ABSTRACT

A number of attempts has been made to unravel the effects of natural essential oils (EOs) and fragrances on the human central nervous system (CNS). Among these attempts, two major lines of research have been followed to identify psychoactive, particularly stimulating and sedative, effects of fragrances. On the one hand, researchers have investigated the inuence of EO and fragrances on brain potentials that are indicative of the arousal state of the humans by means of neurophysiological methods. On the other hand, behavioral studies have elucidated the effects of EOs and fragrances on basic and higher cognitive functions, such as alertness and attention, learning and memory, or

12.1 Central Nervous System Effects of Essential Oils in Humans ............................................. 345 Eva Heuberger 12.1.1 Introduction .............................................................................................................. 345 12.1.2Activation and Arousal: Denition and Neuroanatomical Considerations ..............348 12.1.3 Inuence of Essential Oils and Fragrances on Brain Potentials Indicative of Arousal.... 349

12.1.3.1 Spontaneous Activity in the Electroencephalogram (EEG) ...................... 349 12.1.3.2 Contingent Negative Variation ................................................................... 353

12.1.4Effects of Essential Oils and Fragrances on Selected Basic and Higher Cognitive Functions.................................................................................................. 354 12.1.4.1Alertness and Attention ............................................................................. 355 12.1.4.2 Learning and Memory ............................................................................... 358 12.1.4.3 Other Cognitive Tasks................................................................................360