NEURAL REPRESENTATIONS OF SEQUENCE MEMORY IN THE JACKDAW BRAIN

Cognitive functions, such as spatial navigation and episodic memory, rely on the ability to process sequentially linked events. Research in non-human primates suggests that, in the prefrontal cortex (PFC), sequences are encoded at the population level, where joint information for the item kept in mind and its ordinal rank is represented. Simultaneously, phase synchrony and replay, in hippocampus, are involved in sequence encoding during active movement.
To assess if these are general principles of sequence encoding, we probed sequence memory in the European jackdaw (Corvus monedula), a species belonging to the corvid family displaying primate-like cognitive abilities. We trained two jackdaws to remember a sequence of three spatial locations, in an arena. By association, the birds learned that each location corresponded to a symbol. They visited the three locations and, after a delay, reported the order of their visits, via the serial selection of the location’s corresponding symbol. The required visit order was randomized, generating 6 possible sequences. After training, both jackdaws performed above 85% of the trials correctly.
Using a wireless data logger and silicon probes, we recorded neural spiking and local field potentials, simultaneously, in hippocampus and the nidopallium caudolaterale (NCL - the avian analogue to the PFC), during task performance.
We expect to find similarities between activity in NCL and sequence encoding mechanisms described in the mammalian PFC. We will characterize the mapping of task dimensions in hippocampus, something not sufficiently done in birds.