The effects of lesions to the caudolateral neostriatum on sun compass based spatial learning in homing pigeons

To better define the role of the avian caudolateral neostriatum (NCL) in spatial behavior, we used homing pigeons to explore the effects of NCL lesions on a sun compass based spatial learning task. Although NCL lesioned birds learned the task, they required more sessions to reach criterion than controls. NCL lesioned pigeons were also able to acquire a color discrimination task that was procedurally similar to the sun compass spatial learning task, but they made more errors than controls. Both the deficits observed in sun compass based spatial learning and color discrimination were correlated with the volume of lesion damage to dorsal rather than ventral portions of NCL. Overall, these findings suggest that the role of NCL in homing pigeon navigation from distant unfamiliar locations is not related to a bird's ability to learn stimulus-direction associations using a sun compass. However NCL does appear involved in a pigeon's ability to perform at least some behaviors common to both the color discrimination and the sun compass based spatial learning tasks.