Dopamine agonists reorient visual exploration away from the neglected hemispace.
OBJECTIVE
To study the effects of bromocriptine, a dopamine agonist, on visual search.


BACKGROUND
The anatomic substrate of spatial attention takes the form of a distributed network with interconnected cortical (frontal, parietal, and cingulate) and subcortical (striatal and thalamic) components. Dopamine appears to exert a modulatory effect on the function of this network.


METHODS
Seven consecutive right-handed subjects with right-sided cerebral lesions were studied using a computerized target search paradigm. Eye movements were recorded.


RESULTS
Bromocriptine caused the subjects to spend more time exploring the ipsilesional hemispace and therefore increased the relative neglect of the contralesional left hemispace. However, target detection accuracy did not change. Bromocriptine thus had a differential impact on the exploratory-motor versus sensory-perceptual components of directed attention.


CONCLUSIONS
Our results show that bromocriptine may worsen some aspects of hemispatial neglect in patients with lesions that include the postsynaptic components of ascending dopaminergic pathways.
Grujic
Z
Z
Cognitive Neurology and Alzheimer's Disease Center, Department of Neurology, Northwestern University Medical School, Chicago, IL 60611, USA.
Mapstone
M
M
Gitelman
D R
DR
Johnson
N
N
Weintraub
S
S
Hays
A
A
Kwasnica
C
C
Harvey
R
R
Mesulam
M M
MM
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001288:Attention / Q000187:drug effects* / Q000502:physiology; D001971:Bromocriptine / Q000627:therapeutic use*; D002561:Cerebrovascular Disorders / Q000188:drug therapy* / Q000503:physiopathology* / Q000523:psychology; D018491:Dopamine Agonists / Q000627:therapeutic use*; D005403:Fixation, Ocular; D007839:Functional Laterality; D006801:Humans; D008875:Middle Aged; D011930:Reaction Time; D013028:Space Perception / Q000187:drug effects* / Q000502:physiology; D014794:Visual Fields / Q000187:drug effects* / Q000502:physiology
D018491:Dopamine Agonists; D001971:Bromocriptine