It is now believed that memories are not stored in one place in the brain, but that memory is a brain-wide process in which several areas work in conjunction with each other, sometimes referred to as distributed processing. When a memory is recalled, the imagery, sounds, smells, words and emotions associated are encoded in the same parts of the brain as they were when initially formed and stored. The visual cortex, motor cortex, language area, and then the recall of that memory itself effectively reactivate the neural patterns generated during the original encoding process. There are parallels perhaps with the way a film is produced. The once perfect linear narrative of a film script is not made by a film crew in the same order, but in a process defined by the availability of locations, actors, and budget management. What arrives with the editor is a tapestry of random scenes, dislocated audio, special effects and multiple examples of each of these. To reconstruct the narrative, the editor pieces these fragments together to recount the original story. Our brain does much the same, starting each time with the same fragments of a memory stored in various locations, and creating a slightly different version of the story every time it is remembered.
This process of storing memories in different areas of the brain may point to the reason why music can unlock them even after the brain is deteriorating. If listening to music triggers five neural pathways as opposed to one or two, there are more chances for the brain to recall a memory that relates to this particular music.
The power of music, is that it stimulates multiple areas of the brain. This fact lends itself to explaining how music manages to source sufficient clues, or parts of the ‘script’, to rebuild the memory enabling some sort of recall even in a damaged brain. There is a standard format or order of processes taking place when the human ear hears a song. Firstly, we ‘hear’ the music in the Temporal Lobe, which considers the rhythm, pitch and melody. Secondly, the lyrics stimulate Broca’s Area and Wernicke’s Area and with this we begin to understand the words, perhaps even proceeding to sing along. Thirdly, the visual cortex in the Occipital Lobe starts to visualise the music; its notation, its performance or something associated with the tune like a scene, a place or a face. Then, the Motor Area responsible for movement is stimulated and the individual may start tapping their feet, tapping a surface or swaying in time to the music. This reaction is human behaviour; a subconscious response associated with listening to music. Lastly, the Medial Prefrontal Cortex is stimulated when there is a particularly strong memory associated with the music.
Research in Finland found that the processing of musical pulses activates motor areas in the brain, and this finding supports the idea that music and movement are very closely linked. In addition, they also found that the Limbic areas of the brain, already known to be linked with emotions, were found to also be engaged in rhythm and tonality processing, thus linking emotions and music. The study confirmed that brain areas related to emotion and reward were activated during intensely pleasurable and emotional moments of music listening.
This strong link formed when music induces movement – particularly reminiscence music – is a solid basis for using music therapies to stimulate both emotional wellbeing through engagement and memory retrieval, and also stimulate movement, which can moderate agitation in sufferers and the difficulties it brings for carers too.