Misgivings about the anatomical or physiological adequacy of inverse solutions have led some seasoned investigators to question ERP generators localized by inverse models to the cingulate gyrus. Given the possible commonality of P3a and the no-go P3 produced in go/no-go tasks (Polich, 2007), it is of interest that when Verleger, Paehge, Kolev, Yordanova, and Jaskowski (2006) localized an equivalent dipole for go/no-go P3 to midline cingulate cortex between areas 24 and 23 (i.e., near motor areas), the authors acknowledged the possibility “…that this is simply the center-of-mass of some widespread effect. …” (p. 311). Likewise, Mathalon, Whitfield, and Ford (2003) recognized the possibility of misallocation by a single midline dipole solution for error-related negativity (ERN) in the anterior cingulate. We defer this discussion to another paper (Tenke & Kayser, 2008), noting only that the apparent precision with which neuronal generators have been localized may be illusory. The precise regional and laminar generator patterns underlying the novelty P3 are still poorly understood.
