B. Diekamp et al., Impairment in a discrimination reversal task after D1 receptor blockade inthe pigeon "prefrontal cortex", BEHAV NEURO, 114(6), 2000, pp. 1145-1155
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.