Schizophrenia and Parkinson's disease lead to equal motor-related changes in cortical and subcortical brain activation: an fMRI fingertapping study.

In schizophrenia and Parkinson's disease, cortical and subcortical motor organization is influenced by primary disease conditions and neuroleptic treatment. Using functional magnetic resonance imaging patients with schizophrenia were compared, according to Diagnostic and Statistical Manual of Mental Disorders (4th edn), under stable treatment with olanzapine (n = 7; OL) or haloperidol (n = 7; HA) to healthy controls (n = 7; HC), patients with schizophrenia without any neuroleptic treatment (n = 7; UN) and to patients with left (n = 7; LHP)- and right (n = 7; RHP)-sided hemiparkinsonism. All subjects performed a unilateral left-handed fingertapping task. All groups had significant activation in the contralateral motor cortex and the putamen (P < 0.001). Different activation patterns between groups within cortical and subcortical regions of interest were revealed. In particular, different subcortical activation patterns were found between OL- and HA-treated patients with schizophrenia. Activation of the contralateral putamen was increased in right-sided hemiparkinsonism. Significant thalamus activation was found in patients under neuroleptic treatment as well as in hemiparkinsonism, whereas the thalamus was not activated in untreated patients with schizophrenia and in healthy controls. Comparing dopaminergic depletion in hemiparkinsonism and dopaminergic blockade in HA-treated patients, an increase in activation was found within the contralateral primary motorcortex, in the ipsilateral putamen and the contralateral thalamus in hemiparkinsonism. In contrast, activation of the contralateral putamen differed between OL and HA, LHP and RHP. These findings confirm that cortical and subcortical motor-related brain loop functions are influenced by both primary neuropsychiatric conditions as well as by treatment effects. It is hypothesized that dopaminergic depletion in hemiparkinsonism and dopaminergic blockade under neuroleptic agents influence basal ganglia activity in a different way; in particular regarding functional connectivity. Basal ganglia and thalamic interaction seems to have a key role in cortical-subcortical interaction.