulated by faulty inhibitory control in subjects with ADHD and, in this respect, could be used as a candidate in the search for endophenotypes in the familial form of this disorder.