Prenatal Complex Rhythmic Music Sound Stimulation Facilitates Postnatal Spatial Learning but Transiently Impairs Memory in the Domestic Chick

Abstract

Early experience has a profound influence on brain development, and the modulation of prenatal perceptual learning by external environmental stimuli has been shown in birds, rodents and mammals. In the present study, the effect of prenatal complex rhythmic music sound stimulation on postnatal spatial learning, memory and isolation stress was observed. Auditory stimulation with either music or species-specific sounds or no stimulation (control) was provided to separate sets of fertilized eggs from day 10 of incubation. Following hatching, the chicks at age 24, 72 and 120 h were tested on a T-maze for spatial learning and the memory of the learnt task was assessed 24 h after training. In the posthatch chicks at all ages, the plasma corticosterone levels were estimated following 10 min of isolation. The chicks of all ages in the three groups took less (p < 0.001) time to navigate the maze over the three trials thereby showing an improvement with training. In both sound-stimulated groups, the total time taken to reach the target decreased significantly (p < 0.01) in comparison to the unstimulated control group, indicating the facilitation of spatial learning. However, this decline was more at 24 h than at later posthatch ages. When tested for memory after 24 h of training, only the music-stimulated chicks at posthatch age 24 h took a significantly longer (p < 0.001) time to traverse the maze, suggesting a temporary impairment in their retention of the learnt task. In both sound-stimulated groups at 24 h, the plasma corticosterone levels were significantly decreased (p < 0.001) and increased thereafter at 72 h (p < 0.001) and 120 h which may contribute to the differential response in spatial learning. Thus, prenatal auditory stimulation with either species-specific or complex rhythmic music sounds facilitates spatial learning, though the music stimulation transiently impairs postnatal memory.

Prenatal Loud Music and Noise: Differential Impact on Physiological Arousal, Hippocampal Synaptogenesis and Spatial Behavior in One Day-Old Chicks

“…In a similar way, auditory stimulation exerts a profound effect on the development of auditory areas as well as hippocampus of chicks (20, 52). Earlier studies from our laboratory have shown improvement in spatial orientation [18] and learning [18], [22] of neonatal chicks after exposure to prenatal species-specific as well as non species-specific sound (music) stimulation at 65 dB, suggesting an early maturation of neural connectivity. In the present study, the beneficial effects of music on learning and memory were seen even with higher sound pressure level of 110 dB.…”

“…The facilitation of learning was observed even at 24 hour post hatch with no further improvement in successive trials following the same sound enrichment protocol suggesting an early maturation of synaptic connectivity following prenatal sound stimulation. Significant memory retention at 72 and 120 hour post hatch with a transient impairment at 24 hour post hatch following prenatal music stimulation was observed [22]. The avian hippocampus is involved in spatial learning as well as in memory [23]–[25] and is connected to the auditory pathway directly as well as indirectly [26]–[29].…”

Repetitive auditory stimulation at a critical prenatal period modulates the postnatal functional development of the auditory as well as visual system in chicks (Gallus domesticus)

“…The incubating conditions as standardized by Kauser et al() were followed. Briefly, eggs were incubated at 36°C ± 1°C temperature and 60–70% relative humidity.…”

“…In chicks, exposure to prenatal auditory stimuli (from E 10) results in an early functional maturation of the auditory system (Wadhwa et al, ; Alladi et al, , ,; Jain et al, ). There is also enhancement of the neural substrate in the mediorostral neostriatum/ hyperstriatum ventrale (MNH, Panicker et al, ) and in the hippocampus (Chaudhury et al, ), facilitation of spatial orientation (Chaudhury et al, ) and learning abilities of the neonatal chicks (Kauser et al, ); suggesting thereby that any specific prenatal sensory stimulus can affect the development of other neural areas that are associated to it or involved in the processing of that particular stimulus (Lickliter, ). In birds, different sensory systems become functional in a stereotypic order, i.e.…”

Maternal Music Exposure during Pregnancy Influences Neonatal Behaviour: An Open-Label Randomized Controlled Trial

“…Music is a noninvasive, culturally acceptable intervention with multiple putative direct and indirect beneficial effects on mother and foetus through the pregnancy and perinatal period. In animals, prenatal music exposure has been shown to improve postnatal spatial learning and memory; to reduce isolation stress [4]. Music has been found to beneficially affect stress response and recovery from critical illness or surgery [5, 6].…”