Discriminating between object categories is a crucial function of primate and bird visual systems. However, brain structures responsible for visual processing greatly differ between birds and mammals.

iscriminating between object categories is a crucial function of primate and bird visual systems. However, brain structures responsible for visual processing greatly differ between birds and mammals.  Here, we examined whether a similar hierarchical organization that operates for processing faces in monkeys also exists in the avian visual system. While pigeons viewed images of faces, scrambled controls, and sine gratings, single neurons were recorded from three visual forebrain regions: the Wulst, the entopallium (ENTO) and mesopallium ventrolaterale (MVL). A greater proportion of single MVL neurons fired to the stimuli, and the population response of MVL neurons distinguished between stimuli with greater capacity than ENTO and Wulst neurons. In contrast to the primate system, no neurons were strongly face-selective and some responded best to the scrambled images. These findings suggest that MVL is primarily involved in processing local features of images, much like the early visual cortex.

Clark, W., Chilcott, M., Azizi, A., Pusch, R., Perry, K. & Colombo, M. (2022) Neurons in the pigeon visual network discriminate between faces, scrambled faces, and sine grating images. Sci Rep 12, 589. https://doi.org/10.1038/s41598-021-04559-z