Modulating central gain in tinnitus: changes in nitric oxide synthase in the ventral cochlear nucleus.

A significant challenge in tinnitus research lies in explaining how acoustic insult leads to tinnitus in some individuals, but not others. One possibility is genetic variability in the expression and function of neuromodulators - components of neural signaling that alter the balance of excitation and inhibition in neural circuits. An example is nitric oxide (NO) - a free radical and potent neuromodulator in the mammalian brain - that regulates plasticity via both pre-synaptic and postsynaptic mechanisms.

Different representations of tooth chatter and purr call in guinea pig auditory cortex.

Multielectrode arrays were used to compare responses to tooth chatter and purr calls from all eight areas of the auditory cortex in anaesthetized guinea pigs. These calls have different behavioural contexts: males emit tooth chatters in aggressive encounters and the purr call during courtship behaviour. Of the two core areas, the primary auditory cortex responded better to both signals than the dorsocaudal core area.