DopaMINE 5 - Exploring self, ownership & reward in ADHD and controls
Research type
Research Study
Full title
DopaMINE 5 - Exploring dopamine, self, ownership and reward in ADHD and neurotypical controls
IRAS ID
338580
Contact name
Eden Kartar
Contact email
Sponsor organisation
University of Bristol
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
The self has a significant impact on cognition, which likely yielded important benefits in our evolutionary past. A widely studied phenomenon in this area is the ‘self-reference effect’ (SRE) on memory, whereby information encoded in relation to one's self is more likely to be remembered, relative to similar information encoded with respect to others. Work pioneered in the Self Lab has extended this by exploring naturalistic forms of self-processing through the domain of object ownership. Even transitory ownership generates robust memory advantages in adults, children, and patients with significant memory impairments. This is further enhanced when items have been chosen. The precise neural mechanism behind these ownership biases remains elusive but research points towards brain areas associated with processing reward, linked with the neurotransmitter dopamine.
Until now, quantifying dopamine levels has been extremely challenging. However, recent research has suggested that this can be indexed from tear fluid using the Schirmer’s Test protocol (Sharma et al, 2019). A thin strip of filter paper is placed under the lower eyelid for a minute or two to collect around 10 microlitres of fluid. Dopamine is also produced throughout the body as a hormone and this can be measured in blood serum. The central aim of this project is to determine whether the level of dopamine measured in tear fluid indexes neurotransmitter levels in the brain or in bodily hormones that can be found in serum. If tear fluid does index cortical dopamine this method could yield useful diagnostic information in conditions associated with atypical levels of the neurotransmitter (i.e., schizohprenia, ADHD, Parkinson's disease). It will also yield insights into the neural mechanism that underpins self-biases in cognition.
We will take tear and blood samples from participants with ADHD (pre- and post-medication) and neurotypical controls to explore dopamine's role in self-biases and symptoms.
REC name
London - City & East Research Ethics Committee
REC reference
26/LO/0130
Date of REC Opinion
9 Mar 2026
REC opinion
Further Information Favourable Opinion