Motivation and attention following hemispheric stroke
E. Olgiati, C. Russell, D. Soto, P. Malhotra, Chapter 15 - Motivation and attention following hemispheric stroke, Editor(s): Bettina Studer, Stefan Knecht, In Progress in Brain Research, Elsevier, Volume 229, 2016, Pages 343-366, ISSN 0079-6123, ISBN 9780444637017, https://doi.org/10.1016/bs.pbr.2016.06.011.
Abstract
Spatial neglect (SN) is an extremely common disorder of attention; it is most frequently a consequence
of stroke, especially to the right cerebral hemisphere. The current view of SN is that it
is not a unitary deficit but a multicomponent syndrome. Crucially, it has been repeatedly
shown that it has a considerable negative impact on rehabilitation outcome. Although a number
of behavioral and pharmacological therapies have been developed, none of these appears to
be applicable to all patients with SN or has proved unequivocally successful in clinical trials.
One potential avenue for therapeutic intervention in neglect relates to the interaction between
motivation and attention. A number of investigators, including ourselves, have observed
a possible motivational component to the syndrome and showed that motivational stimulation
can temporarily improve attention in patients with SN.
In this chapter we review previous work looking at how motivation can modulate attention
in healthy individuals and how it may be affected by neurological disease before discussing
how motivational impairments may contribute to neglect, and how motivation has been used to
modulate neglect. In the final section, we present recent experimental work examining how
reward interacts with attentional biases in patients with SN. In this study, we adapted the classic
Landmark task to explore the mechanisms behind the effect of reward in SN, and found that
centrally located stimuli that were explicitly associated with reward appeared to improve neglect
and reduce rightward bias. Our results suggest that positive motivation, in the form of
anticipated monetary reward, may influence attentional bias via more general mechanisms,
such as alerting and task engagement, rather than directly increasing salience of items in contralesional
space. We conclude by discussing how motivation might be practically integrated
into the rehabilitation of patients with this debilitating disorder.