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Updated: Aug 16, 2026
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A Novel Pavlovian Fear Conditioning Paradigm to Study Freezing and Flight Behavior
Published on: January 5, 2021
A novel role for the infralimbic cortex in conditioned fear responding
Julia R Mitchell1, Samantha Tuberman1, Rylin Lubash1
1Psychology Department, Northeastern University, 360 Huntington Ave., Boston, MA 02115, United States.
Oxford Open Neuroscience
|August 15, 2026
Summary
Learned fear in rodents can manifest as darting, an escape behavior more common in females. This study reveals the infralimbic cortex (IL) drives defensive responses during fear conditioning, independent of its connection to the periaqueductal gray (PAG).
Area of Science:
- Neuroscience
- Behavioral Neuroscience
- Animal Behavior
Background:
- Freezing is the primary indicator of learned fear in rodents, but other responses like darting are understudied.
- Darting, an escape-like fear response, is more prevalent in females and linked to specific behavioral traits.
Purpose of the Study:
- To investigate the neural mechanisms underlying conditioned darting, a less-examined fear response.
- To explore the role of the infralimbic cortex (IL) and its projections to the periaqueductal gray (PAG) in conditioned fear behaviors.
Main Methods:
- Utilized Pavlovian fear conditioning in rodents.
- Measured neural activity via cFos expression in the IL and PAG.
- Employed chemogenetic tools to manipulate IL activity and IL-PAG projections.
Main Results:
- Fear conditioning increased neural activity in the IL of females more than males.
- IL activation correlated with freezing only in 'Darter' phenotypes.
- Inhibiting the IL increased darting and shock response in females, but reduced freezing in both sexes.
Conclusions:
- The infralimbic cortex (IL) plays a crucial role in driving defensive behaviors during fear conditioning.
- This IL function in driving defensive responses is not dependent on its connectivity with the periaqueductal gray (PAG).
- Findings highlight the IL's distinct role in modulating fear responses beyond freezing, particularly in females.
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