Dopamine depletion increases the power and coherence of β-oscillations in the cerebral cortex and subthalamic nucleus of the awake rat
European Journal of Neuroscience. 2005-03-01; 21(5): 1413-1422
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1. Eur J Neurosci. 2005 Mar;21(5):1413-22.
Dopamine depletion increases the power and coherence of beta-oscillations in the
cerebral cortex and subthalamic nucleus of the awake rat.
Sharott A(1), Magill PJ, Harnack D, Kupsch A, Meissner W, Brown P.
(1)Sobell Department of Motor Neuroscience and Movement Disorders, Institute of
Neurology, Queen Square, London WC1N 3BG, UK.
Local field potentials (LFPs) recorded from the subthalamic nucleus (STN) of
untreated patients implanted with stimulation electrodes for the treatment of
Parkinson’s disease (PD) demonstrate strong coherence with the cortical
electroencephalogram over the beta-frequency range (15-30 Hz). However, studies
in animal models of PD emphasize increased temporal coupling in cortico-basal
ganglia circuits at substantially lower frequencies, undermining the potential
usefulness of these models. Here we show that 6-hydroxydopamine (6-OHDA) lesions
of midbrain dopamine neurons are associated with significant increases in the
power and coherence of beta-frequency oscillatory activity present in LFPs
recorded from frontal cortex and STN of awake rats, as compared with the healthy
animal. Thus, the pattern of synchronization between population activity in the
STN and cortex in the 6-OHDA-lesioned rodent model of PD closely parallels that
seen in the parkinsonian human. The peak frequency of coherent activity in the
beta-frequency range was increased in lesioned animals during periods of
spontaneous and sustained movement. Furthermore, administration of the dopamine
receptor agonist apomorphine to lesioned animals suppressed beta-frequency
oscillations, and increased coherent activity at higher frequencies in the cortex
and STN, before producing the rotational behaviour indicative of successful
lesion. Taken together, these results support a crucial role for dopamine in the
modulation of population activity in cortico-basal ganglia circuits, whereby
dopaminergic mechanisms effectively filter out synchronized, rhythmic activity at
beta-frequencies at the systems level, and shift temporal couplings in these
circuits to higher frequencies. These changes may be important in regulating
PMID: 15813951 [Indexed for MEDLINE]