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Activation of the central serotonergic system in response to delayed but not omitted rewards.

Miyazaki KW, Miyazaki K, Doya K - Eur. J. Neurosci. (2010)

Bottom Line: The forebrain serotonergic system is a crucial component in the control of impulsive behaviours.By contrast, during the intermittent reward condition, in which food was given on only about one-third of the site visits, the level of dopamine was lower than that during the immediate reward condition, whereas the level of serotonin did not change significantly.This is the first direct evidence that activation of the serotonergic system occurs specifically in relation to waiting for a delayed reward.

View Article: PubMed Central - PubMed

Affiliation: Neural Computation Unit, Okinawa Institute of Science and Technology, Onna, Okinawa, Japan. kmiyazaki@oist.jp

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Correlations between 5-HT and DA efflux and the number of food pellets. (A) Comparison between 5-HT and DA efflux. (B) Comparison between 5-HT efflux and the number of food pellets acquired in each 5 min sample period. (C) Comparison between DA efflux and the number of food pellets acquired in 5 min.
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fig06: Correlations between 5-HT and DA efflux and the number of food pellets. (A) Comparison between 5-HT and DA efflux. (B) Comparison between 5-HT efflux and the number of food pellets acquired in each 5 min sample period. (C) Comparison between DA efflux and the number of food pellets acquired in 5 min.

Mentions: To test whether there was any reciprocal interaction between 5-HT and DA, as predicted from the opponent theory, we examined the correlation between 5-HT and DA efflux every 5 min. There was no significant negative or positive correlation between 5-HT and DA efflux (r= −0.051, P=0.54) in any of the three reward conditions or in any of the conditions combined (Fig. 6A). We further checked whether the 5-HT and DA efflux correlated with the behavioural measures of food consumption and distance moved every 5 min. Although there was no significant correlation between 5-HT efflux and food consumption (r= −0.011, P=0.88) (Fig. 6B), DA efflux was significantly correlated with food consumption (r=0.30, P=0.0003) (Fig. 6C). 5-HT efflux had a significant negative correlation with distance moved during the task (r= −0.24, P=0.0011). However, a low level of 5-HT efflux would not be simply related to locomotion, as 5-HT efflux was lowest during the rest period (Fig. 4A and D). DA efflux had no significant correlation with distance moved (r= −0.14, P=0.09). Neither 5-HT nor DA efflux was significantly correlated with the time between the tone presentation at the home-base circle and the nose-poke at the food site (r=0.12, P=0.12 and r= −0.11, P=0.19, respectively).


Activation of the central serotonergic system in response to delayed but not omitted rewards.

Miyazaki KW, Miyazaki K, Doya K - Eur. J. Neurosci. (2010)

Correlations between 5-HT and DA efflux and the number of food pellets. (A) Comparison between 5-HT and DA efflux. (B) Comparison between 5-HT efflux and the number of food pellets acquired in each 5 min sample period. (C) Comparison between DA efflux and the number of food pellets acquired in 5 min.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3040841&req=5

fig06: Correlations between 5-HT and DA efflux and the number of food pellets. (A) Comparison between 5-HT and DA efflux. (B) Comparison between 5-HT efflux and the number of food pellets acquired in each 5 min sample period. (C) Comparison between DA efflux and the number of food pellets acquired in 5 min.
Mentions: To test whether there was any reciprocal interaction between 5-HT and DA, as predicted from the opponent theory, we examined the correlation between 5-HT and DA efflux every 5 min. There was no significant negative or positive correlation between 5-HT and DA efflux (r= −0.051, P=0.54) in any of the three reward conditions or in any of the conditions combined (Fig. 6A). We further checked whether the 5-HT and DA efflux correlated with the behavioural measures of food consumption and distance moved every 5 min. Although there was no significant correlation between 5-HT efflux and food consumption (r= −0.011, P=0.88) (Fig. 6B), DA efflux was significantly correlated with food consumption (r=0.30, P=0.0003) (Fig. 6C). 5-HT efflux had a significant negative correlation with distance moved during the task (r= −0.24, P=0.0011). However, a low level of 5-HT efflux would not be simply related to locomotion, as 5-HT efflux was lowest during the rest period (Fig. 4A and D). DA efflux had no significant correlation with distance moved (r= −0.14, P=0.09). Neither 5-HT nor DA efflux was significantly correlated with the time between the tone presentation at the home-base circle and the nose-poke at the food site (r=0.12, P=0.12 and r= −0.11, P=0.19, respectively).

Bottom Line: The forebrain serotonergic system is a crucial component in the control of impulsive behaviours.By contrast, during the intermittent reward condition, in which food was given on only about one-third of the site visits, the level of dopamine was lower than that during the immediate reward condition, whereas the level of serotonin did not change significantly.This is the first direct evidence that activation of the serotonergic system occurs specifically in relation to waiting for a delayed reward.

View Article: PubMed Central - PubMed

Affiliation: Neural Computation Unit, Okinawa Institute of Science and Technology, Onna, Okinawa, Japan. kmiyazaki@oist.jp

Show MeSH
Related in: MedlinePlus