Neural and psychological mediators of trait impulsivity: cortico-striatal circuitry and catecholaminergic neuromodulation
type: CreativeWork
description: Impulsivity is a multidimensional trait in humans and other mammalian species. It is widely regarded as the tendency to act rapidly, without appropriate foresight and underlies many psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), mood disorders such as depression and mania, and substance use disorder (SUD). Research has shown that impulsivity is a non-unitary construct, characterised by distinct behavioural manifestations and, accordingly, distinct neural substrates. This thesis focuses on elucidating the psychological and neural mechanisms of waiting impulsivity in experimental rats trained on the 5-choice serial reaction time task (5CSRTT). The psychological processes involved in this behaviour are yet to be fully understood. However, aspects of sustained attention, urgency, motivation, and delay-aversion are all likely to play a role in shaping this behaviour. Although the neural substrates and neurotransmitter systems underlying waiting impulsivity have been extensively investigated, there are still many unanswered questions. Some of the questions that this work aims to address are: 1) can we refine our understanding of the psychological mechanism that influence premature responses, specifically the extent to which these are driven by motivated behaviour or, instead, negative urgency? 2) Does waiting impulsivity confer advantages in specific experimental contexts and what are the neurotransmitter mechanisms regulating this? 3) Can we refine our understanding of the precise neural circuits involved in the execution of a premature response? 4) How does impulsivity and attention on the 5CSRTT compare with performance on other tasks of sustained attention? Are there any shared neural processes? To investigate these questions, I used a range of experimental approaches spanning behavioural testing to systemic and local (intra-cerebral) pharmacology, brain lesions and chemogenetics. In chapter 2, I show that premature responses are inf…
abstract: Impulsivity is a multidimensional trait in humans and other mammalian species. It is widely regarded as the tendency to act rapidly, without appropriate foresight and underlies many psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), mood disorders such as depression and mania, and substance use disorder (SUD). Research has shown that impulsivity is a non-unitary construct, characterised by distinct behavioural manifestations and, accordingly, distinct neural substrates. This thesis focuses on elucidating the psychological and neural mechanisms of waiting impulsivity in experimental rats trained on the 5-choice serial reaction time task (5CSRTT). The psychological processes involved in this behaviour are yet to be fully understood. However, aspects of sustained attention, urgency, motivation, and delay-aversion are all likely to play a role in shaping this behaviour. Although the neural substrates and neurotransmitter systems underlying waiting impulsivity have been extensively investigated, there are still many unanswered questions. Some of the questions that this work aims to address are: 1) can we refine our understanding of the psychological mechanism that influence premature responses, specifically the extent to which these are driven by motivated behaviour or, instead, negative urgency? 2) Does waiting impulsivity confer advantages in specific experimental contexts and what are the neurotransmitter mechanisms regulating this? 3) Can we refine our understanding of the precise neural circuits involved in the execution of a premature response? 4) How does impulsivity and attention on the 5CSRTT compare with performance on other tasks of sustained attention? Are there any shared neural processes? To investigate these questions, I used a range of experimental approaches spanning behavioural testing to systemic and local (intra-cerebral) pharmacology, brain lesions and chemogenetics. In chapter 2, I show that premature responses are inf…
author: Toschi, Chiara
language: eng
keywords: impulsivity, attention, 5CSRTT, cortico-striatal circuits, dopamine
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2022-02-20
date modified: 2026-07-22T22:24:00Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.83096