Spatial segregation of piriform output neurons toward cognitive and emotional networks

The piriform cortex (PCx), commonly considered to be the primary olfactory sensory cortex, differs from other mammalian sensory cortices by not displaying a stimulus-specific spatial organization but rather displaying widely distributed odor-evoked activity. However, there is evidence of a PCx spatial organization based on output neuron targeting. Here, we performed double-labeled retrograde tracing to reveal neuronal populations of PCx output neurons that project to two regions affiliated with different behavioral significance, the basolateral amygdala (BLA) and lateral orbitofrontal (LO) cortex networks. We found that PCx neurons projecting to BLA and LO are distinct in spatial distribution with minimal overlap, supporting the hypothesis that while odor input is distributed randomly across the PCx, PCx output neurons are organized into target-specific neuronal populations that potentially serve as functional units for odor encoding and odor-guided behavior.