Effect of Smelling Green Tea Rich in Aroma Components on EEG Activity and Memory Task Performance

Abstract

We investigated the memory task performance and the central nervous activity after smelling two kinds of pan-fired Japanese green tea to examine their physical and psychological effects. Twenty eight subjects participated in this study. We used Koushun and Kouju for test samples, which were made by different manufacturing processes. After smelling each odor sample, a memory task and an arithmetic task were used to test mental stress. Electroencephalogram (EEG) was recorded before and after smelling the test samples, and EEG activity was estimated for 4 frequency bands (alpha 1, alpha 2, beta 1 and beta 2). The profiles of mood states (POMS) and the visual analog scale (VAS) after mental stress task were completed for subjective assessments. The results showed that the odor of Kouju may induce a positive emotion. It may also affect the EEG band power of beta 1 at right frontal region and improve memory task performance.

The Sample Size Matters: To What Extent the Participant Reduction Affects the Outcomes of a Neuroscientific Research. A Case-Study in Neuromarketing Field

“…The power-supply interference was removed with a notch filter at 50Hz. Moreover, signals were bandpass filtered by a 5th-order Butterworth filter [2,30] Hz) in order to remove interferences in frequencies not of interest. Independent component analysis (ICA) was then performed, in particular by employing the SOBI algorithm [37], to remove Independent Components related to ocular and muscular activity.…”

“…In fact, thanks to the increasing shared knowledge and recent scientific evidence produced by the neuroscientific community, behavioural neuroscience is experiencing an exponential growth in terms of applied research [13][14][15]. Recently, new terms have been coined, such as Neuroergonomics, Neuromarketing, Neuroaesthetics, and others, to include the new neuroscientific disciplines that aim at investigating neurophysiological correlates of humans' behaviour at work [16][17][18], including driving a car [19][20][21][22][23][24], watching television [25][26][27], having a sensorial experience [28][29][30], and in any other activity of daily life. In the context of applied neurosciences, when physiological signals are acquired in real environments, several factors work against the ease of participant recruitment.…”

“…This number was deemed appropriate to assume the results were reliable, i.e., representative of the theorical population, in line with the scientific literature [32]. These subgroups were chosen since: (i) in the literature there is a large consensus considering [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] the optimal range of participants in neuroimaging studies [33]; (ii) in order to perform Analysis of Variance, the number of cases (i.e., 630) has to be much higher than the number of groups (i.e., five). The experimental task consisted of watching four TV spots with different lengths (30,30,20, and 15 s) during which electroencephalographic (EEG) signal and autonomic measures, i.e., heart rate (HR) and galvanic skin response (GSR), were acquired.…”

“…These subgroups were chosen since: (i) in the literature there is a large consensus considering [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] the optimal range of participants in neuroimaging studies [33]; (ii) in order to perform Analysis of Variance, the number of cases (i.e., 630) has to be much higher than the number of groups (i.e., five). The experimental task consisted of watching four TV spots with different lengths (30,30,20, and 15 s) during which electroencephalographic (EEG) signal and autonomic measures, i.e., heart rate (HR) and galvanic skin response (GSR), were acquired. The data analysis explored the correlation and the error between the outcomes for the total sample size and the considered subgroups of subjects.…”

Influence of Fragrances on Human Psychophysiological Activity: With Special Reference to Human Electroencephalographic Response

“…Watanabe et al [63] found that impaired higher-order olfactory processing in temporal lobe epilepsy patients may inhibit the effects of the ylang-ylang aroma on the P300. Yoto et al [103] investigated the memory task performance and the central nervous activity after smelling two kinds (Koushun and Kouju) of pan-fired Japanese green tea to examine their physical and psychological effects. The results showed that the odor of Kouju may induce a positive emotion.…”