Association between cerebral hemodynamics low‐frequency oscillations and working memory load: A noninvasive optical mapping study

Abstract In human cerebral hemodynamics, low‐frequency oscillations (LFOs) occur due to the sympathetic nervous system and blood pressure regulation. LFOs have recently been reported to be associated with cognitive‐behavioral performance, though their functional relevance to cognitive load remains unclear. Here, we employed functional near‐infrared spectroscopy to record changes in oxygenated (Δ[oxy‐Hb]) and deoxygenated (Δ[deoxy‐Hb]) hemoglobin concentrations in the prefrontal cortex (PFC) of 47 healthy young adults (aged 18–23) during N‐back working memory tasks and extracted LFOs from the cerebral hemodynamic data to study their relationship with working memory load. Increasing the task load led to a marked decrease in both LFO power and LFO peak amplitude of Δ[oxy‐Hb], alongside an increase in LFO peak frequency and PFC activation, revealing a load‐dependent feature of cognitive engagement. Correlations between LFO power and behavioral performance, including accuracy and response time, were observed. LFOs and their characteristic parameters exhibited a strong effect on working memory load, indicating the potential of LFOs in cerebral hemodynamics as a sensitive marker for quantifying the cognitive load effect of brain activity.