Science News
from research organizations

'Eating with the eyes' is hard-wired in the brain

Scientists captured activity in a brain circuit that links visual perception of food and feeding motivation in fish

Date:
April 20, 2017
Source:
Research Organization of Information and Systems
Summary:
Scientists have discovered prey detector neurons in the visual system that project to the feeding center in the hypothalamus, and they observed neurons in this circuit firing upon seeing prey. The study demonstrates the presence of hard-wired circuitry that conveys visual information to the center that regulates feeding motivation in zebrafish.
Share:
FULL STORY

This is a Zebrafish larva trying to catch prey.
Credit: Copyright National Institute of Genetics (NIG)

Have you ever wondered why just seeing food can make your mouth start to water? By visualizing neuronal activity in specific areas of the zebrafish brain, scientists at the National Institute of Genetics (NIG) in Japan have revealed a direct link between visual perception of food and feeding motivation. The study, published in the April 20, 2017 issue of Nature Communications, suggests that "eating with the eyes" is deeply rooted in evolution.

"In vertebrate animals, feeding behavior is regulated by a brain area called the hypothalamus. The hypothalamic feeding center integrates information about bodily energy requirements and environmental food availability. Zebrafish, like humans, mostly use vision for recognition of food or prey. It was not known how the hypothalamus receives visual information about prey. We first demonstrated that neurons in the hypothalamus do indeed respond to the sight of prey. Then we looked for neurons in the visual system that responded to prey and discovered 'prey detector' neurons in an area called the pretectum. Furthermore, we found a direct neural link connecting the prey detector neurons to the hypothalamic feeding center," Dr. Muto, the leading author of the study, explained.

The key to this discovery has been recent progress in the development and improvement of the highly sensitive, genetically encoded calcium indicator GCaMP, which can be used to monitor neuronal activity in the form of calcium signals. Another important technology is the ability to control the specific neurons in which GCaMP is expressed. This was critical for recording distinct calcium signals from identifiable neurons.

Prof. Kawakami, the senior author, showed us his zebrafish facility where thousands of fish tanks can be seen, each of which contains genetically different fish that can turn on, or drive the GCaMP expression in different types of cells in the brain or in the body. This collection of driver fish lines is being used to study various tissues and cell types by zebrafish researchers all over the world. Of the nearly 2,000 such driver fish lines in the lab, two played important roles in the current study: one for the imaging of the prey detector neurons, and the other for the feeding center in the hypothalamus.

"Successful brain imaging was made possible through development of our genetic resources on which I have spent more than twenty years. This is the power of zebrafish genetics. This work showcases a successful application of our genetic resources in the study of brain function," Prof. Kawakami said.

"Our study demonstrates how tightly visual perception of food is linked to motivational feeding behavior in vertebrate animals. This is an important step toward understanding how feeding is regulated and can be modulated in normal conditions as well as in feeding disorders," Dr. Muto said.


Story Source:

Materials provided by Research Organization of Information and Systems. Note: Content may be edited for style and length.


Journal Reference:

  1. Akira Muto, Pradeep Lal, Deepak Ailani, Gembu Abe, Mari Itoh, Koichi Kawakami. Activation of the hypothalamic feeding centre upon visual prey detection. Nature Communications, 2017; 8: 15029 DOI: 10.1038/NCOMMS15029

Cite This Page:

Research Organization of Information and Systems. "'Eating with the eyes' is hard-wired in the brain: Scientists captured activity in a brain circuit that links visual perception of food and feeding motivation in fish." ScienceDaily. ScienceDaily, 20 April 2017. <www.sciencedaily.com/releases/2017/04/170420090211.htm>.
Research Organization of Information and Systems. (2017, April 20). 'Eating with the eyes' is hard-wired in the brain: Scientists captured activity in a brain circuit that links visual perception of food and feeding motivation in fish. ScienceDaily. Retrieved May 26, 2017 from www.sciencedaily.com/releases/2017/04/170420090211.htm
Research Organization of Information and Systems. "'Eating with the eyes' is hard-wired in the brain: Scientists captured activity in a brain circuit that links visual perception of food and feeding motivation in fish." ScienceDaily. www.sciencedaily.com/releases/2017/04/170420090211.htm (accessed May 26, 2017).

RELATED STORIES