The Physiologist's Friend Simulator
PhysioFriend lets you plot receptive fields of simulated retinal and
cortical cells. It is intended for classroom demonstration of cell response
properties. You can hear the cell responses as though you were doing a recording
from a live animal. You can choose between photoreceptor, horizontal cell, on
and off bipolar cells, on and off ganglion cells, and several types of cortical
cells. You can use bar, edge, or grating stimuli. You will hear how the cell
responds as you use your mouse to move the stimulus. The stimulus orientation,
contrast, size, spatial frequency can be easily manipulated through the
keyboard.
PhysioFriend is 100% written in Java. All
you need is the Java run time environment (at least version 1.3+) and a sound
card--if you want to hear the cells. (If you don't have a sound card, you can
still see the cells responses on an activity meter.)
Requirements:
Apple's Java Runtime Environent is apparently far
behind other releases. PhysioFriend does not seem to run well, even under the
JRE 1.3.1 that ships with OS10.2. The components of PhysioFriend show up very
strangely and response is extremely slow. For the moment, it looks like you
cannot run PhysioFriend on Macs.
- Java Run Time
Environment (JRE) version 1.3+. Available for Windows, Linux, Macintosh
and other platforms. As of right now, Apple's OS 10.1 comes with Java
installed, but only version 1.3. If you are on another platform you will
probably need to install the JRE if you have not done so already.
- Java compatible sound card. Java seems to know about most sound cards.
Downloading, installing, and running PhysioFriend:
- Download and launch the
latest version of PhysioFriend in one step if you have Java Web Start
installed.
- Java Web Start does the download, install, and launch in one step, and
it keeps you automatically up-to-date with the latest version of
PhysioFriend. Java Web Start comes by default in Mac OS 10.1. For other
platforms, it is installed by default in Java 1.4.1+, and is available as a
separate download for other Java versions.
- If you have Java installed, you may not have Java Web Start as well, so
you may need to install the updater to get Web Start.
- Under linux, installing
the Java RPM does not install Java Web Start. You still need to go the Java
installation directory (typically something like
/usr/java/j2re1.4.1) and then unzip the Java Web
Start archive and run a separate installer script to get Web Start.
- If you're having trouble with getting Mozilla to recognize the jnlp
type, you may need to install Java Web Start as a
helper application to use with files with the .jnlp extension.
- For Windows, you can download a Windows installer. Run
Setup.exe to install PhysioFriend along with Start Menu and Desktop
shortcuts.
- For other platforms without Java Web Start but with the JRE (1.3+)
installed, download friend.jar. From the command line, PhysioFriend
can be started with
java -jar friend.jar
Quick user guide
-
- You won't hear anything because the photoreceptor is not a spiking cell,
but you can observe the response of the photoreceptor on the activity bar on
the right.
- To get help on the keyboard shortcuts, use the Help menu or hit F1.
- To select the cell you want to observe, use the Cell menu.
- If the cell is a spiking cell, you will hear its spikes and you can see
the spike rate on the activity meter. If the cell is a graded cell you will
only see the response on the activity meter.
- To select the stimulus you want to use, use the Stimulus menu.
- To view the photoreceptor locations, select View.../Photoreceptors
- Explore the menus and try the popup menu on the tangent screen. There are
many keyboard shortcuts that you can pick up from the menus or from the Hot
Key help.
How it works
PhysioFriend does a relatively simple-minded simulation of the cells. The
intention is not to simulate the beautiful complexity of the visual system, but
just to capture some aspects of how the cells seem to respond. These cell
responses should pass the Turing test—they should behave and sound like real
cells.
Version information
If you use Java Web Start, you will always be up-to-date with the latest
version.
Authors
PhysioFriend was written by Christof Marti and
Tobi Delbruck at the Institute of Neuroinformatics, University
and ETH Zurich, Switzerland.