The Orbitofrontal Cortex Is Required for Learned Modulation of Innate Olfactory Behavior

Area of Science:

• Neuroscience
• Animal Behavior
• Olfactory Processing

Background:

• Animals possess innate responses to environmental cues like odors.
• Learning is essential for adapting innate responses to changing needs and risks.
• Mechanisms for learned modulation of innate olfactory responses in mammals are not well understood.

Purpose of the Study:

• To investigate the neural mechanisms underlying the learned override of innate olfactory responses in mice.
• To determine the role of the orbitofrontal cortex (OFC) in modulating innate odor aversion through learning.

Main Methods:

• Developed a novel olfactory assay where thirsty mice choose between attractive and aversive odors for water.
• Utilized optogenetic and chemogenetic silencing techniques to inactivate the OFC.
• Measured odor-evoked neural activity using c-fos expression in specific brain regions.

Main Results:

• Mice learned to prefer an aversive odor over an attractive odor when water availability was reduced at the attractive port.
• Silencing the OFC prevented the learned override of innate odor preferences.
• OFC inactivation suppressed neural activity in limbic structures like the amygdala, lateral septum, and bed nucleus of the stria terminalis.

Conclusions:

• The orbitofrontal cortex (OFC) is essential for learned modulation of innate olfactory-driven behaviors.
• The OFC signals to limbic structures to override innate responses to odors based on learned value.
• This study reveals a neural circuit for flexible behavioral adaptation in response to changing environmental demands.