We all know the power of an old song to trigger vivid memories that seem to transport us back in time and space. What songs bring back emotional memories from your past? The songs we love become woven into a neural tapestry entwined with the people, seasons, and locations throughout our lifespan. What is the neuroscience behind the ability of music to evoke such strong memories of the people and places from our past?
This morning, I was standing in line at the convenience store and the song Please Come to Boston from 1974 came on in the background. I hadn't heard this song in years. Suddenly, I was overcome by flashbacks of people, places, and strong emotions linked to that song from many stages of my life. In particular, the song reminded me of someone that I fell in love with during my adolescence. The deep neural connection that music creates to romance, heartbreak—and a wide range of other joyful and painful memories—is a universal phenomenon.
Has a song on the car stereo, or in a store, recently caught you off guard and brought back a tidal wave of memories? Why do autobiographical memories linked to music remain so rich and textured? Interestingly, it appears that if you haven't heard a song in years, the neural tapestry representing that song stays purer and the song will evoke stronger specific memories of a time and place from your past. The memories linked to overplayed songs can become diluted because the neural network is constantly being updated.
The Neuroscience of Vivid Musical Memories
A series of recent studies have found that listening to music engages broad neural networks in the brain, including brain regions responsible for motor actions, emotions, and creativity.
In the first study of its kind, Amee Baird and Séverine Samson, from the University of Newcastle in Australia, used popular music to help severely brain-injured patients recall personal memories. Their pioneering research was published on December 10, 2013 in the journal Neuropsychological Rehabilitation.
Although their study only involved a small number of participants, it is the first to examine ‘music-evoked autobiographical memories’ (MEAMs) in patients with acquired brain injuries (ABIs), rather than those who are healthy or suffer from Alzheimer’s disease.
In their study, Baird and Samson played snippets from "Billboard Hot 100" number-one songs in a random order to people with ABI. The songs—taken from the whole of the patient’s lifespan from age five—were also played to control subjects with no brain injury. All participants were asked to record how familiar they were with a given song, whether they liked it, and what memories the song evoked.
Interestingly, the highest number of MEAMs in the whole group was recorded by one of the ABI patients. In all those studied, the majority of MEAMs were of a person, people or a life period, and were typically positive. Songs that evoked a memory were noted as being more familiar and more well-liked than songs that did not trigger a MEAM. This is common sense.
Two previous studies identified the broad range of neural networks that are engaged when we listen to music. A 2009 study from the University of California, Davis mapped the brain while people listened to music and found specific brain regions linked to autobiographical memories and emotions are activated by familiar music. The UC Davis study titled, "The Neural Architecture of Music-Evoked Autobiographical Memories," was published in the journal Cerebral Cortex.
The discovery may help to explain why music can elicit strong responses from people with Alzheimer's disease, said the study's author, Petr Janata, associate professor of psychology at UC Davis' Center for Mind and Brain. The hub that music activated is located in the medial prefrontal cortex region—right behind the forehead—and one of the last areas of the brain to atrophy over the course of Alzheimer's disease.
"What seems to happen is that a piece of familiar music serves as a soundtrack for a mental movie that starts playing in our head. It calls back memories of a particular person or place, and you might all of a sudden see that person's face in your mind's eye," Janata said. "Now we can see the association between those two things—the music and the memories."
To assure the best chance that students would associate at least some of the tunes with memories from their past, Janata also chose songs randomly from "Billboard Hot 100" charts from years when each subject would have been 8 to 18 years old. After each excerpt, the student responded to questions about the tune, including whether it was familiar or not, how enjoyable it was, and whether it was associated with any particular incident, episode or memory.
The study revealed that, on average, a student recognized about 17 of the 30 excerpts, and of these, about 13 were moderately or strongly associated with an autobiographical memory. As in the recent Australian study, songs that were linked to the strongest, most salient memories were the ones that evoked the most vivid and emotion-laden responses.
When Janata studied the fMRI images and compared them to these self-reported reactions, he discovered that the degree of salience of the memory corresponded to the amount of activity in the upper (dorsal) part of the medial prefrontal cortex. This correlation supports Janata's hypothesis that this brain region helps link music and memory.
Janata was also able to create a model for mapping the tones of a piece of music as it moves from chord to chord and into and out of major and minor keys. By making tonal maps of each musical excerpt and comparing them to their corresponding brain scans, he discovered that the brain was tracking these tonal progressions in the same region as it was experiencing the memories: in the dorsal part of the medial prefrontal cortex, as well as in regions immediately adjacent to it. And in this case, too, the stronger the autobiographical memory, the greater the "tracking" activity.
Music Engages Brain Regions Linked to Motor Actions, Emotions, and Creativity
In a 2011 study, Finnish researchers used a groundbreaking method that allowed them to study how the brain processes different aspects of music, such as rhythm, tonality and timbre (sound color) in a realistic listening situation. Their study was published in the journal NeuroImage.
The researchers discovered that listening to music activates wide networks in the brain, including areas responsible for motor actions, emotions, and creativity. Their method of mapping revealed complex dynamics of brain networks and the way music affects us. For this study, participants were scanned with functional Magnetic Resonance Imaging (fMRI) while listening to a stimulus with a rich musical structure, a modern Argentinian tango.
The Finnish researchers correlated temporal evolutions of timbral, tonal, and rhythmic features of musical stimulus. While timbral feature processing was associated with activations in cognitive areas of the cerebellum, and sensory and the default mode network gray matter of the cerebral hemispheres, musical pulse and tonality processing recruited cortical and subcortical cognitive, motor and emotion-related circuits.
The researchers found that music listening recruits the auditory areas of the brain, but also employs large-scale neural networks. For instance, they discovered that the processing of musical pulse recruits motor areas in the cerebellum and cerebrum, supporting the idea that music and movement are closely intertwined.
Limbic areas of the brain, known to be associated with emotions, were also found to be involved in rhythm and tonality processing. Processing of timbre was associated with activations in the so-called default mode network, which is assumed to be associated with mind-wandering and creativity.
"Our results show for the first time how different musical features activate emotional, motor and creative areas of the brain," concluded Professor Petri Toiviainen from the University of Jyväskylä. "We believe that our method provides more reliable knowledge about music processing in the brain than the more conventional methods."
Conclusion: Music Has Broad Therapeutic Potential
In sum, the Finnish researchers combined neuroimaging, acoustic feature extraction, and behavioral methods, and revealed the large-scale cognitive, motor and limbic brain circuitry is engaged while listening to music. In addition, their study has practical and potential therapeutic relevance because it creates a way to observe individual neural processing based on how someone responds to music based on his or her unique history.
As a potential tool for helping patients regain their memories, Amee Baird and Séverine Samson conclude that: “Music was more efficient at evoking autobiographical memories than verbal prompts of the Autobiographical Memory Interview (AMI) across each life period, with a higher percentage of MEAMs for each life period compared with AMI scores. Music is an effective stimulus for eliciting autobiographical memories and may be beneficial in the rehabilitation of autobiographical amnesia, but only in patients without a fundamental deficit in autobiographical recall memory and intact pitch perception.”
Petr Janata concludes that because autobiographical memories linked to music seem to be spared in people with Alzheimer's disease, one of his long-term goals is to use this research to help develop music-based therapy for people with the disease. He said, "What's cool about this is that one of the main parts of the brain that's tracking the music is the same part of the brain that's responding overall to how autobiographically salient the music is."