Music and cerebral hemodynamics

Neuroplasticity Changes of Rat Brain by Musical Stimuli during Fetal Period

OBJECTIVE

Fetal development of the central nervous system is an important and sensitive stage which is affected by many external and internal stimuli. This study aimed to investigate effect of musical stimuli on fetal rat brain.

MATERIALS AND METHODS

In this experimental study, twelve female Wistar rats were selected and evenly assigned to control and musical groups. The females were mated with a male rat of the same genotype. Musical group was exposed to classic music with 60 dB power for 90 minutes twice per day from 2(nd) to 20(th) day of gestation. The control rats were handled similar to the musical group, but were not exposed to music. Before parturition, all the dams were anesthetized, and their blood samples were obtained and used for corticosterone (COS) measurement. They were transcardially perfused by electron microscope (EM) fixative agent. The fetal brains were extracted intact and used for slice preparation. Horizontal slices were made for electron microscope preparation, and images were taken and analyzed in terms of cell density and morphological changes.

RESULTS

EM observation indicated significant morphological difference in cellular and intercellular spaces between the two groups. Music-treated fetuses had significantly higher cell density in parietal cortex and music-treated dams had lower COS level.

CONCLUSION

It was concluded that prenatal music would have a great impact on neuroplasticity of fetal rat brain, at least indirectly. Although the rat fetuses cannot hear until birth, music-induced reduction in COS blood level of dams might be the reason for neuroplasticity of fetal brain.

Cortical plasticity induced by short-term multimodal musical rhythm training

Performing music is a multimodal experience involving the visual, auditory, and somatosensory modalities as well as the motor system. Therefore, musical training is an excellent model to study multimodal brain plasticity. Indeed, we have previously shown that short-term piano practice increase the magnetoencephalographic (MEG) response to melodic material in novice players. Here we investigate the impact of piano training using a rhythmic-focused exercise on responses to rhythmic musical material. Musical training with non musicians was conducted over a period of two weeks. One group (sensorimotor-auditory, SA) learned to play a piano sequence with a distinct musical rhythm, another group (auditory, A) listened to, and evaluated the rhythmic accuracy of the performances of the SA-group. Training-induced cortical plasticity was evaluated using MEG, comparing the mismatch negativity (MMN) in response to occasional rhythmic deviants in a repeating rhythm pattern before and after training. The SA-group showed a significantly greater enlargement of MMN and P2 to deviants after training compared to the A- group. The training-induced increase of the rhythm MMN was bilaterally expressed in contrast to our previous finding where the MMN for deviants in the pitch domain showed a larger right than left increase. The results indicate that when auditory experience is strictly controlled during training, involvement of the sensorimotor system and perhaps increased attentional recources that are needed in producing rhythms lead to more robust plastic changes in the auditory cortex compared to when rhythms are simply attended to in the auditory domain in the absence of motor production.

Functional Cerebral Distance and the Effect of Emotional Music on Spatial Rotation Scores in Undergraduate Women and Men

The influence of listening to music on subsequent spatial rotation scores has a controversial history. The effect is unreliable, seeming to depend on several as yet unexplored factors. Using a large sample (167 women, 160 men; M age = 18.9 yr.), two related variables were investigated: participants' sex and the emotion conveyed by the music. Participants listened to 90 sec. of music that portrayed emotions of approach (happiness), or withdrawal (anger), or heard no music at all. They then performed a two-dimensional spatial rotation task. No significant difference was found in spatial rotation scores between groups exposed to music and those who were not. However, a significant interaction was found based on the sex of the participants and the emotion portrayed in the music they heard. Women's scores increased (relative to a no-music condition) only after hearing withdrawal-based music, while men's scores increased only after listening to the approach-based music. These changes were explained using the theory of Functional Cerebral Distance.

Left hemispheric lateralization of brain activity during passive rhythm perception in musicians

The nature of hemispheric specialization of brain activity during rhythm processing remains poorly understood. The locus for rhythmic processing has been difficult to identify and there have been several contradictory findings. We therefore used functional magnetic resonance imaging to study passive rhythm perception to investigate the hypotheses that rhythm processing results in left hemispheric lateralization of brain activity and is affected by musical training. Twelve musicians and 12 nonmusicians listened to regular and random rhythmic patterns. Conjunction analysis revealed a shared network of neural structures (bilateral superior temporal areas, left inferior parietal lobule, and right frontal operculum) responsible for rhythm perception independent of musical background. In contrast, random-effects analysis showed greater left lateralization of brain activity in musicians compared to nonmusicians during regular rhythm perception, particularly within the perisylvian cortices (left frontal operculum, superior temporal gyrus, inferior parietal lobule). These results suggest that musical training leads to the employment of left-sided perisylvian brain areas, typically active during language comprehension, during passive rhythm perception.

Ontogenetic Features of the Psychophysiological Mechanisms of Perception of the Emotional Component of Speech in Musically Gifted Children

The cerebral mechanisms underlying musical-artistic ability were addressed by studying psychophysical measures of the perception of emotional information contained in speech in musically gifted children. Studies involved 46 schoolchildren and 48 young musicians, in three age groups: 7-10, 11-13, and 14-17 years. A test sentence was presented with three emotional intonations (joy, anger, and unemotional) via headphones; subjects' responses identifying the type of emotion were recorded. Dispersion analysis revealed age and gender characteristics in the mechanisms of recognition of emotions: thus, boy musicians led their classmates in the development of these mechanisms by 4-6 years, while girl musicians led by 1-3 years. In girls, musical training facilitated increases in the role of the left hemisphere in processing the emotional intonation of speech, while in boys, the initially marked dominance of the left hemisphere was not retained during further training.

Right Temporal Lobe Activation When Listening to Emotionally Significant Music

The cerebral activation when normal elderly participants (6 women, 6 men, M age = 70 years) listened to self-selected emotionally significant music was investigated. Musical memories and preferences were discussed in an interview, and a piece of music with great emotional significance to the participant was selected and later played during measurement of the regional cerebral blood flow (rCBF). Measurements were made during silence, individually selected emotional music, and standard neutral music. The right temporal lobe showed a significant (p < .01) increase in rCBF when the emotional music was compared to silence. A temporal lobe asymmetry (right > left) during emotional music was also significant (p < .01). A decrease in the left prefrontal areas reached significance (p < .05) when standard music was compared to silence. For the emotional music, the right prefrontal area showed a decrease (p < .05). Emotional music thus activates right temporal and deactivates prefrontal regions in the right hemisphere.