Brief user Manual for NAPS (Neuron Action Potential Simulator)

V 1.0 Output

 

 

1)      Open NAPS Version 1.0 Output. There are two operating modes for this program, Voltage Trace mode Neuron Waveform mode. Voltage Trace mode loads previously created output signals (i.e. data saved from NAPS V 1.0 Output) and sends them to the DAC board. Neuron Waveform Mode loads data that was created in NAPS V 1.0 Input and uses it to create an output signal. The “Mode?” switch is located in the very top dark blue box in the front panel.

 

For Neuron Waveform Mode

 

2)      Before clicking the “Run Program” button, the user must specify the device number of the board used to output the generated signal. This control is located in the red box on the front panel.

 

3)      Immediately after clicking the “Run Program” button, a dialog box will appear that will ask for the “Output Project Name” and “Saved Input Project Name”. The input for “Output Project Name” will be used to save data that you create in NAPS V 1.0 Output (i.e. voltage traces, spike times, channel size, and EEG signal). The input for “Saved Input Project Name” is used to load the data which you created in NAPS V 1.0 Input (i.e. waveforms, firing rates, etc).  It may take a few seconds to load the waveforms so be patient.

 

4)      Once the project names have been entered, the program will begin to generate data for each channel created. You can view the signal that is being sent to each channel with the “View Channel” control. A raster plot is also generated for each second of data produced. The neurons are color coded to distinguish channel location.

 

5)      The user also has the ability to generate spike times based on a Poisson distribution or a simple impulse train. The control for the train type is located in the dark blue box second from the top. Toggling the “Train Type” switch will change between an impulse train and a Poisson train of neuron spikes.

 

6)      There are four other parameters of the output signal that may be altered during the runtime of the program, time length of generated data, output signal gain, baseline noise and firing rate for each neuron.

 

i) The control for the time interval of the output voltage trace and EEG signal is located in light blue box in the top left of the front panel.

 

ii) The output voltage gain control is located below the output signal display.

 

iii) The baseline noise controls are also located below the display of the output signal. The user can specify a mean frequency for the noise as well as its bandwidth. However, the bandwidth may not be more than double the mean frequency.

 

iv) To change the firing rate of a neuron, simply use the “Neuron #” to specify the neuron you would like to change and use the “New Firing Rate” to specify a new firing rate. Once the user has made the desired changes, click the “Enter Rate” button. The change in the firing rate can be easily viewed in the raster plot in the large light blue display. To save the data produced in NAPS V 1.0 Output (as described in step 3) press the “Save Voltage Trace and Times Switch” switch.

 

 

7)      There are three parameters of the EEG output signal that may be altered during the runtime of the program, relative amplitude of spectra peak #1 to baseline, relative amplitude of spectra peak #2 to baseline, and EEG amplitude. The controls for relative amplitude of spectra peak #1 to baseline and the relative amplitude of spectra peak #2 to baseline merely determine which of the two frequencies in the designed EEG signal is dominant. For example, if the relative amplitude of spectra peak #1 is set very high while the relative amplitude of spectra peak #2 is set very low, the EEG signal will be primarily composed of frequency 1,which was specified in the NAPS input program.

 

8)      If the user would like to output the constructed voltage trace and EEG signal to the DAC board simply flip the “Output to Board” switch in the dark blue box located second from the top. The user can alter this setting during runtime.

 

 

For Voltage Trace Mode

 

9)      Like Neuron Generation Mode, the user must specify the device number of the board that will be used to output the saved voltage trace and EEG signal. Also, the user must specify if they would like to loop the saved voltage trace. Simply flip the “Loop Voltage Trace?” switch to loop the saved data.

 

10)  Immediately after the “Run Program” button has been clicked, a dialog box will   appear that will ask you for the project name which the user would like to load.    This will be a project, which you saved in the Neuron Generation mode of NAPS V 1.0 Output. It may take a few seconds to load the saved waveforms so be patient.

 

11)  After loading the project, the output signal for a selected channel and a raster plot for each second of data can be viewed on the front panel. To view a different channel’s output, simply use the view channel control below the output display.

 

12)  If the user would like to output this voltage trace to the DAC board simply flip the “Output to Board” switch in the dark blue box located second from the top. The user can alter this setting during runtime.

 

 

 

(Note: Spike times are sorted to ensure that no two neurons fire at the same time. If two spikes are generated at the same time, 1 ms is added to a neuron’s spike time to correct for the overlap. All of these changes are saved in the spike times file.)

 

Known Bugs:

 

1) Flipping the “Output to Board” switch more than two times will cause a buffer error and the program will be forced to stop. The error is caused by the buffer not releasing old samples. Future versions of the program will correct this bug.