Hsing-Hao Lee¹ (), Marisa Carrasco^1,2; ¹Department of Psychology, New York University, ²Center for Neural Science, New York University

[BACKGROUND] Covert spatial attention and visual adaptation are two fundamental visual processes that can help manage the limited bioenergetic resources according to the task demand. Visual perception is heterogeneous around the visual field: it is better along the horizontal than the vertical meridian (horizontal-vertical anisotropy, HVA), and better along the lower than the upper vertical meridian (vertical meridian asymmetry, VMA), reflecting well-established performance fields. Neither endogenous (voluntary) nor exogenous (involuntary) attention alter performance fields, whereas adaptation is stronger at the horizontal than the vertical meridian, reducing the HVA. Here we ask, whether and how endogenous and exogenous attention affect the performance asymmetries before and after adaptation at the cardinal meridians. [METHODS] To equate discriminability across the four cardinal locations, we titrated contrast thresholds while observers performed an orientation discrimination task on a vertically-tilted Gabor (±2.5°, 5 cpd) in the neutral condition, with and without adaptation to 100%-contrast vertical Gabor adaptors. They then performed the same task with informative central (endogenous) pre-cues (Experiment 1) or uninformative peripheral (exogenous) pre-cues (Experiment 2) indicating the target location. The pre-cue either matched (valid-cue), mismatched (invalid-cue) or provided no location information (neutral-cue). Performance was quantified using d′. [RESULTS] Titration results were consistent with previous studies, showing (1) typical HVA and VMA in contrast thresholds in the non-adapted condition, and (2) stronger adaptation at the horizontal than the vertical meridian. Results from the attentional tasks showed that, in both adapted and non-adapted conditions, each endogenous and exogenous attention improved or impaired performance in the valid or invalid conditions, respectively, to a similar extent across cardinal meridians. [CONCLUSION] Despite the distinct flexibility and temporal dynamics of endogenous and exogenous attention, both types of attentional effects remained uniform across cardinal meridians before and after differential adaptation. Thus, they do not interact with adaptation around polar angles.

Acknowledgements: NIH NEI R01-EY027401 to MC. Taiwan’s Government Fellowship for Studying Ph.D. Abroad, the Ministry of Education in Taiwan and 2025 National Science and Technology Council (NSTC) Taiwanese Overseas Pioneers Grants (TOP Grants) for PhD Candidates to HHL