Diego Laplange, Ph.D.Leon Levy Presidential Fellow in Neuroscience
Shelby White and Leon Levy Center for Mind, Brain and Behavior
Awareness of auditory stimuli
Contrary to naïve intuition, most tasks performed by our brains bypass conscious processing altogether. These include exquisite computations involving both cortical and subcortical structures, whose performance may even be impaired by thinking about it. We are thus not our consciousness. We may wrongly believe we are, though, because that is all we are aware of. Why, where and how is the decision of broadcasting a percept to the conscious machinery carried out? Studies in humans and monkeys are beginning to find neuronal activity that distinguishes awareness vs. unawareness to external stimuli. I aim to establish rodents as model animals for the study of these basic conscious processes. Rats and mice display a wide range of behavior and cognition and can be studied at the neuronal and circuit level. On top of technical advantages, this choice of species allows one to look for homologies in the neural implementations across mammals. I hope for this evolutionary perspective to enhance our understanding of animal consciousness, including our own.
Vocal communication in rodents
Looking for rich natural auditory stimuli to probe awareness in rats I became interested in their vocal communication. Rats produce vocalizations that span the frequency range from the sonic to the ultrasonic. Sonic calls are scarce and produced only in extreme scenarios like predator encounters. Emission of prolonged 22 kHz calls correlates with aversive and fearful conditions and has been shown to convey alert to listeners. Above 40 kHz, rats produce a rich repertoire of vocalizations spanning a wide range of frequency, modulation and duration. Studies on these ultrasonic vocalizations (USVs) have shown a correlation with positive situations like satiety, reward and social interaction, although the fine semantics of call types within this family remains elusive.
On the syntax side, a few studies have shown that mice can sequence USVs in neither random nor completely stereotyped motifs, but syntax remains unexplored in rats. We have now started lines of research to probe the capabilities of this communication system, including syntax, vocal interplay, cognitive control and vocal learning.
Yevgeniy Sirotin, PhD. - Neuroscience Fellow, The Rockefeller University
Maria N. Geffen, PhD. - Assistant Professor, University of Pennsylvania School of Medicine
Marcelo Magnasco, PhD. - Professor, The Rockefeller University
Matthew Dornfeld - Graduate Student, The Rockefeller University
Mariano Sigman - Professor, University of Buenos Aires
Martín Elias Costa - Graduate Student, University of Buenos Aires
Dr. Laplagne obtained his M.Sc. and Ph.D. from the University of Buenos Aires, School of Sciences. Before coming to Rockefeller in 2009, he held a postdoctoral position at the Edmond and Lily Safra International Neuroscience Institute (Brazil).