Cross-modal relationships of neural gating with the subjective perception of respiratory and somatosensory sensations.

Abstract

Neural gating is a phenomenon whereby the response to a stimulus in the electroencephalogram (EEG) is attenuated when preceded by an identical stimulus. Attenuation of paired auditory clicks has repeatedly been shown to be affected in mental disorders, for example, schizophrenia. Neural gating has also been measured for respiratory and somatosensory sensations, however the attenuation of bodily relevant stimuli has not yet been systematically related to the subjective perception of bodily sensations. This research direction is potentially relevant to explaining disease trajectories in psychosomatic conditions characterized by chronic breathlessness and/or pain. In the present study, we recorded high-density EEG from 85 healthy young adults while they experienced brief paired respiratory occlusions and brief paired electrocutaneous stimulation of the wrist. The event-related potential N1 was measured centro-laterally in response to the second relative to the first stimulus to quantify neural gating in both sensory domains. Participants experienced resistive loaded breaths and electrocutaneous stimuli of various intensities, rated their perceived intensity and unpleasantness, and performed magnitude estimation. Relationships of respiratory and somatosensory neural gating to the subjective intensity and unpleasantness of sensations, as well as the ability to discriminate sensations of varying intensities, were investigated intra-modally and cross-modally. We report significant relationships of the somatosensory neural gating to perceived intensity and unpleasantness of respiratory and somatosensory sensations, with the stronger neural gating relating to a stronger subjective intensity and unpleasantness. We discuss these unexpected findings through the lens of individual differences and different theoretical accounts on the origins of cortical attenuation of repetitive stimuli.