Divergent projections of the prelimbic cortex bidirectionally regulate active avoidance

Maria M Diehl, Jorge M Iravedra-Garcia, Jonathan Mora´n-Sierra, Gabriel Rojas-Bowe, Fabiola N Gonzalez-Diaz, Viviana P Valentı´n-Valentı´n, Gregory J Quirk

eLife (2020)

DOI: https://doi.org/10.7554/eLife.59281

The conceptual gap or the scientific question: how the inhibitory signals in prelimbic cortex (PL) support avoidance behaviors?

How the authors proposed the question: this is a following study of their previous paper (shared in yesterday, 2021-09-07Inhibitory signal in the rostral prelimbic cortex drives active avoidance behaviors - 简书 (jianshu.com)). The downstream targets (basolateral amygdala ,BLA, and ventral striatum, VS) were selected also based on one of their previous study (Neural Structures Mediating Expression and Extinction of Platform-Mediated Avoidance, JNS, 2014). So this study belongs to a persistent enquiry of the neural mechanisms of active avoidance behaviors.

Brief summary: optogenetically activating the PL-VS and PL-BLA pathways decreased and increased active avoidance behaviors, respectively. Suppressing the PL-BLA pathway decreased avoicance behaviors, while suppressing the PL-VS pathway had no significant effects on avoidance responses. Furthermore, activating/suppressing the BLA-VS pathway enhanced and reduced avoidance behaviors. Taken together, PL could directionally modulate avoidance behaviors through the projections to VS and BLA; and PL and BLA could oppositely control avoidance behaviors via VS.

The series studies from Gregory J Quirk's lab well exemplified the strategy repeatly odopted by researchers in rodent behavioral neuroscience.  First, well-controlled behaviors were developed; then brain region and pathway dependent perturbations were emplyed to narrow down the potential brain areas involved; and then neural activity within different brain areas was monitored under distinct experimental conditions; then computational models were proposed to account for those experimental observations.

One key node of the strategy is how to pick up the potential brain areas to verify at the very beginning. An efficient and wise choice should be delving into the literatures, especially those old ones. The sloppy and unwise one is screening extensively.

The ongoing question(s) inspired by the current study: how the suppression of PL-VS and BLA-VS pathways affects the neuronal activity of VS neurons? And what about the corresponding correlates with avoidance behaviors?