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LR10 Lab Rat Interface Module

The Lab Rat HAL is the nexus for all interactions with the Lab Rat interface module. The Lab Rat is only available in Synapse Lite software. The LR10 HAL is an independent object in the Processing Tree. However, the acquisition processing and I/O functionality are internally dependent on Corpus software and emulated RZ2 hardware.

LR10 Block Diagram, showing the analog amplifier enabled

LR10 Options

Controls for analog and digital amplifiers, synthetic neural data generation for experiment testing, and multi I/O communications are modified within the Lab Rat object. Here, subcomponents can be enabled or disabled, and their settings can be adjusted prior to experimental run time. The four tabs of the LR10 are: Analog Amp, Digital Headstage, Fake Brain, and Other I/O.

Analog Amp

The Analog Amp page controls the 16-channel analog neural input on the Lab Rat interface module. From this page, the user can: enable/disable the amplifier, control how many channels of input to read, and adjust the sampling rate and filter settings of the amplifier. When the amplifier is enabled, the amplifier ID will appear as a Gizmo output at the top of the HAL and can be connected to other gizmos for further signal processing, with your selected channel count and amp ID.

LR10 Analog Amp Options

Option Description
Imp Check Show online impedance testing results for the connected electrodes. See Runtime Interface.
Sampling Rate Set the Sampling Rate to match the desired frequency band of your incoming signals (or leave at 'System Rate' if you are unsure). By default, the sampling rate matches that of the emulated RZ2.
DC Coupled Remove the 0.4Hz high pass filter on the input signals and record DC potentials.
Reference Mode Select the mode from the drop-down menu.
Local - all channels use a single reference (pin 5 on the DB26).
Differential - each even channel acts as a reference for the odd channel before it. Note: the output channels will be mapped for you to remove duplicate channels.
Filter Set the anti-aliasing low pass filter cutoff as a percentage of the sampling rate.
Set to Base Type If you are unsure, use Set to Base Type to configure the amp with default settings based on common signal types.

Digital Headstage

Enable the Digital Headstage when using an Intan-based digital headstage.

LR10 Digital Headstage Options

Option Description
Imp Check Show online impedance testing results for the connected electrodes. See Runtime Interface.
Sampling Rate Set the Sampling Rate to match the desired frequency band of your incoming signals (or leave at 'System Rate' if you are unsure). By default, the sampling rate matches that of the emulated RZ2.
Low Pass Filter Choose a value for the low pass filter implemented on the digital headstage chip. If Low Pass Filter is set to "Auto," the cutoff frequency will be configured according to the conversion table below.
Use DSP Filter Adds additional low pass filtering (performed by Corpus), matched to the selected Low Pass Filter frequency. This removes high-frequency digital noise that is added by the digital headstage chip.
High Pass Filter Implemented on chip.

'Auto' low pass filter settings for different sub amp sampling rates

Digital Amp
Sampling Rate
LP Auto
Filter Cutoff
750 Hz 300 Hz
1.5 kHz 750 Hz
3 kHz 1.5 kHz
6 kHz 3 kHz
12 kHz 5 kHz
25 kHz 10 kHz

Fake Brain

The Fake Brain is a synthetic data generator. This is a useful tool for designing experiments with well-behaved signals. The Fake Brain acts like an amplifier, and streams generated signals from the Lab Rat into Corpus. This means that you can connect Gizmo inputs to the Fake Brain output. Please take care to double-check that you are not handling and saving synthetic data during real experiments.

LR10 Fake Brain Options

Option Description
Mode Enable the Run-time Control to change the type of generated waveforms dynamically. These include:
Normal: default mode, includes LFP and spikes.
Hash: like Normal, but spikes reduced by a factor of 2.
LFP Only: like Normal but no spikes.
Tetrode: like Normal, but spikes on each group of four channels fire synchronously.
Sync 100 Hz: spikes fire at 100Hz on all channels.
Tone 30 Hz: A 30Hz ~700uV sine wave on all channels.
Tone 1 kHz: A 1kHz ~70uV sine wave on all channels.
Tone Ref: A 100Hz ~700uV sine wave on all channels.
Stim Sync Simulate inhibitory or excitatory input to the fake spike modes (Normal, Hash, Tetrode) with the Stim Sync option.
You can enable this with an external device input, like the Bit0 BNC connector on the front of the LR10, to modulate firing rate with external hardware. When the Stim Sync input is activated, certain spike shapes are inhibited (fire less) and others are excited (fire more). To control the stim sync using only the LR10, use the Gizmo Input option.

Technical Detail


See the FB128 section of the System 3 Manual for more information on the Fake Brain modes.

Other I/O Tab

LR10 Other I/O Tab

Option Description
Digital I/O Monitor Shows you the logic state of all digital I/O on the Lab Rat at run time.
ADCs You can choose to save the analog inputs coming into the "A/D" connector to disk or just view them during your experiment.

Lab Rat digital and analog I/O are passed to the emulated RZ2 processor in Corpus. This allows common support of these inputs and outputs across TDT system configurations. Software configuration of the multi I/O parameters is controlled in the RZ HAL. The Jump to... section takes users to the appropriate RZ HAL page for I/O configuration. For more information, please overview See RZ Options..

Option Description
Digital I/O 16 bits of digital input (8 bit-addressable, 8 word-addressable) are available.
ADC Two channels of ADC input are available as single-channel inputs or combined into a multi-channel signal for further processing.
DAC Two channels of DAC output are available as single-channel outputs or can be combined and controlled by a multi-channel signal. Each DAC channel can be tied to the output of a Gizmo, such as the Electrical Stimulation or File Stimulation gizmos.

Runtime Interface

LR10 Runtime Interface

When Digital I/O Monitor is enabled on the Other I/O Tab, the state of all 16 bits is shown on the runtime interface in binary format.

If Show Value is selected for the ADCs option on the Other I/O Tab, the current voltage on the ADC inputs will be shown at runtime.

If Run-Time Control Mode is enabled in the Fake Brain Tab, you can change the fake signal type dynamically.

If the Imp Check option is enabled for the analog and/or digital headstage, use the interface button to switch the LR10 into impedance checking mode. The current impedance values of the connected electrode will update on the user interface. During the impedance check, the signals returned from the amplifier will be the value of the impedance, in MOhm.

If the impedance of an electrode is above 500 kOhm, the monitor will return a value of "High Imp."

Pinouts

The pinouts are looking into the connector.

AC16LR Headstage

DB25 Connector

Pin Name Description Pin Name Description
1 C0 Port C Bit Addressable 14 C1 Port C Bit Addressable
2 C2 Digital I/O 15 C3 Digital I/O
3 C4 Bits 0, 2, 4, 6 16 C5 Bits 1, 3, 5, 7
4 C6 +3.3V, 10mA max per bit 17 C6 +3.3V, 10mA max per bit
5 GND Ground 18 A0 Port A Word Addressable
6 A1 Port A Word Addressable 19 A2 Digital I/O
7 A3 Digital I/O 20 A4 Bits 0, 2, 4, 6
8 A5 Bits 1, 3, 5, 7 21 A6 +3.3V, 10mA max per bit
9 A7 +3.3V, 10mA max per bit 22 ADC1 Analog Input Channel 1
±3V, 20mA max
10 ADC2 Analog Input Channel 2
±3V, 20mA max
23 VBUS +5V, 150mA max
11 VCC +3.3V, 250mA max 24 DAC1 Analog Output Channel 1
±3V, 20mA max
12 DAC2 Analog Output Channel 2
±3V, 20mA max
25 V+ +3.3V, 150mA max
13 V- -3.3V, 150mA max

DB26 Neural Input - Shared Reference Mode

Pin Name Description Pin Name Description
1 A1 Analog Input Channels 14 V+ Positive Voltage (+2.5V)
2 A2 15 GND Ground
3 A3 16 GND Ground
4 A4 17 V- Negative Voltage (-2.5V)
5 Ref Reference 18 HSD Headstage Detect
6 HSD Headstage Detect 19 HSD
7 A5 Analog Input Channels 20 A6 Analog Input Channels
8 A7 21 A8
9 A9 22 A10
10 A11 23 A12
11 A13 24 A14
12 A15 25 A16
13 AltRef Not Used 26 NC Not Used

DB26 Neural Input - Differential Mode

Note

There are 8 (+) channels and 8 (-) channels per DB26 connector.

Pin Name Description Pin Name Description
1 A1(+) Analog Input Channels 14 V+ Positive Voltage (+2.5V)
2 A1(-) 15 GND Ground
3 A2(+) 16 GND Ground
4 A2(-) 17 V- Negative Voltage (-2.5V)
5 NC Not Used 18 HSD Headstage Detect
6 HSD Headstage Detect 19 HSD
7 A3(+) Analog Input Channels 20 A3(-) Differential Input Channels
8 A4(+) 21 A4(-)
9 A5(+) 22 A5(-)
10 A6(+) 23 A6(-)
11 A7(+) 24 A7(-)
12 A8(+) 25 A8(-)
13 GND Ground 26 NC Not Used

Note

Contact TDT technical support (+1.386.462.9622 or support@tdt.com) before attempting to make any custom connections.