Detection threshold for inspiratory resistive loads and respiratory-related evoked potentials

Abstract

The relationship between detection threshold of inspiratory resistive loads and the peaks of the respiratory-related evoked potential (RREP) is unknown. It was hypothesized that the short-latency and long-latency peaks of the RREP would only be elicited by inspiratory loads that exceeded the detection threshold. The detection threshold for inspiratory resistive loads was measured in healthy subjects with inspiratory-interruption or onset load presentations. In a separate protocol, the RREPs were recorded with resistive loads that spanned the detection threshold. The loads were presented in stimulus attend and ignore sessions. Onset and interruption load presentations had the same resistive load detection threshold. The P(1), N(f), and N(1) peaks of the RREP were observed with loads that exceeded the detection threshold in both attend and ignore conditions. The P(300) was present with loads that exceeded the detection threshold only in the attend condition. No RREP components were elicited with subthreshold loads. The P(1), N(f), and P(300) amplitudes varied with resistive load magnitude. The results support the hypothesis that there is a resistive load threshold for eliciting the RREPs. The amplitude of the RREP peaks vary as a function of load magnitude. The cognitive P(300) RREP peak is present only for detectable loads and when the subject attends to the stimulus. The absence of the RREP with loads below the detection threshold and the presence of the RREP elicited by suprathreshold loads are consistent with the gating of these neural measures of respiratory mechanosensory information processing.

Cortical Processing of Respiratory Occlusion Stimuli in Children with Central Hypoventilation Syndrome

“…P1 amplitude is correlated with stimulus intensity (20,22), and with load magnitude estimation (22,25). Occurring at approximately the same time as P1, but…”

“…A P300 response is a frequent response to inspiratory occlusion stimuli (14-16, 21, 22, 26) even when subjects are not asked to attend to the stimuli (12). As with the P1 and Nf, the P300 only occurs when the stimulus intensity exceeds detection threshold (20), and is believed to represent a higher level of cognitive processing of the stimulus following the integration of lower-order sensory features.…”

“…In non-REM sleep, the RREP waveform consists of a series of late components: the P2, N350, N550, and P900 (12,16,20,23,24,27,28). In adults, the response is dominated by the N550 response (12,16,27,28); in children, the predominant component is the earlier N350 (23,24).…”

“…The RREP method provides a unique way to investigate the neural integration mechanisms mediating respiratory load perception during both wakefulness (4,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and sleep (12,14,16,23,24).…”

Reprint of “Breathing and sense of self: Visuo-respiratory conflicts alter body self-consciousness”

“…During quiet breathing in healthy individuals, a refined sensorimotor network permanently monitors the state of the respiratory system, but this information is gated out and quiet breathing normally does not give rise to any conscious perception (Chan and Davenport, 2008;Davenport et al, 2007;Davenport and Vovk, 2009). Increases in respiratory-related afferent traffic above the gating threshold generate respiratory sensations.…”