Age-related changes in the neural gating of respiratory sensations in humans

Abstract

IntroductionNeural gating of respiratory sensations (NGRS) characterizes the brain's ability to filter out repetitive respiratory sensory stimuli. This mechanism plays a crucial role in the neural processing of respiratory stimuli. However, whether aging affects the NGRS in healthy adults is still unclear. Therefore, we aimed to measure the effect of age on NGRS as well as the corresponding S1 and S2 components of the respiratory-related evoked potentials (RREP).MethodsThree age groups of healthy adults participated in this study: a young group (YG, 20–39 years), a middle-aged group (MG, 40–59 years), and an old group (OG, =/>60 years). NGRS was measured by the RREP in the electroencephalogram in response to short-paired respiratory occlusion stimuli (S1 and S2). The S2/S1 ratio of the RREP N1 amplitude (the negative deflection of the RREP at approximately 85–135 ms), was used to characterize NGRS.ResultsThe results showed a significantly smaller N1 S2/S1 ratio in YG than in MG (p=0.01) and OG (p=0.03). Further analysis showed that the S1 N1 amplitude was larger for the YG compared to the MG (p=0.03) and OG (p=0.007). Moreover, age was significantly correlated with the N1 S2/S1 ratio (r=0.43), with higher age relating to higher N1 S2/S1 ratios.ConclusionsThe greater N1 S2/S1 ratios observed in older adults suggest that aging has a negative impact on the neural gating of respiratory sensations. This might contribute to increased experiences of respiratory sensations such as dyspnea in aging adults.