UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

The relationship between serotonin, decision-making and mood

Faulkner, P; (2014) The relationship between serotonin, decision-making and mood. Doctoral thesis , UCL (University College London). Green open access

[img]
Preview
PDF
THESIS - FINAL.pdf
Available under License : See the attached licence file.

Download (1MB)

Abstract

The serotonin (5-HT) system has been implicated in both depression and reward and punishment processing. This thesis presents data from four studies designed to better understand the role of serotonin in decision-making and mood. Following the general introduction and description of the main experimental methods, the first experimental chapter presents a study that examined the relationship between naturally-varying 5-HT1A receptor availability, measured using positron emission tomography, and decision-making in healthy volunteers. This study identified correlations between 5-HT1A receptor availability in the hippocampal complex and both impulsivity and sensitivity to the probability of an outcome during decision-making. The second experimental chapter examined decision-making in healthy volunteers 3 days following MDMA (3,4-methylenedioxymethamphetamine) administration, when serotonin transmission is thought to be reduced. A specific type of decision-making process, “pruning” (the reflexive avoidance of aversive outcomes when searching through a tree of potential decisions), was significantly attenuated 3 days following MDMA administration. However, the expected positive relationship between the attenuation in this decision-making process and low mood was not observed. The third experimental chapter attempted to extend this finding using the acute tryptophan depletion method, which removes tryptophan (the precursor to serotonin) from the diet and is thought to reduce serotonin synthesis. Performance on three decision making tasks (pruning, gambling and impulsivity) was examined in healthy volunteers following tryptophan depletion. Results revealed that treatment decreased participants’ choosing of high probability gambles. The final chapter examined pruning in unmedicated depressed patients, and found that they behaved very similarly to healthy volunteers when evaluating aversive outcomes in the context of a tree of potential decisions, despite the hypothesised disruption to the serotonin system in this disorder. These experiments provide a more complete understanding of the relationship between serotonin, decision-making and mood, and are discussed in relation to theories of depression that pose a central role for disrupted decision-making.

Type: Thesis (Doctoral)
Title: The relationship between serotonin, decision-making and mood
Open access status: An open access version is available from UCL Discovery
Language: English
Keywords: Serotonin, Decision-Making, Mood, Depression, Reward, Punishment, Tryptophan, MDMA, Pruning
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1417578
Downloads since deposit
663Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item