Synaptic transmission and recognition memory: time course of changes in N-methyl-D-aspartate receptors after imprinting.
Previous studies have shown that a restricted region of the chick forebrain (the intermediate and medial parts of the hyperstriatum ventrale, IMHV) is crucial for the learning process of imprinting. A learning-related increase in N-methyl-D-aspartate (NMDA) receptor binding has previously been shown in the left IMHV 8.5 hr after training with an imprinting stimulus. The present experiments showed that this increase in binding in the left IMHV does not occur until 6-8.5 hr after training: There was no significant change in binding in either the left or right IMHV less than 0.5, 3, or 6 hr after training. No significant change in binding occurred in the right IMHV 8.5 hr after training. It is probable that the increase in binding in the left IMHV is associated with the recognition memory of imprinting.