My central interest is the evolution of behavioral and brain complexity, specifically learning and memory. Why do some lineages show a heavy investment in brains while others do not? We focus on the Cephalopod Molluscs because they have the largest brains of invertebrates (allometrically scaling with vertebrates), show complex behaviors, and importantly have a living representative of the ancestral condition: the Chambered Nautilus. My research focuses on changes in learning and memory capabilities over the course of invertebrate evolution, and the origin and function of supporting neural and sensory systems in species with large brains. I often perform comparative work among octopuses, cuttlefishes and Nautilus to determine what features of brains and behavior are analogous and which are homologous.
Another critical component of my research is to determine how the environment and evolution have shaped the learning and memory capabilities of animals that primarily rely upon nonvisual information to make navigation decisions. My two model systems are the Chambered Nautilus (for the sense of smell) and the freshwater crayfish, Procambarus clarkii (for the sense of touch). I focus on what kinds of sensory information animals collect from their environment, what they remember of that information and for how long, and how they then use that information to make important orientation decisions.
We pursue three interrelated lines of research in my laboratory. First, we investigate learning and memory capabilities in nautilids, a monophyletic group in the cephalopod molluscs that retains many pleisiomorphic features. Comparative study of the complex behavior across all cephalopods may help us to understand the evolution of neural and behavioral complexity in the entire class. We have found evidence of convergence between cephalopod brains and vertebrate brains, despite vast differences in the components comprising the brain (neurons, axons). We pursue studies of Pavlovian conditioning, spatial navigation, tactile learning, chemical learning, and chemical signaling in intraspecific behavior, while also attempting to identify the compounds involved. Second, we investigate the neural underpinnings of these complex behaviors: where does this learning take place, identifying analogous and/or homologous learning centers in cephalopods, labeling of neuronal activity during conditioning, whole-brain recordings, and neuroanatomy and neurochemistry (in collaboration with Dr. Binyamin Hochner, Hebrew University). Third, we use crayfishes as a model for the haptic sense, or guided tactile behavior. Here we pair classical conditioning and open-field methods to measure haptic contributions to learning and memory of the environment in a relatively “simple” neuroanatomical model. These algorithms are then implemented in “Craybot” a tactile robot in development with Tony Prescott’s laboratory at the University of Sheffield.