Spectral Clustering of Low-Frequency Fluctuations in FMRI Data Reveal a Distinct Separation Between the Superior Temporal Sulcus and the Superior Temporal Gyrus

Gabriele Lohmann¹, Jonas Obleser¹, Angela Friederici¹, Robert Turner¹

Low Frequency Fluctuations (LFFs) are known to represent a large portion of the variance of the BOLD signal. Furthermore, such fluctuations generally have significant spatial coherence. Task-dependent condition-locked fMRI data has confirmed an important role of the superior temporal cortex in many language and hearing related processes. Within this area, many studies have claimed to identify activation distinct to superior temporal gyrus (STG) and superior temporal sulcus (STS). Using a data-driven clustering technique applied to LFFs, we found a clear separation between STS and STG that showed a high inter-subject consistency.