Temporary Blindness in Adult Mice Can Improve Auditory Processing

A paper published this week in Neuron provides intriguing evidence that sensory deprivation in adulthood can change neural circuits. This surprising finding builds on our formidable understanding of the impact of deprivation on sensory performance in young mammals, and may have major implications in the clinic. The study, led by Emily Petrus of John Hopkins University, showed that removing visual input in adult mice improves auditory processing at the cortical level.

After placing the mice in total darkness for 6-8 days, the group returned them to normal light-dark conditions and then performed single unit recordings in the thalamocortical recipient layer of the auditory cortex. This revealed that the thalamic input to the primary auditory cortex was potentiated, and spike reliability was increased. They also report a similar potentiation to layer IV neurons of the primary visual cortex following deafening. This suggests the possibility of cross-modal potentiation across multiple senses, highlighting the considerable interaction between the neural circuits sub-serving vision and hearing. Furthermore, they demonstrated that this potentially useful plasticity is reliant upon the potentiated sense being intact (i.e. the temporarily blinded mice cannot be also deafened).

The authors suggest that manipulating cross-modal compensations in the adult mammalian brain might represent a viable treatment strategy for sensory disorders. For example, it may be possible to utilise blindness-induced potentiation of auditory processing to treat some forms of childhood hearing loss. However, the marked changes provoked in the ‘blinded’ mouse only lasted weeks, and to be clinically relevant they must have longer lasting effects.