Laboratory of Nachum Ulanovsky

Research interests

Neural Codes for Natural Navigation in the Bat Hippocampal Formation

Our lab focuses on elucidating the neural basis of spatial cognition, navigation, spatial memory and social memory in the mammalian hippocampal formation – using bats as a novel animal model that we pioneered.  We develop tiny wireless-electrophysiology systems (neural-loggers), weighing only a few grams, which enable recording from the bat's brain during natural behaviors, including navigation and social interactions. Our study species, Egyptian fruit bats, are excellent navigators and highly-social mammals – making them a great model organism for behavioral neuroscience. They are also large bats, weighing ~150-180 gr – allowing them to fly freely while carrying our neural-loggers, together with miniature tracking devides, audio-loggers, and more.  Some of our main results in recent years included: the finding that in flight, 3D hippocampal place cells have nearly spherical 3D place fields.  Recordings in the bat presubiculum revealed 3D head-direction tuning in many cells, which could serve as a 3D compass; and surprisingly, this compass followed a toroidal coordinate system - providing an interesting biological solution to the discontinuity and non-commutativity problems assiciated with a standard spherical coordinate system.  We also discovered a new population of neurons in the hippocampus that are tuned to the egocentric direction and distance to navigational goals - a vectorial representation of spatial goals, which could provide a neural mechanism for goal-directed navigation. Other studies included discovering grid-cells in the entorhinal cortex of crawling bats, without theta oscillations – arguing against theta-based models of grid cells; the disovery of a surprising optimization principle in the sonar system of Egyptian fruit bats; and an outdoors study where we tracked bat navigation in the wild, using tiny GPS dataloggers – which provided evidence for a 'cognitive map' on a 100-km scale in bats. 

Overall, our general approach is to take advantage of the unique properties of bats – their temporally-discrete sensory system (sonar) and excellent vision, and their 3D flight abilities – in order to ask general questions in Systems Neuroscience; particularly questions that are difficult to address in rodents.  Our long-term vision is to develop a "Natural Neuroscience" approach for studying the neural basis of behavior – tapping into the animal's natural behaviors in complex, large-scale, naturalistic settings – while not compromising on rigorous experimental control. We firmly believe that pursuing such an approach will lead to novel and surprising insights about the Brain.