Effect of cue type on covert and presaccadic attention

• Grant number: 22/10867-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2022
• End date: July 31, 2024
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Gustavo Rohenkohl
• Grantee: Maria Fernanda Rodrigues Guimarães
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 17/10429-5 - Long-range brain connectivity during active visual behavior, AP.JP

Abstract

The human visual system has a limited processing capacity considering all the information available in the visual world. Thus, attentional shifts are constantly selecting the most significant items for current goals. This selection can be modulated by top-down and bottom-up factors, referred respectively as endogenous (EnA) and exogenous attention (ExA), the first usually associated with central cues and the second with peripheral cues. Attentional shifts are generally accompanied by saccadic eye movements, continuously made to bring objects of interest to the center of the retina - the fovea, in order to improve visual accuracy. Notably, attention is oriented to the saccade target before the eyes start to move, selectively enhancing peripheral visual perception, which is called presaccadic attention (PSA). In psychophysical experiments, however, EnA and ExA have been broadly investigated using covert attention tasks, i.e. without eye movements, while in PSA tasks, central and peripheral cues are employed indiscriminately. Thereby, how exactly PSA relates to top-down and bottom-up manipulation remains to be established. This project aims to fill this gap through a psychophysical experiment, in which human subjects will be tested on a dual-task paradigm, in order to compare how performance on target discrimination changes through different time bins, under four conditions: eye fixation with central (1) and peripheral (2) cues, and eye movement with central (3) and peripheral (4) cues. It is hypothesized that both cue types will be efficient in capturing PSA, and an early improvement in discrimination performance is expected, comparing with covert orienting. This study will clarify specific characteristics of PSA, comprising behavioral evidence to evaluate if the concepts of EnA and ExA are appropriate for this phenomenon, and to whether PSA is, in fact, a different (sub)type of attention. Altogether, this research will contribute to elucidate how the human visual system selects and processes information, providing basis to carefully investigate the interaction between presaccadic and covert attention.