scholarly journals Ghrelin enhances food odor conditioning in healthy humans: an fMRI study

2018 ◽  
Author(s):  
Jung Eun Han ◽  
Johannes Frasnelli ◽  
Yashar Zeighami ◽  
Kevin Larcher ◽  
Julie Boyle ◽  
...  

SummaryVulnerability to obesity includes eating in response to food cues, which acquire incentive value through conditioning. The conditioning process is largely subserved by dopamine, theorized to encode the discrepancy between expected and actual rewards, known as the reward prediction error (RPE). Ghrelin is a gut-derived homeostatic hormone that triggers hunger and eating. Despite extensive evidence that ghrelin stimulates dopamine, it remains unknown in humans if ghrelin modulates food cue learning. Here we show using functional magnetic resonance imaging that intravenously administered ghrelin increased RPE-related activity in dopamine-responsive areas during food odor conditioning in healthy volunteers. Participants responded faster to food odor-associated cues and perceived them to be more pleasant following ghrelin injection. Ghrelin also increased functional connectivity between hippocampus and ventral striatum. Our work demonstrates that ghrelin promotes the ability of cues to acquire incentive salience, and has implications for the development of vulnerability to obesity.

Cell Reports ◽  
2018 ◽  
Vol 25 (10) ◽  
pp. 2643-2652.e4 ◽  
Author(s):  
Jung Eun Han ◽  
Johannes Frasnelli ◽  
Yashar Zeighami ◽  
Kevin Larcher ◽  
Julie Boyle ◽  
...  

Author(s):  
Han JE ◽  
Frasnelli J ◽  
Zeighami Y ◽  
Larcher K ◽  
Boyle J ◽  
...  

2020 ◽  
Author(s):  
Pramod Kaushik ◽  
Jérémie Naudé ◽  
Surampudi Bapi Raju ◽  
Frédéric Alexandre

AbstractClassical Conditioning is a fundamental learning mechanism where the Ventral Striatum is generally thought to be the source of inhibition to Ventral Tegmental Area (VTA) Dopamine neurons when a reward is expected. However, recent evidences point to a new candidate in VTA GABA encoding expectation for computing the reward prediction error in the VTA. In this system-level computational model, the VTA GABA signal is hypothesised to be a combination of magnitude and timing computed in the Peduncolopontine and Ventral Striatum respectively. This dissociation enables the model to explain recent results wherein Ventral Striatum lesions affected the temporal expectation of the reward but the magnitude of the reward was intact. This model also exhibits other features in classical conditioning namely, progressively decreasing firing for early rewards closer to the actual reward, twin peaks of VTA dopamine during training and cancellation of US dopamine after training.


2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S11-S11
Author(s):  
Teresa Katthagen ◽  
Jakob Kaminski ◽  
Andreas Heinz ◽  
Ralph Buchert ◽  
Florian Schlagenhauf

Abstract Background Increased striatal dopamine synthesis capacity (DSC) has consistently been reported in patients with schizophrenia (Sz). However, the functional mechanism translating this into behavior and symptoms remains unclear. It has been proposed that heightened striatal dopamine may blunt dopaminergic reward prediction error (RPE) signaling during reinforcement learning. Methods In this study, we investigated striatal DSC and RPEs and their association in unmedicated Sz and healthy controls. 23 healthy controls (HC) and 20 unmedicated Sz took part in an FDOPA-PET scan measuring DSC and underwent fMRI scanning, where they performed a reversal learning paradigm. We compared groups regarding DSC und neural RPE signals and probed the respective correlation (23 HC and 16 Sz for both measures). Results There was no significant difference between HC and Sz in DSC. Taking into account comorbid alcohol abuse revealed that only patients without such abuse showed elevated DSC in the associative and sensorimotor striatum, while those with abuse did not differ from HC. Patients performed worse during learning, accompanied by a reduced RPE signal in the ventral striatum. In HC, the DSC in the limbic striatum correlated with higher RPE signaling, while there was no significant association in patients. DSC in the associative striatum correlated with higher positive symptoms, and blunted RPE signaling was associated with negative symptoms. Discussion Our results suggest that dopamine modulation of RPE is impaired in schizophrenia. Furthermore, we observed a dissociation with elevated DSC in the associative and sensorimotor striatum contributing to positive symptoms and blunted RPE in the ventral striatum to negative symptoms.


NeuroImage ◽  
2014 ◽  
Vol 100 ◽  
pp. 405-413 ◽  
Author(s):  
Deniz Atalayer ◽  
Spiro P. Pantazatos ◽  
Charlisa D. Gibson ◽  
Haley McOuatt ◽  
Lauren Puma ◽  
...  

10.1038/nn802 ◽  
2002 ◽  
Vol 5 (2) ◽  
pp. 97-98 ◽  
Author(s):  
Giuseppe Pagnoni ◽  
Caroline F. Zink ◽  
P. Read Montague ◽  
Gregory S. Berns

2016 ◽  
Vol 104 (6) ◽  
pp. 1515-1522 ◽  
Author(s):  
Floor van Meer ◽  
Laura N van der Laan ◽  
Lisette Charbonnier ◽  
Max A Viergever ◽  
Roger AH Adan ◽  
...  

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