Spike Acquisition Entity Properties

Spike Acquisition Entity Properties

The acquisition entity settings are shown on the properties page when a spike plot or AE is selected in the properties tree.

Spike Acquisition Entity Settings

Spike Acquisition Entity General Settings


1. Acquisition Entity Name	This is the unique name that is used to identify this spike acquisition entity. It is the name you chose when you created the acquisition entity.
2. Sub System Name	This is the name of the recording system from where this acquisition entity will receive its data.
3. Sampling Frequency	This is the rate at which __prod_name is sampling data for this acquisition entity.
4. Sub Sampling	This command allows you to record data for a particular acquisition entity at a lower sampling rate than other acquisition entities. The sub sampling interleave tells __prod_name to process only every Nth (where N is the Value specified) sample obtained from the recording hardware. This can also be seen as a sampling divisor. This setting cannot be changed while __prod_name is recording. The value must be between 1 and 3 for spike acquisition entities. Example: An __lynxsx_hardware_name Acquistion Amplifier system samples all channels at 32000 Hz. Suppose you want to sample SC2 at 16000 Hz. You would type 2 in the box and hit enter. This will only process every 2nd sample, giving an effective sampling rate of 16000 Hz. Multiple Spike entities can be updated with a global selection .
5. Input Inversion Setting	__prod_name will automatically invert incoming AD data before it is processed if this box is checked, and positive voltage is in the up direction. When the box is NOT checked, __prod_name will not adjust the polarity of the incoming AD data and positive voltage is in the down direction.
6. Acquisition Entity Processing Enable	Enables (checked) or disables (unchecked) the processing of data by the acquisition entity. If record processing is disabled, records will not be able to be displayed, sent to NetCom or saved to a file. Raw data file processing will still occur if it is enabled (see -SetRawDataFile). When processing is disabled, the Write Records to File setting is disabled.
7. Data File Name	All Spike records will be saved to the file that is shown right beneath this title.
8. Reference Selection	Allows you to select the reference to use for this acquisition entity. Only references currently allowed by the referencing hardware will be shown in this list. If a reference you wish to use is not shown in this list, you can select More Reference Options... from the list to launch the HRS Setup dialog . This dialog will indicate which channels are currently assigned to the local reference buses, 0-7. From the Acquisition Entities Properties page, you can unasign one of the references currently in use by a set of acquisition entities. This action will free up (1) bus line that was assigned the reference. If an acquisition entity shares one of its AD channels with other acquisition entities, the reference for all acquisition entities using that AD channel will be changed. In the case of tetrodes and stereotrodes, this will involve more than one AD channel. Example: CSC1's source is AD Channel 0 and TT1's sources are AD Channels 0, 1, 2 and 3. If the reference for CSC1 is changed to Subject Ground, not only will AD channel 0 change its reference to Subject Ground, but so will AD Channels 1, 2 and 3. This happens because all channels on TT1 must use the same reference.
9. Spike Detection Setup	Launches the Spike Detection Setup dialog .
10. Auto Threshold Multiplier	Sets the value to be used for auto threshold processing. Valid input values are in the range of 0.5 to 5.0.
11. Run Auto Thresholding	Begins the auto thresholding processing for spike acquisition entities. After collecting sufficient data from the incoming signal, each acquisition entity will calculate a new threshold. The resulting threshold is the mean of the signal data received by the acquisition entity, plus the standard deviation of the signal multiplied by the Auto Threshold Multiplier

Spike Acquisition Entity Channel Setup

In addition to single electrode spike detection, __prod_name has the ability to detect spikes on stereotrodes (2 channels) or tetrodes (4 channels). Each of these channels have settings that can vary independently of each other. This section will allow you to adjust those settings.


1. Channel Edit Selection	In this list you will see an entry for each sub channel in the current spike acquisition entity. When you click on a channel, the threshold and input range values for that channel will be shown in the threshold and input range entry boxes, and can be changed. You can select more than one channel for editing (stereotrodes and tetrodes only) by holding down the Ctrl or Shift key and clicking on the other channels you wish to edit. When you have more than one channel selected for edit, the values from the lowest channel number selected will be shown in the threshold and input range edit boxes. Changing one of these values with multiple channels selected will apply the entered value to all selected channels. At least one channel must be selected in order to change any of the values for any of the channels.
2. Sub Channel Enable	Enables or disables a particular channel of a spike acquisition entity. Disabling a channel will cause __prod_name to not process any data on that channel. When a channel is disabled, the waveform plot will change to show that the channel is disabled as shown in the following image: If the waveform plot is too small, the DISABLED text will not be visible. Once the channel is enabled, it will display data normally.
3. Channel Number	This number identifies each of the channels of this acquisition entity. This number is for identification purposes only.
4. A/D Channel Number	This is the AD channel on the acquisition subsystem where data is obtained for this spike channel.
5. Spike Detection Value	This is the current spike detection value for this spike channel. The value shown depends on what method of spike detection is being used for this spike acquisition entity (See Spike Detection Setup ). Threshold : The threshold value will be shown in microvolts. Slope: The slope value will be shown as microvolts/microseconds.
6. Input Range	This is the current input range in microvolts for this spike channel. The input range will always be from the negative of this number to the positive (i.e. in the above image, channel 1's input range is from -2500 to 2500 microvolts).
7. Range Entry	This value will be in microvolts and must be a whole number within the current input range. If you change the input range to a value that is less than the current threshold, the threshold will be adjusted to be equal to the input range you entered. This value cannot be changed while __prod_name is recording.
8. Spike Detection Entry	Here you will be able to change the value of the current spike detection value for this spike channel. What is shown depends on what method of spike detection is being used for this spike acquisition entity (See Spike Detection Setup ). This value cannot be changed while __prod_name is recording. Threshold : The threshold value is in microvolts, and must be less than the current input range.. Slope: The slope value is entered as a voltage change in microvolts over an amount of time in microseconds.

Spike Detection Setup

Clicking on the Spike Detection Setup button allows __prod_name to change the way that it detects spikes, and what data is saved when a spike is detected. Here you will be able to adjust those settings.


1. Acquisition Entity Name	This is the unique name that is used to identify this spike acquisition entity. It is the name you chose when you created the acquisition entity.
2. Detection Type	Here you will specify how __prod_name will extract spikes from the continuous neurological data. You may choose from the following options: Threshold: When a signal is detected that is higher than a specified threshold, __prod_name will begin to look for the peak of the spike. After that peak is detected, it will align the peak using the alignment point setting and save 32 points of data to a spike record. Slope: When a signal is detected that has a particular rise in voltage over a period of time, __prod_name will begin to look for the peak of the spike. After that peak is detected, it will align the peak using the alignment point setting and save 32 points of data to a spike record.
3. Alignment Point Setting	Each spike will contain 32 points of data. When __prod_name detects a spike, it will record 32 points of data around the peak of that spike. The alignment point tells __prod_name how many points of data before and after the peak of the spike should be saved. Example: Assume you have your alignment point set at 8. When __prod_name detects a spike, it will save the 7 points of data before the peak of the spike, and the 24 points of data after the peak.
4. Retrigger Time Setting	Sets the amount of time to wait after a spike has been detected before searching for the next spike. This setting can be useful if there are rapidly firing spikes, or echoes present on a particular acquisition entity. This avoids having portions of spikes appear in two separate records. This can be any value between 250 and 1000000 microseconds.
5. Dual Threshold Enable	Sets dual spike thresholding for the specified acquisition entity. This tells __prod_name that a spike can be either in the positive or negative direction. If checked (enabled), __prod_name detects spikes that are above the current threshold setting and below the negative of the threshold setting. If unchecked (disabled), __prod_name will only detect spikes that are above the current threshold setting. Example: If the current threshold setting is 5000 microvolts, and dual thresholding is enabled, signals that have a value above 5000 microvolts and below -5000 microvolts will be classified as spikes.
6. Clear Clusters Button	Clears all defined clusters for the specified acquisition entity. Once cleared, all cluster definitions for this acquisition entity will be lost.
7. Close Button	Clicking either this button or the X at the top right of the window will close the window.

Spike Acquisition Entity Filtering Setup

The DAS utilizes Digital Signal Processing (DSP) filters. DSP filtering uses the computer to filter signals, and does not physically change the signal before it is processed by __prod_name.


1. Low and High Cut DSP Filter Enable	__prod_name has the ability to process all signals using digital signal processing (DSP). Checking this box will turn the high cut (low pass) and low cut (high pass) DSP filter on (checked) or off (unchecked) for the specified acquisition entity. Changing the enabled sate does not affect the actual filter value of the DSP filter, it simply enables or disables the filter. All channels of an acquisition entity are filtered using the same settings. Disabling DSP filtering can be used to alleviate CPU load on high channel count systems or older computers. When the box is unchecked (disabled), you will not be able to change the filter value or number of taps.
2. Low and High Cut Filter Value	Sets the frequency that __prod_name will use for the high cut (low pass) or low cut (high pass) digital signal processing (DSP) filter on all channels of the specified acquisition entity. The filter frequency has no effect if high cut filtering is disabled. High cut filters will only allow signals whose frequency is below this value to be recorded by __prod_name and low cut filters will only allow signals whose frequency is above this value. DSP filters have no effect on data being written to a raw data file (see -SetRawDataFile -SetRawDataFile ). This value is in hertz, and can be any value (including decimal values) between 0.1 Hz and 10000.0 Hz. This value can only be changed when DSP filtering is enabled.
3. Low and High Cut DSP Filter Taps	Digital signal processing (DSP) taps determine the amount of rolloff for the DSP filter. If you notice the cut filter is allowing signals that are too far beneath (low cut) or above (high cut) your setting to be processed by __prod_name, you may want to increase (low cut) or decrease (high cut) this value. __prod_name will normally select a tap value that is appropriate for the specific filter frequency. Lowering the number of taps can be useful to alleviate CPU load on large channel count systems or older computers. This value can only be changed when DSP filtering is enabled. If the frequency value is changed to a value that is not available with the current number of taps, __prod_name will change the number of taps to the closest appropriate value.
4. Low and High Cut DSP Filter Type	Shows the type of DSP filter being used by __prod_name for the given filter frequency. This can be one of the following: FIR : A finite impulse response filter is being used to filter the data. DCO: Uses a running average to remove the DC component from the AC signal. None: No DSP filtering is being applied to the incoming data.
5. DSP Delay Compensation	The delay associated with the current DSP filter settings which __prod_name is automatically compensating for.