Supervised classifier model predicts mouse phenotype based on spike signatures.

A. Schematic of network changes causing motor impairments in mouse models for ataxia, dystonia, and tremor. Dotted lines indicate lack of neurotransmission. Color-coded lines indicate primary affected cell type. B. Example of spike firing rate averaged over previous 50 ms at each occurring spike for the 5 s spike train in B’. B’’ 1 s spike train for the duration indicated in the square box in B’. C. Histograms of instantaneous firing rate (ISI-1) of the full 30 s spike train used in the classification model. D. Classifier model based on training data set (control: n = 29 cells, N = 9 mice; ataxia: n = 19, N = 5; dystonia: n = 19, N = 8; tremor: n = 21, N = 6). E. Predicted phenotype of mice based on spike properties in validation data set (control: n = 30 cells, N = 9 mice; ataxia: n = 18, N = 5; dystonia: n = 17, N = 9; tremor: n = 18, N = 5). Categories on X-axis indicate the origin of the recorded neurons. F. and G. Scatterplot of spike train parameters used to classify neural signatures. Colored boxes indicate the predicted phenotype, colors of circles indicate the origin of the recorded neurons.

PC = Purkinje cell; CN = cerebellar nuclei; IO/CF = inferior olive/climbing fiber.

Spike signatures in ataxia models with different etiologies.

A 5 s example spike trains (and 1 s inset) of representative cerebellar nuclei neurons recorded in each mutant mouse model. Left: example cell from early disease progression (4-month-old) ataxic Atxn1154Q/+ mouse. Right: example cell from late disease progression (11-month-old) ataxic L7Cre;Ank1fl/fl mouse. B. Histograms of instantaneous firing rate (ISI-1) of the full 30 s spike train of the example cells in A. C. Proportion of predicted spike signatures in each of the mouse models. D. and E. Scatterplot of spike train parameters used to classify neural signatures. Colored boxes indicate the predicted phenotype, colors of circles indicate the origin of the recorded neurons. Control: N = 11, n= 55; Atxn1154Q/+: N = 4, n = 24; L7Cre;Ank1fl/fl: N = 3, n = 14. C-E. are based on classifier model in Figure 1D.

Spike signatures in dystonia models with different etiologies.

A 5 s example spike trains (and 1 s inset) of representative cerebellar nuclei neurons recorded in each mutant mouse model. Left: example cell from mildly dystonic Pdx1Cre;Vglut2fl/flmouse. Right: example cell from severely dystonic cerebellum ouabain infusion mouse. B. Histograms of instantaneous firing rate (ISI-1) of the full 30 s spike train of the example cells in A. C. Proportion of predicted spike signatures in each of the mouse models. D. and E. Scatterplot of spike train parameters used to classify neural signatures. Colored boxes indicate the predicted phenotype, colors of circles indicate the origin of the recorded neurons. Control: N = 6, n= 28; Pdx1Cre;Vglut2fl/fl: N = 4, n = 21; cerebellum ouabain infusion: N = 4, n = 20. C-E. are based on classifier model in Figure 1D.

Spike signatures in tremor models with different etiologies.

A 5 s example spike trains (and 1 s inset) of representative cerebellar nuclei neurons recorded in each mutant mouse model. Left: example cell from Car8wdl/wdl mouse with complex phenotype including severe tremor. Right: example cell from Car8wdl/wdl mouse with complex phenotype treated with propranolol to treat tremor. B. Histograms of instantaneous firing rate (ISI-1) of the full 30 s spike train of the example cells in A. C. Proportion of predicted spike signatures in each of the mouse models. D. and E. Scatterplot of spike train parameters used to classify neural signatures. Colored boxes indicate the predicted phenotype, colors of circles indicate the origin of the recorded neurons. Control: N = 4, n= 14; Car8wdl/wdl: N = 9, n = 19; Car8wdl/wdl + propranolol: N = 6, n = 15. C-E. are based on classifier model in Figure 1D.

Spike signatures in cerebellar nuclei neurons can be induced by specific stimulation paradigms of Purkinje cells.

A. Schematic of experimental setup with recordings in awake, head-fixed mice. B. Optopatcher recordings of cerebellar nuclei neurons. The opsin is expressed in Purkinje cells (pink) and recordings of nuclei neurons are performed. PC = Purkinje cell; CN = cerebellar nuclei; IO/CF = inferior olive/climbing fiber. C. Example validation that light stimulation of inhibitory Purkinje cells (blue bars) inhibits nuclei neurons during light stimulation. The lower trace is a blown-up view of the boxed area in the upper trace. D. Example of spike firing rate averaged over previous 50 ms at each occurring spike for the 5 s spike train in D’. D’’ 1 s spike train for the duration indicated in the square box in D’. Blue bars indicate light stimulation and are specific for ataxia, dystonia, and tremor (see methods for light stimulation parameters). All example traces originate from the same nuclei neuron, indicating that the cell’s spike signature can change depending on the light stimulation paradigm. E. Histograms of instantaneous firing rate (ISI-1) of the full 30 s spike train, observe the shift in distribution from baseline during the different stimulation paradigms. F. Proportion of cells of each predicted spike signature during each of the light stimulations based on classifier model in Figure 1D. Control: n = 11 cells, N = 4 mice; ataxia: n = 9, N = 3; dystonia: n = 7, N = 3; tremor n = 9, N = 4. G. and H. Scatterplot of spike train parameters used to classify neural signatures. Colored boxes indicate the predicted phenotype, colors of circles indicate the origin of the recorded neurons.

Induced spike signatures elicit distinct cerebellar phenotypes.

A. Schematic of external view of bilateral optical fiber implant. B. Schematic of a coronal section from a mouse cerebellum with bilateral optic fiber implants directed towards the cerebellar nuclei. FN = fastigial nucleus. IN = interposed nucleus. DN = dentate nucleus. C. Photomicrograph of a Nissl-stained coronal section from a mouse cerebellum that had been implanted with optic fibers. Arrows = optic fiber tracks. Dotted lines surround the cerebellar nuclei indicated in B. Scale = 1 cm. D. Schematic of a mouse with bilateral optic fiber implants freely moving in a tremor monitor. E-K. Data associated with gait measurements. E-H. Example footprints from a single mouse before stimulation (baseline, E) and during ataxia (F), dystonia (G), and tremor stimulation (H). Scale = 1 cm. I-K. Measurements of gait including the length of the hindpaw stride (I), forepaw stride (J), and distance between the hind and forepaws (K). N = 8. * = p ≤ 0.05. ** = p ≤ 0.01. L. Example images of phenotypes associated with dystonia. 1 = erect tail. 2 = high stepping. 3 = kinked tail. 4 = hyperextension of the limbs. 5 = splayed toes. M. Dystonia rating of mice before stimulation and during stimulation with each paradigm. N = 8. * = p ≤ 0.05. N. Tremor signals detected via tremor monitor from a mouse before and during stimulation with each paradigm. Horizontal scale = 1 sec. Vertical scale = 50 mV. O. Population average power spectrums of tremor. Solid line = mean power. Shaded region = SEM. P. Peak tremor power of mice before and during stimulation with each paradigm. N = 8. * = p ≤ 0.05. ** = p ≤ 0.01. Q-S. 2-D comparisons of gait (hind to fore distance), dystonia (rating), and tremor (peak power) measurements from all mice. N = 8. T. 3-D plot of data in Q-S.

Validation of mouse models of motor disorders. Each model used in this manuscript is listed in the table with the type of model that it is, the predominant phenotype reported for the model, motor behaviors that have been quantified relative to control animals (effect direction is noted when difference is statistically significant), and anatomical changes associated with the model. Only congruent and/or undisputed findings in mice are included. Abbreviations used: Purkinje Cell (PC), vesicular GABA transporter (Vgat), immunohistochemistry (IHC), wheat germ agglutinin (WGA), tyrosine hydroxylase (TH), vesicular glutamate transporter 2 (Vglut2), inferior olive (IO), electromyography (EMG), cerebellar nuclei (CN), spinocerebellar ataxia type 1 (SCA1), carbonic anhydrase-related protein 8 (Car8), granule cell (GC), climbing fiber (CF), mossy fiber (MF), lateral hypothalamus (LH), not available (NA).