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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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Cerebral glucose metabolism (CGM) differences obtained for the FGlu flavour compared to the FNaCl flavour.(A) Three-dimensional skinned representation of the pig’s brain with global CGM differences found in the FGluvs FNaCl contrast. The (x y z) coordinates are indicated below the representation. (B) Sagittal and coronal MRI sections showing significant CGM differences in the FGluvs FNaCl contrast. The threshold for significance was set at P<0.05 (uncorrected). The x or y coordinates are indicated below each section. Positive t-values (green, yellow and red) indicate more activation in the FGlu condition than in the FNaCl condition, while negative t-values (blue and purple) indicate more deactivation in the FGlu condition than in the FNaCl condition. F, Front; B, Back; R, Right; L, Left; OFC, orbitofrontal cortex; AMY, amygdala; STG, superior temporal gyrus; PHC, parahippocampal cortex; DACC, dorsal anterior cingulate cortex; VACC, ventral anterior cingulate cortex; VPCC, ventral posterior cingulate cortex. Other abbreviations: see Figures 5 and 6.
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pone-0037968-g007: Cerebral glucose metabolism (CGM) differences obtained for the FGlu flavour compared to the FNaCl flavour.(A) Three-dimensional skinned representation of the pig’s brain with global CGM differences found in the FGluvs FNaCl contrast. The (x y z) coordinates are indicated below the representation. (B) Sagittal and coronal MRI sections showing significant CGM differences in the FGluvs FNaCl contrast. The threshold for significance was set at P<0.05 (uncorrected). The x or y coordinates are indicated below each section. Positive t-values (green, yellow and red) indicate more activation in the FGlu condition than in the FNaCl condition, while negative t-values (blue and purple) indicate more deactivation in the FGlu condition than in the FNaCl condition. F, Front; B, Back; R, Right; L, Left; OFC, orbitofrontal cortex; AMY, amygdala; STG, superior temporal gyrus; PHC, parahippocampal cortex; DACC, dorsal anterior cingulate cortex; VACC, ventral anterior cingulate cortex; VPCC, ventral posterior cingulate cortex. Other abbreviations: see Figures 5 and 6.

Mentions: The APFC, the right OFC, the left DLPFC, the PHC and some parts of the cingulate cortex were less activated in the FGlu – FNaCl contrast (Figure 7). The right CAU, GP and PUT were less activated, while the left PUT was more activated in the FGlu condition than in the FNaCl condition (Figure 7). The left inferior and superior temporal gyrus was more activated and the right temporal gyrus was less activated in the FGlu condition than in the FNaCl condition (Figure 7).


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)

Cerebral glucose metabolism (CGM) differences obtained for the FGlu flavour compared to the FNaCl flavour.(A) Three-dimensional skinned representation of the pig’s brain with global CGM differences found in the FGluvs FNaCl contrast. The (x y z) coordinates are indicated below the representation. (B) Sagittal and coronal MRI sections showing significant CGM differences in the FGluvs FNaCl contrast. The threshold for significance was set at P<0.05 (uncorrected). The x or y coordinates are indicated below each section. Positive t-values (green, yellow and red) indicate more activation in the FGlu condition than in the FNaCl condition, while negative t-values (blue and purple) indicate more deactivation in the FGlu condition than in the FNaCl condition. F, Front; B, Back; R, Right; L, Left; OFC, orbitofrontal cortex; AMY, amygdala; STG, superior temporal gyrus; PHC, parahippocampal cortex; DACC, dorsal anterior cingulate cortex; VACC, ventral anterior cingulate cortex; VPCC, ventral posterior cingulate cortex. Other abbreviations: see Figures 5 and 6.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3368353&req=5

pone-0037968-g007: Cerebral glucose metabolism (CGM) differences obtained for the FGlu flavour compared to the FNaCl flavour.(A) Three-dimensional skinned representation of the pig’s brain with global CGM differences found in the FGluvs FNaCl contrast. The (x y z) coordinates are indicated below the representation. (B) Sagittal and coronal MRI sections showing significant CGM differences in the FGluvs FNaCl contrast. The threshold for significance was set at P<0.05 (uncorrected). The x or y coordinates are indicated below each section. Positive t-values (green, yellow and red) indicate more activation in the FGlu condition than in the FNaCl condition, while negative t-values (blue and purple) indicate more deactivation in the FGlu condition than in the FNaCl condition. F, Front; B, Back; R, Right; L, Left; OFC, orbitofrontal cortex; AMY, amygdala; STG, superior temporal gyrus; PHC, parahippocampal cortex; DACC, dorsal anterior cingulate cortex; VACC, ventral anterior cingulate cortex; VPCC, ventral posterior cingulate cortex. Other abbreviations: see Figures 5 and 6.
Mentions: The APFC, the right OFC, the left DLPFC, the PHC and some parts of the cingulate cortex were less activated in the FGlu – FNaCl contrast (Figure 7). The right CAU, GP and PUT were less activated, while the left PUT was more activated in the FGlu condition than in the FNaCl condition (Figure 7). The left inferior and superior temporal gyrus was more activated and the right temporal gyrus was less activated in the FGlu condition than in the FNaCl condition (Figure 7).

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