The ERP of auditory reaction tasks

Do the epochs of the reaction time data appear anywhere in the appropriate evoked potentials if a task and its evoked potential are made together One can try to subtract the evoked potential from the task related potential. Schroeder et al. (1995) have usedERP(a21)-ERP(all). 

Paz-Caballero et al. (1992) have used a task with 9 possible positions in two possible arrangements (square or circle). The subjects were asked to respond to the square containing the spot in the top central position by pressing a key. Therefore their task could be coded as vll,l (9 locations and two forms). They then applied a subtraction procedure to compute ERP(vll,l)-ERP and obtained very interesting differences between the ERPs in discrimination and passive tasks. 

Their difference potential called 2-1 (ERP of discrimination task minus ERP of passive task) lasts about 500 ms. 

Paz-Caballero et al.(1992) found three ERP components related to stimulus selection processes N2, P3 and N3. Especially the N2 component has been associated with stimulus evaluation according to task relevance. 

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