Piriform cortex ablations block navigational map learning in homing pigeons

Young homing pigeons were subjected to ablations of the piriform cortex or left intact and allowed to learn a navigational map. Three months later, control and piriform cortex lesioned pigeons were released from three unfamiliar locations. Control pigeons oriented homeward indicating successful navigational map learning. In contrast, piriform cortex ablated pigeons consistently oriented east, took more time to return home and were more likely to get lost. The results demonstrate that piriform cortex ablations in young homing pigeons disrupt navigational learning. The data support the conclusion that participation of the piriform cortex is necessary for navigational map learning, and its role in navigational learning cannot be substituted for by other telencephalic olfactory processing regions. Further, the results show that the role of olfactory cues in building up the navigational map cannot be replaced by other non olfactory environmental stimuli.