Neural-behavioral dissociation under acute high-altitude stress: an exploratory ERP study of non-specific neural recruitment and rTMS effects.

Abstract

Objective: Acute high-altitude hypobaric hypoxia impairs executive functions, yet the dynamic relationship between behavioral performance and neuroelectric activity remains unclear. This study aimed to explore the neural compensatory mechanisms underlying cognitive dysfunction induced by high-altitude stress and to conduct an exploratory investigation of the potential modulatory effects of repetitive transcranial magnetic stimulation (rTMS).

Methods: Thirty-one healthy adults completed a Flanker task while undergoing EEG recording at three time points in a repeated-measures design: at baseline (G1), immediately after 24 h of simulated high-altitude hypobaric hypoxia (3,600 m; G2), and after three consecutive days of active 1 Hz repetitive transcranial magnetic stimulation (rTMS) applied to the right dorsolateral prefrontal cortex (DLPFC) (G3). We analyzed behavioral (reaction time, accuracy) and event-related potential (N2, P3 amplitude) outcomes. Importantly, we calculated conflict effect difference scores (ΔN2, ΔP3) to isolate neural activity specific to conflict processing.

Results: Reaction times were significantly faster at G2 and G3 than at G1 (p < 0.001), with accuracy remaining stable. N2 and P3 amplitudes were significantly enhanced at G2 and G3 relative to G1 (all p < 0.05). ΔN2 did not differ across time points, whereas ΔP3 showed a transient increase from G1 to G2 (p < 0.01) and returned to baseline at G3. As an exploratory study without a sham control, causal interpretations are limited, but the findings reveal clear dissociation between overall neural activity and conflict-specific processing.

Conclusion: Acute high-altitude stress increases neural activity related to conflict monitoring and attentional allocation. This enhancement reflects non-specific neural recruitment rather than improved specificity in conflict processing. Exploratory observations indicate that rTMS further elevates P3 amplitude without selectively modulating conflict-specific responses. Conflict effect scores (ΔN2, ΔP3) show promise as sensitive markers for evaluating neurocognitive states under hypoxic stress.