Petri Net Description of Biological Neural Circuits for Fast Hardware Prototyping
Authors: Carlo daCunha, Rodrigo Pena, Marcos Turqueti
Organizations: Helen and John C. Hartmann Department of Electrical Engineering, New Jersey Institute of Technology, 323 Martin Luther King Jr. Blvd., Newark, 07102, NJ, USA. · School of Applied Engineering and Technology, New Jersey Institute of Technology, 323 Martin Luther King Jr. Blvd., Newark, 07102, NJ, USA. · Department of Biological Sciences, Florida Atlantic University, 5353 Parkside Drive, Jupiter, 33458, FL, USA. · Electronic Systems Group, Lawrence Berkeley National Laboratory, 1 Cyclotron Road., Berkeley, 94720, CA, USA.
Current approaches to simulating biological neural circuits, whether on general-purpose hardware or dedicated neuromorphic platforms, remain constrained by fixed-timestep numerical integration, hardware-imposed precision limits, and an inability to guarantee timing correctness for event-driven spiking dynamics under real-time constraints. Here, we propose a Petri net description of biological neural circuits that overcomes these limitations by modeling neurons, synapses, and spike events as a T-timed Petri net with formally verifiable timing semantics, enabling deadline-guaranteed real-time execution and analytically tractable correspondence to continuous-time leak-integrate-and-fire dynamics, independent of the underlying integration timestep. To test the model, we present the results of three simulated microcircuits: feedback inhibition, lateral inhibition, and hierarchical feature detector. The Petri neuron reproduces the expected dynamical signatures of each circuit while providing formally bounded timing guarantees throughout, with worst-case response times matching analytical predictions across all three cases.
Figures & tables
Figure 1: Phases of a biological action potential. Depolarization (rapid voltage rise past threshold), repolarization (voltage returns toward rest), hyperpolarization (transient overshoot below resting potential), and the subsequent return to rest via ionic pump activity. The refractory period spans repolarization and hyperpolarization, during which the neuron is unresponsive (absolute) or requires elevated excitation to fire (relative). This cycle motivates the input-gating, threshold-firing, and recovery transitions of the Petri neuron in Fig. 2 .
Figure 2: Petri net representation of the Petri neuron, mapping accumulation, threshold firing, axonal propagation, and refractory recovery onto places and transitions.
Tinput
Tspike
Tprop
Trec
Tleak
pacc
1/0/+1
0/θ/−θ
0/0/0
0/0/0
0/1/−1
prdy
0/0/0
0/1/−1
0/0/0
1/0/+1
0/0/0
ppre
0/0/0
1/0/+1
0/1/−1
0/0/0
0/0/0
pout
0/0/0
0/0/0
1/0/+1
0/0/0
0/0/0
prec
0/0/0
1/0/+1
0/0/0
0/1/−1
0/0/0
Table 1: Incidence matrix with entries C+/C−/C . θ denotes the current token count of pacc at firing time (flush arc).
Figure 3: Firing rate as a function of input excitation I/Ith for the LIF model (Eq. 3 ) and the Petri neuron (Eq. 5 ), parameterized via the Padé mapping. Agreement is close for spontaneous and moderate firing ( f<50 Hz), with relative error shrinking further as I increases into the high-frequency regime.
Machine
Nom. (ms)
Mean
Std
p99
ϵ (max)
AMD
1
9.7
2.3
16.9
95.9
5
171.4
221.6
717.2
901.9
10
207.4
227.7
728.2
917.7
50
198.6
234.7
728.6
885.0
100
252.0
240.8
730.0
905.3
RP2040
1
0.03
0.17
1.00
1.00
Table 2: AMD Linux POSIX timer and RP2040 time jitter. All values in μ s. ϵ denotes the worst-case absolute error ( N=10,000 ).
Figure 4: Feedback inhibition network. Chevron indicates an excitatory synapse, while the small black disks indicate inhibitory synapses.
Parameter
E
I
R [M Ω ]
30–60
337
C [ ×10−10 F]
1.3–4
0.44–0.74
τ [ms]
8–12
15–25
L [mm]
1–3
4–8
Table 3: Neuronal parameters of excitatory (E) and inhibitory (I) neurons in a typical feedback-inhibition network.
Figure 5: Inter-event interval histogram for the firing of E and I neurons in a feedback inhibition network simulated using Petri neuron.
Figure 6: Lateral inhibition microcircuit motif with excitatory neurons EA,B and inhibitory interneurons IA,B .
Figure 7: IEIH of excitatory neurons and their firing rates as a function of time.
Figure 8: The hierarchical feature detector consisting of a 2×2 grid, simple neurons S that capture lines, and complex neurons C that indicate the presence of horizontal and vertical lines.
Spiking neural networks process information through discrete, time-dependent neural events, aiming for efficient computation and biologically inspired learning.
Department of Mathematics, Ludwig-Maximilians-Universität München · Munich Center for Machine Learning · Departments of Mathematics and Statistics & Data Science, University of California, Los Angeles +2
Instituto de Microelectrónica de Barcelona (IMB-CNM), Consejo Superior de Investigaciones Científicas (CSIC) Cerdanyola del Vallès, Spain · Department of Neurobiology, University of California Los Angeles (UCLA) Los Angeles, USA · Joint Senior authors
RAMLab, Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester NY, USA · Iontronic and Nanoelectronics Lab, School of Physics and Astronomy, Rochester Institute of Technology, Rochester NY, USA · Brain Lab, Department of Computer Engineering, Rochester Institute of Technology, Rochester NY, USA