Visual transients, such as a bright flash, reduce the proportion of saccades executed, ∼60-125 ms after flash onset, a phenomenon known as saccadic inhibition (SI). Across three experiments, we apply a similar time-course analysis to the amplitudes and velocities of saccades. Alongside the expected reduction of saccade frequency in the key time period, we report two perturbations of the "main sequence": one before and one after the period of SI. First, saccades launched between 30 and 70 ms, following the flash, were hypometric, with peak speed exceeding that expected for a saccade of similar amplitude. This finding was in contrast to the common idea that saccades have passed a "point of no return," ∼60 ms before launching, escaping interference from distractors. The early hypometric saccades observed were not a consequence of spatial averaging between target and distractor locations, as they were found not only following a localized central flash (experiment 1) but also following a spatially generalized flash (experiment 2). Second, across experiments, saccades launched at 110 ms postflash, toward the end of SI, had normal amplitude but a peak speed higher than expected for that amplitude, suggesting increased collicular excitation at the time of launching. Overall, the results show that saccades that escape inhibition following a visual transient are not necessarily unaffected but instead, can reveal interference in spatial and kinematic measures.

Beyond the point of no return: Effects of visual distractors on saccade amplitude and velocity / Buonocore, Antimo; Mcintosh, Robert D.; Melcher, David Paul. - In: JOURNAL OF NEUROPHYSIOLOGY. - ISSN 0022-3077. - STAMPA. - 115:2(2016), pp. 752-762. [10.1152/jn.00939.2015]

Beyond the point of no return: Effects of visual distractors on saccade amplitude and velocity

Buonocore, Antimo;Melcher, David Paul
2016

Abstract

Visual transients, such as a bright flash, reduce the proportion of saccades executed, ∼60-125 ms after flash onset, a phenomenon known as saccadic inhibition (SI). Across three experiments, we apply a similar time-course analysis to the amplitudes and velocities of saccades. Alongside the expected reduction of saccade frequency in the key time period, we report two perturbations of the "main sequence": one before and one after the period of SI. First, saccades launched between 30 and 70 ms, following the flash, were hypometric, with peak speed exceeding that expected for a saccade of similar amplitude. This finding was in contrast to the common idea that saccades have passed a "point of no return," ∼60 ms before launching, escaping interference from distractors. The early hypometric saccades observed were not a consequence of spatial averaging between target and distractor locations, as they were found not only following a localized central flash (experiment 1) but also following a spatially generalized flash (experiment 2). Second, across experiments, saccades launched at 110 ms postflash, toward the end of SI, had normal amplitude but a peak speed higher than expected for that amplitude, suggesting increased collicular excitation at the time of launching. Overall, the results show that saccades that escape inhibition following a visual transient are not necessarily unaffected but instead, can reveal interference in spatial and kinematic measures.
2
Buonocore, Antimo; Mcintosh, Robert D.; Melcher, David Paul
Beyond the point of no return: Effects of visual distractors on saccade amplitude and velocity / Buonocore, Antimo; Mcintosh, Robert D.; Melcher, David Paul. - In: JOURNAL OF NEUROPHYSIOLOGY. - ISSN 0022-3077. - STAMPA. - 115:2(2016), pp. 752-762. [10.1152/jn.00939.2015]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11572/144220
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