Fear Conditioning TTL Interface

6 events · BNC-6 multi-channel · 4 chambers

Overview

The Fear Conditioning TTL interface uses the complex 9-byte protocol to route 6 distinct event types to separate BNC channels on the BNC-6 connector. This allows your recording system to distinguish shock delivery, tone CS, white noise, light, and trial boundaries on independent digital input channels — no post-hoc event parsing required.

Multi-chamber support (up to 4 chambers) enables simultaneous fear conditioning with independent TTL outputs per chamber. Each event frame includes a chamber ID byte, so multi-chamber rigs can use a single TTL module with channel-multiplexed output.

Setup Instructions

  1. Connect the TTL module via USB and note the COM port.
  2. In ConductMaze Settings > TTL, enable TTL output and select BNC or BNC-6 connector type.
  3. For BNC-6: connect each numbered BNC output to a separate digital input channel on your recording system. Channel 1 = trial boundaries, Channel 2 = tone, Channel 3 = white noise/light, Channel 4 = shock.
  4. For single BNC: all events share one channel. Use pulse duration differences to distinguish events post-hoc.
  5. Configure TTL signal mapping in Settings > TTL > Signals. Default: StartTrial:1:3.3, EndTrial:1:3.3, Tone:2:5, WhiteNoise:3:5, Light:3:5, Shock:4:5.
  6. Set the ttl_millis parameter (default 1000ms) to control pulse duration for pulse-type events.
  7. Run a manual test: trigger each event type and verify the correct BNC channel activates on your recording system.

Common Pitfalls

  • ⚠StartTrial and EndTrial are STATE signals on BNC-6 (voltage stays high/low) but PULSE signals on single BNC. If you switch connector types, your analysis scripts may need updating.
  • ⚠WhiteNoise and Light share BNC channel 3 by default. If your paradigm uses both, remap one to channel 5 or 6 in the TTL signal configuration.
  • ⚠Voltage differs by signal type: trial boundaries use 3.3V, stimuli use 5V. Ensure your recording system input range accommodates both levels.
  • ⚠In multi-chamber mode, all chambers share the same BNC outputs. Events from different chambers are serialized with chamber ID in the frame — your recording system sees multiplexed pulses on each channel.

Methods Text (Copy-Paste)

Fear conditioning events were synchronized with neural recordings using the ConductMaze TTL module (ConductScience, Skokie, IL) via a BNC-6 multi-channel connector. Six event types (trial start/end, tone CS, white noise, light, foot shock US) were routed to independent BNC channels using 9-byte serial frames (115,200 baud, 10ms resolution). Trial boundary signals were transmitted as sustained states (3.3V), while stimulus events were delivered as 5V pulses of configurable duration.

Suggested text for the Methods section of your manuscript.

Compatible Products

ME-OC-TTL

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