On Earth, although we no longer depend on our sense of smell for survival, the " flavour " of our food and drink comes primarily from our sense of smell. In Space, astronauts report a significant degradation of sense of smell and taste in long term flight. Clinical research on aromatherapy measures physiological and behavioural responses including EEG alpha wave band fluctuation patterns and cardiac response patterns. Studies show an anatomical link between the nose and brain as one of the most direct compared to other senses. We perceive, we feel, and subconsciously we define our optimum comfort zone. Aromatic scents, ointments and solutions impact memory, emotion and attention. The author reviews the action mechanisms of aromatics on human physiology to recognize neurophysiological and psychophysiological benefits as well as limit of use. Several applications using aromatic plants modalities are suggested to further develop the design of Space horticulture units and devices.
Human performance deterioration in extreme conditions challenges the viability of critical scenarios during a space mission. Exposure to space flight environment, including microgravity appears to increase the stress on the sensory-motor controls regulatory system in the brain because it is calibrated to operate under gravity. Any pre-existing central dysfunction can allow an input overload which can cascade to and alter other related functions down the functional hierarchy, such as physical (fine postural control, coordination and dexterity, strength, reaction time, fatigue, space perception/orientation) cognitive(trajectory control, attention and vigilance, time awareness, decision making, concentration, and memory), and emotional (motivation, self-control, calmness/aggressiveness). This phenomenon has direct influence on an individual's tendency for "error proneness". An objective and reproducible assessment and measurement methodology based on 18 years of observation and experience in medical neurophysiology allows pre-mission detection of such dysfunction. Paradigms, sensory-motor regulatory controls mechanisms, key test parameters, and clinical application are reviewed and briefly discussed.
Posture and gait controls underlie the fundamental physical and cognitive human factors necessary for astronauts' safety and performance in Space. This central subsystem is adversely affected when exposed to an extreme or hostile environment. A specific stimulation, using dermal optical sensitivity, can be provided to the central nervous system to counteract peripheral stimulations due to microgravity as well as other negative stressors. We believe using dermal optical sensitivity-based stimulation can be key in the performance enhancement necessary to ensure human based space mission viability and success.
The effects of two fragrance oils on the human central nervous system (CNS) were studied using neurophysiological measurements. Twenty healthy volunteers inhaled either lavender or jasmine following a fragrance-free session. Lavender increased auditory reaction time and slowed critical flicker fusion frequency irrespective of the subjects' preference. Prolongation of coefficient of variation of R-R intervals were noted only in those who liked the fragrance, regardless of the inhaled fragrance. The fragrance-specific characteristic changes were noted on quantitative EEG; a decrease of fast activity during lavender inhalation, and a decrease of slow activity during jasmine. At the same time, the subjects' liking influenced the EEG changes. The effects of fragrance oils must be considered from two significant factors: psychological and physiological.
The consumption of foods and beverages is inseparably linked to the stimulation of the human chemical senses, odor and taste. The sensation of odor (smell) is triggered by highly complex mixtures of small, rather hydrophobic molecules from many chemical classes that occur in trace concentrations and are detected by receptor cells of the olfactory epithelium inside the nasal cavity. The nonvolatile chemical messengers of the sense of taste interact with receptors located on the tongue and impart, though not limited by polarity or molecular size, four basic impressions only: sweet, sour, salty, and bitter. Also perceived inside the oral cavity, but transmitted to the brain by nonspecific and trigeminal neurons, are pungent, cooling and hot principles.
Rapidly increasing knowledge about the high complexity of food aromas requires selection or ranking procedures as to the importance of the particular components for flavour impression. For this purpose the concept of aroma values has been discussed which calculates quantitative data in connection with aroma effectiveness of the compounds. The simplification of the concept with respect to the practical application, however, can change the natural system and lead to erroneous conclusions. There are not only interactions between aroma substances of sensoric-physiological character which may not be ignored. Physical conditions like lipid content, distribution of aroma compounds between aqueous and lipid phase or the sorption of volatile substances to the polymer nutrients in foodstuffs are of influence, too.