RESUMEN
The proboscis extension response (PER) has been widely used to evaluate honeybees' (Apis mellifera) learning and memory abilities, typically by using odors and visual cues for the conditioned stimuli. Here we asked whether honeybees could learn to distinguish between different magnitudes of the same type of stimulus, given as two speeds of air flux. By taking advantage of a novel automated system for administering PER experiments, we determined that the bees were highly successful when the lower air flux was rewarded and less successful when the higher flux was rewarded. Importantly, since our method includes AI-assisted analysis, we were able to consider subthreshold responses at a high temporal resolution; this analysis revealed patterns of rapid generalization and slowly acquired discrimination between the rewarded and unrewarded stimuli, as well as indications that the high air flux may have been mildly aversive. The learning curve for these mechanosensory stimuli, at least when the lower flux is rewarded, more closely mimics prior data from olfactory PER studies rather than visual ones, possibly in agreement with recent findings that the insect olfactory system is also sensitive to mechanosensory information. This work demonstrates a new modality to be used in PER experiments and lays the foundation for deeper exploration of honeybee cognitive processes when posed with complex learning challenges.
RESUMEN
Many clinical and research efforts aim to develop antidepressant drugs for those suffering from major depressive disorder (MDD). Yet, even today, the available treatments are suboptimal and unpredictable, with a significant proportion of patients enduring multiple drug attempts and adverse side effects before a successful response, and, for many patients, no response at all. Thus, a clearer understanding of the mechanisms underlying MDD is necessary. In the 'Brain Development and Disease' class of our Master's program in Cognitive Sciences, we ask students to collect data about the expression of a gene whose altered expression and/or function is related to a brain disorder. The students' final exam assignment consists of writing a research article in which the collected data are discussed in relation to the relevant disorder. In the course of one of these assignments, we identified the FKBP5 gene as a key player uniting two major hypotheses of MDD pathogenesis and treatment response. FKBP5 controls biological processes including immunoregulation and glucocorticoid function, both of which are separately implicated in the development and prognosis of MDD. Gene expression analyses from the human, non-human primate and mouse Allen Brain Atlases revealed that FKBP5 is expressed in brain regions involved in MDD, particularly at ages susceptible to early-life stressors. Data re-analysis from published studies confirmed that FKBP5 expression is upregulated in relevant brain regions in human MDD and preclinical mouse models of MDD. Our experience shows that classes engaging students in data collection and analysis projects may effectively result in novel data-driven hypotheses.
