Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fish frozen in fear

20.12.2010
Fear responses of zebrafish are controlled by brain structures of previously unknown function

A brain structure called the habenula is crucial for modifications of fear responses in zebrafish, according to a new study by researchers from the RIKEN Brain Science Institute, Wako(1). The zebrafish dorsal habenula is subdivided into two regions, each connected to different brain structures, but the function of each, and the significance of their connections, was unclear.

Hitoshi Okamoto and his colleagues used fluorescent dyes to trace the neural pathways from the interpeduncular nucleus (IPN), which recves connections from the dorsal habenula region . They fond that the dorsal IPN projects to midbrain structures called the dorsal raphe nucleus and griseum centrale. The corresponding structures in the mammalian brain have been implicated in responses to fear and stress, suggesting that the habenula–IPN pathway in zebrafish is also involved in these responses.

To investigate this, the researchers created transgenic zebrafish expressing tetanus toxin in the lateral subnucleus of the dorsal habenula. The toxin blocks neurotransmission, preventing neurons in that region from sending signals.

The transgenic fish were then subjected to an established fear conditioning task, in which a red light is repeatedly paired with an electric shock. Normally, the fish learn to associate the two stimuli, and become agitated—recognized by an increase in the frequency of turning—in the presence of the light alone. However, when the transgenic fish encountered the red light after the fear conditioning task, they froze rather than escaping. Okamoto and colleagues observed these differences between the transgenic fish and controls during the fear conditioning task. Both froze the first time they encountered the red light; the controls started to become agitated the second time, but the transgenic fish continued to freeze.

The exploratory behavior of the transgenic fish was no different from that of the controls, showing that their responses to fear conditioning were not due to abnormal sensory or motor function. Instead, the results suggest to the researchers that the transgenic fish cannot modify their fear response after new experiences. They therefore conclude that experience-dependent modifications of fear responses are controlled by the neurons in the lateral subnucleus of the dorsal habenula in the zebrafish.

“We would like to know whether the same regulation mechanism works in mammals, including humans,” says Okamoto, “and would also like to extend our research to reveal the functions of the other parts of the habenula.”

The corresponding author for this highlight is based at the Laboratory for Developmental Gene Regulation, RIKEN Brain Science Institute.

Journal information

1. Agetsuma, M., Aizawa, H., Aoki, T., Nakayama, R., Takahoko, M., Goto, M., Sassa, T., Amo, R., Shiraki, T., Kawakami, K., et al. The habenula is crucial for experience-dependent modification of fear responses in zebrafish. Nature Neuroscience 13, 1354–1356 (2010).

gro-pr | Research Asia Research News
Further information:
http://www.riken.jp
http://www.researchsea.com

Further reports about: Brain IPN Okamoto RIKEN Science TV brain structure transgenic fish

More articles from Life Sciences:

nachricht Closing in on advanced prostate cancer
13.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Visualizing single molecules in whole cells with a new spin
13.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>