Master Thesis MSTR-2026-41

BibliographyAhuja, Priyanka Sanjeevkumar: Evaluating Temporal Dimensionality Reduction Methods for ERP-Structured EEG Data.
University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Master Thesis No. 41 (2026).
84 pages, english.
Abstract

Electroencephalographic (EEG) data is a high-dimensional, noisy time series capturing the continuous evolution of neural response patterns. Dimensionality reduction methods such as Principal component analysis (PCA) and T-distributed Stochastic Neighbor Embedding (tSNE) have been used to analyze such data; however, they group time points by amplitude similarity rather than temporal order, making them unable to preserve the sequential structure. Existing time-aware approaches, such as Temporal-Potential of Heat-diffusion for Affinity-based Trajectory Embedding (T-PHATE) and Brain-dynamic Convolutional-Network-based Embedding (BCNE), address this by explicitly encoding temporal autocorrelation into the embedding, yet both have only been demonstrated on continuous recordings such as fMRI and not on epoched ERP-structured Electroencephalography (EEG) data. This study addresses this research gap and evaluates time-aware dimensionality reduction methods on Event-related Potentials (ERP) structured EEG data, investigating whether temporal awareness yields more meaningful embeddings than time-agnostic approaches. ERP components were simulated using the UnfoldSim package, and T-PHATE and BCNE were evaluated along with standard methods under two approaches: condition-averaged input and single-trial projection via grand average. The results show that T-PHATE and BCNE recover temporally ordered trajectories with condition-specific divergences, while time- agnostic methods yield fragmented embeddings. These findings suggest that time-aware methods offer a more faithful representation of ERP data and can be used for exploratory analysis of complex experimental designs

Department(s)University of Stuttgart, Institute of Visualisation and Interactive Systems, Visualisation and Interactive Systems
Superviser(s)Ehinger, Jun.-Prof. Benedikt; Mikheev, Vladimir
Entry dateAugust 13, 2026
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