Neural Circuitry for Target Selection and Action Selection in Animal Behavior

Animal behaviorists have long strived for a comprehensive understanding of the proximate and ultimate causes of complex behavior, and we propose that recent advances in neurobiology can help reshape or clarify this behavior-oriented understanding. We begin with an overview of current views of neural circuit mechanisms that mediate target selection and action selection. In target selection, different stimuli compete for priority in sensory-motor processing. Action selection is the process by which multiple possible motor actions compete for priority in a manner which balances the needs of the animal with opportunities or threats in the environment. We next discuss spatial and temporal aspects of target and action selection, highlighting how neurophysiological responses to complex displays depend on spatial and temporal components of multisensory stimuli. We use two examples-(1) spatial attention as an example of target selection in the vertebrate midbrain and (2) goal-directed locomotion as an example of action selection in the insect central complex-to further clarify neural circuit dynamics as they relate to target and action selection, and their interaction. We suggest that a deeper understanding of neural circuit properties will introduce new hypotheses into behavioral studies, especially those aimed at understanding the evolution of complex displays based on receiver sensory biases. Additionally, knowledge of neural circuit properties can elucidate ways in which current context and previous experience can together modify neural circuit dynamics to produce complex context-dependent behavioral responses that often characterize animal behavior.