Orthonasal olfactory blockage determines the neural reorganization in the brain: first minutes

Title

Orthonasal olfactory blockage determines the neural reorganization in the brain: first minutes

Introduction

We aim to conduct a neurophysiological study of neocortical mechanisms for the effects of olfactory sensation on functional activity of human brain under temporary obstruction of nasal breathing as model of olfactory dysfunction.

Methods

123 healthy volunteers participated in this study. EEG was registered during the rest state (5 min), olfactory blockage (5 min), under odor stimulation with the lemon essential oil (5 min) and renewal of nasal breathing (5 min).

Results

The onset of orthonasal olfactory sensory blockage was accompanied by an increase in the power of processes of local synchronization of beta frequency in the caudal regions of the brain, with simultaneous enhancement of the coherence of the theta band in parietal-occipital zones and a certain enhancement of the interfrontal and intrahemispherical left-side and right-side interactions in the beta2-subband. Thus, the sudden cessation of olfactory detection led to activation of thalamo-cortical loops and top-down control systems (search for the olfactory signal). The prolongation of the nasal blockage, despite the possibility of activation of the retronasal route of odor perception and odorized air, was accompanied by a definite inhibition of distant interactions in the posterior regions of the brain in the 0-band and a significant decrease in right-brain long-distant and parietooccipital beta2-subband functional connectivity.

Conclusion

Restoration of nasal breathing and olfactory perception is accompanied by sufficiently powerful activation of interhemispheric long and short distance information interactions in the thetal,2 and betal frequency bands, which indicated an increase in cognitive activity of the brain - the development of memory processes, focusing attention.