In a series of behavioral experiments complemented by single-unit recordings in pigeons (Columba livia), we show how visual information affects working memory performance. Behaviorally, complex pictures were associated with higher working memory performance compared to uniform gray pictures. This effect was accompanied by a high-dimensional multiplexed neuronal code for the representation of complex stimuli. When processing gray stimuli, neurons exclusively represented the upcoming choice. The prolonged and low-dimensional representation of the gray pictures resulted in a decay of the memory trace and a decrease in performance. In contrast, high stimulus complexity is associated with persistent neuronal multiplexing, resulting in enhanced working memory performance.

Pusch, R., Packheiser, J., Azizi, A., Sevincik, C. S., Rose, J., Cheng, S., Stüttgen, M. C. & Güntürkün, O. (2023). Working memory performance is tied to stimulus complexity. Communications biology, 6(1).