Seminar Details
2016-04-19 (14:00) : Saccadic mask inhibition: from "it-has-to-be-a-collicular-mechanism" to the impossible color quest
At Euler building (A002)
Organized by Mathematical Engineering
Speaker :
Daye, Pierre
Abstract :
This presentation will be divided into two parts. First, I will present a robust mechanism called "saccadic mask inhibition" induced by displaying a distractor a short period after a saccadic target has been presented. The distractor delays the initiation of a large proportion of saccades but has little effect on landing positions. Physiologically, it is postulated that the saccadic mask inhibition results from a competition between the target and the distractor in the visuomotor maps of the superior colliculus without any cortical involvement. To test this assumption, we updated the original version of the protocol to include conditions in which the collicular involvement is disputable. Because of the nature of the updated protocol, we had to create a new test to evaluate the color perception of each subject. For more than three decades, researchers have worked on a protocol to evaluate the perception of color isoluminance. One of the major issues of the current protocols is that they require a response of the subjects (e.g. "this color is more lighter/darker than this one"). Aside from the obvious bias that could be induced by an answer of the subjects, these protocols could not be used on non-cooperative subjects (infants, patients, monkeys, etc). We developed a new protocol that can be used to evaluate the isoluminance between two colors without requiring a perceptual answer of the subject. Using a combination of the two tests, we were able to demonstrate that the saccadic mask inhibition mechanism does not originate from the superior colliculus but involves cortical mechanisms.