It is thought that the dorsal ACC is primarly involved in cognitive processing<ref>Bush G, Luu P & Posner MI, Cognotve and emotional influances in the anterior cingulate cotrex, Trends. Cogn. Sci. 4, 215-222 (2000)</ref>. It is part of the learning mechanism, that learn the positive and negative outcomes of actions in neutral tasks<ref>Botvinick M; Nystrom LE; Fissell K; Carter CS; Cohen JD: Conflict monitoring versus selection-for-action in anterior cingulate cortex. Nature 1999; 402:179—181</ref><ref>Kerns JG; Cohen JD; MacDonald AW 3rd; Cho RY; Stenger VA; Carter CS: Anterior cingulate conflict monitoring and adjustments in control. Science 2004; 303:1023—1026</ref><ref>Carter CS; Macdonald AM; Botvinick M; Ross LL; Stenger VA; Noll D; Cohen JD: Parsing executive processes: strategic vs evaluative functions of the anterior cingulate cortex. Proc Natl Acad Sci USA 2000; 97:1944—1948</ref><ref>Egner T; Hirsch J: The neural correlates and functional integration of cognitive control in a Stroop task. Neuroimage 2005; 24:539—547</ref> and with correlation with rostral ACC, it is involved in emotional learning. It is also a reward mechanism, that gives "globals enrgizing factor", to actions that in the past seems to be rewarding<ref>Struss DT et al.,2005, Multiple frontal systems controlling response speed, ''Neuropshichologia'', 43: 396-417</ref>. Rats with lisions in the ACC, prefer less effortful mission with less reward, to tasks with more effortful with more reward<ref>Walton ME at al, 2003, Fanctional specilization within medial frontal cortex of the antirior cingulate for evaluating effort-related decisions, ''J Neurosci'', 23: 6475-6479</ref>.The ACC motivation mechanism is dependent on dopamin<ref>Assadi SM, Yucel M & Pantelis C, 2009, Dopamin Modulates neural netowrks involved in effort-based decision making, ''Neurosci Biobehav'', 33: 383-393</ref><ref>Alexander MP, 2001, Chronic akinetic mutism after mesanphilic-diancphelick infraction: remediated with dopaminergic medications, ''Neurohabil Nural Repai'', 15:151-156</ref>.  Hypothesis: The Meutation in Dopamin receptor D2 may lower the amount of dopamin recived by the ACC, thus it may be the cause that make people with Atention Deficit Disorder ([[ADD]]), have lack of motivation to engage in effortful actions and decision making.