Abstract
In the current study, we used fiber photometry and optogenetics to make temporally precise observations and manipulations of locus coeruleus (LC) activity during learning in a trace fear conditioning task. Although the LC is typically thought to modulate neural activity via the release of norepinephrine (NE), several recent studies have suggested that it may also release dopamine (DA) into the hippocampus and other cortical regions. In some cases, it appears that DA release from LC into the HPC may be more important for memory than norepinephrine. The effects of DA release on memory formation have primarily been studied using reward and spatial learning tasks. However, many studies have demonstrated that dopamine is released in several brain regions (eg. nucleus accumbens, prefrontal cortex, amygdala). Here, we extend this data by providing direct evidence that LC activity increases both DA and NE content in the hippocampus and by showing that DA release is important for trace fear memory formation, but the release of NE is not.
Competing Interest Statement
The authors have declared no competing interest.
