Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hamster study shows how our brains recognize other individuals

09.03.2006


Imagine seeing a former high school classmate you always wanted to know better. Then imagine seeing that kid who used to push you in the hallways. Do you react differently? What happens in your brain during these encounters?



In fact, different areas of the brain react differently when recognizing others, depending on the emotions attached to the memory, a team of Cornell University research psychologists has found. The team, led by professor of psychology Robert Johnston, has been conducting experiments to study individual recognition.

But rather than crash high school reunions with an MRI machine in tow, the researchers stayed in their laboratory and created social encounters between golden hamsters. Then they examined the animals’ brains for evidence of those encounters.


Last year Johnston’s team conducted the first experiment to demonstrate the neural basis of individual recognition in hamsters and identify which areas of the brain play a role. The results were published in the Dec. 7, 2005, issue of the Journal of Neuroscience.

Better understanding these mechanisms, Johnston said, may be of central importance in treating certain forms of autism, Asperger syndrome, psychopathy and social anxiety disorders.

"This ability to recognize individuals underlies social behavior in virtually all vertebrates and some invertebrates as well," explained Johnston. "Humans clearly have an incredible ability to recognize, remember and store huge amounts of information about individuals -- even individuals we have never actually met. This ability is the core of circuits that one might call the social brain."

Johnston’s team uses hamsters to study recognition because their brains are strikingly similar to ours. "They are more sophisticated than you might think," he noted.

In the latest experiment, a male hamster encountered two individuals that he knew equally well but had different interactions with the previous day: a male that defeated him in a fight and a male that he had never fought. The encounters mimicked those that occur in the wild.

The hamster fled from the winning male but was attracted to the neutral male -- suggesting that he both recognized the individuals and remembered his experiences with them.

An hour later, the researchers removed the hamster’s breath-mint-sized brain and injected it with antibodies and enzymes. The antibodies bond to specific proteins produced by recently active brain cells, and the enzymes convert chemicals in the cells into colored dyes, leaving behind a map of where the action was. This technique, called immunohistochemistry, is also used to diagnose cancerous cells in humans.

Next the brain was frozen with dry ice, shaved into very thin slices using a miniature slow-moving guillotine and then studied under a microscope to determine where the dyes were activated.

"Functional MRIs provide similar information from human brains, but those images are relatively fuzzy and lack the spatial resolution necessary for small animals," explained Johnston. "With immunohistochemistry, on the other hand, we can see each individual cell that was activated."

The researchers found activity in the brain’s anterior dorsal hippocampus and amygdala, among other areas. They then repeated the experiment with another hamster whose anterior dorsal hippocampus was numbed with lidocaine, a local anesthetic, and found that the animal did not avoid the individual who had defeated him.

"It showed us that this region is necessary for recognition memory," said Johnston. "The hippocampus has also been implicated for recognition memory in humans."

Although hamsters recognize individuals by smell, whereas humans use largely sight and sound, Johnston said that the underlying mechanism is the same. The other authors of the Neuroscience article are first author and former Cornell graduate student Wen-Sung Lai ’03, graduate student Leora Ramiro and former undergraduate Helena Yu ’03. The National Institute of Mental Health supported the research.

Blaine Friedlander | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>