METHOD FOR MEASURING THE RESPONSE TO OLFACTIVE STIMULI

Abstract

The invention relates to a method of screening a fragrance or a flavouring using functional Magnetic Resonance Imaging to assess the ability of said fragrance or flavouring to elicit a “well-being” effect.

Claims

1. A method of identifying a fragrance or a flavouring which elicits a well-being effect, wherein the method comprises determining whether the Angular Gyrus is activated in subjects smelling said fragrance or said flavouring, wherein the determination includes taking fMRI brain scans of the subjects.

2. The method of claim 1, which further comprises determining whether the Frontal Inferior Cortex and/or the Frontal Medial Cortex is/are activated in subjects smelling said fragrance or said flavouring.

3. The method of claim 1, comprising: a) submitting a group of subjects to a first protocol comprising: having each subject of said group smell a control odour; capturing functional Magnetic Resonance Imaging (fMRI) brain scans of each subject smelling the control odour so as to detect the brain activity of each subject; b) submitting the same group of subjects to a second protocol comprising: having each subject of said group smell a fragrance or a flavouring to be tested; capturing fMRI brain scans of each subject smelling the fragrance or the flavouring to be tested so as to detect the brain activity of each subject; c) averaging the brain activity of all subjects as obtained in the first protocol and in the second protocol; and d) contrasting the resulting averaged brain activity obtained in the second protocol with the resulting averaged brain activity obtained in the first protocol and determining from the contrast a number of adjacent activated voxels in the Angular Gyrus; wherein if the number of adjacent activated voxels thus determined is equal to or greater than a threshold value, then the tested fragrance or the tested flavouring elicits a well-being effect.

4. The method of claim 3, wherein step d) further comprises determining from the contrast a number of adjacent activated voxels in the Frontal Inferior Cortex and/or the Frontal Medial Cortex, wherein additional confirmation that the tested fragrance or the tested flavouring elicits a well-being effect is obtained if the number of adjacent activated voxels thus determined is equal to or greater than said threshold value.

5. The method of claim 3, wherein steps c) and d) are respectively replaced by steps c1) and d1): c1) contrasting, for each subject, the brain activity obtained in the second protocol with the brain activity obtained in the first protocol whereby a number of adjacent activated voxels is determined; d1) averaging the resulting contrasted brain activity of all subjects.

6. The method of claim 3, wherein the control odour is air or an odourless perfumery solvent diluted in air.

7. The method of claim 3, wherein the group of subjects comprises at least 5, preferably at least 10 subjects.

8. The method of claim 3, wherein the threshold number of adjacent activated voxels is ten.

9. A method for preparing an accord or a fully formulated fragrance which comprises: a) identifying at least one fragrance which elicits a well-being effect by the method of claim 1; b) formulating said at least one fragrance thus identified into an accord or a fully formulated fragrance.

10. Use of a fragrance which elicits a well-being effect in a household product, a laundry product, a candle, a personal care product or a cosmetic product.

11. The use of claim 10, wherein the fragrance comprises one or more of orange oil, citrus oil, ethyl vanillin and nonalactone gamma.

12. A method for preparing a flavouring preparation, a food product, an oral care product or a beverage which comprises: a) identifying at least one flavouring which elicits a well-being effect by the method of claim 1; b) formulating said at least one flavouring thus identified into a flavouring preparation, a food product, an oral care product or a beverage.

13. Use a flavouring which elicits a well-being effect in a flavouring preparation, a food product, an oral care product or a beverage.

14. The use of claim 13, wherein the flavouring comprises one or more of orange oil, citrus oil, ethyl vanillin and nonalactone gamma.

15. The method of claim 4, wherein steps c) and d) are respectively replaced by steps c1) and d1): c1) contrasting, for each subject, the brain activity obtained in the second protocol with the brain activity obtained in the first protocol whereby a number of adjacent activated voxels is determined; d1) averaging the resulting contrasted brain activity of all subjects.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0040] The FIGURE represents a fMRI experimental block design used in the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0041] In one aspect, the present invention provides a method of identifying a fragrance or a flavouring which elicits a well-being effect, wherein the method comprises determining whether the Angular Gyrus is activated in subjects smelling said fragrance or said flavouring.

[0042] In some embodiments the method further comprises determining whether the Frontal Inferior Cortex and/or the Frontal Medial Gyrus Cortex is/are also activated in said subjects.

[0043] In some embodiments, the determination of the activation of the Angular Gyrus and optionally of the Frontal Inferior Cortex and/or the Frontal Medial Gyrus Cortex includes taking fMRI brain scans of the subjects.

[0044] In some embodiments the method comprises: [0045] a) submitting a group of subjects to a first protocol comprising: [0046] having each subject of said group smell a control odour; [0047] capturing functional Magnetic Resonance Imaging (fMRI) brain scans of each subject smelling the control odour so as to detect the brain activity of each subject; [0048] b) submitting the same group of subjects to a second protocol comprising; [0049] having each subject of said group smell a fragrance or a flavouring substance to be tested; [0050] capturing fMRI brain scans of each subject smelling the fragrance or the flavouring to be tested so as to detect the brain activity of each subject; [0051] c) averaging the brain activity of all subjects as obtained in the first protocol and in the second protocol; and [0052] d) contrasting the resulting averaged brain activity obtained in the second protocol with the resulting averaged brain activity obtained in the first protocol and determining from the contrast a number of adjacent activated voxels in the Angular Gyrus; wherein if the number of adjacent activated voxels thus determined (from the contrast) is equal to or greater than a threshold value, then the tested fragrance or the tested flavouring elicits a well-being effect.

[0053] In some embodiments, step d) further comprises determining from the contrast a number of adjacent activated voxels in the Frontal Inferior Cortex (FIC) and/or the Frontal Medial Cortex (FMC), wherein additional confirmation that the tested fragrance or the tested flavouring elicits a well-being effect is obtained if the number of adjacent activated voxels determined (from the contrast) in the FIC and/or the FMC is equal to or greater than the same threshold value as used for the Angular Gyrus.

[0054] Sniffing any odour elicits brain activity due to odour processing, which is detected by fMRI as detailed below. The present invention is based on the surprising finding that activation of the Angular Gyrus and optionally of the Frontal Inferior Cortex and/or the Frontal Medial Cortex, in response to smelling a fragrance or a flavouring is evidence that the odour is associated with a state of “well-being”.

[0055] The method of the invention comprises a first step, step a), where subjects within a group of subjects each smell a control odour and the brain activity of each subject is determined using fMRI. The group of subjects typically comprises at least 5 subjects, preferably at least 10 subjects. The control odour is preferably air or a solvent diluted in air. Any odourless solvent commonly used in fragrance or flavouring creation, e.g. di-propylene glycol, propylene glycol, MCT (Medium Chain Triglycerides) oil or triethyl citrate, can be used in the method of the invention. In some embodiments, the control odour can also be a fragrance or a flavouring as defined above (e.g. an individual material such as, for example coffee extract, or an accord or an existing fragrance or flavouring against which a new fragrance or flavouring is tested) which has been shown (using fMRI) not to activate the Angular Gyrus.

[0056] In a second step, step b), the same group of subjects smells a test fragrance or a test flavouring and the brain activity of each subject is again determined using fMRI.

[0057] The control odour and the fragrance or the flavouring are delivered to one of the subjects’ nostrils via an olfactometer. To avoid the nasal passages becoming dry, the control odour and the fragrance or flavouring are preferably humidified before being introduced into the nose.

[0058] In a third step, step c), the brain activity of all subjects having smelt the control odour is averaged, and the brain activity of all subjects having smelt the test fragrance or flavouring is also averaged.

[0059] In a fourth step, step d), the brain activities averaged in step c) for the test fragrance or flavouring and the control odour are contrasted. As a result of the contrast the number of adjacent activated voxels in 3D space, i.e. adjacent voxels with significantly different blood flow (or activity), namely voxels which pass student t-test (p<0.005 or more preferably p<0.001) in the brain area studied is determined. Voxels are typically cubes, or cuboids, measuring, for example, about 0.5 mm to about 7 mm per side. When voxels are adjacent to one another they typically form what is known as a cluster. The number of voxels in a cluster is referred to as the cluster size. To determine if a brain area has been activated, the number of adjacent activated voxels obtained from the contrast is compared to a threshold value. A threshold value of 10 is commonly used in fMRI research, for example see Liebermann and Cunningham, Soc Cogn Affect Neuroscience, 2009 Dec 4(4), p423.

[0060] Accordingly, in some embodiments the threshold value is 10. In some embodiments, the threshold value is 20. In some embodiments, the threshold value is 30. In some embodiments, the threshold value is 50.

[0061] If the number of adjacent activated voxels from the contrast of the test fragrance or the test flavouring with the control odour is equal to or greater than the threshold value, in the Angular Gyrus, then the tested fragrance or flavouring elicits a well-being effect.

[0062] Additional confirmation that a test fragrance or flavouring elicits a well-being effect can come from performing the same analysis to the Frontal Inferior Cortex and the Frontal Medial Cortex.

[0063] In some embodiments, steps c) and d) are respectively replaced by steps c1) and d1): [0064] c1) contrasting, for each subject, the brain activity obtained in the second protocol with the brain activity obtained in the first protocol whereby a number of adjacent activated voxels is determined; [0065] d1) averaging the resulting contrasted brain activity of all subjects.

[0066] A typical example of the overall experimental approach used is described below.

Subject Selection

[0067] It is required that subjects be able to read and write and have the capacity to provide informed consent. Potential subjects are excluded if they have current or past psychiatric disorder other than simple phobias but including substance abuse/dependence as determined by the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) (First et al, Structured clinical interview for DSM-IV axis I disorders - patient edition. SCID-I/P, Version 2.0. New York, Biometric Research Department: New York State Psychiatric Institute (1995)); a history of neurologic disease; a currently unstable medical condition; used psychotropic medication within 5 half-lives of the procedure time; any metal implants or shrapnel which would make an MRI procedure unsafe; irremovable medical devices such as pacemakers or fixed hearing aids; previous inability to tolerate an MRI procedure; or claustrophobia severe enough to induce substantial anxiety in closed spaces. Other exclusion criteria include age under 9 years, history of any disease known to have an impact on the olfactory function (e.g. Diabetes, Parkinson Disease, Renal failure, etc). A complete ENT (ear, nose and throat) examination excluded pathology that could interfere with the olfactory ability: acute or severe chronic rhinitis or sinusitis, severe septum deviation, history of trauma, nasal polyps, etc. Subjects also completed a handedness inventory for the participation in the experiment. It is preferred to avoid variations due to gender or handedness, so subjects are selected to comprise panels or groups of a single sex and having the same predominant hand.

[0068] Having passed the selection criteria above only normosmic subjects were selected for the test. Various tests are available commercially to ensure that subjects have a normal sense of smell. Such tests vary from odor identification tests to more sophisticated threshold and discrimination tests. Any suitable test should be validated and reliable. In the example given below a “Sniffin’ Sticks” test was used to assess the olfactory function. For further information on Sniffin Sticks see T Hummel et al. Sniffin Sticks: Olfactory Performance Assessed by the Combined Testing of Odor Identification, Odor Discrimination and Olfactory Threshold in Chem. Senses 1997 vol 22 pp39-52 or T Hummel et al. Screening Olfactory Function with a Four Minute Odor Investigation Test Reliability Normative Data and Investigations in Patients with Olfactory Loss in Ann. Otol. Rhinol. and Laryngol. 2001 vol 110 pp976-981. Sniffin Sticks are available from Burghardt Gmbh Wedel Germany. For odour presentation the cap is removed by the experimenter for approximately 3 s and the pen’s tip is placed approximately 2 cm in front of both nostrils. The odour identification test involves the assessment of 12 common odours (cinnamon, banana, lemon, liquorice, pineapple, coffee, cloves, rose, leather, fish, orange, peppermint). Using a multiple choice task, identification of individual odorants was performed from a list of 4 descriptors per odour. The interval between odour presentations was 20-30 s. All measurements were performed in a quiet, air-conditioned room. 10 or more correct responses were required for participation in the subsequent experiments.

Preparation of Test Samples

[0069] Test fragrances and test flavourings were prepared to have approximately equal olfactive intensity using an expert panel.

fMRI Scanner

[0070] Any suitable MRI device can be used to achieve the desired fMRI images, which is capable of operating using a spin echo, echo planar imaging (SE-EPI) sequence. This EPI protocol is optimized detecting subtle changes in blood oxygen levels in the brain over time. EPI scanning is an effective way to measure changes in the blood oxygen level dependent (BOLD) signal which has been shown to correlate reliably with changes in neural activity. Scans were taken which covered the whole brain allowing the continuous monitoring of the whole brain throughout each assessment. Suitable MRI scanners are available from Siemens AG, Phillips, GE Healthcare, Varian, Toshiba and Hitachi.

Olfactometer

[0071] Any olfactometer can be used, which is suitable for use with an fMRI scanner. Suitable olfactometer designs have been reported by Kobal (Electroencephalography and clinical neurophysiology 71, 241-250, 1988), Sobel (J. Neuroscience methods 78, 115-123, 1997) and Sommer et al (J. Neurosci. Methods 209, 189-194, 2012). Suitable commercial olfactometers are available from Burghart Medezintechnik GmbH of Wedel Germany. To minimize head movement odorants are applied intranasally by means of a canula with an inner diameter of 2-3 mm. This canula is inserted ~1 cm into the naris such that its opening lies beyond the nasal valve. Presentation of odourants does not simultaneously activate mechano- or thermoreceptors in the nasal mucosa, as odour pulses are embedded in a constantly flowing thermostatted (36° C.), humidified (80% RH) air stream (typically 1-8 l/min) which quickly becomes undetectable after a few minutes. Hence, subjects do not perceive any change when the olfactometer switches from a no-stimulus to a stimulus condition and vice versa, nor do subjects experience any interference from mechanical or thermal stimulation. Air flow rates are determined by mass-flow controllers, which along with switching valves, are computer-controlled. Thus, the equipment allows the setup of sequences of stimuli with different quality, intensity, duration, or interstimulus interval and multiple repetitions to achieve the maximum accuracy and precision in sample presentation.

Statistical Data Analysis

[0072] Methods for the statistical analysis of changes in brain activity are well known in the art and, for some brain activity measuring devices, computer software packages are commercially available which are specifically adapted to analyze the data. For example, SPECT, PET or MRI data can be analyzed using the Dot or EMMA (Extensible MATLABⓇ Medical image Analysis) packages which are both freely available from the MNI, or the Statistical Parametric Mapping (SPM) software package which is freely available from the Functional Imaging Laboratory of the Wellcome Department of Imaging Neuroscience at the University College of London, UK (www.fil.ion.ucl.ac.uk/spm/). The EMMA and SPM software are based upon the MATLABⓇ programming language (MathWorks, Inc., Natick, Mass.), with additional routines in the C programming language. An SPM module is incorporated into the commercially available MEDx software (Medical Numerics, Inc., Sterling, Va. USA).

[0073] The SPM software uses a parametric statistical model at each voxel, using a general linear model to describe the variability of the data in terms of experimental and confounding effects, and residual variability. Hypotheses expressed in terms of the model parameters are assessed at each voxel with univariate statistics. Temporal convolution of the general linear model for fMRI enables the application of results from serially correlated regression, permitting the construction of statistic images from fMRI time series. The multiple comparisons problem of simultaneously assessing all the voxel statistics is addressed using the theory of continuous random fields, assuming the statistic image to be a good lattice representation of an underlying continuous stationary random field. Results for the Euler characteristic lead to corrected p-values for each voxel hypothesis. In addition, the theory permits the computation of corrected p-values for clusters of k voxels exceeding a given threshold, and for entire sets of supra-threshold clusters, leading to more powerful statistical tests at the expense of some localizing power (see Friston et al., Magnetic Resonance in Medicine 35 346-355 1996 and citations thereof).

[0074] The statistical approach used to evaluate the general set of fMRI data is a time-series variant of the Analysis of Variance (ANOVA) form of a general linear model. The statistical analysis tests each voxel of the brain, for each subject, against the null hypothesis (that over the duration of the testing the rise and fall of the BOLD signal coming from that voxel does not correlate with the onsets and offsets of the cycles of presentation of odours). A weighted model is created that begins with a simple square wave type model of the on-off timing events for a single task variable of interest.

[0075] The ANOVA model allows regressors to be used to model nuisance variables. In the present invention, the global signal strength of the whole brain is used as such a regressor. The global signal strength of the brain will account for fluctuations in the brain caused by respiratory cycles, cardiac flow cycles, blinking etc. These signal variations occur across the whole brain and may often be a greater magnitude than the localized changes in the BOLD signal resulting from the olfactory signal. These signal variations occurring across the brain can be subtracted from the measured fMRI signals to show the signals resulting from the odour stimuli.

[0076] The resulting product of the ANOVA computation on a single-person’s fMRI data is a 3-dimensional matrix of t-values which can be represented as a 3-dimensional map. This t-value map can then be converted into a probability map (a map of corresponding p-values) and the results can be displayed graphically at whatever threshold is desired (e.g. p<0.005). The results may be overlain on a higher-resolution MRI image, in order to facilitate identification of finer-grained cortical structures.

[0077] In order to combine the data from more than one subject, each subject’s brain is first normalized into a common 3-dimensional stereotactic space before each individual’s t-map is computed. Then the value of the sum of the contrast weights for each voxel from each subject computed during the ANOVA (basically, the numerator of the t-statistic) is entered as a single data point in a new, “second-level” t-statistic computation. In this second-level computation, then, the mean value for each voxel across subjects is modeled as the effect term and the variance between subjects as the error term. An important consequence of this approach to keep in mind is that it is very unlikely that a voxel will show significant activation on the group-level map, unless virtually all of the subjects show activation at that voxel. Also, brain areas are only considered to be activated if a number of adjoining voxels (from the contrast) show a statistical significance above the designated probability standard.

[0078] For purposes of statistical analysis and graphical display, the raw data on brain activity is usually grouped into voxels corresponding to fixed volumes of the subject brain. The voxel size can be varied depending upon the resolution capability of the brain activity measuring device or the desired degree of precision in identifying brain regions. It should be noted, however, that smaller voxels have worse signal to noise ratios and greater susceptibility artifacts due to partial volume effects. Functional voxels are cubes, or cuboids measuring, for example, 0.5 mm to 7 mm per side (e.g., 2.4×2.4×3.0 mm.sup.3). The data can then be displayed graphically by colour-coding the voxels according to some statistical value and showing cross-sections in which levels of activity or changes in levels of activity are mapped in two-dimensions. By generating a series of such co-planar cross-sections, the entire brain volume can be mapped.

[0079] When conducting statistical analyses on brain images, investigators can select an appropriate probability value for assessing statistical significance. The particular value chosen can vary depending upon the purpose of the statistical analysis and the level of certainty required. In the studies described in the example the level for statistical significance was chosen to be p<0.001.

[0080] The method described above makes it possible to identify fragrances or flavourings which elicit a well-being effect through stimulation of the Angular Gyrus, and optionally stimulation of the Frontal Inferior Cortex and/or the Frontal Medial Cortex.

[0081] Accordingly, in another aspect the present invention relates to fragrances and flavourings identified by said method.

[0082] Such fragrances may be accords or fully formulated fragrances, or may be used to formulate accords or fully formulated fragrances that will in turn elicit a well-being effect through the activation of the angular gyrus, and optionally activation of the Frontal Inferior Cortex and/or the Frontal Medial Cortex, when smelled or worn.

[0083] Another aspect of the invention thus relates to a method for preparing an accord or a fully formulated fragrance which comprises: [0084] a) identifying at least one fragrance which elicits a well-being effect by the method described above; [0085] b) formulating said at least one fragrance sample thus identified into an accord or a fully formulated fragrance.

[0086] Fragrances identified to elicit a well-being effect by the method described above can be used in consumer products such as household products, candles, laundry products, personal care products and cosmetic products (including alcoholic fragrances and eau de cologne). Such products include detergents, e.g. laundry detergents, fabric softeners and conditioners, air care, toilet care, shampoos, hair conditioners, skin lotions, body oils, deodorants, sunscreen products.

[0087] In some embodiments the fragrance comprises one or more of orange oil, citrus oil, ethyl vanillin and nonalactone gamma.

[0088] Another aspect of the invention relates to a method of manufacturing a consumer product as defined above, which method comprises: [0089] a) identifying at least one fragrance which elicits a well-being effect by the method described above; [0090] b) incorporating said at least one fragrance thus identified into a consumer product.

[0091] In some embodiments the at least one fragrance identified is formulated into an accord or a fully formulated fragrance before incorporation into the consumer product.

[0092] Flavourings identified to elicit a well-being effect by the method described above can be used in flavouring preparations, food products, oral care products or beverages.

[0093] Another aspect of the invention thus relates to a method for preparing a flavouring preparation, a food product, an oral care product or a beverage which comprises: [0094] a) identifying at least one flavouring which elicits a well-being effect by the method described above; [0095] b) formulating said at least one flavouring thus identified into a flavouring preparation, a food product an oral care product or a beverage.

[0096] In some embodiments the flavouring comprises one or more of orange oil, citrus oil, ethyl vanillin and nonalactone gamma.

[0097] The invention is illustrated by the following, non-limiting example.

Example 1

[0098] An initial panel of 100 subjects were asked to rate intensity, well-being and (hedonic) valence using Likert type scales. Intensity was rated on a scale from 1 to 10 (1 = not at all strong, 10 = very strong); well-being was rated on a scale from 1 to 10 (1 = no association, 10 = strongly associated); valence was rated from a scale from -5 to +5 (-5 = very unpleasant, +5 = very pleasant). The subjects were invited to smell a series of 14 odours with an approximately equal odour intensity (neat oil from bottles with an opening of 6 cm in diameter) which were presented in a randomised order, each of these odours being either strongly or weakly associated to well-being. The subjects rated “white flower” (6.96 ± 2.09) and “orange” (7.22 ± 1.90) as strongly associated to well-being whereas “coffee” (4.81 ± 2.85) was rated as weakly associated to well-being.

[0099] Odour White flower - Fragrance formula IMP234647C - was created around a vanilla effect (ethyl vanillin) and a coconut effect (nonalactone gamma).

[0100] Odour Citrus - Fragrance/Flavouring formula FJJ232836D - was created around cold-pressed orange oil, fractionated orange oil, so called folded orange oil, and other cold-pressed citrus oils.

[0101] Odour Coffee - Coffee C’less CI-1020 - is a natural coffee extract purchased from Robertet SA, France) suitable for use in fragrance and flavourings. It was selected as not having a strong association with well-being.

[0102] 44 subjects were recruited (23 male and 21 female) from this initial panel to participate to the fMRI tests; they rated the odours “white flower”, “citrus” and “coffee” as reported in the table below.

TABLE-US-00001 N= 44 Hedonic (Mean ± SD) Well-being (Mean ± SD) Intensity White flower 3.23 ± 1.75 7.45 ± 1.90 6.70 ± 2.06 Citrus 2.77 ± 1.68 7.05 ± 1.66 6.89 ± 1.94 Coffee -0.43 ± 2.48 4.98 ± 2.17 6.48 ± 1.93

[0103] The recruited 44 subjects had a mean age of 25 years old. Data for 1 subject was removed from the fMRI analysis due to excessive movement. Subjects received a structured medical history (Welge-Luessen and Hummel editors, 2013, Management of Smell and Taste Disorders - A Practical Guide for Clinicians, published by Thieme, ISBN 9783131545213, p49-57, DOI: 10.1055/b-002-89586) which included questions on demographics, smoking and drinking habits, medications, current disorders, family history of any neurodegenerative disease and general nasal health status.

[0104] All subjects reported a normal sense of smell which was ascertained using an odour identification test (with maximum score of 16) from the “Sniffin' Sticks” olfactory test battery (Oleszkiewicz et al., 2018, The Laryngoscope, 128(7), 1518-1522, https://doi.org/10.1002/lary.26985). This test was performed within a forced choice paradigm where subjects have to identify 16 odours at supra- threshold concentrations using flash cards with four descriptors each (Kobal et al., 2000, European Archives of Oto-Rhino-Laryngology: Official Journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS): Affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery, 257(4), 205-211. hitps://doi.org/10.1007/s004050050223). Participants reached an average score of 13.6 ± 1.4 (mean ±SD).

[0105] The experiments were conducted according to the Helsinki declaration. The ethics committee at the medical faculty of the Technical University of Dresden approved the study design. Subjects were recruited by putting flyers on campus. They provided written informed consent.

The fMRI Experiment was then Performed as Described Below

[0106] Odour stimuli were delivered bilaterally to both nostrils of subjects in the scanner via an air dilution computer controlled olfactometer (Sommer, J. U., W. Maboshe, M. Griebe, C Heiser, K. Hormann, B. A. Stuck, and T. Hummel. “A Mobile Olfactometer for Fmri-Studies.” J Neurosci Methods 209, no. 1 (Jul. 30, 2012): 189-94. hitps://dx.doi.org/10.1016/j.jneumeth.2012.05.026), that allowed alternation between olfactory (ON) and non olfactory (OFF) stimulation conditions. Odours were embedded in a 2L/min constant airflow. Each functional run was comprised of 11 OFF or “baseline” blocks (14 scans each) and 10 ON blocks (9 scans each). Odours were delivered intranasally during the ON session for 8 seconds and odourless air for 12 seconds during the OFF session. Each subject underwent four functional runs with one type of odour presented in one run. The odours were randomly presented to the subjects lying in the scanner. Across subjects the sequence of these runs was randomized using a Latin Square. Subjects could communicate orally through the scanner intercom system as needed. After the functional runs, anatomy scans were acquired. Between runs 2 min breaks were included. The overall scanning time was approximately 50 min. The results for 3 stimuli are reported.

[0107] Participants were trained to use the velopharyngeal closure technique (breathing only through the mouth by lifting the soft palate) during the scan. This technique enables olfactory stimulation to be unaffected by respiration patterns. This procedure also prevents the participants from sniffing of the odours which produces percept-unrelated activation in olfactory-eloquent structures (Mainland & Sobel, 2006, Chem. Senses 31, p 181-196).

[0108] The FIGURE shows the fMRI experimental block design showing paradigm of odour presentation where ON session = 9 scans (10 blocks) and OFF session = 14 scans (11 blocks) totalling 244 scans.

[0109] Data acquisition performed on a 3T MRI scanner (Siemens Medical Systems, Erlangen, Germany) at the Neuroimaging Center, Dresden, Germany using a 32-channel head coil. A total of 248 functional images were collected per individual using a T2 single-shot echo-planar imaging (EPI) sequence: TR = 869 ms, TE = 38 ms, 58° flip angle, no interslice gap, 210 × 210 mm field of view. A high-resolution structural T1 image was acquired using a 3D magnetization prepared gradient rapid acquisition gradient echo (MPRAGE) sequence (TR = 2000 ms, TE = 1.95 ms, 256×256 mm.sup.2 field of view, (anatomical) voxel size 1×1×1 mm.sup.3 from the anatomical sequence).

[0110] Task-driven general linear model approach (GLM) using Statistical Parametric Mapping (SPM) software (Penny et al.,2006, Statistical parametric mapping: The analysis of functional brain images. Elsevier. ISBN: 9780123725608) was used for analysis of the fMRI data. Neuro-imaging data were pre- and post-processed using SPM12 (Wellcome Department of Cognitive Neurology, London, UK, implemented in Matlab R2018b; The MathWorks, Inc., Natick, MA, USA). Functional image volumes were pre-processed, starting with realignment and unwarp. The voxel size from the functional sequence was 2.4×2.4×2.4 mm.sup.3. Functional data were registered, realigned to correct the problems of movement and then coregistered to the corresponding structural images. Further the spatially normalized (stereotactically transformed into MNI ICBM152-space; MNI-template supplied by SPM12) and smoothed images (by means of a 8×8×8 mm.sup.3 FWHM Gaussian filter) were analyzed.

[0111] From the main block design (the FIGURE), 10 blocks of ON and OFF phases were used to increase stimulus related BOLD signals. We compared ON phases for presented stimuli, versus OFF phases (air), and ON.sub.well-being versus ON.sub.not .sub.well-being for N= 43. To restate and add further detail, each functional run comprised of alternate ON and OFF periods. In total, there were 10 ON periods, each of 8 seconds and 11 OFF periods each of 12 seconds, and each period consisted of several scans. For the analysis, we discarded the last OFF block and used 10 OFF and 10 ON blocks. SCANS: For OFF, we chose the last 9 scans from 14 (12/0.869 - 12 time periods of 0.869 seconds) scans and for ON we chose the last 5 scans from 9 (8/0.869) scans per period (or phase or block). As there is delay in BOLD we chose the last scans from ON and OFF with TR (Temporal Resolution) of 0.869 seconds. In a simplified way we can say: [0112] ON AVERAGE based on 4 runs × 10 blocks × 5 scans (8 samples of 0.869 s), [0113] OFF AVERAGE based on 4 runs × 10 blocks × 9 scans (12 samples of 0.869 s).

[0114] Whole brain activations (from the contrasts) significant at Family Wise Error (FEW) corrected <0.05 and p uncorrected < 0.001 with cluster size (k) ≥ 10 voxels are reported. For clusters having multiple peaks, one with the highest t- value was chosen. MNI coordinates are presented at x, y and z, L- left hemisphere, R- right hemisphere. Significant brain regions were labelled with AAL3 toolbox - Automated Analytical Labelling Atlas - (http://www.gin.cnrs.fr/en/tools/aal-aal2/) (Rolls et al., 2020, Neurolmage, 206, 116189, https://doi.org/10.1016/j.neuroimage.2019.116189).

[0115] To restate, a cluster, k, of a minimum 10 adjacent activated voxels in 3D space was set as the threshold value (p uncorrected <0.001), for the experiment based on the SPM analysis when contrasting the fragrance test sample to the control odour. “YES” means at least 10 adjacent voxels were activated. The contrast was first determined for a well-being associated odour (fragrance test sample) versus air as the control odour (considered to be odourless) and then for a well-being associated odour (fragrance test sample) versus a non well-being associated odour as the control odour. Results are presented in Table 2 (ON vs OFF) and Table 3 (ON.sub.well-being vs ON.sub.notwell-being) below.

TABLE-US-00002 Odour (ON> OFF) K k≥10 YES / NO xyz Region COFFEE NO CITRUS 61 YES -44 50 2 Frontal Medial Cortex_L 13 YES -50 40 -4 Frontal Inferior Cortex_L 24 YES 44 50 6 Frontal Medial Cortex_R 19 YES -44 44 16 Frontal Medial Cortex_R 203 YES -44 -62 44 Angular Gyrus_L 30 YES 36 -68 50 Angular_Gyrus R WHITE FLOWER 247 YES 46 -64 48 Angular_Gyrus R 229 YES -38 -70 50 Angular_Gyrus L 73 YES -48 18 -4 Frontal Inferior Cortex_L 40 YES -42 44 0 Frontal Medial Cortex_L 15 YES -22 46 28 Frontal Medial Cortex_L

[0116] The results show that the odours Citrus and White Flower activated the Angular Gyrus, the Frontal Inferior Cortex and the Frontal Medial Cortex, whereas the Coffee odour activated none of these brain areas.

[0117] From the result in Table 2, consistent with Table 1 we can assign Citrus and White Flower odours as being associated with well-being, and the Coffee odour as not being associated with well-being

TABLE-US-00003 k k≥10 YES/NO xyz Region Citrus vs Coffee (Citrus > Coffee) 41 YES 58 -52 24 Angular gyrus R White flower vs Coffee (White flower > Coffee) 42 YES 56 -50 26 Angular gyrus R ON.sub.well-being corresponds to Citrus or White Flower ON.sub.not .sub.well-being corresponds to Coffee

[0118] The results show that the odours Citrus and White Flower activated the Angular Gyrus when compared to Coffee odour.

[0119] In conclusion, both odours associated with well-being activated the Angular Gyrus.

Example 2

[0120] A further, separate, sniff-test was conducted in Germany (Cologne) with a normal representative population of n=80. The subjects were asked to smell odour samples in blind (no scent identifier) and answer the question “to what extend do you agree or disagree that this fragrance conveys well-being?” A scale from 1 to 5 was used (1 = disagree strongly, 2 = disagree somewhat; 3 = neither agree or disagree, 4 = agree somewhat, 5 = agree strongly). White flower odour (4.⅕) and citrus odour (3.⅘) were rated as being strongly associated with well-being. In addition, the subjects were also asked to give 3 words which they spontaneously associated with these two odours. The words sweet, soft, light, pleasant were associated to a greater degree. It was also noted that the scents with high well-being rated were also well appreciated (liked) by the respondents.

[0121] Aspects of the present disclosure are further illustrated by reference to the following, non-limiting embodiments. [0122] 1. A method of identifying a fragrance or a flavouring which elicits a well-being effect, wherein the method comprises determining whether the Angular Gyrus is activated in subjects smelling said fragrance or said flavouring, [0123] 2. The method of paragraph 1, which further comprises determining whether the Frontal Inferior Cortex and/or the Frontal Medial Cortex is/are activated in subjects smelling said fragrance or said flavouring. [0124] 3. The method of paragraph 1 or paragraph 2, wherein the determination of the well-being effect includes taking fMRI brain scans of the subjects. [0125] 4. The method of paragraph 1, comprising: [0126] a) submitting a group of subjects to a first protocol comprising: [0127] having each subject of said group smell a control odour; [0128] capturing functional Magnetic Resonance Imaging (fMRI) brain scans of each subject smelling the control odour so as to detect the brain activity of each subject; [0129] b) submitting the same group of subjects to a second protocol comprising: [0130] having each subject of said group smell a fragrance or a flavouring to be tested; [0131] capturing fMRI brain scans of each subject smelling the fragrance or the flavouring to be tested so as to detect the brain activity of each subject; [0132] c) averaging the brain activity of all subjects as obtained in the first protocol and in the second protocol; and [0133] d) contrasting the resulting averaged brain activity obtained in the second protocol with the resulting averaged brain activity obtained in the first protocol and determining from the contrast a number of adjacent activated voxels in the Angular Gyrus; wherein if the number of adjacent activated voxels thus determined is equal to or greater than a threshold value, then the tested fragrance or the tested flavouring elicits a well-being effect. [0134] 5. The method of paragraph 4, wherein step d) further comprises determining from the contrast a number of adjacent activated voxels in the Frontal Inferior Cortex and/or the Frontal Medial Cortex, wherein additional confirmation that the tested fragrance or the tested flavouring elicits a well-being effect is obtained if the number of adjacent activated voxels thus determined is equal to or greater than said threshold value. [0135] 6. The method of paragraph 4 or paragraph 5, wherein steps c) and d) are respectively replaced by steps c1) and d1): [0136] c1) contrasting, for each subject, the brain activity obtained in the second protocol with the brain activity obtained in the first protocol whereby a number of adjacent activated voxels is determined; [0137] d1) averaging the resulting contrasted brain activity of all subjects. [0138] 7. The method of any one of paragraphs 4-6, wherein the control odour is air or an odourless perfumery solvent diluted in air. [0139] 8. The method of any one of paragraphs 4-7, wherein the group of subjects comprises at least 5, preferably at least 10 subjects. [0140] 9. The method of any one of paragraphs 4-8, wherein the threshold number of adjacent activated voxels is ten. [0141] 10. A method for preparing an accord or a fully formulated fragrance which comprises: [0142] a) identifying at least one fragrance which elicits a well-being effect by the method of any one of paragraph 1-9; [0143] b) formulating said at least one fragrance thus identified into an accord or a fully formulated fragrance. [0144] 11. Use of a fragrance which elicits a well-being effect in a household product, a laundry product, a candle, a personal care product or a cosmetic product. [0145] 12. The use of paragraph 11, wherein the fragrance comprises one or more of orange oil, citrus oil, ethyl vanillin and nonalactone gamma. [0146] 13. A method for preparing a flavouring preparation, a food product, an oral care product or a beverage which comprises: [0147] a) identifying at least one flavouring which elicits a well-being effect by the method of any one of paragraphs 1-9; [0148] b) formulating said at least one flavouring thus identified into a flavouring preparation, a food product, an oral care product or a beverage. [0149] 14. Use a flavouring which elicits a well-being effect in a flavouring preparation, a food product, an oral care product or a beverage. [0150] 15. The use of paragraph 14, wherein the flavouring comprises one or more of orange oil, citrus oil, ethyl vanillin and nonalactone gamma. [0151] 16. The methods or uses according to any of the preceding paragraphs, wherein the well-being effect is associated with one or more of the following attributes: sweet, soft, light, pleasant.

[0152] Although the presently disclosed subject matter and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the presently disclosed subject matter, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized according to the presently disclosed subject matter. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

[0153] In addition to the various embodiments depicted and claimed, the disclosed subject matter is also directed to other embodiments having any other possible combination of the features disclosed and claimed herein. As such, the particular features presented herein can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter includes any suitable combination of the features disclosed herein. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.

[0154] It will be apparent to those skilled in the art that various modifications and variations can be made in the device, method, and system of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents.

[0155] For any patents, patent applications, publications, product descriptions, and protocols are cited throughout this application, the disclosures of all of which are incorporated herein by reference in their entireties for all purposes.