Alpha peak frequency affects visual performance beyond temporal resolution

Recent work suggests that the individual alpha peak frequency (IAPF) reflects the temporal resolution of visual processing: individuals with higher IAPF can segregate stimuli at shorter intervals compared to those with lower IAPF. However, this evidence mainly comes from studies focusing on short intervals, with stimulus onset asynchronies (SOA) rarely extending beyond a single alpha cycle (e.g., ~100 ms). Here, we investigated the relationship between IAPF and performance in visual backward masking (VBM), which allowed us to test the effects of IAPF for longer SOAs than an alpha cycle. A group of healthy controls (N = 79) and schizophrenia patients (N = 121), who generally exhibit lower IAPF, were tested in conditions with a Vernier shown alone, a Vernier followed by a mask at two SOAs (30 and 150 ms), or only a mask. Our results show that IAPF can predict VBM performance in all conditions with a Vernier. Furthermore, in both the control and schizophrenia groups, individuals with higher IAPF showed reduced masking effects, even when the SOA of 150 ms exceeded the alpha cycle. These findings challenge the notion that IAPF is exclusively related to temporal resolution and visual processing within a single alpha cycle. We discuss alternative mechanisms by which IAPF determines visual performance.