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Exposures to conditioned flavours with different hedonic values induce contrasted behavioural and brain responses in pigs.

Clouard C, Jouhanneau M, Meunier-Salaün MC, Malbert CH, Val-Laillet D - PLoS ONE (2012)

Bottom Line: Surprisingly, the F(NaCl) food was also preferred over the F(Glu) food during the first test only, suggesting that, while LiCl i.d. infusions led to a strong flavour aversion, glucose infusions failed to induce flavour preference.As for brain imaging results, exposure to aversive or less preferred flavours triggered global deactivation of the prefrontal cortex, specific activation of the posterior cingulate cortex, as well as asymmetric brain responses in the basal nuclei and the temporal gyrus.In conclusion, postingestive visceral stimuli can modulate the flavour/food hedonism and further feeding choices.

View Article: PubMed Central - PubMed

Affiliation: INRA, UR1341 ADNC (Alimentation & Adaptations Digestives, Nerveuses et Comportementales), Saint Gilles, France.

ABSTRACT
This study investigated the behavioural and brain responses towards conditioned flavours with different hedonic values in juvenile pigs. Twelve 30-kg pigs were given four three-day conditioning sessions: they received three different flavoured meals paired with intraduodenal (i.d.) infusions of 15% glucose (F(Glu)), lithium chloride (F(LiCl)), or saline (control treatment, F(NaCl)). One and five weeks later, the animals were subjected to three two-choice feeding tests without reinforcement to check the acquisition of a conditioned flavour preference or aversion. In between, the anaesthetised pigs were subjected to three (18)FDG PET brain imaging coupled with an olfactogustatory stimulation with the conditioned flavours. During conditioning, the pigs spent more time lying inactive, and investigated their environment less after the F(LiCl) than the F(NaCl) or F(Glu) meals. During the two-choice tests performed one and five weeks later, the F(NaCl) and F(Glu) foods were significantly preferred over the F(LICl) food even in the absence of i.d. infusions. Surprisingly, the F(NaCl) food was also preferred over the F(Glu) food during the first test only, suggesting that, while LiCl i.d. infusions led to a strong flavour aversion, glucose infusions failed to induce flavour preference. As for brain imaging results, exposure to aversive or less preferred flavours triggered global deactivation of the prefrontal cortex, specific activation of the posterior cingulate cortex, as well as asymmetric brain responses in the basal nuclei and the temporal gyrus. In conclusion, postingestive visceral stimuli can modulate the flavour/food hedonism and further feeding choices. Exposure to flavours with different hedonic values induced metabolism differences in neural circuits known to be involved in humans in the characterization of food palatability, feeding motivation, reward expectation, and more generally in the regulation of food intake.

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Related in: MedlinePlus

Relationship between the quantity of food consumed during the last conditioning session and brain metabolism for the voxel with the highest t-value (2.52) in the left anterior prefrontal cortex.Least-square regression line: R2 = 0.11709. The (x, y, z) coordinates of the voxel are indicated in the y-axis legend. The statistical value for the voxel is P = 0.009. The open circles indicate the adjusted data (% error) for the subjects.
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pone-0037968-g008: Relationship between the quantity of food consumed during the last conditioning session and brain metabolism for the voxel with the highest t-value (2.52) in the left anterior prefrontal cortex.Least-square regression line: R2 = 0.11709. The (x, y, z) coordinates of the voxel are indicated in the y-axis legend. The statistical value for the voxel is P = 0.009. The open circles indicate the adjusted data (% error) for the subjects.

Mentions: The brain metabolism in 18 and 11 structures out of 34 was correlated with the quantity of food consumed during the last session of conditioning and food consumption during the preference tests performed 1 week after conditioning, respectively. Hereafter, we focused on the ROIs for which regression analysis was significant at P<0.01 for at least one voxel – the stereotactic coordinates [x y z] of the voxel with the highest t-value are indicated. Five out of the 6 voxels for which the metabolism was correlated with consumption data were located in the left hemisphere. The amount of food consumed during conditioning was significantly correlated with metabolism in the left ([−4 30 −2], t = 2.5, P = 0.009; Figure 8) and right ([2 34 −2], t = 2.6, P = 0.005) APFC, the left DLPFC ([−4 41 9], t = 2.6, P = 0.008) and the left CAU ([−6 9 9], t = 2.7, P = 0.007). The amount of food consumed during preference tests was significantly correlated with metabolism in the left APFC ([−6 30 3], t = 2.8, P = 0.005) and the left IC ([−8 30 3], t = 2.7, P = 0.007).


Exposures to conditioned flavours with different hedonic values induce contrasted behavioural and brain responses in pigs.

Clouard C, Jouhanneau M, Meunier-Salaün MC, Malbert CH, Val-Laillet D - PLoS ONE (2012)

Relationship between the quantity of food consumed during the last conditioning session and brain metabolism for the voxel with the highest t-value (2.52) in the left anterior prefrontal cortex.Least-square regression line: R2 = 0.11709. The (x, y, z) coordinates of the voxel are indicated in the y-axis legend. The statistical value for the voxel is P = 0.009. The open circles indicate the adjusted data (% error) for the subjects.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368353&req=5

pone-0037968-g008: Relationship between the quantity of food consumed during the last conditioning session and brain metabolism for the voxel with the highest t-value (2.52) in the left anterior prefrontal cortex.Least-square regression line: R2 = 0.11709. The (x, y, z) coordinates of the voxel are indicated in the y-axis legend. The statistical value for the voxel is P = 0.009. The open circles indicate the adjusted data (% error) for the subjects.
Mentions: The brain metabolism in 18 and 11 structures out of 34 was correlated with the quantity of food consumed during the last session of conditioning and food consumption during the preference tests performed 1 week after conditioning, respectively. Hereafter, we focused on the ROIs for which regression analysis was significant at P<0.01 for at least one voxel – the stereotactic coordinates [x y z] of the voxel with the highest t-value are indicated. Five out of the 6 voxels for which the metabolism was correlated with consumption data were located in the left hemisphere. The amount of food consumed during conditioning was significantly correlated with metabolism in the left ([−4 30 −2], t = 2.5, P = 0.009; Figure 8) and right ([2 34 −2], t = 2.6, P = 0.005) APFC, the left DLPFC ([−4 41 9], t = 2.6, P = 0.008) and the left CAU ([−6 9 9], t = 2.7, P = 0.007). The amount of food consumed during preference tests was significantly correlated with metabolism in the left APFC ([−6 30 3], t = 2.8, P = 0.005) and the left IC ([−8 30 3], t = 2.7, P = 0.007).

Bottom Line: Surprisingly, the F(NaCl) food was also preferred over the F(Glu) food during the first test only, suggesting that, while LiCl i.d. infusions led to a strong flavour aversion, glucose infusions failed to induce flavour preference.As for brain imaging results, exposure to aversive or less preferred flavours triggered global deactivation of the prefrontal cortex, specific activation of the posterior cingulate cortex, as well as asymmetric brain responses in the basal nuclei and the temporal gyrus.In conclusion, postingestive visceral stimuli can modulate the flavour/food hedonism and further feeding choices.

View Article: PubMed Central - PubMed

Affiliation: INRA, UR1341 ADNC (Alimentation & Adaptations Digestives, Nerveuses et Comportementales), Saint Gilles, France.

ABSTRACT
This study investigated the behavioural and brain responses towards conditioned flavours with different hedonic values in juvenile pigs. Twelve 30-kg pigs were given four three-day conditioning sessions: they received three different flavoured meals paired with intraduodenal (i.d.) infusions of 15% glucose (F(Glu)), lithium chloride (F(LiCl)), or saline (control treatment, F(NaCl)). One and five weeks later, the animals were subjected to three two-choice feeding tests without reinforcement to check the acquisition of a conditioned flavour preference or aversion. In between, the anaesthetised pigs were subjected to three (18)FDG PET brain imaging coupled with an olfactogustatory stimulation with the conditioned flavours. During conditioning, the pigs spent more time lying inactive, and investigated their environment less after the F(LiCl) than the F(NaCl) or F(Glu) meals. During the two-choice tests performed one and five weeks later, the F(NaCl) and F(Glu) foods were significantly preferred over the F(LICl) food even in the absence of i.d. infusions. Surprisingly, the F(NaCl) food was also preferred over the F(Glu) food during the first test only, suggesting that, while LiCl i.d. infusions led to a strong flavour aversion, glucose infusions failed to induce flavour preference. As for brain imaging results, exposure to aversive or less preferred flavours triggered global deactivation of the prefrontal cortex, specific activation of the posterior cingulate cortex, as well as asymmetric brain responses in the basal nuclei and the temporal gyrus. In conclusion, postingestive visceral stimuli can modulate the flavour/food hedonism and further feeding choices. Exposure to flavours with different hedonic values induced metabolism differences in neural circuits known to be involved in humans in the characterization of food palatability, feeding motivation, reward expectation, and more generally in the regulation of food intake.

Show MeSH
Related in: MedlinePlus