Impairment in a discrimination reversal task after D1 receptor blockade inthe pigeon "prefrontal cortex"

Dopamine (DA) is known to modulate cognitive functions of the prefrontal co rtex (PFC) of mammals, especially via D1 receptor mechanisms. Like the PFC, the neostriatum caudolaterale (NCL) of birds is characterized by dopaminer gic input, and NLC and PFC lesions cause similar deficits. The significance of DA in a color discrimination reversal was assessed by evaluating the ef fects of bilateral infusions of the D1 receptor antagonist SCH 23390 into t he NCL of pigeons (Columba livia). Reversal deficits were qualitatively sim ilar to those in mammals. At a low dose, perseveration occurred predominant ly to the incorrect stimulus. Higher doses caused additional spatial persev eration. The data demonstrate, for the first time, that D1 receptor mechani sms in the NCL of pigeons contribute substantially to its function in cogni tive processes. Thus, the avian NCL and mammalian PFC could represent funct ionally equivalent neural networks under control of the DA system.