Figure 2.

Visual imprinting in birds. The stimulus captured by the retina is projected to the thalamus DLA and Wust, a region of the hyperpallium analogous to the mammalian primary visual cortex. Through connections to the IHA and HDCo, visual signaling reaches the IMM, the main structure involved in long-term memory, early learning, and imprinting. During the sensitive period, amounts of glutaminergic neurons and NMDAr in this zone increase to promote imprinting. AMY, amygdala; DLA, dorsolateralis anterior thalami; Dopa, dopamine nuclei; GLU, glutamate; HDCo, hyperpallium densocellulare; Hipp, hippocampus; IHA, hyperpallium apical; IMM, intermediate medial mesopallium; MSt, medial striatum; NMDAr, N-methyl-D-aspartate receptors; OT, optic tectum.