Ishita Agarwal¹ (), Sung-Mu Lee¹, Jinho Lee¹, Anne B Sereno¹; ¹Purdue University

Attention selectively modulates neural activity, enhancing the processing of task-relevant visual features. However, it remains unclear how neural activity differs between shape-selective and spatial-selective attentional focus in different brain regions. Many existing attention-related tasks are complex, making them difficult for individuals with attentional deficits to perform, or require a significant amount of practice (e.g., dual-task or task-switching paradigms). Additionally, many imaging studies use visual stimuli such as shapes, objects, or faces without adequately controlling for factors like luminance, color, and size, which introduces variability in brain responses, reducing reliability and sensitivity. Finally, previous paradigms often focus attention on a single dimension of an object (e.g., color or location) rather than examining multiple aspects of attention simultaneously, limiting their generalizability. To address these issues, this study used identical stimuli in a simple, well-controlled experimental paradigm designed to reliably assess the effect of varying attentional focus. Participants performed a 1-back repetition task where, in separate fMRI blocks but using the same stimuli, participants need to pay attention to either the shape or the location of images. Whole-brain analyses across MNI-defined brain regions revealed that attending to shape, compared to passive viewing condition, elicited increased activity in the ventral stream such as temporal parietal junction. In contrast, attending to location, compared to passive viewing condition, predominantly elicited increased activity in dorsal stream such as supramarginal gyrus. These findings highlight region-specific neural activation, demonstrating that shape-selective and spatial-selective attentional focus selectively engages distinct brain regions. We will discuss how these findings advance our understanding of how attention to shape and location of objects dynamically modulates neural activity within the visual system.

Acknowledgements: NIH CTSI and Purdue University