TDK conference 2013

The so-called “Mozart effect” indicated that a musical environment might improve learning capacity and spatial elligence in humans. The animals' spatial learning and memory performance was tested in an 8-arm radial maze, and their spontaneous exploratory activity was investigated in an open field (OF) apparatus. Twelve male rats were exposed twice daily on the 1st (habituation) week, and once daily from 2nd (acquisition of the task) week to end of the 10th week - to a 8.5-min-long arrangement of Mozart’s K 448: “Sonata for Two Pianos in D Major”. There was a continuous white background noise of 40 dB and 25 lux illumination in the testing room. The control group did not receive the musical stimuli. The number of the animals' urination and defecation was individually recorded during the OF-test and the body weights were measured daily in the course of the experiment. At the end of 10th week, blood count and biochemical tests were carried out from tail vein blood of six animals from each group. The weight of the removed brain, thymus, heart, lung, liver, spleen, kidneys and adrenals was measured during dissection and histologic samples from the thymus and adrenals were taken from six animals per group. Rats receiving acoustic exposure (Mozart’s music) showed, in the maze learning capacity and memory test, significant improvement of reference memory (59.76±4.24 vs. 75.36±5.53%, p=0.00155), in the return after the resting period (83.42±3.06 vs. 88.78±2.74%, p=0.01929), and in 4-hour-interval long-lasting WM retention (60.52±2.49 vs. 65.97±2.87%, p=0.01258); data control vs. musical group, respectively. The spontaneous locomotor activity of the control and music-exposed animals during the OF-test did not show significant differences. The rate of change of exploration during the ten weeks of the experiment was influenced only by the age of the animals but not by the musical effect. There was no important difference between the emotional state of control and music-treated rats, neither in their relative organ weights of lien, thymus and hepar, related to 1/100 of body weight; but the analogous relative weight of the music treated rats’ heart and liver was significantly reduced (retarded in development). The rats’ body weight gain was also not influenced by the music. The subsequent (histo)pathological examination did not show any alterations in the thymus and the adrenals, but the music exposed group had higher serum cortisol and glucose levels. As a conlusion, this particular music in human hearing range was appropriate for improving hippocampus-dependent spatial learning capacity, but the spontaneous exploratory activity practically did not change. Music did not cause chronic stress or distress to the animals, but caused mild stress that promoted learning process and memory fixation.