Task-switching in oculomotor control: unidirectional switch-cost when alternating between pro- and antisaccades

Area of Science:

• Neuroscience
• Cognitive Psychology
• Oculomotor Research

Background:

• Antisaccade tasks involve suppressing reflexive eye movements (prosaccades) and inverting target locations.
• These tasks increase activation in cortical oculomotor networks due to cognitive demands.
• The study investigates if this increased activity leads to residual inhibition of oculomotor planning networks.

Purpose of the Study:

• To determine if antisaccades cause residual inhibition in oculomotor planning networks.
• To examine the effects of task-switching on prosaccade and antisaccade performance.
• To investigate the neural mechanisms underlying saccade task switching.

Main Methods:

• Participants performed an antisaccade task with single, exogenous targets.
• Blocked (AABB) and random task-switching schedules were employed.
• Reaction times for prosaccades and antisaccades were measured across task repetitions and switches.

Main Results:

• Prosaccades showed longer and more variable reaction times following a task switch (switch-cost).
• Antisaccades did not exhibit significant differences between task-repetition and task-switch trials.
• This unidirectional switch-cost for prosaccades was consistent across both blocked and random schedules.

Conclusions:

• Top-down processes for antisaccades likely induce residual inhibition in oculomotor networks.
• This inhibition specifically impacts subsequent prosaccade planning, creating a unidirectional switch-cost.
• Findings suggest a mechanism where antisaccade execution temporarily suppresses oculomotor planning networks.