Mapping the Visual Pathways of Chickens Using Novel 3D Imaging Technique

The Problem

Traditional imaging techniques like MRI are expensive and often inaccessible to many researchers. This limitation hinders the ability to study complex neuroanatomical structures in animals, including avian species like broiler chickens.

Researchers in Arkansas sought to better understand the diverse functions of neurological pathways that control vision in chickens and needed a way to image samples without damaging or distorting the tissue. Understanding avian visual systems can help provide future insights into poultry behavioral patterns.

The Work

Researchers with the Arkansas Agricultural Experiment Station sought to address these challenges by helping to develop a more affordable and straightforward imaging technique.

Wayne Kuenzel, professor of physiology and neuroendocrinology, worked with University of Arkansas graduate student Parker Straight and Paul Gignac, associate professor of cellular and molecular medicine with the University of Arizona College of Medicine — Tucson, to map the tectofugal and thalamofugal visual pathways of a chicken brain.

They used a hybrid method of conventional histochemistry and a newer imaging method called diceCT, which stands for “diffusible iodine-based contrast-enhance computer tomography.”

DiceCT is like an MRI, Straight explained, but instead of using a large magnet and radio waves, it uses iodine to stain the tissue so that a viewer can see groups of cells among fiber tracts. DiceCT uses X-ray scans to “digitally” slice the biological subject being studied.

The Results

Using the hybrid methods of histochemistry and diceCT, the scientists successfully mapped the intricate neurological pathways that control vision in chickens. The researchers produced high-quality 3D images, allowing viewers to see the entire pathway in one image, enhancing the teaching of how the pathway works.

Moreover, the researchers found that the tectofugal pathway may have a broader role in visual processing than previously thought, potentially influencing both motion and color perception in birds.

The Value

The hybrid method of 3D scanning used in this research can be used to study neurobiology at a large scale, such as brain region morphology, and at a more detailed scale, such as looking at a single neurological pathway. The new method offers a less expensive way to create quality 3D images resembling MRI technology. It can also benefit teaching complex anatomy and expand the tools of animal science researchers.

This method’s affordability and accessibility may increase the number of investigations into animal neurobiology using 3D methods, ultimately benefiting both research and teaching. Straight also hopes the study will prompt more research on animal neurobiology and how it compares to the neurobiology of humans.