Processing of Visual and Social Stimuli in the Green Anole Lizard Brain

Many studies of animal behavior use video technology to mimic live interactions and minimize the variability of natural animal behavior. Here, I seek to understand how information processing differs among Anolis carolinensis (green anole lizards) exposed to a live lizard compared to a video representation of a lizard. I conducted behavioral trials in which I placed a male lizard in a visually neutral arena, presented it with visual information from a live anole or from carefully constructed video playback, and recorded their behavioral responses. Each lizard (n=40) was randomly assigned to one of four treatments – Live Anole (two live males interacting with each other), Anole Video (focal lizard shown video of a lizard displaying on a perch), Scrambled Video (focal lizard shown video of a lizard displaying on a perch, but with the pixels scrambled to remove social context), or Control (focal lizard shown video of a stationary perch). Immediately after each trial, lizard brains were flash-frozen in isopentane. To measure neural activity, I then used immunocytochemistry to quantify expression levels of the immediate early gene c-fos in two visual brain regions, the Nucleus Rotundus (NROT) and Lateral Geniculate Nucleus (LGN), and one social brain region, the Pre-Optic Area (POA). Behaviorally, I found that lizards in the Live Anole and Anole Video conditions did not differ in social display behaviors (pushups and dewlap extensions) or attentiveness, but lizards in both these conditions displayed more than lizards in the Scrambled Video and Control conditions – evidence that suggests there is no difference in lizard’s behavioral responses to live lizards compared to video lizards. I also found evidence for the inhibitory nature of the POA, as the POA showed the least neural activity in the Live Anole condition, and there was a negative correlation between attentiveness and POA activity within the Live Anole condition. Finally, I saw no differences in LGN and NROT activity across the four treatments, providing evidence that lizards process visual information in the visual brain regions independently of the social context of that information. Overall, this study provides a greater understanding of the behavioral similarities, but neural differences, in visual and social processing of a live anole compared to a video representation of an anole, suggesting caution in the use of video representations of behavior