Connector Box

NAC 2.0 Connector Box The connector box allows you to conveniently connect your instruments to the IOtech Daqboard/2000 data acquisition card in your PC. Connect the cable on the back of the box to the IOtech Daqboard/2000 data acquisition card. Connect your instruments to the connectors on the front of the connector box. The various connectors are:

  • Eight BNC jacks labelled CH0, CH1, CH2, CH3, CH4, CH5, CH6, and CH7 that serve as recording channels.
  • Two BNC jacks labelled AOUT0 and AOUT1. Use these to output ±10V 16-bit analog waveforms at a sampling rate of 50 kHz.
  • One 3.5 mm stereo phone jack. Use this to output 50 kHz audio waveforms to computer speakers.
  • Four BNC jacks labelled DOUT0, DOUT1, DOUT2, and DOUT3. Use these to output digital TTL waveforms (trigger pulse patterns for stimulators) at a sampling rate of 50 kHz.
  • Two BNC jacks labelled D0 and D1. Use these non-waveform-quality digital outputs to switch TTL-triggered devices on and off during the course of an experiment.
NAC 2.0 Connector Box

We explain these connectors in more detail below.

Recording Channels CH0, CH1, ..., CH7

For most experiments, each recording electrode feeds into some signal conditioning device such as an amplifier and/or a filter (esp. low cut and/or anti-alias). The output of the signal conditioning device(s) for each recording electrode is connected to one of the 8 input channels CH0, ..., CH7 of the NAC 2.0 connector box. Although your original signal need not be a voltage (it could be a current, for example), the output of your signal conditioning device must be a voltage within the range ±10V (or less, depending on the gain you set on the DaqBoard/2000 data acquisition card). The NACGather data acquisition program assumes that the original signal that you are measuring is directly proportional to the voltage it measures.

Digital Output Waveform Channels DOUT, DOUT1, DOUT2, and DOUT3

Most users have a stimulator that delivers the actual current or voltage pulse to a stimulation electrode in the brain tissue. When used with NAC 2.0, the stimulator is typically set up to output one pulse to the stimulation electrode each time the stimulator receives a TTL trigger pulse from NAC. NACGather is set up to output digital waveforms that are patterns of trigger pulses sent to the stimulator(s) from one or more of the digital waveform output channels DOUT0, ..., DOUT3.

Note that because the NACGather software can deliver just about any pattern of trigger pulses, for most experiments, you may not need to purchase an expensive stimulator to generate patterns of stimulations (e.g., bursts, trains, etc.). You may be able to save money by purchasing a stimulator that simply outputs a single stimulation pulse to your stimulation electrode for each trigger pulse that the stimulator detects in the digital waveform from one the digital output waveform channels DOUT0, DOUT2, ..., DOUT3. Use NACGather to generate the stimulation patterns.

Analog Output Waveform Channels AOUT and AOUT1

In some cases, the user may have a stimulation device whose output is proportional to a voltage waveform. In this case, the user may send analog waveforms from output channels AOUT0 and /or AOUT1 to the stimulator. The advantage of this is that the user can control stimulation amplitude, duration, and waveform from within the NACGather program instead of by manually adjusting stimulator controls.

Stereo Phono-Jack

The 3.5 mm stereo phone jack fits most computer speakers and headphones. You can use this for experiments in which you want to stimulate an animal with sound rather than an electrical impulse. NACGather can read in uncompressed WAV files (a common sound file format), resample them to 50 kHz, and play them to (amplified) speakers while data is recorded on the recording channels. Note that the left and right sound channels are shared with analog waveform outputs AOUT0 and AOUT1.

Non-Waveform Digital Output Channels D0 and D1

The NAC 2.0 connector box has two non-waveform digital outputs, D0 and D1 that output TTL digital values (0V or 5V). These channels are meant to be used to turn devices (e.g., pumps) on or off from within NACGather during the course of an experiment. The user can set these channels to automatically change at the beginning or end of stages of an experiment or the user can manually change these digital outputs within the NACGather data acquisition program.

The types of changes that can be made on these channels are

  1. pulse high (0V→5V→0V),
  2. pulse low (5V→0V→5V),
  3. go high (0V→5V) and
  4. go low (5V→0V).