Tectal CRF receptors modulate the behavioral response of Xenopus laevis to live prey but not visual prey cues.

Tradeoffs between feeding and defensive behaviors are critical for survival, but their physiological underpinnings are not well known. Here, we investigate how a satiety peptide, corticotropin-releasing factor (CRF), acts within a novel location, the visual system (the optic tectum, OT), to modulate multisensory prey detection and the microstructure of feeding behavior. The OT has CRF-producing interneurons and CRF receptors, threat exposure increases OT CRF concentrations, and that CRF acts on receptors in the OT to decrease feeding behavior. We hypothesized that CRF in the OT may impact visual, lateral line, and/or multiple sensory processing to alter feeding. We predicted that OT CRF decreases responses to 1) a purely visual prey cue and 2) a live, multisensory prey item. We microinjected one of four doses of CRF bilaterally into the tecta of newly metamorphosed Xenopus laevis. We then exposed frogs to visual prey cues and then to live, multi-sensory prey (worms). We repeated the behavioral assays after 72 h to determine if any effects were long-lasting. Overall, frogs robustly responded to live and visual prey cues. CRF did not alter behavioral responses to the visual prey cues but did decrease select prey-capture behaviors and increase select avoidance-like behaviors following exposure to live prey. Our results suggest visual processing is not the primary sensory modality impacted by tectal CRF. These data provide a novel (i.e., extrahypothalamic) location for satiety peptide action and link neuroendocrine responses to ecological context of feed/flee tradeoffs.