This component allows constrution of histograms and density plots for spiking activity of selected cells as a funcion of position or other activity measurements.
The ColorPanel to the left shows the populations exported from the network just as in the RatGridView component. Right-click on populations in the network display of the main lab window to toggle whether or not they are made accessible for the spike analysis.
The activity is shown using the CcmbColor table specified by cellCT, and can be replayed with the buttons and slider at the bottom. Clicking cells in this ColorPanel with the left mouse button marks them for use in the current display. When active, they are highlighted with yellow borders.
To the right is an array of options, most of which can be used together, but which are not necessarily useful in all combinations. The defaultNx parameter is used in the left-hand display. IT sets the number of columns to use for populations which are not already laid out in a grid. This is purely for display convenience and does not change the analysis.
When drawing histograms [see below], hgramDx is the X-increment between bins, in whatever the units are for the current abscissa. The integers imNx and imNy set the number of bins to use for 2-D density displays along the X and Y axes. In general these should be adjusted to take account of the number of spikes being dispalyed so as to make best use of the data without too much noise - few bins for a small number of spikes, more bins if justified by high spike densities.
The next two quantities specify what should be used for each axis. For each one there is the same range of choices, including time, X and Y positions, parallel and perpendicular projections with respect to some measurement line marked in the environment [see below], reference phase (see below) and time from a given stimulus.
The style option specifies how the data is to be displayed. If set to points, then one dot is drawn for each spike in the selected cells. The position depends on the xaxis and yaxis choices. For example, if these are respectively ratPositionX and ratPositionY then for each spike in the soelected cells, a dot is drawn at the position of the rat when that spike occurred. With this axis choice, one can also click the outline checkbox to have the outline of the environment superimposed on the display.
If the style is set to density, then instead of drawing dots for the individual spikes, it shows a rectangular density plot, of resolution imNx by imNy, CcmbColor coded according to imageCT. The value of each element in the image is the total number of spikes on the selected cells occuring while the xaxis and yaxis variables are within the corresponding range. Although the above has been described in connection with the rat position, any of the other quantities can also be used for the axes.
The third display style draws a histogram with bins of width hgramDx. The data used to construct the histogram are the values of the variable specified for the xaxis at the times of spikes in the selected cells. The yaxis variable is ignored in this case.
Position data is always available for the spike analysis, and comes via the position input to the RatNetwork. Configuration of the other measured quantities - progress along paths through the environment and phases - is the responsability of the user. A path can be specified in the RatEnvironment component by adding an invisible (to the rat) line for the path and setting its projectOnto flag to true. As yet, only one such line is allowed in any environment. As the rat moves around, its position relative to this line (parallel and perpendicular projection) is recorded. These data are available as the parlProjection and perpProgection quantities for the xaxis and yaxis parameters.
For plotting phases, you must first make sure that the point [input node, cell, stimulus node in an IaFNetwork, or output node] with the sinusoidally varying potential is exported from the RatLabEditor and appears in the left hand side of the current frame. If not, right click on the population in the network display of RatLabEditor.
To specify which cell to use for the phases, right-click on it in the grid display of cells. It will be outlined in cyan. Note that only one cell can be chosen for the phase variable at one time, whereas many cells (marked in yellow) can be selected for spike dispaly. The phase of the selected cell is computed and made available to the spiking display with the name "phase". You can plot points, histograms or density displays of any of the other quantities against the phase.
The computation of the phase is performed from the actual activity of the selected point, so it is not strictly necessary that the point have a sinusoidal profile. Other choices may produce useful results [eg spikes in one cell relative to the phase of another] but the result may be noisy or unpredictable for inputs which are irregular.