329 LIF on a Ring Topology
329 : LIF on a Ring Topology
- Author: Taylor Kergan
- Description: LIF neurons connected in a ring that displays different firing patterns.
- GitHub repository
- Clock: 0 Hz
How it works
This project implements eight leaky integrate-and-fire (LIF) neurons that are connected in a ring topology. Each neuron:
- Integrates input current over time
- Leaks voltage according to a decay constant
- Fires when voltage reaches threshold
- Influences its neighbors through coupling currents
The system supports multiple firing patterns:
- Independent: Neurons fire based only on their input current
- Wave: Activity propagates around the ring
- Synchronous: All neurons tend to fire together
- Clustered: Neurons form synchronized pairs
- Burst: Strong neighbor coupling creates burst patterns
How to test
The system can be tested through several inputs:
- Base current (ui_in[7:3]): Controls the fundamental firing rate
- Pattern select (ui_in[2:0]): Chooses the firing pattern
- Coupling strength (uio_in[7:0]): Sets the strength of inter-neuron connections
To observe behavior:
- Monitor spike outputs (uo_out[7:0]): Each bit represents one neuron's spikes
- Watch voltage state (uio_out[7:0]): Shows membrane potential of first neuron
- Run different patterns to see:
- Wave propagation
- Synchronization
- Burst patterns
- Clustering effects
Test sequence:
- Apply reset (rst_n)
- Enable system (ena)
- Set desired pattern and current
- Monitor outputs for expected behavior
External hardware
N/A.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | Pattern select bit 0 (LSB) | Spike output from neuron 0 | Coupling strength bit 0 (LSB) |
| 1 | Pattern select bit 1 | Spike output from neuron 1 | Coupling strength bit 1 |
| 2 | Pattern select bit 2 (MSB) | Spike output from neuron 2 | Coupling strength bit 2 |
| 3 | Base current scaling bit 0 (LSB) | Spike output from neuron 3 | Coupling strength bit 3 |
| 4 | Base current scaling bit 1 | Spike output from neuron 4 | Coupling strength bit 4 |
| 5 | Base current scaling bit 2 | Spike output from neuron 5 | Coupling strength bit 5 |
| 6 | Base current scaling bit 3 | Spike output from neuron 6 | Coupling strength bit 6 |
| 7 | Base current scaling bit 4 (MSB) | Spike output from neuron 7 | Coupling strength bit 7 (MSB) |