Connectivity between nidopallium caudolateral and visual pathways in color perception of zebra finches

Abstract

Researchers demonstrated an elegant ability for red discrimination in zebra finches. It is interested to understand whether red activates exhibit much stronger response than other colors in neural network levels. To reveal the question, local field potentials (LFPs) was recorded and analyzed in two visual pathways, the thalamofugal and the tectofugal pathways, of zebra finches. Human studies demonstrate visual associated telencephalons communicate with higher order brain areas such as prefrontal cortex. The present study determined whether a comparable transmission occurs in zebra finches. Telencephalic regions of the thalamofugal (the visual Wulst) and the tectofugal pathway (the entopallium) with their higher order telencephalon, nidopallium caudolateral (NCL) were simultaneously recorded. LFPs of relay nuclei (the nucleus rotundus, ROT) of tectofugal pathway were also acquired. We demonstrated that LFP powers in the tectofugal pathway were higher than those in the thalamofugal pathway when illuminating blue lights. In addition, the LFP synchronization was stronger between the entopallium and NCL. LFPs also revealed a higher Granger causality from the direction of entopallium to NCL and from ROT to entopallium. These results suggest that zebra finches’ tectofugal pathway predominately processing color information from ROT to NCL, relayed by entopallium, and blue could trigger the strongest response.

Mapping the avian visual tectofugal pathway using 3D reconstruction

“…The NCL, the caudal portion of the lateral nidopallium, sits caudal to the NIL and has been a proposed homolog of the mammalian prefrontal cortex on the basis of connectivity, dopaminergic innervation, and that it is a multisensory convergence domain (Fernández et al., 2019; Hartmann & Güntürkün, 1998; Hsiao et al., 2020). The NCL has functional significance in color perception, reversal learning, and selection/execution of perceptual responses (Hartmann & Güntürkün, 1998; Hsiao et al., 2020; Lengersdorf et al., 2014). The NCL is often paired with the temporo‐parieto‐occipital area because it is difficult to distinguish between the two, which is the case in our GSM and Nissl stained series.…”