Early social enrichment leads to reduced anhedonia and HPA axis activation but increased floating in the forced swim test at adulthood: are these mice more or less vulnerable to “depression”?
-
1
Istituto Superiore di Sanita, Italy
During the early postnatal phase, important processes that shape the mammalian brain take place. This highly plastic period offers the possibility to epigenetic factors to affect brain development. In order to study the role of early experiences on adult brain and behavior, we exposed mouse pups to an early social enrichment: the Communal Nest (CN). CN consists in a single nest where three mothers keep their pups together and share care-giving behavior from birth to weaning. In the CN, maternal behavior and peer interactions are markedly increased. At adulthood, mice reared in CN display a number of phenotypical traits having face validity with a reduced vulnerability to depression. In particular, when compared to mice reared in standard laboratory conditions (SN), CN mice display more elaborate social skills, reduced anhedonia following social stress and a reduced activation of the hypothalamic-pituitary-adrenal axis after acute or prolonged exposure to social challenge. These behavioral and neuroendocrine modifications are accompanied by higher brain BDNF levels. By contrast, in the forced swim test, CN mice display longer floating time, usually considered as a depression-like response. These apparently discordant results may be put coherently together when the forced swim test is performed according to the original pharmacological protocol. Indeed, while acute fluoxetine administration reduces immobility in both CN and SN mice, chronic fluoxetine administration -- which is effective in humans -- increases immobility in SN mice up to the level shown by CN group, confirming that they appear less vulnerable to depression-like behavior. Overall, the present findings confirm the crucial role played by the early social experiences in shaping adult brain and behavior and indicate the CN mouse as a model of reduced vulnerability to depression.
Supported by EU project INTELLIMAZE contract n 037965
Conference:
41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009.
Presentation Type:
Poster Presentation
Topic:
Poster presentations
Citation:
Branchi
I,
D-Andrea
I,
Cirulli
F and
Alleva
E
(2009). Early social enrichment leads to reduced anhedonia and HPA axis activation but increased floating in the forced swim test at adulthood: are these mice more or less vulnerable to “depression”?.
Conference Abstract:
41st European Brain and Behaviour Society Meeting.
doi: 10.3389/conf.neuro.08.2009.09.099
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
08 Jun 2009;
Published Online:
08 Jun 2009.
*
Correspondence:
Igor Branchi, Istituto Superiore di Sanita, Rome, Italy, igor.branchi@iss.it