Learning under stress: how the insect brain copes

Insects can adjust their behaviours through learning and memory, but this rather costly capacity is often impacted by stressors. Here, we address how this impact can be mediated by hormones and neuropeptides that are part of the insect physiological response to stress. While we only have a partial view of the involved regulatory interactions, recent work has contributed to unravel how these signals can modulate neural activity in response to stress. By targeting different neuron populations and/or processes, they appear to participate in a coordinated modulation that can either downregulate or preserve different aspects of learning and memory. However, our current knowledge is based on studies restricted to fruit flies and honey bees, usually focusing on a single stressor at a time. Thus, we call for comparative studies between responses to multiple stressors, and across a larger panel of species since these two models already appear to have notable specificities, possibly be related to solitary or social lifestyle.