################################################################### # Conductance analysis (VmT) # # # # based on the publication # # # # Martin Pospischil, Zuzanna Piwkowska, Thierry Bal and # # Alain Destexhe "Extracting Synaptic Conductances from Single # # Membrane Potential Traces", Neuroscience 158: 545-552, 2009. # # # ################################################################### The application extracts the parameters of the distributions of excitation and inhibition from a single current clamp recording, based on a maximum likelihood method. The application is run on pieces of the voltage trace that are delimited by spikes or a maximal length. As output, for each interval a line is written to the output file, containing the number of datapoints and the distribution parameters (in uS) of the current run as well as the momentary average. The application is started by invoking the command 'python VmT.py' from the system prompt. In order for this to work, the python scripting language along with the packages 'Numeric' and 'pylab' need to be installed. Adjustable parameters are given in the header.py file and comprise: vmFile - input file name containing the voltage time course as a single column resfile - output file name Iext - constant injected current in nA gtot - total input conductance in uS C - capacitance in nF gl - leak conductance in uS Vl - leak reversal potential in mV Ve - reversal potential of excitation in mV Vi - reversal potential of inhibition in mV te - correlation time constant of excitation in ms ti - correlation time constant of inhibition in ms vt - threshold for spike detection in mV dt - time between two datapoints in ms t_pre - excluded time preceding spike t_post - excluded time after spike n_smooth - SD in timesteps of the Gaussian filter that is used for smoothing n_ival - max nb of intervals analysed n_minISI - min nb of datapoints in interval n_maxISI - max nb of datapoints in interval g_start - starting point for minimisation [ge,se,si] in uS