Abstract
When selecting a feature (e.g., the color red) in the visual field, target-related neural signals are enhanced globally across the visual field, operating independently of location (e.g., Martinez-Trujillo & Treue, 2004). Several studies have reported age-related declines in these effects of feature-based attention (e.g., Quigley et al., 2010). Using EEG, we here examined these age-related impairments more closely in older adults by measuring target and distractor processing within and outside the focus of attention. This allowed us to test 1) whether older adults show attentional modulations of a target relative to a distractor feature, and 2) to what extend the effects of feature-based attention spread across locations. Participants were instructed to attend to one of two overlapping colored dot arrays on one side of the visual field (left or right), and to detect brief intervals of coherent motion in the target colored dots (e.g., red) while ignoring any changes in distractors (e.g., blue; cf. Störmer & Alvarez, 2014). To measure the global properties of feature-based attention, another dot array was presented at the unattended side of the screen that either matched the target color or not. All dot arrays flickered at different frequencies, allowing the recording of distinct steady-state visual evoked potentials (SSVEPs) for each color. For the attended side, we found that visual processing was enhanced for the target relative to the distractor color (t(15) = 3.58; p < 0.01), indicating that top-down attention still effectively modulates lower-level feature representations in old age. However, SSVEP amplitudes did not show consistent effects for colors presented in the unattended visual half-field. Together these results suggest that feature-based modulations within the focus of attention are maintained in old age, but that the global properties of feature-based attention are less robust.
Meeting abstract presented at VSS 2018