Guide to Biopac and Acqknowledge
Physio Recording Software
Updated on 9/10/12
This guide is meant to be a quick reference for collecting physiological data from your
subject using the Biopac system and the Acqknowledge software. Currently we are able
to collect respiration and pulse data from subjects. Send me an email if you are looking
for more in-depth explanations and/or would like to discuss acquiring different data.
Hardware:
Biopac MP150 (Fig. 1):
This is the actual data
acquisition unit that
allows us to collect the
physio data. This connects
to the Eye Tracking PC
via a crossover cable. The
power switch is located on
the back left side of the
unit. Once turned on,
nothing has to be done
with the unit.
Nonin Pulse Oximeter
(Fig. 2): The Nonin is our
MRI compatible pulse
oximeter that connects to
the Biopac so that a
subject’s pulse can be
collected. Prior to turning
on the Acqknowledge
software, make sure that
the Nonin is also turned
on, otherwise you won’t
get a signal! The power
switch is located on the
face of the device.
Respirator Belt (Fig. 3):
The respirator belt is
comprised of two units; a
small blue and white
bladder that is located on
the face of the magnet,
and an actual respirator
belt that is used to secure
the bladder onto your
subject’s chest.
Figure 1 - Biopac MP150 Unit
Figure 2 - Nonin Pulse Oximeter
Figure 3 - Respirator Belt
Setup: Biopac and starting Acqknowledge
The first step is to turn on the Biopac system and start the Acqknowledge software.
1.
2.
The power button for the Biopac can be found on the back left side of the device.
Simply push in the black button and the device will start up. Note: that it will take
about a minute for the computer to recognize that the device is on. DO NOT open
up Acqknowledge until the notification pops up on the bottom right side of the
screen. The notification is a generic notification about limited connectivity of
some sort; just know that it’s only ok to proceed once the message pops up.
Once the Biopac is on and you receive the notification, go ahead and click on the
“Template.acq” file on the desktop to open up Acqknowledge. Note: You could,
in theory, open up any Acqknowledge file or open up a brand new one of your
own. But Template.acq is preset with all the required channels and settings so you
don’t have to do any configuration to get started. Simply open the file and click
“Start” and you’re set.
Setup: Respirator belt and pulse ox
This section outlines how to go about placing the sensors on your subject.
1. Before laying your subject on the bed, place the respiration sensor approx. over
their diaphragm and secure it using the belt. Don’t worry too much about getting
it tightly around the subject. That can be adjusted later on when they are lying
down. NOTE: The sensor and belt can be placed over the subject’s clothes,
though I’d advise having them remove any jackets or sweaters. If they complain
about the room being cold, we have plenty of blankets.
2. Once your subject is lying on the bed and positioned correctly, feel free to adjust
the belt to make it tighter. Obviously they should still be able to breath
comfortably, but you want to get a nice clear signal from the sensor.
3. Next place the pulse oximeter on their index finger. It can work on any finger, but
the index is easier to place and most comfortable for the subject. Secure it to their
finger using the attached Velcro strap, making sure not to wrap it too tightly or
else it weakens the signal.
4. Go back into the control room and turn on the Nonin. Verify that a signal is
coming through.
Figure 4 - Acqknowledge running
Setup: Using Acqknowledge
This section is pretty straightforward and goes over the basic information you need to
know about the software. If you want to do more with it, then contact me.
1. With everything plugged in and the software running, hit the start button on the
Acqknowledge screen. This starts the recording process and you’ll see the green
and red signals (respirator belt and pulse ox, respectively) coming in. Figure 5
gives you a rough idea of what the signals should look like.
2. Once your EPI sequence actually starts running, you’ll also notice the TTL signal,
the channel on the bottom of the screen, start to come in. It will be a 5V pulse,
with the duration between them being the TR of your sequence.
3. If everything is connected properly and the sensors are placed correctly, then the
signals should be easily visible and distinguishable.
4. Once you are happy with the signal quality, you can start and stop the recording
whenever by hitting the GREEN start button (which changes to RED when the
software is in recording mode).
5. After you stop a recording you can save it by going to FILE > SAVE AS and
entering a file name. The files are saved in the EXPERIMENTS folder in MY
DOCUMENTS. I typically then close down the program and reopen another one
by clicking the template, though you can easily just clear the recording instead.
NOTE: Typically users only record data during sequences and stop recording in between
while they either talk to subjects or set up for the next scan. It’s entirely up to you how
you want to record, though I can tell you that it’s much easier to analyze and store data
that is broken up according to sequences rather than one long recording of your entire
session.
And that’s basically all you need to know in order to record physiological data. If you
have any questions or would like to know more about the system, configure your own
workspace, add another physiological recording, etc. then send me an email and we can
discuss it.