Behavior in a visual search task with moving dot stimuli

Understanding the neuronal mechanisms underlying the allocation and processing of visual attention requires a well-designed behavioral task that allows investigators to clearly describe the behavioral effects of attention. Here, we introduce a behavioral paradigm in which one, two, or four moving dot stimuli are used in a visual search paradigm that includes two additional attentional conditions. Two animals were trained to make a saccade to a target (a dot patch with net rightward motion) and hold central fixation if no target was present. To implement covert visual attention, we included trials in which a 100% valid spatial cue appeared and trials in which the color of the fixation point indicated, with 100% validity, which of four colored dot patches the animals should attend to. We analyzed the behavior in terms of reaction times and signal detection theory metrics d-prime (representing sensitivity) and criteria. In both animals, we found that reaction times were greater for larger set sizes and that the introduction of an attentional cue reduced the reaction times substantially. We also found that both animals showed increases in criteria, but no change in sensitivity, as set size increased and the attentional cues led to an increase in sensitivity, with only some change in criteria. Our results illustrate how the animals perform this task and imply that both animals chose similar strategies. Importantly, this strategy will allow future neurophysiological studies to probe not only the effects of attention but also will give the possibility of seeing whether different neural mechanisms drive changes in criteria and d-prime. NEW & NOTEWORTHY The aim of this study was to design a behavioral paradigm that would allow us to probe the neural mechanisms of attention. The study describes the behavior of animals performing a visual search task with up to four moving dot stimuli and two forms of visual attention. We find that the animals use similar strategies to perform the task, leading to similar changes in reaction times and signal detection theory metrics d-prime and criteria.

Automated summary

This study introduces a behavioral paradigm to investigate the neural mechanisms of attention. The results show that introducing attentional cues significantly reduces reaction times and affects sensitivity and criteria.