Does altered nitric oxide generation by neurons of the cochlear nucleus have a role in producing tinnitus?

Nitric oxide is a potent neuromodulator involved in Hebbian memory formation in the hippocampus and neuroplasticity in many brain regions including the cochlear nucleus (CN), the first stage in the subcortical auditory system. In this project we will investigate the role of nitric oxide plasticity in the generation and maintenance of neural responses that may give rise to tinnitus.
Tinnitus is often associated with hearing loss and, while there is currently no cure, many millions of people worldwide seek help to alleviate the distress that it causes. The mechanisms of tinnitus are not yet understood (see Berger et al., 2014, for review), but hearing loss may contribute to tinnitus by increasing neural gain in the cochlear nucleus to compensate for the reduced external input. We found that, in an animal model of tinnitus (noise-exposed guinea pig), nitric oxide expression was increased in excitatory neurons and decreased in inhibitory neurons in the CN (Coomber et al., 2014). In this project we will investigate how these changes in nitric-oxide expression may alter neural gain. We will use specially designed multi-electrode arrays to characterize single neurons in the CN of guinea pigs with noise-induced hearing loss in one ear. Neuronal activity will be compared from the impaired and intact sides and specific nitric oxide donors or blockers will be applied locally or across the whole nucleus. Brains will be examined immunohistochemically to assess the degree of change in nitric oxide expression in specific cell types following hearing loss.
Applicants will be expected to have a first- or upper second-class degree, or an MSc, in psychology, physiology, neuroscience or a related discipline. They should have an interest in hearing science, electrophysiology or neuropharmacology. Information on how to apply can be found at: http://www.ihr.mrc.ac.uk/pages/postgraduates/postgraduate_homepage.

With Dr Mark Wallace, Dr Chris Sumner and Prof. Alan Palmer