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Fear extinction is impaired in aged rats
Payton K Robinson1, Erisa Met Hoxha1, Destine Williams1
1Department of Psychological Sciences, Purdue University, West Lafayette, IN, 47907, USA.
Geroscience
|February 13, 2024
Summary
Aging impairs extinction learning and alters neural activity in rats. Aged rats failed to reduce freezing behavior and showed abnormal gene expression in brain regions critical for cognitive flexibility.
Area of Science:
- Neuroscience
- Cognitive Aging
- Animal Models
Background:
- Normal aging leads to cognitive decline, particularly in cognitive flexibility.
- Extinction learning, the reduction of learned responses, is a key aspect of cognitive flexibility.
Purpose of the Study:
- To investigate the impact of normal aging on extinction learning and associated neural activity in rats.
- To compare extinction learning and neural changes in young versus aged Long Evans rats.
Main Methods:
- Delay fear conditioning followed by extinction trials (CS-alone presentations) or a no-extinction control.
- Assessment of freezing behavior as a measure of fear response.
- Measurement of immediate early gene zif268 expression in the basolateral amygdala and anterior retrosplenial cortex.
Main Results:
- Young rats showed reduced freezing after extinction, while aged rats did not.
- Extinction led to decreased zif268 expression in specific brain areas in young rats, but not in aged rats.
- Aged rats exhibited increased zif268 expression across examined brain regions.
Conclusions:
- Normal aging significantly impairs extinction learning in rats.
- Aging is associated with altered neural activity patterns in brain regions involved in cognitive flexibility.
- Neural dysfunction may precede observable cognitive deficits in aging.
