Fine-tuned Brains

Your parents were right when they encouraged you to continue with your music lessons. Though it probably was obvious that you would never perform at Carnegie Hall, your musical training fine-tuned your brain to identify emotional cues in sound, according to Northwestern University researchers.

Nina Kraus, the Hugh Knowles Professor of Communication Sciences and Neurobiology at Northwestern University, has sought to demonstrate just how important music training is in auditory development. She conducts studies to determine how musical training affects the nervous system. Now, for the first time, her research provides biological evidence that musical training enhances an individual's ability to recognize emotion in sound.

Kraus received a two-year, National Science Foundation research grant that funded pioneering work in neurobiology. Specifically, the purpose of the study is to examine how music training influences sensory processes that are necessary for successful communication and learning.

Scientists know that emotion is carried less by the linguistic meanings of words than by the way the sound is communicated. Kraus' work reveals that brain changes involved in playing a musical instrument enhance one's ability to detect subtle emotional cues in conversation.

"Enhanced sensitivity in musicians is not surprising given that musicians must attend to the detailed acoustic properties of sound on a daily basis," said Kraus. "Due to its spectral complexity, wide frequency range and large variations in tone duration, music serves as an extremely effective vehicle for auditory training.

Kraus studied how musicians (with musical training before and after age seven) and non-musicians process sound. Using three acoustic correlates--pitch, timing and timbre--study participants heard a 250 millisecond fragment of a distressed baby's cry while they watched a subtitled nature film. The research team used scalp electrodes to measure electrical responses to the sound in the brainstem, which connects the auditory nerve to the cerebral cortex.

The results showed that the musicians had a heightened response to the complex portion of the sound, where the frequency rapidly changes. However, when the musicians heard the simple sections of the sound they had lower responses.

"We found that musicians showed enhanced responses to the most acoustically complex portion of the stimulus and decreased activity to the more periodic, less complex portion," said Kraus. "It is as if the musicians conserve neural resources while processing simpler sounds (economy) and deploy them to more thoroughly respond to complex sounds (enhancement)."

The study found that the more years of musical training and the earlier the age in which the musical studies began, the more enhanced their nervous systems were to process emotion in sound. Historically, it has been thought that the auditory brainstem is fixed, that information flows through without changing any of the circuits. Kraus' research shows that it is not only trainable, but more malleable than previously thought.

Musical training and neurological development

Musicians exhibit greater sensitivity to the nuances of emotion in speech with their fine-tuning abilities. This ability to detect emotion is a fundamental skill that is needed for social and professional interactions.

What links emotion in both language and music is their common acoustic and neural processing. Research has shown that extensive experience in one area may provide benefits to the other.

"The field of sensory neuroscience is reframing its perspective on how sensory systems work. We used to believe the sensory apparatus was hard-wired. Now, converging evidence shows that our sensory systems are shaped by cognitive functions--how we use sound. It appears that the cognitive and sensory functions are linked," said Kraus.

In a normal functioning brainstem, inputs like music and language shape early auditory cortical processing. A disrupted auditory brainstem pathway is exhibited through language and reading disorders. Music acts as a reinforcement of the pathway and may provide preventive or rehabilitative benefits. By measuring the responses of the auditory portion of the brainstem of musicians, researchers gain a better insight into how they could treat deficiencies.

Use with autism and language disorder therapy

The acoustic sounds that musicians skillfully process are the very same ones that children with autism and dyslexia have difficulty translating.

Since Kraus' research has shown that musical training can change the auditory system and enhance verbal skills, it would not be a stretch to say that children with language processing disorders and impaired emotional perception could benefit from playing an instrument.

"There are parts of the brain that are specialized for music and other parts that are specialized for speech, but the brainstem is a common pathway for both signals. Since our work indicates a common pathway for music, language and emotional sounds, training in music could conceivably help children with language disorders," Kraus said.

There has not been much study on the effects of listening to music, but learning to play an instrument has been shown to have benefits. Rather than simply possessing a natural talent for music, it is really practicing that makes the difference. Musical training not only teaches you to play an instrument, it refines how your brain processes sound.

"Engaging in high-level cognitive processes like music enhances your sensory system," said Kraus. "We hope to see increased resources for music education in schools."