TY - JOUR T1 - Graded co-expression of ion channel, neurofilament, and synaptic genes in fast-spiking vestibular nucleus neurons JF - The Journal of Neuroscience JO - J. Neurosci. DO - 10.1523/JNEUROSCI.1500-19.2019 SP - 1500-19 AU - Takashi Kodama AU - Aryn Gittis AU - Minyoung Shin AU - Keith Kelleher AU - Kristine Kolkman AU - Lauren McElvain AU - Minh Lam AU - Sascha du Lac Y1 - 2019/11/12 UR - http://www.jneurosci.org/content/early/2019/11/12/JNEUROSCI.1500-19.2019.abstract N2 - Computations that require speed and temporal precision are implemented throughout the nervous system by neurons capable of firing at very high rates, rapidly encoding and transmitting a rich amount of information, but with substantial metabolic and physical costs. For economical fast spiking and high throughput information processing, neurons need to optimize multiple biophysical properties in parallel, but the mechanisms of this coordination remain unknown. We hypothesized that coordinated gene expression may underlie the coordinated tuning of the biophysical properties required for rapid firing and signal transmission. Taking advantage of the diversity of fast-spiking cell types in the medial vestibular nucleus of mice of both sexes, we examined the relationship between gene expression, ionic currents, and neuronal firing capacity. Across excitatory and inhibitory cell types, genes encoding voltage-gated ion channels responsible for depolarizing and repolarizing the action potential were tightly co-expressed, and their absolute expression levels increased with maximal firing rate. Remarkably, this coordinated gene expression extended to neurofilaments and specific presynaptic molecules, providing a mechanism for coregulating axon caliber and transmitter release to match firing capacity. These findings suggest the presence of a module of genes which are co-expressed in a graded manner and jointly tune multiple biophysical properties for economical differentiation of firing capacity. The graded tuning of fast-spiking capacity by the absolute expression levels of specific ion channels provides a counterexample to the widely-held assumption that cell-type specific firing patterns can be achieved via a vast combination of different ion channels.SIGNIFICANCE STATEMENTAlthough essential roles of fast-spiking neurons in various neural circuits have been widely recognized, it remains unclear how neurons efficiently coordinate the multiple biophysical properties required to maintain high rates of action potential firing and transmitter release. Taking advantage of diverse fast-firing capacities among medial vestibular nucleus neurons of mice, we identify a group of ion channel, synaptic, and structural genes that exhibit mutually correlated expression levels which co-vary with firing capacity. Co-expression of this fast-spiking gene module may be a basic strategy for neurons to efficiently and coordinately tune the speed of action potential generation and propagation and transmitter release at presynaptic terminals. ER -