How do we remember sounds?
Our ability to remember sounds can be boosted with magnetic stimulation, suggests a new study published in the journal Neuron.
Remembering and manipulating (in our minds) the sounds to which we are exposed is absolutely crucial for human life since this ability allows us to understand sentences, and thus to communicate. How does sound memory work? Can it be improved? These are some of the answers that the new study attempts to unlock.
A team of scientists from McGill University’s Montreal Neurological Institute aimed at better understanding auditory memory. Previous studies have shown that a brain neural network known as dorsal stream is linked with certain aspects of sound memory. However, much has remained unknown to the world of science: for instance, the dorsal stream holds in its midst rhythmic electrical pulses called theta waves whose role has not been deciphered—until now. Study senior author Sylvain Baillet and his team, therefore, set out to unveil the mysteries of the interactions between the theta waves and sound memory; they paid particular attention to enhancing memory.
Volunteers who enlisted their participation for the study went through auditory memory tasks whereby they had to identify a sequence of tones that had been reversed. During the performance of this activity, they were subjected to a combo of magnetoencephalography (MEG) and electroencephalography (EEG) which were meant to capture the frequency of theta waves. The subjects were, then, required to do the same tasks while being exposed to transcranial magnetic stimulation (TMS) of the same theta frequency so that the theta waves would be enhanced. The effect thereof was measured.
The findings show the TMS, when matching the frequency of the brain theta waves, caused the participants to perform better at the sound memory tests. However, when the TMS was not at the same rhythm as the natural waves, performance did not appear to be boosted. This shows that the manipulation of the theta waves is likely to have an impact on auditory memory.
Study first author Philippe Albouy explains that their study reveals that “matched, self-generated brain oscillations” can boost human behaviour in a specific manner. He adds that the same methodology can be used for other cognitive processes like vision and learning.
Furthermore, TMS could, one day, be used to protect from memory loss resulting from conditions like Alzheimer’s.