Reward sensitivity predicts dopaminergic response in spatial neglect
Ikusi/ Ireki
Data
2020Egilea
Li, Korina
Bentley, Paul
Nair, Ajoy
Halse, Omid
Barker, Gareth
Russell, Charlotte
Malhotra, Paresh A.
Korina Li, Paul Bentley, Ajoy Nair, Omid Halse, Gareth Barker, Charlotte Russell, David Soto, Paresh A. Malhotra, Reward sensitivity predicts dopaminergic response in spatial neglect, Cortex, Volume 122, 2020, Pages 213-224, ISSN 0010-9452, https://doi.org/10.1016/j.cortex.2018.09.002.
Laburpena
It has recently been revealed that spatial neglect can be modulated by motivational factors
including anticipated monetary reward. A number of dopaminergic agents have been
evaluated as treatments for neglect, but the results have been mixed, with no clear
anatomical or cognitive predictors of dopaminergic responsiveness. Given that the effects
of incentive motivation are mediated by dopaminergic pathways that are variably
damaged in stroke, we tested the hypothesis that the modulatory influences of reward and
dopaminergic drugs on neglect are themselves related.
We employed a single-dose, double-blind, crossover design to compare the effects of
Co-careldopa and placebo on a modified visual cancellation task in patients with neglect
secondary to right hemisphere stroke. Whilst confirming that reward improved visual
search in this group, we showed that dopaminergic stimulation only enhances visual
search in the absence of reward. When patients were divided into REWARD-RESPONDERs
and REWARD-NON-RESPONDERs, we found an interaction, such that only REWARD-NONRESPONDERs
showed a positive response to reward after receiving Co-careldopa, whereas
REWARD-RESPONDERs were not influenced by drug. At a neuroanatomical level, responsiveness
to incentive motivation was most associated with intact dorsal striatum.
These findings suggest that dopaminergic modulation of neglect follows an ‘inverted U’
function, is dependent on integrity of the reward system, and can be measured as a
behavioural response to anticipated reward.