Sensory deprivation regulates the development of the hyperpolarization-activated current in auditory brainstem neurons

Hassfurth, Benjamin; Magnusson, Anna K.; Grothe, Benedikt und Koch, Ursula (2009): Sensory deprivation regulates the development of the hyperpolarization-activated current in auditory brainstem neurons. In: European Journal of Neuroscience, Vol. 30, No. 7: pp. 1227-1238

Abstract

Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are highly expressed in the superior olivary complex, the primary locus for binaural information processing. This hyperpolarization-activated current (I-h) regulates the excitability of neurons and enhances the temporally precise analysis of the binaural acoustic cues. By using the whole-cell patch-clamp technique, we examined the properties of I-h current in neurons of the lateral superior olive (LSO) and the medial nucleus of the trapezoid body (MNTB) before and after hearing onset. Moreover, we tested the hypothesis that I-h currents are actively regulated by sensory input activity by performing bilateral and unilateral cochlear ablations before hearing onset, resulting in a chronic auditory deprivation. The results show that after hearing onset, I-h currents are rapidly upregulated in LSO neurons, but change only marginally in neurons of the MNTB. We also found a striking difference in maximal current density, voltage dependence and activation time constant between the LSO and the MNTB in mature-like animals. Following bilateral cochlear ablations before hearing onset, the I-h currents were scaled up in the LSO and scaled down in the MNTB. Consequently, in the LSO this resulted in a depolarized resting membrane potential and a lower input resistance of these neurons. This type of activity-dependent homeostatic change could thus result in an augmented response to the remaining inputs.

• Item Type: Journal article
• Faculties: Biology > Department Biology II > Neurobiology
• Subjects: 500 Science > 570 Life sciences; biology
• ISSN: 0953-816X
• Language: English