Animal study: temporary blindness can boost hearing



Links between the senses are well known but a recent study conducted in mice has provided scientific evidence that hearing can be boosted by withdrawal of exposure to light. The findings were published in the journal Neuron in last February.

Research teams from Johns Hopkins University and the University of Maryland (USA) evaluated hearing in two groups of study mice using electrophysiology to measure responses to sound. One group was kept in completely dark conditions for a week, while the control group was exposed to natural light. They found that mice kept in the dark were able to hear softer sounds and that there were changes in the structure of the auditory cortex in the brain, where sound is processed.

One of the study investigators, Hey-Kyoung Lee from Johns Hopkins University in Baltimore, explains: “We were quite surprised to see the changes because there is no known anatomical connection that is directly between these two areas. It happened quite rapidly, which I really did not expect.” Dr Kanold from Maryland, last author on the paper, adds, “We are not growing any new neurons; we are simply strengthening existing connections in the auditory cortex.”

The effect observed in the study animals lasted for several weeks after reintroduction of light. The teams hope that the effect can be made permanent and that it may have some potential for use in humans, specifically in terms of improved hearing. Understanding the mechanisms involved may open up ways of boosting these processes, without directly depriving people of light.

Source: BBC News Health, Digital Journal