Schedule of Events | Symposia

Fronto-parietal contributions to temporal, spatial, and category biases in visual working memory

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Sihan Yang¹ (siy009@ucsd.edu), Jason M. Scimeca², Anastasia Kiyonaga¹; ¹University of California, San Diego, ²Louisiana State University

Working memory (WM) recall and representations can be biased by recent perceptual history, concurrent perceptual input, and prior knowledge. WM-related activity is distributed across the cortex, but it’s unclear what unique contributions different cortical activations make to preserving WM fidelity or integrating WM information across time, space, and existing knowledge. Here we build on a prior study of fronto-parietal WM functions to examine how specific regions contribute to WM biases — influences from recent trial history (serial bias), concurrently-maintained items (swap errors and surrounding bias), and semantic knowledge (color-category bias). During fMRI, participants completed a color WM recall task, wherein set-size varied from trial-to-trial. Individual functional activations were used to guide transcranial magnetic stimulation (TMS) to three critical regions: superior intraparietal sulcus (sup-IPS), inferior intraparietal sulcus (inf-IPS), and mid-lateral prefrontal cortex (PFC). Behavioral analyses revealed strong interactions between multiple types of WM bias. E.g., serial biases were minimized for more prototypical (categorical) colors and when concurrent WM items were more similar to each other. TMS also impacted bias magnitudes, but depended on a combination of TMS site and set-size. E.g., serial biases increased at higher set sizes under control stimulation, but PFC stimulation dampened that increase. Given that serial biases are thought to adaptively smooth noisy representations, this implies that the targeted region of PFC critically underlies this temporal integration process. These results suggest complex interdependence between multiple sources of WM bias, highlighting the role of fronto-parietal regions in not just WM maintenance but spatial and temporal context integration.

Topic Area: EXECUTIVE PROCESSES: Working memory