arXiv:2507.17224v1 Announce Type: cross Abstract: Extracellular recordings are brief voltage fluctuations recorded near neurons, widely used in neuroscience as the basis for decoding brain activity at single-neuron resolution. Spike sorting, which assigns each spike to its source neuron, is a critical step in brain sensing pipelines. However, it remains challenging under low signal-to-noise ratio (SNR), electrode drift, and cross-session variability. In this paper, we propose HuiduRep, a robust self-supervised representation learning framework that extracts discriminative and generalizable features from extracellular spike waveforms. By combining contrastive learning with a denoising autoencoder, HuiduRep learns latent representations that are robust to noise and drift. Built on HuiduRep, we develop a spike sorting pipeline that clusters spike representations without supervision. Experiments on hybrid and real-world datasets demonstrate that HuiduRep achieves strong robustness and the pipeline matches or outperforms state-of-the-art tools such as KiloSort4 and MountainSort5. These findings demonstrate the potential of self-supervised spike representation learning as a foundational tool for robust and generalizable processing of extracellular recordings.