Search

Antisaccades require the top-down suppression of a stimulus-driven prosaccade (i.e., response suppression) and the inversion of a target's spatial location to mirror-symmetrical space (i.e., vector inversion). Moreover, recent work has shown that antisaccade amplitudes are characterized by a statistical summary representation (SSR) of the target eccentricities included in a stimulus-set--a result suggesting that antisaccades are supported via the same relative visual information as perceptions. The present investigation sought to determine whether response suppression and the disruption of real-time control or vector inversion contribute to a SSR in oculomotor control. Participants completed pro- and antisaccades (target eccentricities of 10.5°, 15.5°, and 20.5°) in blocks of trials that differed with regard to the frequency that individual target eccentricities were presented. The manipulation of target eccentricity frequency was used to determine whether the most frequently presented target within a stimulus-set (i.e., the SSR) influences saccade amplitudes. Moreover, we disrupted the real-time control of prosaccades by requiring participants to suppress their response for a brief visual delay (i.e., 2000 ms: so-called delay prosaccade). As expected, antisaccades and delay prosaccades produced equivalent reaction times. In turn, amplitudes for delay prosaccades were refractory to the manipulation of target eccentricity frequency, whereas antisaccades were biased in the direction of the most frequently presented target within a stimulus-set. Accordingly, we propose that vector inversion contributes to the mediation of target eccentricities via a SSR and that such a phenomenon provides convergent evidence that a relative visual percept mediates antisaccades.

Poster presented at Vision Sciences Society St. Pete Beach, FL, USA, 16 – 22 May, 2014 The concurrent presentation of a target and a remote (i.e., contralateral, foveal) distractor increases the planning times of stimulus-driven prosaccades (i.e., the remote distractor effect, RDE). Conversely, distractors presented within proximal (i.e., ipsilateral) relations with the target are refractory to planning costs and affect the accurate nature of saccade amplitudes (i.e., the global effect: Findlay, 1982). In the present investigation, we sought to determine whether antisaccade planning is similarly influenced by the presentation of a remote and proximal distractor. Indeed, the basis for this question stems from the fact that the non-standard mapping between stimulus and response in the antisaccade task provides a basis for determining whether the sensoryor motor-related features of a distractor influence oculomotor planning times. In Experiment 1, participants completed proand antisaccades in a condition that entailed a single and exogenously presented target (i.e., control condition) and conditions wherein the target was presented simultaneously with distractors at remote (i.e., contralateral, foveal) or ipsilateral locations relative to the target. Results for prosaccade latencies showed the aforementioned RDE, whereas antisaccade latencies for all distractor locations were increased compared to their control condition counterparts. Experiment 2 involved same basic methods as Experiment 1 with the exception that we precued distractor location to reduce the attentional demands associated with disentangling target and distractor locations at response cueing. Results confirmed the findings of Experiment 1 in that antisaccade latencies were increased across each distractor location. Moreover, the antisaccade latency cost was increased when the spatial properties of the distractor were congruent with motor-related task goals. Based on these findings, we propose that the nonstandard nature of antisaccades renders a general increase in oculomotor planning times regardless of the distractor’s spatial properties. Further, we propose the spatial relations between distractor and motor-related goals elicit an increased inhibition of oculomotor networks than the spatial relations between distractor and veridical stimulus location.