We study avoidance behaviors in rats using a platform-mediated active avoidance task. Rats learn to avoid a tone-signaled footshock by moving to a platform located in a corner opposite of a food bar. Using single unit recordings and in vivo optogenetics, previous work has revealed that neurons in the rostral prelimbic prefrontal cortex (rPL) exhibit inhibitory responses to the tone that signal avoidability (Diehl et al., 2018 eLife). Moreover, optogenetically opposing this inhibition impairs avoidance, suggesting that an avoidability signal resides in rPL. Functional mapping experiments are beginning to reveal that the tone-induced inhibition observed in rPL projects to the ventral striatum (VS) to drive avoidance, whereas tone-induced excitation in rPL projects to the basolateral amygdala (BLA) to drive avoidance (Diehl, et al., 2020 eLife).
Active avoidance under social conditions
Do rats learn avoidance differently in the presence of another rat? This is one of the many research questions in the Diehl Lab. Similar to learning active avoidance alone (above), rats learn to avoid the tone-signaled footshock by stepping onto a platform at the cost of access to a lever that delivers sucrose pellets. Two rats are placed in the same chamber to determine if rats learn differently under this social condition. The relationship between the two rats may also affect avoidance learning (if partner has previously learned avoidance or is naïve to the task, if the partner is familiar or unfamiliar, etc.).
Social dominance tube test
Social dominance in rodents can be measured using a tube test in which two rats are placed on either ends of a long plexiglass tube. After meeting in the middle and investigating one another, eventually, one rat pushes the other rat out and deemed the "winner." We use the tube test to understand how aversive learning (through fear conditioning or avoidance training) may affect dominance status.
Single unit electrophysiology
Record single cell activity using multichannel electrode arrays in rats performing active avoidance and other behaviors
Manipulate discrete brain regions or their pathways to determine neural circuits of avoidance and other behaviors