Multichannel Systems NeuroExplorer - Manual (Page 103)

Position ISI mode Average interval between two consecutive position data points (in
seconds).
Mean Firing Rate Mean firing rate (mean of all the firing rates for all the cells).
St. Dev. Firing Rate Standard deviation of the firing rate (st. dev. of all the firing rates for all the
cells).
Firing Fields The number of firing fields.
Field N Num Cells The number of cells in the firing field N.
Field N Centroid X X coordinate of the field N centroid.
Field N Centroid Y Y coordinate of the field N centroid.
Field N Peak Rate Maximum firing rate among the cells inside the firing field N.
Field N Spikes Number of spikes in field N.
Field N Time Spent Total time spend in the field N.
Field N Rate Average firing rate in field N ( Field N Spikes divided by Field N Time
Spent ).
Field N Coherence Coherence measures the local smoothness of the firing rate distribution in
the field. It is the Pearson correlation of the firing rate in each cell (pixel)
with the firing rate averaged over the pixel and its 8 nearest neighbors.
Algorithm
If Fix Positions is set to Use 4 Neighbors, NeuroExplorer will analyze X and Y position variables
and do the following:
for each point x[t], calculate the average of its 4 neighbors:
aver = (x[t-2]+x[t-1]+x[t+1]+x[t+2])/4
if abs(x[t] - aver) > FixThreshold, then assign x[t] the average of its neighbors:
x[t] = aver
If Fix Positions is set to Ignore Bad, NeuroExplorer will ignore position points that have coordinates
that are within 0.001 of the specified 'bad' X and X values.
If Fix Positions is set to Interpolate, NeuroExplorer, for position points that have coordinates that
are within 0.001 of the specified 'bad' X and X values, the X and Y values are interpolated using the
closest previous valid position and the closest next valid position.
The following steps are then performed:
The position space is divided into cells with width ( XMax - XMin )/ Number of Bins (X) and height (
YMax - YMin )/ Number of Bins (Y).
For each cell, the number of visits to this cell and the time spent in the cell are calculated.
For each of the neuron firing times, the position of the animal is calculated using linear interpolation of
animal positions before and after the spike.
For each cell, the number of times the neuron fired in this cell is calculated.
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