audiology 2012

<p>All other parameters as in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1000092#pcbi-1000092-g010" target="_blank">Figure 10</a>. (A) Individual mean synaptic currents of all nonsensory nodes. (B) Total synaptic currents averaged across the nonsensory sheet. The injection of the externally evoked sensory currents into the prior activity actually has a slightly desynchronizing effect.</p

Tuning curves of the PTNs.

<p>(<b>A</b>) Tuning curve of the PTN dendritic compartment. The amplitude of the dendritic response current (vertical axis) is modulated by the orientation of the cortical wave pattern (horizontal axis). Heavy black line indicates the mean amplitude of the dendritic response for any given wave orientation. Shaded region indicates the 90% confidence interval. The large variation is due to local defects in the wave pattern. (<b>B</b>) The likelihood of the soma responding at each of the dominant firing rates. (<b>C</b>) Net firing rates of a population of neurons in response to wave orientation.</p

Modeling the descending motor system.

<p>(<b>A</b>) Major fiber tracts of the descending motor system, redrawn from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003260#pcbi.1003260-Gray1" target="_blank">[105]</a>. Axons of the pyramidal tract neurons (red) descend from the motor cortex to monosynaptically innervate motor neurons in the spinal cord. (<b>B</b>) Schematic representation of the dendritic arbors of a typical pyramidal tract neuron (PTN). The apical dendrites project widely throughout the superficial layers of cortex and thus are ideally placed to detect surface wave patterns in the neural activity (top). (<b>C</b>) Simulated cortical wave pattern. (<b>D</b>) The descending motor model. Cortical wave patterns are generated by a sheet of spatially-coupled phase oscillators (circles, 1–8). These wave patterns are spatially filtered by the dendritic trees of the pyramidal tract neurons to produce an amplitude-modulated oscillatory current at the soma. Spikes initiated by the PTN are transmitted to a randomly selected pool of motor neurons (MN) in the spine. Each MN integrates the incoming spikes to produce a muscle drive spike train. Net muscle drive is quantified by simulated Electromyogram (EMG). The cortical wave model is adapted from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003260#pcbi.1003260-Heitmann1" target="_blank">[17]</a>. The MN and EMG models are adapted from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003260#pcbi.1003260-Boonstra1" target="_blank">[41]</a>.</p

The cortical model.

<p>(<b>A</b>) Profiles of the spatial coupling kernel along its major and minor axes of orientation. (<b>B</b>) Contours of the spatial coupling kernel. (<b>C</b>) Exemplar oscillator pattern with this coupling kernel. Shading indicates phase. Black lines indicate the orientation of the kernel axes. (<b>D</b>) Frequency spectrum of the simulated local field potential (LFP) superimposed on the distribution of the autonomous oscillator frequencies (Osc). The latter is normally distributed with M = 20 Hz and SD = 4 Hz. (<b>E</b>) Time course of the simulated local field potential. (<b>F</b>) Time course of MEG signal recorded over human motor cortex during a precision grip task.</p

Support vector machine classification accuracy.

<p>Bagging results for support vector machine classification accuracy using 6 features and resampling training/testing data 1000 times. Treatment refers to the labeling of the data where ‘Pre’ and ‘Post’ refer to if the data labels were shuffled before or after vector training.</p

Modular structure of one healthy individual, where brown, green, cyan, yellow and dark blue represent the 5 different modules.

<p>Connections are drawn in the color of the modules if it connects nodes from the same modules, otherwise in black. Negative connections are marked in red. (a) is a fully connected graph, where correlation coefficients are modified by the distance penalty described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041282#pone.0041282.s001" target="_blank">Appendix S1A</a>, (b) and (c) have been thresholded to retain only 12% of edges.</p

Workflow for data processing, statistical testing and machine learning in this study.

<p>All steps are described in detail in the methods section of this paper. Two analysis types were used, one for groupwise comparisons, and one for machine learning classification. The difference in modularity identification was selected so no groupwise information would influence the data used for machine learning. Thresholding and the calculation of all metrics with the exception of modularity was identical between the two analysis types.</p