Interplay of senses: Study reveals brain’s adaptive responses to changes in vision and audition

Researchers from the IMT School for Advanced Studies Lucca in Italy, in collaboration with the University of Ulm in Germany, have made new discoveries regarding the brain’s ability to adapt to changes in sensory input. Previous studies have shown that even temporary visual deprivation, such as covering one eye for a few hours, can induce changes in how the brain processes visual information. However, it was unclear whether these changes also affected other senses.

In their recent study, the researchers blindfolded 20 participants and asked them to count flashes of light while being presented with sound beeps. They recorded the participants’ brain activity using electroencephalography (EEG) with millisecond precision. The researchers found that neural activity in response to both visual and auditory stimuli was altered after the removal of the eye patch.

The study’s first author, Alessandra Federici, explained that even a short period of monocular deprivation (occlusion of one eye with an eye patch for approximately two hours) affected auditory processing. Specifically, they observed a selective increase in neural response to sounds. This means that even a minor disruption in visual experience can cause a shift in the balance between vision and hearing.

Interestingly, the effects of monocular deprivation were paradoxical. After the eye patch was removed, the brain became more sensitive to visual information from the previously occluded eye, suggesting that the lack of input led to an increase in neural excitability. Additionally, the brain became more susceptible to auditory input, but only when the non-patched eye was used to monitor the environment.

Davide Bottari, the principal investigator of the study, highlighted the profound impact that continuous sensory experience has on the brain. He noted that while previous studies have demonstrated the plasticity of the senses after extended sensory deprivation, such as in cases of blindness and deafness, these findings reveal the high degree of plasticity and interdependence between the senses.

The study’s results demonstrate the brain’s remarkable capacity to adapt to changes in sensory input, affecting not only the deprived sense but also other senses. This understanding of sensory interplay could have implications for the development of more effective rehabilitation protocols for various diseases and disabilities, such as amblyopia.

The research has been published in the journal NeuroImage.

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