Western classical music has a profound impact on brain activity, especially in people with treatment-resistant depression. Scientists analyzing brain waves and neural imaging have found that music synchronizes neural oscillations between brain regions linked to sensory and emotional processing, resulting in improved mood. These findings suggest that personalized music therapy may become an effective tool in the treatment of depression, particularly when combined with other sensory stimuli.
Depression is a significant public health challenge, affecting approximately 4.4% of the world’s population and being a leading cause of global disability. Approximately half of patients with major depressive disorder (MDD) develop treatment-resistant depression (TRD), characterized by a lack of response to conventional interventions, highlighting the urgent need for new antidepressant treatments.
Among non-pharmacological approaches, listening to music has shown to be a promising strategy with broad therapeutic potential. Music is capable of evoking emotions, making it a valuable tool for studying affective responses and their neural correlates.
While it is widely acknowledged that classical music can influence mood, a recent study published in the journal Cell Reports reveals how scientists in China used brainwave measurements and neural imaging techniques to demonstrate the positive effects of Western classical music on the brain.
The goal of the research is to identify more effective ways to use music to activate the brain in people who do not respond well to other treatments, such as those with ESRD.
Music has the unique ability to modulate neural activity in subcortical brain structures, influencing these areas via the auditory cortex. This paves the way for potential advances in the use of music-based treatments for psychiatric disorders associated with dysfunction in these regions.
Music-induced emotion is strongly linked to the brain’s reward circuitry, in which the bed nucleus of the stria terminalis (BNST), part of the extended amygdala, plays a crucial role. The BNST regulates reward-related behaviors such as mating, and its activation can enhance the desire for this behavior in mice.
Concerning emotion processing, neuroimaging studies in humans indicate that both the amygdala and the BNST share similar functional properties, including the response to ambiguous threats.
Both brain structures react transiently to immediate threats but also show increased activity during prolonged exposure to threatening situations. These insights reinforce the central role of these regions in emotional processing and behavioral responses to stimuli.
(A) Patients underwent music treatment while recording LFPs in the BNST-NAc circuit and temporal EEG signals. (B) Comparison of visual depression and anxiety scores on the visual analog scale for depression (VAS-D) and visual analog scale for anxiety (VAS-A) between the sadness and excitement groups after listening to music. (C) Correlation analysis between the degree of music appreciation and improvement in depressive symptoms (n = 13). (D) Patients were regrouped based on the scale results. (E) Summary of the entire experimental procedure. DOI: 10.1016/j.celrep.2024.114474
The nucleus accumbens (NAc) plays a central role in the reward circuitry, being especially sensitive to negative emotional cues. The BNST and NAc form a functionally integrated network in this circuitry.
Anatomical studies suggest that the GABAergic pathway between the BNST and NAc is directly involved in neural responses associated with depression. Activation of the BNST may enhance NAc responses, helping to reduce negative emotional experiences.
Initial research indicates that music-induced emotions are linked to activity in this BNST-NAc circuit. Music influences the reward circuitry through two main mediators: the auditory cortex and the motor cortex. Auditory processing of music, initiated in the primary auditory cortex, coordinates neuronal activity, activating the reward circuitry and generating emotional responses.
Martorell and colleagues demonstrated that specific auditory frequencies can entrain auditory cortical neurons, changing their firing pattern from spontaneous irregular activity to coordinated action, promoting neuroprotective effects.
In this context, the scientists used implants to monitor brain activity in a circuit connecting the BNST to the NAc in 13 patients with treatment-resistant depression. They recorded electroencephalogram (EEG) signals from the scalp, as well as intracranial recordings from the BNST and NAc while the patients listened to classical music.
The participants were divided into two groups: those with low musical appreciation and those with high musical appreciation, to investigate the correlation between music and activity in the reward circuit.
Using these implants, the researchers found that patients in the high music appreciation group showed more significant neural synchronization and better antidepressant effects.
In contrast, those in the low music appreciation group showed more modest results. The antidepressant effects of music appear to occur through the synchronization of neural oscillations between the auditory cortex, responsible for sensory processing, and the reward circuit, which processes emotional information.
“This study reveals that music induces a three-way blockade of neural oscillations in the cortical-BNST-NAc circuit through auditory synchronization,” explains Professor Bomin Sun, director of the Center for Functional Neurosurgery at Shanghai Jiao Tong University.
By dividing the patients into groups, the researchers were able to analyze the antidepressant mechanisms of music more precisely and propose personalized music therapy plans that improve treatment outcomes.
For example, inserting theta-frequency noise into the music increased oscillatory coupling between the BNST and the NAc, which led patients with low musical appreciation to report greater enjoyment of the music.
Several pieces of Western classical music were used in the study, an intentional choice since most participants were unfamiliar with this genre, thus avoiding potential interference caused by familiarity.
The research team’s next steps will include exploring how the interaction between music and deep brain structures affects depressive disorders. They also plan to introduce additional sensory stimuli, such as visual imagery, to assess the potential therapeutic benefits of multisensory stimulation in the treatment of depression.
READ MORE:
Auditory entrainment coordinates cortical-BNST-NAc triple time locking to alleviate the depressive disorder
Xin Lv; Yuhan Wang; Yingying Zhang; Yunhao Wu; Valerie Voon
Volume 43, Issue 8114474. August 27, 2024
Abstract:
Listening to music is a promising and accessible intervention for alleviating symptoms of major depressive disorder. However, the neural mechanisms underlying its antidepressant effects remain unclear. In this study on patients with depression, we used auditory entrainment to evaluate intracranial recordings in the bed nucleus of the stria terminalis (BNST) and nucleus accumbens (NAc), along with temporal scalp electroencephalogram (EEG). We highlight music-induced synchronization across this circuit. The synchronization initiates with temporal theta oscillations, subsequently inducing local gamma oscillations in the BNST-NAc circuit. Critically, the incorporated external entrainment induced a modulatory effect from the auditory cortex to the BNST-NAc circuit, activating the antidepressant response and highlighting the causal role of physiological entrainment in enhancing the antidepressant response. Our study explores the pivotal role of the auditory cortex and proposes a neural oscillation triple time-locking model, emphasizing the capacity of the auditory cortex to access the BNST-NAc circuit.