New research reveals how older adults tap into hidden brain reserves, using auditory regions to compensate for memory decline during music recognition.
Study: Age-related neural changes underlying long-term recognition of musical sequences. Image Credit: Inside Creative House / Shutterstock
In a recent study published in the journal Communications Biology, researchers examined age-related changes in brain activity by comparing the neural responses of young and older adults to memorized and varied musical sequences.
Their findings indicate that older adults experience distinct shifts in brain organization during music recognition, suggesting complex compensatory neural mechanisms that help maintain memory processes despite declining predictive capabilities.
Background
Aging often brings changes to the brain that affect cognitive abilities, including memory and attention. Understanding these changes is vital for identifying early signs of age-related brain decline.
Previous research has explored how aging impacts the brain's ability to adapt, with some theories suggesting that older adults can compensate for cognitive decline by using different brain regions or networks.
Studies show that activities like music can enhance brain flexibility and help maintain cognitive functions. While much is known about how aging affects basic brain processes, less is understood about how older adults process and recognize familiar sounds, particularly in the auditory domain.
About the study
The scientists suggested that as people age, their brains reorganize to adapt during tasks like recognizing musical sequences. Instead of just showing weaker brain signals, they expected the brain to demonstrate a qualitative change in function by using backup systems.
Specifically, they thought older adults would show less activity in parts of the brain linked to memory (like the hippocampus) and more activity in areas responsible for hearing (like the auditory cortex) to compensate.
To test their hypothesis, researchers recruited and tested 76 participants (young adults aged 18-25 and older adults aged 60-81) on auditory memory. They listened to a short piece of music, memorized it, and were later asked to identify if new musical sequences were part of the original or different.
Brain activity was recorded using magnetoencephalography (MEG). The study compared the brain responses of younger and older adults to understand how they recognize and detect changes in auditory sequences.
The study recorded brain activity using a 306-channel MEG scanner and analyzed it with magnetic resonance imaging (MRI) scans. Data included heart and eye movement recordings to remove unwanted signals. Participants' working memory (WM) and musical training were also assessed.
Behavioral data, such as reaction times and response accuracy, were analyzed, and differences between younger and older adults were evaluated. Brain activity was further processed, removing noise, and reconstructed to understand the spatial and temporal brain dynamics involved in auditory recognition tasks.
To analyze the data, researchers averaged brain activity over significant clusters and used statistical tests to identify differences. They also examined specific brain regions and considered factors like WM and musical training. Analyses included comparing age groups and accounting for multiple factors to understand how age and expertise affect brain responses.
Findings
Researchers found that older adults were less accurate than younger adults in recognizing specific musical sequences. Statistical analyses revealed that older participants scored lower on recognizing certain sequences compared to younger participants. The study also revealed that higher education levels, WM capacity, and years of musical training were linked to better recognition performance.
Regarding reaction times, older adults took longer to respond, but this difference was not statistically significant after further analysis. WM scores were the only significant covariate affecting reaction times, with higher WM associated with quicker responses.
Brain activity analyses showed that older adults generally had reduced brain activity compared to younger adults, especially in areas related to auditory processing and memory.
However, older participants displayed increased activity levels in some regions when processing the first tone of sequences. The study also identified that the oldest group among the older participants had a particularly reduced brain activity.
Overall, the findings suggest that aging affects both the accuracy and neural processing of musical recognition, with educational background, WM, and musical training playing important roles in performance.
Conclusions
The study reveals that age-related changes in brain function affect how musical sequences are recognized and predicted. Older adults show marked increased activity in the left auditory cortex when recognizing familiar sequences. This indicates a compensatory mechanism due to reduced activity in memory-related brain regions like the hippocampus and inferior temporal cortex.
However, older adults struggle more with recognizing altered musical sequences, indicating a diminished ability to process novelty and prediction errors.
The study successfully integrated neurophysiological data with behavioral performance, providing insights into the compensatory mechanisms in aging brains. It supported existing theories by showing how older adults adapt to cognitive challenges. However, the study's focus on musical sequences might not generalize to other types of cognitive tasks, and researchers did not fully explore the impact of hearing loss.
Investigating how different types of cognitive tasks and hearing loss affect brain function in aging could provide a deeper understanding of cognitive decline. Future studies incorporating additional imaging techniques, such as functional MRI, could further validate and expand these findings.
Journal reference:
- Age-related neural changes underlying long-term recognition of musical sequences. Bonetti, L., Fernández-Rubio, G., Lumaca, M., Carlomagno, F., Olsen, E. R., Criscuolo, A., Kotz, S. A., Vuust, P., Brattico, E., & Kringelbach, M. L. Communications Biology (2024). DOI: 10.1038/s42003-024-06587-7, https://www.nature.com/articles/s42003-024-06587-7