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SUMMARY:How perception informs urgent saccadic choices: halting\, accelera
 tion\, and deceleration - Emilio Salinas (Wake Forest School of Medicine)
DTSTART:20190521T100000Z
DTEND:20190521T110000Z
UID:TALK124612@talks.cam.ac.uk
CONTACT:Yul Kang
DESCRIPTION:The choice of where to look next is guided by current perceptu
 al information as well as internal factors such as motivation\, current go
 als\, prior experience\, etc.  I will discuss the development and testing 
 of a mechanistic framework that describes how perceptual and motor-plannin
 g processes dynamically interact and give rise to saccadic choices.  In tr
 aditional studies of choice behavior\, a decision based on sensory informa
 tion is made first and is then followed by a motor report.  Choices concei
 ved in such a serial fashion progress slowly (hundreds of ms) --- but unde
 r natural viewing conditions the median time between gaze fixations is sho
 rt (200--250 ms)\, and the next saccade is always being planned. Our appro
 ach is to manipulate time pressure to reveal how perception and attention 
 guide saccadic choices under more temporally realistic conditions\, i.e.\,
  when the perceptual evaluation occurs rapidly (< 50 ms) and informs oculo
 motor plans that are already ongoing. By combining behavioral\, neurophysi
 ological\, and theoretical work\, we have developed a modeling framework t
 hat (1) is applicable to a wide range of urgent-choice tasks\, (2) replica
 tes rich psychophysical data in great detail\, and (3) is firmly consisten
 t with activity recorded in the frontal eye field (FEF). In this framework
 \, perception influences ongoing target selection by halting\, acceleratin
 g\, or decelerating developing motor activity. These three forms of dynami
 cal interaction explain in quantitative detail the rapid temporal variatio
 ns in psychometric performance observed in our urgent tasks\; for example\
 , how exogenous (saliency-driven) and endogenous (rule-driven) influences 
 compete when the goal is to look away from a salient stimulus.
LOCATION:Cambridge University Engineering Department\, CBL\, BE4-38 (http:
 //learning.eng.cam.ac.uk/Public/Directions)
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