Weiler J, Heath M. Oculomotor task switching: alternating from a nonstandard to a standard response yields the unidirectional prosaccade switch-cost. J Neurophysiol 112: 2176 -2184. First published August 13, 2014 doi:10.1152/jn.00352.2014.-The completion of an antisaccade (i.e., a nonstandard task) lengthens the reaction time (RT) of a subsequent prosaccade: a behavioral phenomenon termed the unidirectional prosaccade switch-cost. One explanation for the unidirectional prosaccade switch-cost is suppressing a stimulusdriven prosaccade during the preceding antisaccade trial engenders a residual inhibition of the oculomotor networks that support prosaccade planning (i.e., the oculomotor inhibition hypothesis). Alternatively, the unidirectional prosaccade switch-cost may reflect the persistent activation of the antisaccade's nonstandard task rules (i.e., task set), which delays the planning of the next prosaccade (i.e., task-set inertia hypothesis). To determine which hypothesis provides the most parsimonious account for the unidirectional prosaccade switch-cost, participants alternated between pro-and antisaccades wherein task instructions (i.e., pro-and antisaccade) were provided before (i.e., classic cuing) or concurrent (i.e., delayed cuing) with response cuing. Importantly, pro-and antisaccades elicited via the delayed cuing condition required the suppression of a stimulus-driven prosaccade at response cuing (i.e., response suppression) to discern the appropriate to-be-performed task. Results showed that classic and delayed antisaccades, but not delayed prosaccades, lengthened the RT of subsequent prosaccades. That delayed prosaccades, which require response suppression for their successful execution, did not lengthen the RT of subsequent prosaccades indicates that the oculomotor inhibition hypothesis does not account for the unidirectional prosaccade switchcost. Instead, the current findings are in line with the assertion that the task set associated with a nonstandard antisaccade persists inertially and delays the planning of a subsequent prosaccade (i.e., task-set inertia hypothesis).oculomotor; reaction time; response suppression; saccade; task set THE DEMANDS OF OUR ENVIRONMENT require that we periodically override habitual actions to produce a context or task-appropriate response. For example, the Canadian tourist in Ireland must resist the reflexive urge to first look left when crossing a street, and instead first look right, or risk being struck by the traffic coming from an unfamiliar direction. The prosaccade and antisaccade tasks are experimental corollaries to the aforementioned example; indeed, these tasks respectively permit the evaluation of how a prepotent response (i.e., prosaccade) or its volitional and less-practiced, but goal-relevant, counterpart (i.e., antisaccade) are planned and executed. In particular, the experimentally based prosaccade task requires participants to fixate a central stimulus and subsequently saccade to an exogenously presented target. Notably, the direct overlap betwe...