[3H]MK-801 binding asymmetry in the IMHV region of dark-reared chicks is reversed by imprinting.

Glutamate NMDA-type receptor binding in the intermediate medial hyperstriatum ventrale (IMHV) of dark-hatched chicks is lateralized. This lateralization was found to be markedly influenced by imprinting. In dark-reared chicks the binding of the selective ligand [3H]MK-801 was two-fold higher in the right IMHV than in the left IMHV. In contrast, imprinted chicks have significantly higher levels of [3H]MK-801 binding in the left IMHV region than in the right IMHV. Imprinting results in 2a learning-related increase in NMDA-type receptor binding levels in the left IMHV, whereas [3H]MK-801 binding levels in the right IMHV remain unchanged by imprinting. Thus, the plasticity present in the NMDA-type receptor system and associated with imprinting appears to occur in the left hemisphere only.