Related Experiment Videos
Steroid-dependent plasticity in the medial amygdala
1Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA. b-cooke@northwestern.edu
Neuroscience
|December 7, 2005
Summary
Adult androgen levels can change brain structure related to sex behavior, demonstrating significant neural plasticity. Environmental factors also influence androgen secretion and brain responses.
Area of Science:
- Neuroscience
- Endocrinology
- Behavioral Biology
Background:
- Sex differences in behavior are traditionally linked to neonatal gonadal steroids.
- Adult hormone levels can influence and even reverse established sex-specific behaviors.
Purpose of the Study:
- To investigate the plasticity of adult neural substrates controlling sex behavior.
- To determine the role of circulating androgens in adult brain morphology and sex behavior.
Main Methods:
- Sex-reversal of circulating androgen levels in adult rats.
- Analysis of soma size and regional volume in the posterodorsal subnucleus of the medial amygdala.
- Correlation of seasonal androgen variation with neural morphology in Siberian hamsters.
Main Results:
- Sex-reversing androgen levels altered posterodorsal subnucleus of the medial amygdala soma size and volume in adult rats.
- Both androgen and estrogen receptor activation were crucial for maintaining masculine cell size, while estrogen alone maintained masculine volume.
- Seasonal changes in androgen levels correlated with posterodorsal subnucleus of the medial amygdala plasticity in hamsters, influenced by photoperiod and social cues.
Conclusions:
- Circulating androgens are vital for maintaining the morphology of the posterodorsal subnucleus of the medial amygdala in adults.
- Environmental factors significantly regulate androgen secretion and the brain's responsiveness to androgens.