Learning and memory: regional changes in N-methyl-D-aspartate receptors in the chick brain after imprinting

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 85; no. 8; pp. 2849 - 2853
• Main Authors: McCabe, B.J, Horn, G
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.04.1988; National Acad Sciences
• Subjects: ACIDE AMINE; AMINO ACIDS; AMINOACIDOS; Animals; Aspartic Acid - analogs & derivatives; Aspartic Acid - metabolism; Behavioral neuroscience; Behavioral psychophysiology; Binding sites; Biological and medical sciences; BRAIN; Carboxylic acids; CEREBRO; Chemical suspensions; Chickens - physiology; CHICKS; EDUCACION; EDUCATION; ENCEPHALE; Female; Functional Laterality; Fundamental and applied biological sciences. Psychology; Glutamates - metabolism; Imprinting (Psychology) - physiology; Kinetics; Male; Memory; Memory - physiology; N-Methylaspartate; NERVOUS SYSTEM; POLLITO; Postsynaptic density; POUSSIN; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Receptors; Receptors, N-Methyl-D-Aspartate; Receptors, Neurotransmitter - metabolism; SISTEMA NERVIOSO; Standard error; Synapses; SYSTEME NERVEUX; Training; Central nervous system; Basal ganglion; Print; Vertebrata; Binding capacity; Acquisition process; Animal; Excitatory aminoacid; Chicken; Mnemonic recognition; Aves; Synaptic receptor; Neurotransmission
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.8.2849

An extensive series of experiments has implicated a restricted region of the chick forebrain in the learning process of imprinting. The region is the intermediate and medial part of the hyperstriatum ventrale (IMHV). Previous studies have shown that training is associated with an increase in the area of the postsynaptic density of axospinous synapses in the left but not the right IMHV. The postsynaptic density is a site of high receptor density, and at least some axospinous synapses are excitatory. We found that imprinting is associated with a 59% increase in N-methyl-D-aspartate-sensitive binding of the excitatory amino acid L-[3H]glutamic acid in the left IMHV. The increase is probably due to an increased number of binding sites. The profile of sensitivity of the sites to a series of amino-, phosphono-substituted carboxylic acids (2-amino-3-phosphonopropionate to 2-amino-8-phosphonooctanoate) is characteristic of N-methyl-D-aspartate-type receptors. There were no significant effects of training on binding in the right IMHV. The effect of training on left IMHV binding could not be attributed to light exposure, arousal, or motor activity per se but was a function of how much the chicks learned. The changes in the left IMHV could increase the effectiveness of synaptic transmission in a region crucial for information storage and so form a neural basis for recognition memory.