PT  - JOURNAL ARTICLE
AU  - Proix, Timothée
AU  - Perich, Matthew G.
AU  - Milekovic, Tomislav
TI  - Interpreting dynamics of neural activity after dimensionality reduction
AID  - 10.1101/2022.03.04.482986
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.03.04.482986
4099  - http://biorxiv.org/content/early/2022/03/07/2022.03.04.482986.short
4100  - http://biorxiv.org/content/early/2022/03/07/2022.03.04.482986.full
AB  - Recorded activity of cortical neurons during behavior is often analyzed with dimensionality reduction methods. The resulting oscillatory trajectories have been interpreted as signatures of latent oscillatory dynamical systems. Here we show that oscillatory trajectories arise as a consequence of the horseshoe effect after applying dimensionality reduction methods on signals that approximately exhibit continuous variation in time, regardless of whether latent oscillatory dynamical systems are present or not. We show that task-relevant information is instead contained in deviations between oscillatory trajectories, which we account for by introducing a new model that goes beyond the dichotomy between representational and dynamical systems models of neural activity. Our findings help interpret the results of dimensionality reduction analyses.Competing Interest StatementThe authors have declared no competing interest.