MEA Channel Mappings
When creating a Neurorighter rig for in-vitro experiments using multi-electrode arrays (MEA's), one must be mindful of the path each electrode takes through the device to reach a certain input on the NI DAQ. This page details a few numbering conventions for each link in this path and a table that outlines how to acheive a functional path from channel to DAQ without modification of the Neurorighter software.
Numbering Conventions
Before outlining each connection that needs to be made, it is important to adopt a standard numbering scheme for each device in the complete system. We start at the MEA and work back to the NI DAQ. Images in this section are modified from manuals for components made by Multichannel Systems (http://www.multichannelsystems.com) and National Instruments (http://www.ni.com/).
The MEA
MCS uses [Column Row] indexing to label electrodes in their standard array. The location of the electrodes with the corresponding CR number is given in the image below. The black rectangle represents the orientation of the large ground electrode. In addition to CR numbering, the Neurorighter software uses linear indexing (row-wise from top left) to label channels.
(Modified From: Multi-Channel System MEA 1060 Amplifier Manual)
The MCS Data Cable
After a singal is recorded on the MEA, it is amplified by the MCS preamp, and is send via an MCS data cable to Neurorighter's recording (bottom) PCB. The numbering convention for the socket (when looking down at the MCS preamp) is as follows:
(Modified From: Multi-Channel System MEA 1060 Amplifier Manual)
The MCS data cable that plugs into this socket has the mirror scheme (horizontally):
(Modified From: Multi-Channel System MEA 1060 Amplifier Manual)
The MEA Recording PCB
We number the channels on each of the four output headers (grey) on the Neurorighter recording PCB as in the following diagram. The diagram is a representation of the recording PCB viewed from above.
Signals get from the recording PCB to the breakout boxes by travelling through 34 conductor (17 channel) ribbon cables. Because all measurements are made against a common reference (the ground electrode), we only use half 17 of the 34 conductors available per breakout box. Specifically, if starting from the right as in the figure above, we only use the even numbered conductors, the odd numbered conductors all connect to ground. Note that the in connectivity spreadsheet below, the "PC board" numbers refer to channels, not the conductors (multiply the "channel number" by two to get the corresponding, even, "conductor number"). As in the MCS data cable, the number of these conductors on the ribbon header simply match the number of the channels on the matching output header output on the recording PCB.
The SCB 68 Breakout Boxes
Pin-out Labeling Conventions
Please see the following document from NI: http://digital.ni.com/public.nsf/allkb/B478F1BC6556FA2F862571C0007E6062
Recording
Each recording DAQ is capable of sampling from 32 simultaneous analog inputs. Because we are recording from 60 channels (including the reference electrode), two NI DAQ's are used. Each of these DAQ's is supplied with input by two SCB-68 breakout boxes. Thus we have t DAQs: Device 1 and Device 2 and each of these has two breakout boxes: Connector 0 and Connector 1. These devices have the following number conventions:
(Modified From: NI SCB-68 CO Pinout Reference and NI SCB-68 C1 Pinout Reference)
Mapping Scheme for Recording
The following table provides the connections that must be made between each element of the recording system in order for the Neurorighter software to correctly map the location of a recorded signal. All numbering conventions are presented in detail in the Numbering Conventions section above. Note that you can download a PDF of this mapping at the bottom of this page.
