Featured Research

from universities, journals, and other organizations

Brain region essential for social memory identified

Date:
February 23, 2014
Source:
Columbia University Medical Center
Summary:
A small region of the hippocampus known as CA2 is essential for social memory, the ability of an animal to recognize another of the same species, a new study concludes. In humans, the importance of the hippocampus for social memory was famously illustrated by the case of Henry Molaison, who had much of his hippocampus removed by surgeons in 1953 in an attempt to cure severe epilepsy. Molaison was subsequently unable to form new memories of people. A better grasp of the function of CA2 could prove useful in understanding and treating disorders characterized by altered social behaviors, such as autism, schizophrenia, and bipolar disorder.

Brain scans (stock image). In humans, the importance of the hippocampus for social memory was famously illustrated by the case of Henry Molaison, who had much of his hippocampus removed by surgeons in 1953 in an attempt to cure severe epilepsy. Molaison (often referred to as HM in the scientific literature) was subsequently unable to form new memories of people. Scientists have observed that lesions limited to the hippocampus also impair social memory in both rodents and humans.
Credit: Sergey Nivens / Fotolia

Columbia University Medical Center (CUMC) researchers have determined that a small region of the hippocampus known as CA2 is essential for social memory, the ability of an animal to recognize another of the same species. A better grasp of the function of CA2 could prove useful in understanding and treating disorders characterized by altered social behaviors, such as autism, schizophrenia, and bipolar disorder. The findings, made in mice, were published today in the online edition of Nature.

Related Articles


Scientists have long understood that the hippocampus—a pair of seahorse-shaped structures in the brain’s temporal lobes—plays a critical role in our ability to remember the who, what, where, and when of our daily lives. Recent studies have shown that different subregions of the hippocampus have different functions. For instance, the dentate gyrus is critical for distinguishing between similar environments, while CA3 enables us to recall a memory from partial cues (e.g., Proust’s famous madeleine). The CA1 region is critical for all forms of memory.

“However, the role of CA2, a relatively small region of the hippocampus sandwiched between CA3 and CA1, has remained largely unknown,” said senior author Steven A. Siegelbaum, PhD, professor of neuroscience and pharmacology, chair of the Department of Neuroscience, a member of the Mortimer B. Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science, and a Howard Hughes Medical Institute Investigator. A few studies have suggested that CA2 might be involved in social memory, as this region has a high level of expression of a receptor for vasopressin, a hormone linked to sexual motivation, bonding, and other social behaviors.

To learn more about this part of the hippocampus, the researchers created a transgenic mouse in which CA2 neurons could be selectively inhibited in adult animals. Once the neurons were inhibited, the mice were given a series of behavioral tests. “The mice looked quite normal until we looked at social memory,” said first author Frederick L. Hitti, an MD-PhD student in Dr. Siegelbaum’s laboratory, who developed the transgenic mouse. “Normally, mice are naturally curious about a mouse they’ve never met; they spend more time investigating an unfamiliar mouse than a familiar one. In our experiment, however, mice with an inactivated CA2 region showed no preference for a novel mouse versus a previously encountered mouse, indicating a lack of social memory.”

In two separate novel-object recognition tests, the CA2-deficient mice showed a normal preference for an object they had not previously encountered, showing that the mice did not have a global lack of interest in novelty. In another experiment, the researchers tested whether the animals’ inability to form social memories might have to do with deficits in olfaction (sense of smell), which is crucial for normal social interaction. However, the mice showed no loss in ability to discriminate social or non-social odors.

In humans, the importance of the hippocampus for social memory was famously illustrated by the case of Henry Molaison, who had much of his hippocampus removed by surgeons in 1953 in an attempt to cure severe epilepsy. Molaison (often referred to as HM in the scientific literature) was subsequently unable to form new memories of people. Scientists have observed that lesions limited to the hippocampus also impair social memory in both rodents and humans.

“Because several neuropsychiatric disorders are associated with altered social behaviors, our findings raise the possibility that CA2 dysfunction may contribute to these behavioral changes,” said Dr. Siegelbaum. This possibility is supported by findings of a decreased number of CA2 inhibitory neurons in individuals with schizophrenia and bipolar disorder and altered vasopressin signaling in autism. Thus, CA2 may provide a new target for therapeutic approaches to the treatment of social disorders.


Story Source:

The above story is based on materials provided by Columbia University Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Frederick L. Hitti, Steven A. Siegelbaum. The hippocampal CA2 region is essential for social memory. Nature, 2014; DOI: 10.1038/nature13028

Cite This Page:

Columbia University Medical Center. "Brain region essential for social memory identified." ScienceDaily. ScienceDaily, 23 February 2014. <www.sciencedaily.com/releases/2014/02/140223131618.htm>.
Columbia University Medical Center. (2014, February 23). Brain region essential for social memory identified. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2014/02/140223131618.htm
Columbia University Medical Center. "Brain region essential for social memory identified." ScienceDaily. www.sciencedaily.com/releases/2014/02/140223131618.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com
Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins