SpikeMoE: Brain-Inspired Competitive Routing for Flexible Spiking Mixture-of-Experts
Organizations: School of Computer Science and Engineering, University of Electronic Science and Technology of China
Abstract
Spiking Neural Networks (SNNs) enable event-driven computation through biologically inspired dynamics at the neuronal scale, while Mixture-of-Experts (MoE) perform conditional computation through expert selection at the model scale. Integrating their strengths offers potential for flexible neural architectures. A key challenge, however, lies in designing an expert selection mechanism based on spiking activity. To address this, we introduce a spike-based k-WTA Router inspired by competition-inhibition observed in the hippocampal CA1 region. The router incorporates lateral inhibition and refractory period to select Top-K experts according to discrete spike counts. Building on this, we present SpikeMoE, a framework that integrates neuronal-scale spiking dynamics with model-scale expert selection. To address incomplete multisensory inputs in multimodal tasks, we further equip SpikeMoE with a two-stage missing-modality modeling module that combines empirical prototypes from an observed-modality pool with modality-specific learnable embeddings to construct missing-modality representations. Experiments on vision, language, and multimodal benchmarks demonstrate that SpikeMoE achieves state-of-the-art performance among the SNN baselines, matches or exceeds the performance of ANN counterparts, and maintains robustness across diverse missing-modality conditions. These results demonstrate a favorable trade-off between performance and energy efficiency, validating the integration of spiking dynamics with sparse expert computation and highlighting SpikeMoE as a promising approach to energy-efficient brain-inspired computing.
Figures & tables
| Methods | Architecture | Param (M) | Energy Con- sumption (mJ) | Time Step | Top-1 Acc (%) |
|---|---|---|---|---|---|
| Spikformer ( Zhou et al., 2022 ) | Spikformer-8-384 | 16.81 | 12.43 | 4 | 70.24 |
| Spikformer-8-512 | 29.68 | 18.82 | 4 | 73.38 | |
| Spikformer+SEMM ( Zhou et al., 2024 ) | Spikformer-8-384 | 16.05 | 11.50* | 4 | 72.86 |
| Spikformer-8-512 | 28.22 | 17.63* | 4 | 75.93 | |
| Spikformer-8-384 | 16.03 | 11.39 | 4 | 73.22 | |
| Spikformer+k-WTA Router | Spikformer-8-512 | 28.19 | 16.72 | 4 | 75.97 |
| Model | Energy (mJ) | Time | MNLI -m/mm | QQP F1 | QNLI | SST-2 | CoLA | STS-B | MRPC F1 | RTE | Avg. |
|---|---|---|---|---|---|---|---|---|---|---|---|
| BERT base ( Devlin et al., 2019 ) | 51.41 | / | 83.8/83.4 | 90.5 | 90.7 | 92.3 | 60.0 | 89.4 | 89.8 | 69.3 | 83.2 |
| BERT 3L ( Devlin et al., 2019 ) | 12.90 | / | 77.1/77.1 | 85.2 | 85.8 | 88.1 | 31.7 | 85.7 | 86.4 | 66.4 | 75.9 |
| Q2BERT ( Zhang et al., 2020 ) | / | / | 47.2/47.3 | 67.0 | 61.3 | 80.6 | 0.0 | 4.7 | 81.2 | 52.7 | 49.1 |
| ELMo ( Peters et al., 2018 ) | / | / | 68.6/- | 86.2 | 71.1 | 91.5 | 44.1 | 70.4 | 76.6 | 53.4 | 70.2 |
| SpikeBERT ( Lv et al., 2023 ) | 14.30 | 4 | 71.4/71.0 | 68.2 | 66.4 | 85.4 | 16.9 | 18.7 | 82.0 | 57.5 | 59.7 |
| LIF-BERT* ( Gerstner et al., 2014 ; Xing et al., 2024 ) | / | 4 | 35.4/35.2 | 0.0 | 50.5 | 50.9 | 0.0 | 0.0 | 81.2 | 52.7 | 34.6 |
| Missing Ratio | Metric | ANNs | SNNs | Ours | |||||
|---|---|---|---|---|---|---|---|---|---|
| ShaSpec ( Wang et al., 2023a ) | TF ( Zadeh et al., 2017 ) | mmFormer ( Zhang et al., 2022 ) | FuseMoE ( Han et al., 2024 ) | Weight Attention ( Liu et al., 2022 ) | SCA ( Guo et al., 2023 ) | S-CMRL ( He et al., 2025 ) | SpikeMoE | ||
| 0% | F1 | 41.78 0.64 | 43.28 0.36 | 50.22 0.20 | 57.02 0.39 | 50.41 0.44 | 46.95 0.21 | 49.01 0.29 | 59.59 0.23 |
| AUC | 65.08 0.39 | 64.48 0.51 | 74.62 0.49 | 77.26 0.20 | 72.09 0.38 | 70.33 0.46 | 73.94 0.50 | 78.48 0.34 | |
| 10% | F1 | 43.40 0.74 | 40.14 0.13 | 48.66 1.20 | 55.81 0.45 | 48.19 0.52 | 46.81 0.71 | 47.50 0.06 | 56.51 0.12 |
| AUC | 65.45 0.56 | 61.54 0.66 | 73.21 0.76 | 77.05 0.93 | 74.68 0.17 | 70.51 0.02 | 72.12 0.27 | 77.45 0.67 | |
| 20% | F1 | 39.15 0.13 | 42.64 0.30 | 48.51 1.15 | 53.42 0.58 | 47.46 0.02 | 47.43 0.29 | 47.35 0.35 | 53.73 0.92 |
| Testing Modality | Metric | ANNs | SNNs | Ours | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Video | Text | Audio | ShaSpec ( Wang et al., 2023a ) | TF ( Zadeh et al., 2017 ) | mmFormer ( Zhang et al., 2022 ) | FuseMoE ( Han et al., 2024 ) | Weight Attention ( Liu et al., 2022 ) | SCA ( Guo et al., 2023 ) | S-CMRL ( He et al., 2025 ) | SpikeMoE | |
| ✓ | ✓ | F1 | 41.27 0.81 | 34.96 0.72 | 48.25 0.11 | 30.51 2.53 | 25.75 0.53 | 47.55 0.56 | 48.86 0.34 | 69.56 0.23 | |
| AUC | 61.28 0.88 | 59.37 1.12 | 72.72 0.08 | 55.35 1.11 | 54.39 0.12 | 71.98 0.43 | 73.22 0.06 | 74.29 0.18 | |||
| ✓ | ✓ | F1 | 36.99 2.03 | 34.83 0.54 | 35.79 0.55 | 24.29 4.23 | 22.18 0.37 | 46.97 0.08 | 23.82 0.39 | 47.81 0.61 | |
| AUC | 55.79 2.53 | 57.87 0.32 | 52.21 0.31 | 56.24 1.96 | 50.45 0.08 | 68.56 0.23 | 51.55 0.28 | 69.04 0.18 | |||
| ✓ | ✓ | F1 | 43.72 1.64 | 37.25 0.53 | 45.53 0.33 | 20.68 2.14 | 49.40 0.23 | 19.18 0.47 | 48.09 0.21 | 49.47 0.38 | |
| Methods | Missing Ratio=50% | |
|---|---|---|
| F1 | AUC | |
| Fully k-WTA Router | ||
| w/o Lateral Inhibition | ||
| w/o Refractory Period | ||
| w/o Inhibition Strength | ||
Appendix figures & tables7 assets
Supplementary material from the paper’s appendix.
Appendix
| ANNs | SNNs | Ours | ||||||
|---|---|---|---|---|---|---|---|---|
| Metric | ShaSpec | TF | mmFormer | FuseMoE | WeightAttention | SCA | S-CMRL | SpikeMoE |
| Ops (M) | 21.73 | 48.42 | 1577.63 | 199.8 | 47.07 | 32.57 | 289.60 | 45.22 |
| Params | 2,177,406 | 4,211,331 | 11,373,315 | 243,543,180 | 131,585 | 264,192 | 2,685,729 | 2,472,370 |
| AUC | 55.60 0.12 | 60.49 0.80 | 61.87 0.67 | 67.28 0.28 | 65.81 0.05 | 64.49 0.43 | 65.71 0.43 | 67.30 0.71 |
| Energy (mJ) | 20.13 | 25.19 | 40.39 | 11.71 | 10.38 | 16.95 | 14.67 | 5.29 |
| Parameter | Value |
|---|---|
| Number of Expert | 4 for ImageNet-1K and GLUE, 6 for CMU-MOSI and CMU-MOSEI, 4 for UrbanSound8k-AV |
| Top-K Expert | 2 |
| Timesteps | 4 for ImageNet-1K, GLUE and UrbanSound8K-AV; 6 for CMU-MOSI and CMU-MOSEI |
| Learning Rate | 5e-5 |
| Hidden Size | 128 |
| MoE layers | 2 |
| Missing Ratio | Metric | ANNs | SNNs | Ours | |||||
|---|---|---|---|---|---|---|---|---|---|
| ShaSpec ( Wang et al., 2023a ) | TF ( Zadeh et al., 2017 ) | mmFormer ( Zhang et al., 2022 ) | FuseMoE ( Han et al., 2024 ) | Weight Attention ( Liu et al., 2022 ) | SCA ( Guo et al., 2023 ) | S-CMRL ( He et al., 2025 ) | SpikeMoE | ||
| 0% | F1 | 47.48 0.27 | 38.89 0.54 | 56.75 0.47 | 57.04 0.15 | 59.40 0.42 | 59.36 0.06 | 58.09 0.19 | 59.80 0.17 |
| AUC | 67.93 0.56 | 64.26 0.61 | 76.42 0.24 | 78.54 0.42 | 73.59 0.08 | 74.41 0.13 | 72.63 0.21 | 78.63 0.53 | |
| 10% | F1 | 47.41 0.18 | 34.94 1.10 | 55.37 0.47 | 55.90 0.55 | 54.97 0.35 | 56.81 0.35 | 56.23 0.32 | 56.83 0.23 |
| AUC | 69.26 0.22 | 61.05 0.34 | 75.36 0.53 | 76.38 0.39 | 72.18 0.34 | 73.12 0.23 | 73.17 0.09 | 76.47 0.49 | |
| 20% | F1 | 46.54 1.04 | 35.37 0.94 | 52.91 0.75 | 54.44 0.27 | 53.14 0.17 | 54.21 0.11 | 52.84 0.45 | 54.35 0.57 |
| Testing Modality | Metric | ANNs | SNNs | Ours | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Video | Text | Audio | ShaSpec ( Wang et al., 2023a ) | TF ( Zadeh et al., 2017 ) | mmFormer ( Zhang et al., 2022 ) | FuseMoE ( Han et al., 2024 ) | Weight Attention ( Liu et al., 2022 ) | SCA ( Guo et al., 2023 ) | S-CMRL ( He et al., 2025 ) | SpikeMoE | |
| ✓ | ✓ | F1 | 40.75 0.14 | 31.38 0.61 | 56.02 0.56 | 55.85 0.69 | 33.34 0.28 | 52.80 0.76 | 55.62 0.34 | 56.25 0.32 | |
| AUC | 64.47 0.10 | 56.98 0.20 | 76.60 0.39 | 75.81 0.82 | 65.91 0.45 | 71.60 0.04 | 73.21 0.45 | 77.09 0.44 | |||
| ✓ | ✓ | F1 | 38.15 0.92 | 31.73 0.16 | 37.12 0.66 | 49.30 0.67 | 22.00 0.49 | 29.01 0.04 | 22.10 0.20 | 49.50 0.36 | |
| AUC | 58.41 0.10 | 58.41 0.17 | 56.72 0.84 | 56.32 0.62 | 50.91 0.57 | 51.26 0.25 | 50.30 0.06 | 57.08 0.24 | |||
| ✓ | ✓ | F1 | 40.82 0.12 | 31.86 0.23 | 56.06 0.29 | 57.02 0.60 | 56.06 0.48 | 33.90 0.21 | 21.93 0.83 | 58.53 0.02 | |