Сentral mechanisms of neural reorganization under short-term olfactory deprivation

Title Central mechanisms of neural reorganization under short-term olfactory deprivation. Introduction The aim of the study was to investigate the neurodynamics of the human brain during intellectual load under passive perception of trigeminal agent (ammonia). Methods 51 healthy volunteers (male and female students aged 18 to 23 years with no documented manifestations of rhinal pathologies) participated in this study. EEG was registered over a period of 9 minutes during the rest state and 6 minutes during mental arithmetical subtraction under odor stimulation with ammonia. We estimated the spectral power density (SPD) and the levels of coherence of all the frequencies from 0.2 to 35 Hz. Results Odor stimulation with ammonia resulted in generalized activation (depression of low frequency components and partial activation of beta2--subband) and increased levels of cortical integration in theta2-, alphal-, alpha3-and beta2-subbands (mainly in the posterior cortex). We did not observe any pronounced adaptation to the smell during the action of ammonia. We also found that activation of trigeminal chemosensory system did not lead to any deactivation processes in the neocortex. Conclusion Neurodynamics of brain processes in this case likely reflected the interaction of brain systems that exert upstream and downturn control. Perceptions of ammonia did not alter cognitive task-specific reorganization of EEG, but activation processes during intellectual load were less marked in comparison to those in control: we observed strongly pronounced increase of alpha2-subband in the frontal-temporal brain regions during the mental load under stimulation with ammonia.