title: Functional inactivation of the rat hippocampus disrupts avoidance of a moving object.
abstract: The hippocampus is well known for its critical involvement in spatial memory and information processing. In this study, we examined the effect of bilateral hippocampal inactivation with tetrodotoxin (TTX) in an "enemy avoidance" task. In this paradigm, a rat foraging on a circular platform (82 cm diameter) is trained to avoid a moving robot in 20-min sessions. Whenever the rat is located within 25 cm of the robot's center, it receives a mild electrical foot shock, which may be repeated until the subject makes an escape response to a safe distance. Seventeen young male Long-Evans rats were implanted with cannulae aimed at the dorsal hippocampus 14 d before the start of the training. After 6 d of training, each rat received a bilateral intrahippocampal infusion of TTX (5 ng in 1 μL) 40 min before the training session on day 7. The inactivation severely impaired avoidance of a moving robot (n = 8). No deficit was observed in a different group of rats (n = 9) that avoided a stable robot that was only displaced once in the middle of the session, showing that the impairment was not due to a deficit in distance estimation, object-reinforcement association, or shock sensitivity. This finding suggests a specific role of the hippocampus in dynamic cognitive processes required for flexible navigation strategies such as continuous updating of information about the position of a moving stimulus.
authors.affiliation: Institute of Physiology, Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Telensky
authors.forename: Jan
authors.initials: J
authors.lastname: Svoboda
authors.forename: Karel
authors.initials: K
authors.lastname: Blahna
authors.forename: Jan
authors.initials: J
authors.lastname: Bureš
authors.forename: Stepan
authors.initials: S
authors.lastname: Kubik
authors.forename: Ales
authors.initials: A
authors.lastname: Stuchlik
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D006624:Hippocampus / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D013028:Space Perception / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D013779:Tetrodotoxin