Intracranial Stimulator

Discussion in 'The Projects Forum' started by spooge24, Apr 9, 2009.

  1. spooge24

    Thread Starter New Member

    Apr 9, 2009
    I'm a first year electronics engineering student and I have volunteered to design and build a intracranial stimulator for a graduate psychology student's research project. The basic function of this device is to send a square wave pulse to a lab rat's brain. The current is small enough that the rat doesn't feel it. I'll be using the NI ELVIS II system, which already has a signal generator built in that is controlled by software. I would like to make the output around 5 volts DC so I can use digital circuitry for measurements and counters. I need to find a way to vary the current output of the device from 25uA to 250uA. Is there a way to vary the current without having to change the voltage? Any suggestions would be helpful...
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    You could try something similar to the attachment - requires an op-amp, power supply and other components. Basically a controlled current source. Not sure what resistance load it would "see" with animal tissue - presumably fairly low.
  3. thingmaker3

    Retired Moderator

    May 16, 2005
    Ohms law applies even to rat skulls. If the varmint has constant resistance, one must increase the voltage to increase the current.
  4. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    I use large quantities of black coffee for my intracranial stimulation. :D
  5. RiJoRI

    Well-Known Member

    Aug 15, 2007
    I find banging my head against the wall to work, also. :p